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The formulation and use of mixed collectors in sulphide flotation
Abstract
Mixtures of collectors have been widely used for many years in sulphide flotation, and a range of performance benefits have been reported for many different systems. The combinations of collector types have varied, as have the ratios that have been used. Synergistic effects have been obtained (greater than the sum of the parts) and in some cases the mechanisms of this improved behaviour have been identified. These benefits have been attributed to increased carrying capacity of the froth phase, faster kinetics, and more successful recovery of middling or coarse particles. It is the interaction between the various components of the mixed collector system, rather than the individual main effects, that dominate the performance benefits. The process benefits include increased paymetal recoveries and grades – as well as increased rates of recovery whilst using lower dosages of reagents. Various mechanisms have been reported and are discussed. These have been shown to affect different composition/liberation classes and sizes of mineral particles. In recent years, automated quantitative mineralogy and surface analysis technology such as ToF-SIMS have enabled the development of better information, to establish what aspect of the process has been affected. This has been successful mostly for use in a diagnostic capacity. Candidate selection for the mixed collector suite is presently based on experience and contextual knowledge. Predictive properties from these systems are a desirable future goal. Currently optimum combinations are preferably identified experimentally at laboratory scale prior to any plant trial. It is recommended that such laboratory work be performed using a factorial design with replicates and quality controls, such as may be delivered from High-Confidence Flotation Testing. The purpose of this paper is to summarise and review current theory and practice in the usage of mixtures of collectors in sulphide flotation – both in the application and in research in order to develop insights and guidelines to develop a methodology for use in a predictive capacity. A case study demonstrating this approach will be published at a later date.
... Flotation collectors can be classified based on various parameters, depending on their chemical structure, mode of action, application, and environmental impact (Bulatovic, 2007;Drzymala, 2007;Fuerstenau et al., 2007;Laskowski and Ralston, 2015;Nagaraj, 2005;Wills and Finch, 2016). Xanthates, dithiocarbamates, and dithiophosphates are frequently employed as sulphydryl collectors in the process of sulfide flotation (Bulatovic, 2007;Fuerstenau et al., 2007;Lotter and Bradshaw, 2010;Tercero et al., 2019). Examples of molecular structures of these common chemical compounds are presented in Table 1. ...
... When combined, they can target different mineral phases more effectively, resulting in an improved recovery (Güler et al., 2006;Lotter and Bradshaw, 2010;Tercero et al., 2019;Wiertel-Pochopien et al., 2021). In addition to mineralogical properties, there are also structural differences of collectors to affect the flotation process (O'Connor et al., 1990). ...
... They are derived from carbonic acid, wherein two oxygen atoms are substituted with sulfur, and one hydrogen atom is replaced by an alkyl group (Bulatovic, 2007). DTC are formed through the reaction of amines, carbon disulfide, and sodium or potassium hydroxide (O'Connor et al., 1990), and they have the highest collector strength but the lowest selectivity among the collectors listed in Table 1 (Lotter and Bradshaw, 2010). DTP and DTPi have similar structures (Table 1). ...
Collectors play a critical role in the flotation process as they help bubbles to selectively adsorb onto the surface of target mineral particles. The selection of proper collectors and/or their blends is crucial in optimizing the flotation process for specific ores. The existing literature suggests that the use of a combination of different collector types generally results in an improved flotation performance compared to the use of a single collector type. Thus, this paper, for the first time, investigates the influence of commercial thiol collectors NAX (Minova-Ksante Sp. z o.o), AEROPHINE® 3422 (Solvay S.A.), and Aero® MX-5149 (Solvay S.A.), in varying dosages and combinations (blends), on the flotation performance of Kupferschiefer copper ore in the REFLUX Flotation Cell (RFC). This study aims to explore the impact of collectors on copper and silver flotation using new RFC technology and to replace xanthate with an eco-friendly alternative. A scanning electron microscope (SEM)-based automated mineralogy (AM) was applied for selected flotation tests to track minerals affected by collectors and their blends. The findings show that the increase in the type of collector within the blend improves the flotation performance (i.e., recovery, kinetics, and selectivity). Comparing collector mixtures, AEROPHINE® 3422, a blend of isopropyl ethyl thionocarbamate (IPETC) and dithiophosphinate (DTPi), outperformed the NAX (a blend of sodium isobutyl xanthate (SIBX) and sodium ethyl xanthate (SEX) mixture) in both copper and silver flotation.
... All these collector groups have different strength and selectivity properties on different mineral surfaces, as well as different prices and environmental impacts. Many studies in the literature acknowledge that using different combinations of these collectors improves the flotation efficiency, even though the mechanisms between collectors are not fully explained in real-ore flotation apart from single collectorsingle mineral systems (Rao and Forssberg, 1997;Sheridan et al., 2002;Lotter andBradshaw, 2010, Guner et al 2024). Selection of a type of collector and optimization of a dosage are crucial for flotation outcomes in both industrial and batch scales (Nagaraj, 2005). ...
... Both experimental results and modeled output showed that synergism between different substances led to enhanced flotation, but it was impossible to determine the mechanism behind. The potential reason for this improvement can be caused by larger surface coverage of weak/strong site by strong/selective collectors as explained elsewhere (Bradshaw et al., 1998;Lotter and Bradshaw, 2010;McFadzean et al., 2013) or the multilayer formation between metal thiolate (chemisorption between mineral surface and dithiocarbamate) and dixanthogen (physisorption between metal-thiolate and xanthate) (Bagci et al., 2007;McFadzean et al, 2012;Taguta et al., 2018). Using mixtures in the flotation system introduces variability in functional groups and hydrocarbon chain lengths. ...
... Dithiocarbamates are known to have higher collector strength than xanthates due to nitrogen being less electronegative than oxygen, which makes it more inclined to donate electrons. This results in a collector that is less selective (Lotter and Bradshaw, 2010;Bagci et al., 2007). Since R2 and R3 contained types of dithiocarbamates, the xanthate mixture in R1 became more selective within the ternary mixture system. ...
Collector selection is a critical step in flotation, as it has a direct impact on product quality, flotation recovery, and selectivity. Collectors can consist of different components, and their effectiveness can vary depending on the type of ore being processed. The general practice in both literature and in industry is to use a mixture of collectors rather than a single collector. However, the use of a collector mixture introduces several complex issues. It is challenging to determine the specific effects of each collector on different minerals, as well as to understand the synergistic effects of mixed collectors in flotation. This study presents a novel investigation focusing on the impact of blends of NAX, AEROPHINE® 3422, and AERO® MX 5149, in varying dosages and combinations, on the flotation performance of Kupferschiefer copper ore. Kinetics flotation tests were conducted using a mechanical flotation cell with various combinations and dosages of listed collectors. For this investigation, different predictive models such as machine-learning (ML) and conventional regression analyses were developed. For model construction, a database including the results of comprehensive experimental results was constructed. The best performing model was selected considering statistical performance indicators and their performance on unseen data. A sensitivity analysis was conducted on the model to justify contributions of collectors on the copper recovery and grade. The results showed that the ML-based models provide compatible results with the expert opinions and have higher statistical performance than conventional modelling tools. According to the experimental results and models’ findings, it has shown that AEROPHINE® 3422 (a blend of isopropyl ethyl thionocarbamate and dithiophosphinate) was the most influential collector for the copper recovery. In addition, two ternary graphs were generated from the modeled data to formulate mixtures for different grades and recovery priorities.
... Xanthate collectors, and their various modifications, are widely used during flotation of pyrite (Lotter and Bradshaw, 2010). Consideration of the chemistry of the target mineral is important to ensure efficient use of these xanthate collectors, because the mineral chemistry has substantial impact on the electron transfer process during mineral-collector interaction (Xu and Schoonen, 2000). ...
... Determining the extent to which collectors interact with mineral surfaces is fundamentally important because it may shed light on how they induce hydrophobicity. Consequently, collectors having the strongest interaction with mineral surfaces such as xanthates have traditionally been favored (Lotter and Bradshaw, 2010). According to Tadie et al. (2015) and Mhonde et al. (2021), changes in the rest potential after the addition of a collector indicate an interaction between the mineral surface and the collector, whilst the extent of the potential drop says something about the magnitude of such an interaction. ...
... The role of collectors is to enhance the hydrophobic character of the mineral and there is a constant desire to engineer the current commercial collectors to improve mineral flotability. Lotter and Bradshaw (2010) suggest that the rate of oxidation of thiol (xanthate) to dithiolate (dixanthogen) under suitable conditions is effectively catalysed by the nature of the mineral surface. The results in this study illustrate that with varying metal (Ni, Co, Au and As) concentration in pyrite, the ability of the xanthate collector to be oxidized on the mineral surface changes. ...
Pyrite is an important mineralogical component of most sulphide ore deposit classes, where it commonly forms part of the gangue mineralogy, but may also represent an important ore mineral (i.e., auriferous pyrite). Effective and efficient separation of pyrite is thus a crucial step during most ore processing operations, and this is in part influenced by the pyrite mineral chemistry. Here, electrochemical measurements were used to study the reactivity of a series of well-characterised synthetic trace-element substituted pyrite samples under alkaline conditions relevant to industrial flotation. The presence of metals and metalloid impurities (As, Au, Co, and Ni) in pyrite were tested using rest potential measurements to infer oxidation and associated hydrophobicity. In the absence of any collector phases, pure-and Ni-substituted pyrite have the highest rest potential, followed by Co-substituted pyrite and couple-substituted (Co + Au) pyrite, whilst As-substituted pyrite has the lowest measured rest potential. Importantly, the degree of oxidation at the mineral surface correlates linearly with the concentration of each of the substituents, with the largest effect observed when As is the substituent. These results correspond to the semiconducting properties and noble character of each pyrite sample, with n-type pyrite (Au-, Co-and Ni-substituted) associated with noble character and high rest potential, whereas p-type As-substituted pyrite associated with least noble character and lowest rest potential. With the addition of a potassium amyl xanthate collector, the mineral chemistry further had an impact on the probability of dixanthogen formation. Increased substituent concentration in the pyrite lattice decreased the probability of dixanthogen formation, except in a sample where high Au (and moderate Co) was incorporated. These results highlight the importance of developing improved understanding of the impacts of substitution mechanisms on the surface reactivity and flotability of pyrite. Such an understanding will form the foundation for further improved (and engineered) approaches towards reagent design and mixture. This will serve to optimise separation of both gangue and valuable pyrite by using fundamental knowledge to target specific collector bands and flotation domains.
... It has also been reported that sulfide minerals are semiconductors that can accept or donate electrons in an electrochemically active system [9][10][11][12] and their level of floatability is closely related to the pulp potential and the existence of thiolate or dithiolate radicals [13]. This is because some minerals need the thiolate radicals to float, while others need the dithiolate radicals. ...
... This figure also shows that in a broad range of pH and potential, chalcopyrite exhibits the best self-induced floatability, and it has wide lower and upper limits of potential that induce its natural ability to float naturally [8]. It has also been reported that sulfide minerals are semiconductors that can accept or donate electrons in an electrochemically active system [9][10][11][12] and their level of floatability is closely related to the pulp potential and the existence of thiolate or dithiolate radicals [13]. This is because some minerals need the thiolate radicals to float, while others need the dithiolate radicals. ...
... In the case of n-type semiconductors with a negatively charged surface, the thiolate radical will not be able to adsorb on its surface. Instead, the weaker dithiolate will It has also been reported that sulfide minerals are semiconductors that can accept or donate electrons in an electrochemically active system [9][10][11][12] and their level of floatability is closely related to the pulp potential and the existence of thiolate or dithiolate radicals [13]. This is because some minerals need the thiolate radicals to float, while others need the dithiolate radicals. ...
In the present work an intense bibliographic search is developed, with updated information on the microscopic fundamentals that govern the behavior of flotation operations of chalcopyrite, the main copper mineral in nature. In particular, the effect caused by the presence of pyrite, a non-valuable mineral, but challenging for the operation due to its ability to capture a portion of collector and float, decreasing the quality of the concentrate, is addressed. This manuscript discusses the main chemical and physical mechanisms involved in the phenomena of reagent adsorption on the mineral surface, the impact of pH and type of alkalizing agent, and the effect of pyrite depressants, some already used in the industry and others under investigation. Modern collector reagents are also described, for which, although not yet implemented on an industrial scale, promising results have been obtained in the laboratory, including better copper recovery and selectivity, and even some green reagents present biodegradable properties that generate a better environmental perspective for mineral processing.
... The effect of a collector on the mineral surface depends on the length and structure of the above alkyl chain. It is wise to choose the collector with long-chain hydrocarbons and structure as well as functional groups for the flotation of sulfides and PGE minerals (Lotter and Bradshaw 2010). Butyl and isobutyl alkyl chains are highly recommended because the xanthates with longer chain are easy to oxidize to dixanthogen. ...
... Catalysis of isobutyl xanthate radical to dixanthogen by n-butyl DTC(Lotter and Bradshaw 2010). ...
The unique physical and chemical properties of platinum group elements are making them indispensable in many modern industrial applications. Platinum-group minerals are usually beneficiated by flotation or gravity separation followed by flotation. Due to poor liberation characteristics and interstitial attachment of these minerals with base metal sulfides, chromites, and silicates, fine grinding is necessitated. Significant variability of platinum group element deposit types and their mineralogical characteristics create a challenge to choose a proper reagent suite. The present article critically discusses all the factors that affect the flotation of platinum group element bearing minerals, flotation routes, essential gaps, the problems associated with their processing, and suitable reagent suites used in different ore deposits and plant practices.
... The different collectors and their interactions on the recovery and grade has been studied. Bradshaw (1998) and Lotter and Bradshaw (2010) have investigated the effect of the mixed collector on the sulfide flotation (Bradshaw, 1998;Lotter and Bradshaw, 2010). The results show that mixed collector have a positive effect on the rate of surface absorption of collector. ...
... The different collectors and their interactions on the recovery and grade has been studied. Bradshaw (1998) and Lotter and Bradshaw (2010) have investigated the effect of the mixed collector on the sulfide flotation (Bradshaw, 1998;Lotter and Bradshaw, 2010). The results show that mixed collector have a positive effect on the rate of surface absorption of collector. ...
... It is also hypothesised in this study that a collector of relatively lower strength and potency may provide more room for realisation of selectivity within a narrow separation window. The strength of thiol collectors has been noted to follow the order Dithiocarbamate> Xanthates> Dithiophosphate (Lotter and Bradshaw, 2010;Wills and Finch, 2016) relating to differences in structure and electronegativity of donor atoms; O > N > P. This paper therefore aims at investigating the influential role of hydrogen peroxide and collector type on pyrite-arsenopyrite differential flotation identifying surface species responsible for flotation behaviour under different conditions. ...
... Higher flotation recovery was realised for both pyrite and arsenopyrite under acidic condition with mineral recovery decreasing with increasing pulp pH beyond 4. Arsenopyrite was more depressed compared with pyrite and markedly for DTP than PAX. The depression of pyrite and arsenopyrite with increasing pulp pH was attributed to the formation of surface oxidation product as long as the pulp oxidation potential exceeds values required for the formation of the collector dimers, that is, dithiophophatogen and dixanthogen (López Valdivieso et al., 2006;López Valdivieso et al., 2005;Lotter and Bradshaw, 2010;Petrus et al., 2011;Wang and Forssberg, 1990). Figure 3C shows the pulp redox potentials during single pyrite and arsenopyrite flotation with DTP and PAX. ...
The present work investigates the role of hydrogen peroxide and collector type in differential flotation of pyrite and arsenopyrite model minerals without acid pretreatment. Ethylenediaminetetraacetic acid (EDTA) extraction and X-ray photoelectron spectroscopy (XPS) analysis were employed to determine the oxidation extent supplemented with zeta potential, UV–Vis and Time-of-Flight secondary ion mass spectrometry (TOF-SIMS) towards elucidating collector adsorption behaviour and surface species formation. The results showed higher extent of ferric hydroxide was generally observed for arsenopyrite compared to pyrite using EDTA extraction and XPS analysis. A 2 kg/t hydrogen peroxide addition and 120 g/t PAX collector concentration gave the best separation efficiency with 63.1% pyrite and 5.1% arsenopyrite recovery into the flotation concentrate. The addition of hydrogen peroxide (2 kg/t) had a minor effect on the mineral surface oxidation state according to XPS analysis. Thus, the oxidation of adsorbed xanthate ions into hydrophilic monothiocarbonate ion was the more apparent reason for remarkable arsenopyrite depression compared with pyrite. The observation was not affected with change in sequence of reagent addition and presents great opportunity in better, profitable processing of low-grade refractory auriferous sulphide ores.
... Lotter, Bradshaw (2010) e Nyambayo (2014) relatam efeitos positivos na mistura de dois Xantatos. O intuito dessa formulação é proporcionar, devido as diferentes propriedades dos Xantatos, um único coletor que seja suficientemente "forte" para melhorar a recuperação, mas suficientemente "fraco" para melhorar a seletividade. ...
A região da Serra de Carajás, no Pará, é reconhecida pela sua relevância na exploração mineral, com destaque para a extração de ferro e cobre. O presente artigo tem como objetivo principal avaliar o impacto da substituição do coletor PAX pela combinação dos coletores SEX-SIBX no processo de flotação, visando aumentar a recuperação metalúrgica de cobre e ouro. Os testes foram conduzidos com base nas diretrizes de Nyambayo (2014) e embasados em livros e artigos científicos. Os resultados indicaram um aumento de 4,21% na recuperação de cobre e 18,94% na de ouro. A melhor proporção de coletores SEX-SIBX para a recuperação desses metais foi de 20:80, resultando em uma eficiência de 97,44% para cobre e 82,67% para ouro.
... Fatty acid (200-500 g/t), hydroxamic acid (100-300 g/t), and sodium silicate (500-1000 g/t) are commonly used reagents in tungsten flotation [16]. For tungsten-associated polymetallic sulfide ore flotation, it is also necessary to add sulfide mineral flotation reagents, such as xanthate (50-200 g/t) and Aerofloat (100-300 g/t) [17,18]. The addition of various flotation reagents will aggravate the pollution of beneficiation wastewater. ...
The large amount of wastewater containing various pollutants generated during the tungsten beneficiation process has become a bottleneck for the sustainable development of tungsten mining enterprises. Typical pollutants mainly include suspended solids (SSs), silicate ions, metal ions, and residual organic reagents. The direct discharge of untreated tungsten beneficiation wastewater can cause serious harm to the ecological environment, while recycling can significantly affect flotation indicators. In this paper, the sources and characteristics of typical pollutants were analyzed, and various purification techniques were outlined, including coagulation, adsorption, chemical precipitation, oxidation, and biological treatment methods. Among these techniques, coagulation is particularly effective for the removal of SSs, while adsorption and chemical precipitation are recommended for the removal of soluble ions. For residual organic reagents, oxidation methods have demonstrated high treatment efficiencies. The mainstream methods for wastewater recycling were summarized, including centralized recycling, as well as internal recycling at certain stages. For tungsten beneficiation such a complex process, where the quality of wastewater varies greatly between different stages, it is suitable to recycle the wastewater after appropriate treatment at a specific stage. Furthermore, this study provided a perspective on the future directions of tungsten beneficiation wastewater treatment, serving as a reference for related research and industrial practices.
... In copper sulfur flotation separation, low-grade and difficult-to-select copper sulfide ores are often accompanied by precious metals such as gold and silver, so the selection of collectors is particularly crucial. Compared with the traditional flotation method of highdosage xanthate, the combined collector is widely used in the field of mineral flotation due to its advantages of high-efficiency collection and low dosage [28][29][30]. Dhar [31] conducted a systematic study on Nussir copper ore, using a DBD and mixed collectors (SIBX and DBD) system. The results show that compared with using the DBD collector alone, the xanthate-dithiophosphate mixed collector (ratio of 1:3) improved copper grade and recovery. ...
Copper sulfide ores frequently co-occur with pyrite, presenting a significant challenge for their selective separation during beneficiation processes. Despite advancements in flotation technology, there remains a critical need for efficient methods to enhance copper recovery while suppressing pyrite interference, particularly without compromising the associated precious metals such as gold and silver. Current practices often struggle with achieving high selectivity and recovery while maintaining environmental sustainability. Here, we investigate the efficacy of a ternary collector mixture consisting of ammonium dibutyl dithiophosphate (ADD), butyl xanthate (BX), and ethyl xanthate (EX) for the selective flotation of copper sulfide from a complex ore containing 0.79% Cu and associated precious metals (0.233 g/t Au and 5.83 g/t Ag). A combination of lime and hydrogen peroxide as inhibitors was employed to suppress pyrite effectively under alkaline conditions (pH = 11.33). The results demonstrate that the optimized ternary collector system (ADD:BX:EX at a ratio of 1:0.5:0.5) significantly improves the copper grade and recovery at an ultra-low dosage of 10 g/t. The optimized flotation method using the combined collectors and inhibitors effectively separated chalcopyrite from pyrite, achieving a copper concentrate with 20.08% Cu content and a recovery of 87.73%. Additionally, the process yielded notable recoveries of gold (9.22%) and silver (26.66%). These findings advance the field by providing a viable and environmentally conscious approach to the beneficiation of sulfide ores, potentially serving as a blueprint for processing similar mineral deposits while minimizing reagent usage and costs.
... Numerous studies have aimed to evaluate these blends for improving concentrate quality and ensuring environmental compatibility [7,8,18]. Most sources emphasize the use of hydroxamates, carbamates, thiophosphates, dodecylamine, etc., as collector blends alongside xanthates [6,[19][20][21][22][23]. Additionally, investigations have explored the use of esters derived from carboxylic acid, phosphoric acid, alkyl phosphoric acid, and MES (fatty acid methyl ester sulfonates) on various minerals such as clay, wolframite, apatite, etc. [24][25][26][27]. ...
The chalcopyrite deposit in Malanjkhand, India, is the largest copper ore producer in the country. However, its flotation performance has room for improvement. This study used standard flotation experiments using a mechanical flotation cell using a conventional collecting reagent and a collector blend consisting of xanthate and ester. A three-factor, three-level Box-Behnken design was used to statistically evaluate the experimental design. The obtained data were analyzed using an ANOVA, cubic plots, and response surface methods. The goal was to evaluate the effects and interactions of three key process parameters in chalcopyrite flotation: the dosages of sodium silicate (depressant), sodium isopropyl xanthate (collector), and acetoacetic acid n-Octyl ester (co-collector/modifier). The results implied that introducing acetoacetic acid n-Octyl ester along with minor tweaks in the dosages of sodium isopropyl xanthate helped increase copper grades by at least 15%, with good recovery percentiles. Among the three parameters tested, the copper's grade and recovery were considerably positively influenced by the AoE dosage in the collector blend. Employing 0.006 kg/t sodium silicate and 0.0065 kg/t sodium isopropyl xanthate with 0.005 kg/t of acetoacetic acid n-Octyl ester, an optimum copper recovery of 88.87% could be achieved. However, with a sodium silicate dosage of 0.0048 kg/t, a SIPX dosage of 0.008 kg/t, and an AoE dosage of 0.005 kg/t, optimized copper grade (1.55%) could be achieved, which is a 78.1% increase from the feed sample grade. To validate the expected results, verification experiments were carried out, and the experimental findings were found to be on at par with the statistical model predictions. Furthermore, the calculated SPI value of 0.0000147cap Kg −1 for a global index per resident lies between 0 and 1.
... The water suspension is then treated with special collector-containing formulations to form a mineral froth, from which the hydrophilic phase is separated from the hydrophobic phase. Flotation is commonly used with sulfide minerals with collectors like xanthate, black medicine, and thiourethane [41][42][43][44]. Other additives such as pH adjuster, pulp dispersant, silicate mineral inhibitor, foaming agent, etc. are often added to increase flotation recovery efficiency [45][46][47][48][49]. Through this selection process, nickel concentration in solids increases to 10-20%. ...
With the booming of renewable clean energies towards reducing carbon emission, demands for lithium-ion batteries (LIBs) in applications to transportation vehicles and power stations are increasing exponentially. As a consequence, great pressures have been posed on the technological development and production of valuable elements key to LIBs, in addition to concerns about depletion of natural resources, environmental impacts, and management of waste batteries. In this paper, we compile recent information on lithium, nickel, and cobalt, the three most crucial elements utilized in LIBs, in terms of demands, current identified terrestrial resources, extraction technologies from primary natural resources and waste. Most nickel and cobalt are currently produced from high-grade sulfide ores via a pyrometallurgical approach. Increased demands have stimulated production of Ni and Co from low-grade laterites, which is commonly performed through the hydrometallurgical process. Most lithium exists in brines and is extracted via evaporation–precipitation in common industrial practice. It is noteworthy that at present, the pyrometallurgical process is energy-intensive and polluting in terms of gas emissions. Hydrometallurgical processes utilize large amounts of alkaline or acidic media in combination with reducing agents, generating hazardous waste streams. Traditional evaporation–precipitation consumes time, water, and land. Extraction of these elements from deep seas and recycling from waste are emerging as technologies. Advanced energy-saving and environmentally friendly processes are under extensive research and development and are crucial in the process of renewable clean energy implementation.
... Studying the effect of new targeted reagents on small-sized mineral complexes is a fundamental scientific problem. Practical application of the new knowledge will help to develop reagent regimes that meet increased requirements for the quality of flotation concentrates and reduce losses of target metals with tailings [1][2][3][4][5][6][7][8][9][10]. ...
... These can be grouped into the families of xanthate (X), dithiophosphate (DTP), dithiocarbamates (DTC), thionocarbamate, thiocarbamate, mercapto benzothiazole (MBT) and phosphine-based collectors (Castellón et al., 2022). The different collectors (single or mixed) and their interactions on the recovery and grade for copper sulfide flotation have been studied by several researchers (Ackerman et al., 1987;Bradshaw, 1998;Bagci et al., 2007;Lotter and Bradshaw, 2010;McFadzean et al., 2012;Chen et al., 2014;Hassanzadeh and Hasanzadeh, 2016;Molaei et al., 2018;Dhar et al., 2019a;Dhar et al., 2019b;Bazmandeh and Sam, 2021). ...
The Cerattepe (Artvin) mine contains volcanogenic massive sulfide (VMS) deposits in northeastern Turkey. This is a kuroko type deposit located in Late Cretaceous volcanic, intrusive and sedimentary rocks, and has a structure with dense alteration stages. In this study, batch flotation tests were carried out to determine the flotation behavior of a new sample (mix ore), that was the combination of two different ores with different flotation behaviors. The mixed ore contains 2.18% Cu, 1.46% Zn, (Cu/Zn ratio 1.49) 38.35% Fe, and 41.6% S content. An efficient separation of copper minerals from zinc minerals using the conventional selective flotation method could not be achieved due to complex mineralogy and very low liberation degree. Therefore, sequential selective flotation resulted in poor Cu recovery. The effects of flotation parameters such as collector type, collector amount, particle size, and pH conditions, were investigated to obtain a bulk copper-zinc concentrate. The best results were obtained using thionocarbamate (Aero 3894) and dithiophosphine (Aerophine 3418A) collector reagents at d80=40 µm particle size. Under optimal conditions (grain size, d80=40 µm, pH=11, amount of collector reagent 60 g/t (Aero 3894), frother (MIBC)=50 g/t, solid ratio=32%, flotation time=8 min), a bulk copper-zinc concentrate containing 13% Cu and 9.5% Zn was obtained with a copper yield of 84.4% and a zinc yield of 88.9%. The concentrate mass pull was 13%. After rougher and two-stage scavenger flotation, a concentrate (rougher concentrate + scavenger products) was obtained with a mass pull of 22%. Copper and zinc recoveries of this concentrate were 91.8% and 92.5%, respectively.
... In bulk copper-molybdenum flotation, xanthates or their mixtures with different hydrocarbon radical lengths, dithiophosphates and thionocarbamates are used as collectors [10,18]. Most of the dressing plants use several collectors or compositions of individual collectors in bulk, cleaning and scavenger flotation operations [19,20]. Non-polar reagents (diesel fuel, kerosene, engine oil, etc.) together with xanthates are used as molybdenite collectors. ...
Modern trends in technological improvement for producing high-quality rhenium-containing molybdenum concentrates are aimed at developing environmentally friendly solutions com-pared to traditional ones, involving a reduction in consumption or complete replacement of toxic substances and the use of plant reagents and microorganisms and make it possible to eliminate energy-intensive processes of steaming and roasting. It is known that up to 25%–30% of Mo, Cu and Re goes to rough flotation tailings and is lost in wastes. Those losses are a consequence of the ore composition variability, chalcopyrite–molybdenite ratio, an increase in the proportion between primary copper sulfide and finely disseminated molybdenite and the recovery of floating pyrite. High rates of valuable metal recovery into bulk concentrate can be achieved by using new compositions of flotation reagents that selectively change the hydrophobic properties of the target minerals. The application of new reagent compositions, including novel chemicals—dithiopyrylmethane (DTM), composite reagent (CR) and conventional butyl xanthate (ButX)—was theoretically and experimentally substantiated for the effective rhenium extraction in the processing of hard-to-beneficiate complex molybdenum ores. It is identified that DTM forms a complex DTM–Re compound and chemically adsorbed on rhenium-containing molybdenite providing an increase in Re recovery into the bulk Cu–Mo–Re concentrate by 17%, reducing by two times the loss of rhenium with flotation tailings, and the subsequent 97.6% Re extraction of the molybdenum concentrate by autoclave leaching.
... Sulfidien vaahdotuksessa on tavallista käyttää kahta tai useampaa kokoojakemikaalia, joista yksi on varsinainen kokooja ja toiset ns. apukokoojia (Lotter & Bradshaw 2010). Näin voidaan saada parempi vaahdotustulos kuin käyttämällä vain yhtä kokoojaa. ...
... As shown in Figure 10b,c, the difference is not obvious, but as a collector, isoamyl xanthate shows better effects on lead and zinc grades than other collectors. The different effects of these drugs are mainly due to the different hydrocarbon chain lengths and structures of xanthate [29]. It can be found from Figure 10b that under the dosage of 20 g/t, isoamyl xanthate has the best recovery effect on lead and zinc. ...
The lead–zinc ore is a typical low-grade complex polymetallic sulphide ore. Its typical mineralogy is characterized by a high content of cryptocrystalline graphite, low content of lead, zinc, and copper, and fine grain size. However, the aggregation size of sulfide mineral aggregations is coarse, and the symbiotic relationship is relatively simple. Conventional process treatment requires the fine grinding of ore into mineral monomer dissociations followed by preferential flotation, but this method has a poor sorting index and high production cost. In this paper, the grain size of the sulfide mineral aggregates determined by mineralogical studies is used to determine the fineness of the grinding, so that the liberation degree of the sulfide ore in the coarse grinding product reaches 70%, and each flotation process is used to collect rough concentrate. In the first step of flotation, the carbon in lead–zinc sulfide ore was removed by adding #2 oil to the flotation tank at a dosage of 40 g/t. In the second flotation process, the pH was adjusted to 7.2, the dosage of isopropyl xanthate was 20 g/t, the dosage of #2 oil was 30 g/t; the flotation reagent in the third step was isopropyl xanthate, and the dosage was 7.5 g/t, with a #2 oil of 15 g/t. Each flotation process concentrate is collected. Finally, the grades of lead and zinc in the final concentrate were 1.6% and 5.71%, respectively. In addition, the recoveries of lead and zinc were 91.78% and 92.07%, respectively. The yield of tailings was 50.6%. By the flotation of sulfide aggregates, a large number of gangues are avoided to participate in fine grinding, which helps to reduce the energy consumption of the mill.
... It is required to use new beneficiation methods and flotation reagents to increase the efficiency of flotation of ore minerals to improve the processing of finely disseminated ores. Particular difficulties are associated with the processing of the slurry part of the crushed ore, which is usually enriched with non-ferrous, rare, and noble metals [1][2][3][4][5]. Improving the efficiency of flotation can be achieved by using a combination of different collectors [6][7][8][9][10]. ...
The article presents the results of laboratory studies on ore flotation of copper-molybdenum deposits in the East Kazakhstan region of Kazakhstan using a combined reagent. It is required to use new beneficiation methods and flotation reagents to increase the efficiency of flotation of ore minerals to improve the processing of finely disseminated ores. The problem can be solved by using a combination of different collectors. The objective of the research is to increase the recovery of copper and molybdenum during flotation of copper-molybdenum ore using a combined reagent. The studied ore sample contains 0.42% copper; 0.009% molybdenum. A combination of sodium butyl xanthate, TS-100 thionocarbamate, and reaflot in a ratio, in %: 15: 3: 1, was used as a combined flotation reagent. The combined flotation reagent was preliminarily passed through an ultrasonic homogenizer JY96-IIN to obtain a reagent microemulsion before flotation. The optimum dispersion time for the combined flotation reagent is 60 seconds. At the same time, 99.4% are microemulsion particles with a particle size of fewer than 3.7 microns. The use of a combined reagent microemulsion increases the extraction of copper into the copper-molybdenum concentrate by 3.69%, and the extraction of molybdenum by 6.05%. The copper content in the copper-molybdenum concentrate increases by 1.26%. The copper content in the flotation tailings decreases from 0.07 to 0.056%. The consumption of the combined reagent is reduced by 15% in comparison with the basic butyl xanthate.
... Compared to other available collectors such as dithiocarbamate, xanthates are the most widely used as flotation reagent, the maximum consumption of collectors and the most economical sulfide ores collectors [18,19]; a medium-sized producer in China can sell 30,000 tons per year domestically and internationally [20]. Xanthates (R-O-CSSMe) have been shown to have weaker selectivity and better collectivity for sulfide minerals than dithiophosphate [21][22][23][24]. ...
Xanthates are by far the most widely used collectors in the froth flotation beneficiation of sulfide ores. However, the xanthate production process suffers from low yield, low productivity, long reaction time and environmental pollution. To address these issues, an effective method was developed for the synthesis of xanthates using phase transfer catalyst. Sodium isobutyl xanthate was synthesized from isobutyl alcohol ((CH3)2CHCH2OH), sodium hydroxide (NaOH) and carbon disulfide (CS2) with dichloromethane (CH2Cl2) as solvent and cetyltrimethylammonium bromide (CTAB), cetyltrimethylammonium chloride (CTAC), tetrabutylammonium bromide (TBAB) and tetrabutylammonium chloride (TBAC) as phase transfer catalyst. The compound was characterized by elemental analysis, infrared spectrum, 1H NMR and 13C NMR. The influencing factors on the content and yield of sodium isobutyl xanthate including phase transfer catalyst type, phase transfer catalyst dosage and reaction time were studied by single-factor experiments. The influencing factors on the product purity and yield including reaction temperature, solvent volume, material ratio and rotating speed were studied by orthogonal experiments. The results showed that when the amount of TBAC was 3.0%malcohol, the reaction temperature was 35 °C, the solvent volume was 3.5 Valcohol, the rotating speed was 180 rpm, the reaction time was 4 h and the material ratio was n[(CH3)2CHCH2OH]:n(NaOH):n(CS2) = 1:1:1.10, the product yield could be up to 86.66% and the product purity reached 82.56%.
... Although xanthates are the most widely used collectors in the suite of thiol collectors, they yield an unselective float and have led to the development of collectors with higher selectivity against most iron sulphides [21,31]. Dithionocarbamate collectors, developed by Cytec, falls within this category credited for its high selectivity against pyrite in the flotation of copper ores under alkaline conditions [14]. ...
Thionocarbamate collectors are noted for their high flotation selectivity against pyrite under alkaline condition. In this study, selectivity of O-isopropyl-N-ethyl thionocarbamate (IPETC) is investigated in decoupling flotation response of pyrite and arsenopyrite under single mineral and artificial composite systems. The influence of copper addition, collector adsorption behaviour and mineral surface speciation on flotation response were characterised using complementing electrokinetic and spectroscopic techniques. The results showed no pyrite and arsenopyrite flotation at pH 11 until CuSO4 (2.5 × 10⁻⁵ mol/l) addition where arsenopyrite displayed remarkably good, CuSO4 concentration dependent flotation response relative to pyrite. Collector concentration (> 4 × 10⁻⁶ mol/l IPETC) had little effect whilst the flotation response was highly pH dependent. The preferential IPETC adsorption on copper-treated arsenopyrite at pH ≥11, yielding 90% arsenopyrite and 11% pyrite concentrate recovery, was ascribed to chelate formation between sulphur and copper and a synergistic coordination of the σ bond of arsenic and deprotonated nitrogen of IPETC.
Pyrite is the most widely distributed sulfide mineral with a wide range of uses, and pyrite is mainly recovered by means of flotation in practical production, and the commonly used flotation collectors are mainly xanthates with good flotation performance. The adsorption behavior of commonly used collectors ethyl xanthate and butyl xanthate on the surface of pyrite is investigated by using the density functional tight bounding theory (DFTB). The results show that when a single reagent acts on the pyrite surface, butyl xanthate has a stronger effect than ethyl xanthate, and the adsorbed mineral surface shows obvious hydrophobicity. The interaction between ethyl xanthate and butyl xanthate had a stronger effect than that of a single reagent, and the simulation of the flotation environment at ordinary temperature using molecular dynamics revealed that the synergistic adsorption of the two different reagents on the surface of pyrite was more hydrophobic, that is, the synergistic adsorption of the combined collector of ethyl xanthate and butyl xanthate on the surface of pyrite was stronger. The results of the study are of great significance for the synergistic effect between the combined collector and the mineral.
Studies on the dependence of the technological results of non-ferrous sulfide ore (copper—arsenic-bearing and non-arsenic-bearing—lead–zinc, and polymetallic) flotation on the pulp potential Eh are reviewed. Findings on the relation of Eh and collectorless flotation are presented. Changes in the pulp potential due to different gas applications and various reagent additions are considered. The influence of the grinding medium on the pulp Eh and hence on the flotation results is presented through various examples. The relation between the oxidation–reduction potential and reagent effects is exhibited and explained. pH–Eh ranges of different minerals’ flotation, as recorded in various studies, are summarized and visualized jointly for all mentioned ores. It is concluded that the pulp Eh value, considered together with the pH value, is a useful means for flotation selection controlling and deserves further research, especially under industrial conditions. Some problems and difficulties in using pulp Eh for flotation control are discussed.
The Cantung mine is a formerly operating tungsten mine located in western Northwest Territories. As part of the Northern Abandoned Mine Reclamation Program, the Canadian government is looking to remediate the property. This may include reprocessing the tailings to isolate potentially acid-generating sulphide minerals, mitigating any possible environmental liability to the nearby Flat River and its confluences. Cantung’s mineral processing operations produced three concentrates and one tailings product: a high-grade WO3 concentrate; medium grade WO3 concentrate; a copper concentrate; and sulphidic tailings. During periods of low copper prices, chalcopyrite was not recovered from the ore and was instead directed to tailings. Poor recovery from the scheelite gravity separation circuit combined with intermittent chalcopyrite flotation resulted in the tailings containing notable quantities of copper and tungsten, which could potentially be recovered during reprocessing to offset costs. Experimental work was completed on tailings samples collected from tailings pond #3, Cantung’s largest tailings impoundment. Ideal flotation conditions were determined to remove potential acid-generating minerals (mainly pyrrhotite) while also recovering residual valuable minerals, primarily chalcopyrite. A polish grind of the tailings sample prior to flotation was found to increase sulphide mineral recovery. Up to 86% of sulphur and 84% of copper were concentrated into 30% of the sample mass using flotation, while between 80% and 95% of tungsten reported to the sulphide flotation tailings. Future work will investigate collector and dispersant dosages in a mixed xanthate-hydroxamic acid collector system using a design of experiments to optimize conditions for sulphide mineral recovery from the tailings.
Flotation separation of chalcopyrite/pyrite mixtures under Mg(OH)2 depression effectively limits pyrite entrainment into Cu concentrates. However, the Cu concentrate is still negatively affected by the low selectivity of depression by Mg(OH)2 and unavoidable floatability activation of pyrite by surface Cu contamination via galvanic effects. In this study, ethylenediaminetetraacetic acid (EDTA) was used to control the effects of Mg(OH)2 depression on the recoveries of chalcopyrite and pyrite, and to restrict Cu activation in pyrite flotation. Compared with EDTA-free systems, a system with the optimal EDTA dosage (5 × 10−5 M EDTA for 1 × 10−2 M Mg) gave better separation of Mg(OH)2-depressed chalcopyrite and pyrite, with recoveries varying from 63.5 to 94.0% (chalcopyrite) and from 49.9 to 47.5% (pyrite), respectively. Zeta potential measurements and micro-zone X-ray photoelectron spectroscopy (μ-XPS) indicated that Mg(OH)2 detachment was achieved because the surface electropositivity of the Mg(OH)2 colloid decreased because of EDTA chemisorption on its surface as Mg(EDTA)2−. The thermal field-emission scanning electron microscopy-energy dispersive spectroscopy and μ-XPS analysis showed that the preferential removal of surface Cu decelerated Mg(OH)2 removal from the pyrite surface. The results of this study show that moderate EDTA dosages potentially enable effective separation of chalcopyrite and pyrite. EDTA modification is anticipated to optimize the effect of Mg(OH)2 depression on the flotation separation of chalcopyrite and pyrite. This would facilitate cleaner production in Cu pyrometallurgical process.
The paper presents the results of studies on the use of collecting agents in the form of an inverse microemulsion (IМE) of the «water in oil» type (i.e. suspended water droplets are in the oil phase) for the flotation extraction of lead and zinc minerals. Lead and zinc concentrates, lead-zinc ore were used as initial samples for flotation. The content of galena in the lead concentrate was 74.7 %, and the content of sphalerite in zinc was 78.7 %. Basic collecting agents in the IМE composition were potassium butyl xanthate (PBX) and kerosene. A nonionic surfactant (NSA) was used for IМE stabilization. Casein was used as additives to main reagents to remove the negative effect of osmotic pressure during the IМE preparation. Casein was transformed into the active soluble form using sodium sulfide. The particle size in the inverse microemulsion was 12.38 nm. In flotation tests, the following options for feeding reagents to the flotation pulp were studied: IМE, IМE + frother, potassium butyl xanthate + frother. The T-92 reagent was used as a frother. PBX consumption as part of IME and in the traditional feeding was 26 g/ton. The results of laboratory tests showed that the method of feeding flotation reagents in the form of IМE leads to both an increase in the flotation rate of lead and zinc sulfides and an increase in their recovery into a foam product. In addition to the increased flotation speed, tests with the use of IМE in the bulk lead-zinc ore flotation cycle showed an increase in extraction into the ultimate concentrate by 10.8 % for lead, by 38.5 % for zinc, in comparison with the traditional feeding of reagents (collector + frother). An increased selectivity of the IМE effect in relation to zinc sulfides, in comparison with lead sulfides, was noted. The flotation rate coefficient of sphalerite is 7.8 times greater than that of galena. An increase in extraction into the ultimate zinc concentrate is also higher and amounted to 16.78 %, while for the lead concentrate it is 1.9 % under the same conditions.
In this study, mixed collectors containing sodium diisobutyl dithiophosphinate (Aerophine 3418A (3418A), Solvay) and sodium diethyldithiocarbamate (DDTC) were used to improve the flotation of jamesonite, and adsorption mechanism of this system was investigated by means of flotation experiments, FTIR and SEM-EDS analyses, and DFT-D calculation. The results of micro-flotation experiments indicated that 3418A/DDTC mixture with the molar ratio of 1:2 (3418A/DDTC mixture) exhibited excellent selectivity, and presented a shorter conditioning time than conventional DDTC in the flotation of jamesonite. Batch flotation experiments confirmed that 3418A/DDTC mixture could significantly improve the flotation performance of natural refractory Pb-Sb-Zn ore. FTIR and SEM-EDS analyses showed that 3418A and DDTC could perform synergistic chemisorption on jamesonite surface, while the residual amount of 3418A on the surface of jamesonite was significantly higher than that of DDTC. Further analysis with DFT calculation showed that the 3418A could rapidly overcome the binding interactions of surrounding molecules from the micelle and then form effective adsorption in the jamesonite surface, while the DDTC could strengthen the hydrophobic layer due to the H…N hydrogen bonds.
The aim of this study is to investigate the effect of collectors' concentration of the potassium amyl xanthate, sodium isopropyl xanthate and their compositions on the flotation of chalcopyrite. The copper ore sample has been prepared from Ghaleh-Zari mine located in South Khorasan province, Iran. The chemicals of sodium hydroxide, sodium silicate and methyl isobutyl carbinol have been used as pH regulators, dispersants and frother, respectively. The results show that the optimum concentration for the potassium amyl xanthate collector is 100 g per ton, obtaining a product by the grade and recovery of 10.93 and 85.97%, respectively. The optimum concentration for sodium isopropyl xanthate collector was 50 gr per ton, in which the grade and recovery of product were 13.39 and 74.85%, respectively. The optimum combination of potassium amyl xanthate and sodium isopropyl xanthate collectors can be obtained by a ratio of 1: 3 respectively, and the concentration of 50 gr per ton. According to the results, the collectors of potassium amyl xanthate and sodium isopropyl xanthate have more floatabity and more selectivity in flotation of chalcopyrite, respectively.
Effective collectors are essential for the flotation of copper sulphide resources. In this work, we prepared a novel surfactant containing C-O-C groups, O,O'-bis(2-butoxyethyl) ammonium dithiophosphate (BEAT), and mixed it with O-isopropyl-N-ethyl thionocarbamate (IPETC) as an emerging reagent scheme for efficiently improving the flotation recovery of chalcopyrite. Foaming performance tests revealed that BEAT possessed a stronger foaming ability and foam stability than methyl isobutyl carbinol (MIBC). Micro-flotation results indicated that a significant improvement of chalcopyrite flotation recovery of 92.43% was achieved when mixed IPETC/BEAT collectors (BEAT optimal molar fraction of 60%) of 4×10⁻⁵ mol/L at pH 7.0-7.5 were employed. Bench-flotation results of copper sulphide ores showed that compared with IPETC+MIBC (30 g/t + 36 g/t) or BEAT (30 g/t) alone reagent system, a smaller amount of mixed IPETC/BEAT collectors (only 20 g/t) scheme was able to obtain higher Cu recovery and Cu grade. Surface tension results implied that the mixtures provided higher surface activity than individual IPETC, thus exhibiting superior foaming properties and better water solubility. Wettability results suggested that mixed collectors possessed stronger hydrophobicity and superior selectivity towards chalcopyrite against pyrite than single collectors. FTIR results demonstrated that mixed collectors were chemically involved with the chalcopyrite surface through co-adsorption. Intermolecular interaction parameter computation confirmed the positive synergistic effect of mixed collectors.
The chemical properties of the mineral/solution interface have a decisive influence on the flotation behavior of minerals. Here, chalcopyrite, chalcopyrite-pyrite mixture, and chalcopyrite-galena mixture were reacted in 0.1 mM sodium isobutyl xanthate solution at natural pH, then centrifuged, fast-frozen, and characterized with time-of-flight secondary ion mass spectrometry at –125 °C (Cryo-ToF-SIMS) in comparison with the samples thawed in vacuum and measured at room temperature (RT-ToF-SIMS). Cryo-ToF-SIMS of fast-frozen mineral wet pastes allows quasi-in situ characterization of chemical species within the mineral/solution interfacial layer. It was found that dixanthogen was the predominant species of xanthate adsorption products on chalcopyrite and pyrite, while that of galena was lead isobutyl xanthate. In particular, due to the interaction effects between sulfide minerals, the formation of dixanthogen at the mineral/solution interface of chalcopyrite was promoted and inhibited by pyrite and galena, respectively, and the lead ions dissolved from galena were adsorbed to the chalcopyrite surface, resulting in xanthate to react with adsorbed species of lead ions to form lead isobutyl xanthate. This study also observed that the mineral/solution interfacial layer of chalcopyrite-galena mixture was more deficient in sodium ions and calcium ions than those of chalcopyrite and chalcopyrite-pyrite mixture; we proposed that this phenomenon was caused by the repulsion of sodium ions and calcium ions by lead ions dissolved from galena in the electric double layer of minerals.
The microflotation experiments were systematically carried out to investigate the inhibitory effect of citric acid (CA) on the flotation behavior of hornblende and magnesite. When the mixture consisted of sodium oleate and dodecyl phosphate was utilized as a mixed trapping reagent, CA could obviously inhibit the hornblende flotation but had little inhibitory effect on magnesite flotation. The desilication of magnesite flotation was accomplished when CA was employed as the hornblende inhibitor. Moreover, to reveal the adsorption mechanism of CA on the surfaces of hornblende and magnesite, a series of surface analysis techniques, such as X-ray photoelectron spectroscopy (XPS), zeta potential and Fourier transform infrared spectroscopy (FTIR), were conducted. Based on the zeta-potential and FTIR analyses, it is revealed that CA or CA together with collector (sodium oleate and dodecyl phosphate mixture) was applicable for the magnesite flotation tests. In the meanwhile, the introduced CA had obviously hindered the adsorption of sodium oleate and dodecyl phosphate mixtures on the hornblende surface, resulting in a significant difference in the flotation performance of hornblende and magnesite minerals. Moreover, XPS measurements revealed that the strong adsorption of CA on the hornblende surface can be ascribed to its affinity for the negative electron groups of CA and Ca ions.
Flotation is an essential process in beneficiation production. The amount of flotation reagent has a significant influence on the quality of the product. An inappropriate dosing system will lead to metal loss and reagent waste, especially when the nature of the raw ore changes frequently. If the dosing system is not updated in time, it will cause economic losses. Based on digital twin technology and machine learning algorithms, this research designed a digital twin system for iron reverse flotation reagents. Based on the flotation froth image and transformer algorithm, a soft sensor model of tailings grade is established to monitor the product quality in real-time. The flotation dosing model established based on the ELM algorithm automatically updates the reagent system and intelligently assigns the controller. On the basis of stabilizing product quality, this research avoids the waste of reagents and improves the economic benefits of production efficiency. The system was applied in an iron flotation plant, and industrial operation effect verified the method.
The effect of the collector and its blends on sequential flotation of a complex lead-zinc ore has been investigated. Lead-zinc ore collected from Rajasthan, India showed the presence of PbS-2.21%, ZnS-5.92%, FeS2-8.03%, SiO2-20.21%, Al2O3-5.25%, MgO-10.53%, SO3-6.48% and CaO-22.16%. The copper and silver were also traced as minor fractions. Xanthates of different alkyl chain lengths as a collector (individual or mixture in various proportions) were used in the lead circuit to evaluate valuables’ performance in the mineralized pulp. The study could enhance the lead and zinc grade up to 27.95% and 22.6% using PEX (potassium ethyl xanthate) and SIPX (sodium isopropyl xanthate) as a blend. The best overall performance in the recovery of lead and zinc was 74.39% and 82.23%, respectively. However, the studies carried out with individual collectors, PEX and SIPX, showed their best result: 22.06% lead and 20.99% zinc grade, 60.54% lead, and 78.73% zinc recovery. The study confirms the synergies between the two alkyl chain length xanthates in the blend.
In this chapter, the most salient nanoscience and nanotechnology concepts related to extractive metallurgy, specifically mineral froth flotation, are discussed. The most relevant and current findings of nanotechnology‐based research in the domain of mineral processing and a concise overview of recent advances in the application of nanotechnology for improved mineral recovery using froth flotation technology is reported. In this ever‐expanding age of technologies to improve mineral processing, nanotechnology stands as one of the technologies which can revolutionize the mineral processing industry in general. Nanomaterials present novel properties, which can be exploited to generate exceptionally good reagents to improve recoveries and grades of minerals of interest during the froth flotation process. In light of these current developments, insight into potential future research directions for nanotechnology research in the domain of froth flotation of minerals is given.
Polymer and small molecules are often used to modify the wettability of mineral surfaces which facilitates the separation of valuable minerals such as molybdenum disulfide (MoS2) from gangue material through the process of froth flotation. By design, traditional methods used in the field for evaluating the separation efficacy of these additives fail to give proper access to adsorption kinetics and molecule conformation, crucial aspects of flotation where contact times may not allow for full thermodynamic equilibrium. Thus, there is a need for alternative methods for evaluating additives that accurately capture these features during the adsorption of additives at the solid/liquid interface. Here, we present a novel method for preparing MoS2 films on quartz crystals used for Quartz Crystal Microbalance with Dissipation (QCM-D) measurements through an electrochemical deposition process. The resulting films exhibit well-controlled structure, composition, and thickness and therefore are ideal for quantifying polymer adsorption. After deposition, the sensors can be annealed without damaging the quartz crystal, resulting in a phase transition of the MoS2 from the as-deposited, amorphous phase to the 2H semiconducting phase. Furthermore, we demonstrate the application of these sensors to study the interactions of additives at the solid/liquid interface by investigating the adsorption of a model polymer, dextran, onto both the amorphous and crystalline MoS2 surfaces. We find that the adsorption rate of dextran onto the amorphous surface is approximately twice as fast as the adsorption onto the annealed surface. These studies demonstrate the ability to gain insight into the short-term kinetics of interaction between molecules and mineral surface, behavior that is key to designing additives with superior separation efficiency.
Flotation separation is determined by chemical additives which can enlarge the hydrophobicity difference of minerals. Herein, S-[(2-hydroxyamino)-2-oxoethyl]-N,N-dipropyl dithiocarbamate (HAPTC) was firstly developed for the flotation separation of galena and sphalerite. In situ AFM imaging elucidated a much stronger adsorption affinity of HAPTC towards galena (PbS) than that to sphalerite (ZnS) at pH 6.2 and 9.0. The AFM force findings and the extended DLVO theory analyses indicated that HAPTC adsorption promoted the hydrophobicity of galena surface more significantly than that of sphalerite. The micro-flotation results showed that HAPTC achieved a selective flotation separation of galena against sphalerite at pH around 9.0. FTIR and XPS uncovered that both dithiocarbamate and hydroxamate groups in HAPTC participated in the bonding interaction with Pb sites on galena surface with the formation of Pb-S and Pb-O bonds. The results provide implications on developing novel reagents, and the fundamental understanding of their adsorption and hydrophobization to minerals at nanoscale.
Flotation reagents have a complex behaviour in the beneficiation of base minerals in clayey ores. Interaction effects of reagents on the efficiency of copper flotation for a highly clayey low-grade sulphide ore were investigated using a central composite design. Preliminary results showed that sodium-isopropyl-xanthate (SIPX) and O-isopropyl-N-ethyl-thionocarbamate (IPETC) were found to be the most efficient collectors in the presence of lime as the pH regulator. The effects of dosage of collectors (SIPX and IPETC) and the dosage of methyl-isobutyl-carbonyl (MIBC) as frother on the separation efficiency were evaluated at different pH levels. Based on the analysis of variance (ANOVA), the interaction effects of the collector−pH and collector−frother were significant for the separation efficiency. At the low level of collector dosage, increasing pH from 9 to 11 enhanced copper separation efficiency from 81% to 86% for IPETC and from 77% to 86% for SIPX. Results of ANOVA showed that the maximum copper separation efficiency (88.7%) was obtained at the dosages of 8.6 g/t SIPX, 7 g/t IPETC and 20 g/t MIBC at pH 11. Finally, it was concluded that a mixture of SIPX and IPETC collectors was more suitable to treat highly clayey sulphide ores.
The extraction technology for platinum-group metals (PGMs) has changed dramatically in the last 80 years, and the changes
are likely to continue for years to come. This article will review advances in PGM extraction, including developments in semi-autogenous
and fully autogenous milling; flotation equipment applications for treating high-chrome ores; increases in power densities
for future smelting furnaces, and new methods for meeting rising environmental standards.
This paper investigates the effects of thiol collectors: xanthates, dithiophosphates, dithiocarbamates and mixtures of these on the froth flotation performance obtained with a bornite-rich copper sulphide ore from Okiep Copper Mine with a feed grade of 1.8% copper. Batch flotation tests were used to assess the performance in terms of mass-water recovery, sulphur grade-recovery and copper grade-recovery relationships and the Klimpel rate constant for copper recovery. The results showed that the di-ethyl-dithiocarbamate (di C2-DTC) was the weakest collector of copper sulphide minerals. Highest copper recoveries were obtained with the di-ethyldithiophosphate (di C2-DTP), which were accompanied with more watery froths and lower copper grades demonstrating frothing properties in addition to collector action. Superior copper recoveries were obtained with the 90% ethyl xanthate (C2-X):10% di-ethyldithiophosphate (di C2-DTP) and 90% ethyl xanthate (C2-X):10% di-ethyl-dithiocarbamate (di C2-DTC) collector mixtures compared to that obtained with ethyl xanthate at an equivalent collector dosage of 0.139 mol/ton ore (a dosage equivalent to 20 g sodium ethyl xanthate per ton ore). A superior copper grade was obtained with the 90% ethyl xanthate:10% di-ethyl-dithiocarbamate collector mixture at a dosage of 0.0695 mol/ton ore compared to that obtained with ethyl xanthate at the same equivalent dosage.
Synergism may be defined as the enhanced effect obtained from the use of a combination of reagents relative to their individual action. In flotation synergistic effects between collectors and between collectors and frothers have long been recognized in plant practice, although little attention has been paid to them in laboratory studies. The study of such effects between KEtX and sodium diethyl dithiocarbamate (Dtc) in reaction with heazlewoodite (Ni3S2) is described in this paper. Correlation was obtained between flotation recoveries obtained in a modified Hallimond tube, adsorption isotherms for the reagents on the mineral surface and simple measurements of surface tension carried out on a dropping mercury electrode at controlled potentials (the electrocapillary phenomenon). It was hoped that these techniques, together with cyclic voltammetry studies, could be developed into a compact method for studying synergism both for the evaluation of potentially useful systems and to obtain a better understanding of the underlying theoretical principles.
Sulfide mineral systems fall into those in which thiol collectors are adsorbed chemically and those in which dimer formation results from electrochemical oxidation of collector on the mineral surface. Galena, chalcocite, and sphalerite fall into the first category, while pyrite falls into the second. Chalcopyrite exhibits both chemisorption and dimer formation.
The reliability of a set of flotation results is key to minimizing project risk, either at the commissioning of a concentrator or at the point of implementing an improvement to an existing concentrator operation. High-confidence flotation testing (HCFT) was developed for this purpose and is part of the list of technologies at various scales used by Xstrata Process Support (XPS) in addressing these projects. The methodology is based on two principles: one, to ensure that the ore sample is representative and has been well-blended and subsampled; two, to perform the flotation tests in sufficient numbers of replicates with appropriate quality controls, so as to improve the reproducibility of the test data. Across ten years of research on this methodology at Xstrata Process Support, Sudbury, several improvements to the HCFT method and complementary connections between sampling and quantitative mineralogy have been developed. Two case studies are reviewed. These show the capability of this system in both optimizing an existing concentrator operation and in serving a new mine scenario. Further work to improve the efficiency of this procedure has been identified.
The concentrator has a 3075 mtpd copper flotation circuit capable of running twenty-four hours a day under the direct control of an optimizing supervisory computer. Three main streams, continuously monitored by an XRF analyzer, supply circuit information. Circuit efficiency calculations and target setpoints allow the computer to determine the optimum direction based on the grade/recovery relationship. Circuit manipulation is accomplished by pumping of collector and frother reagents together with control of flotation bank pulp levels. The former uses computer controlled diaphragm pumps and the latter is achieved by control loops utilizing a float type level transmitter, variable position dart plugs and a process computer working to setpoints determined by the optimizing computer.
The promoters have found diverse applications in the flotation treatment of metallic and sulphide base and precious metals. Outstanding features include high collecting activity and selectivity, particularly in regard to iron sulphide minerals in alkaline circuit. The greatest usage of dithiophosphates lies in combination with another collector type to enhance the collecting properties of each.-J.M.H.
Electrochemical investigations of the flotation of sulphide minerals are reviewed. Flotation with thiol collectors is interpreted in terms of a 'mixed potential' model. In this model, the process leading to hydrophobicity is the anodic oxidation of the collector at the mineral surface; this is driven by the cathodic reduction of oxygen. Electrochemical studies have identified the products of anodic oxidation as chemisorbed collectors, metal collector compounds, and dithiolates; the products formed in each situation depend on the collector used, the mineral under study and the pretreatment of the mineral surface. Investigations on galena, pyrite and chalcocite are discussed. Electrochemical and X-ray photoelectron spectroscopic studies have been used to determine the surface oxidation products of sulphide minerals in order to elucidate the mechanism of collectorless flotation. The mixed potential mechanism allows consideration of the methods of inhibiting flotation of sulphides with thiols. Examples of depressant action are presented and the relevance of electrochemical investigations to practical flotation is discussed. (Author's abstract)-J.M.H.
The theory of stationary electrode polarography for both single scan and cyclic triangular wave experiments has been extended to systems in which preceding, following, or catalytic (cyclic) chemical reactions are coupled with reversible or irreversible charge transfers. A numerical method was developed for solving the integral equations obtained from the boundary value problems, and extensive data were calculated which permit construction of stationary electrode polarograms from theory. Correlations of kinetic and experimental parameters made it possible to develop diagnostic criteria so that unknown systems can be characterized by studying the variation of peak current, half-peak potential, or ratio of anodic to cathodic peak currents as a function of rate of voltage scan.
Xanthate characteristics with relation to its hydrocarbon chain length has been considered. The free energy associated with one -CH2 group in homologous xanthates was calculated based on the standard redox potential of X2/X− couple and solubility products of transient metal xanthates. The estimated free energy using each method was found to be 690–920 cal and 799–824 cal, respectively, and was in good agreement with that for various homologues.
The paper describes how sulphydryl collector chemistry affects the performance of base-metal sulphide flotation, particularly in terms of kinetics and selectivity. The influences of chemical manipulation on the major types of sulphydryl collectors are illustrated.Examples used include plant and laboratory data from flotation systems involving the following ore types:- •porphyry copper - molybdenum•sedimentary copper•copper - zinc•massive sulphide•copper-lead-zinc complex sulphideSome new developments in base-metal sulphide collectors are described. The responses of different collector types to variation in pulp Eh and pH are illustrated.
Surface tension and contact angle experiments were conducted aiming at studying the synergism of surfactant mixtures on the reduction of surface tension of aqueous solutions and on the hydrophobicity of mineral surfaces. The following systems were studied: 1) Potassium ethyl xanthate with sodium oleate mixtures for pyrite and gold, and 2) Sodium oleate with cetyl trimethyl ammonium bromide (CTAB) mixtures for fluorite and calcite. A synergistic effect of combined reagents was found to enhance the hydrophobicity and also to reduce the surface tension, depending mainly on the proportion of the mixtures.
Adsorption of xanthates on galena, pyrite and sphalerite in the virtual absence of oxygen is presented as a function of xanthate concentration and pH. Adsorption of ethyl xanthate on galena occurs at monolayer coverage independent of pH. In the case of pyrite and sphalerite, adsorption of short-chain xanthates occurs below monolayer coverage at pH values below 8.
From the examination of data from detailed plant surveys and associated laboratory batch testing, the principal effects of particle size in flotation have been identified. The current state of knowledge concerning the role of this variable is discussed in terms of the evidence presented. It is concluded that the minimum degree of hydrophobicity necessary for the flotation of a particle depends upon its size and as a result, recovery-size curves are a valuable diagnostic aid to the assessment of flotation performance. Entrainment is shown to be an important contributory mechanism to the recovery of fine particles which, when coupled with a low rate of genuine flotation, can account for much of the observed behaviour of such fines. The significance of particle size and its consequences in flotation research, in plant operations and in control schemes has been under-rated. The separate conditioning or flotation or both of separate size fractions seems inevitable as ores become increasingly difficult to concentrate.
This book is the premier text on the properties and applications of
surfactants. The third edition is completely updated and revised,
including new information on gemini surfactants (a new type of powerful
surfactant), superspreading (or superwetting) by aqueous surfactant
solutions of highly hydrophobic surfaces (important in agricultural
applications), and dynamic surface tension (an important interfacial
property not covered in the first two editions). * Clearly explains the
mechanisms by which surfactants operate in interfacial processes * Uses
a minimum of mathematics in explanation of topics, making it
easy-to-understand and very user-friendly * Problems are included at the
end of each chapter * Includes many tables of data as reference that are
not compiled elsewhere * Milton J Rosen is an expert in the field of
Surfactant research
The reactions between chalcopyrite, CuFeS2, marcasite, FeS2, pentlandite, (Fe,Ni)9S8, pyrrhotite, FeS1-x, and troilite, FeS, and aqueous solutions of potassium ethylxanthate and decylxanthate have been studied. X-ray photoelectron spectroscopy (XPS) has been used to determine the oxidation state of copper at the chalcopyrite surface. The XPS measurements showed that copper at the surfaces of chalcopyrite is present as copper(I) Qualitative analysis of the alkylxanthate species present on the mineral surfaces after treatment with an aqueous solution of potassium alkylxanthate has been made by means of diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. Solid copper(I) alkylxanthate is the only alkylxanthate species found on the chalcopyrite surfaces. Alkylxanthate ions are sorbed to chalcopyrite surfaces according to a dissolution—precipitation mechanism where copper(I) species are dissolved from the chalcopyrite surfaces, a concentration gradient of copper(I) species is formed around the chalcopyrite particles, and copper(I) alkylxanthate precipitates back on the chalcopyrite surface in the presence of small concentrations of alkylxanthate ions. Large amounts of dialkyl dixanthogen formed in a redox reaction between alkylxanthate ions and highly oxidising species on the marcasite surfaces are present on the marcasite surfaces after treatment with an aqueous solution of alkylxanthate. This oxidising agent is most probably a minor oxidation product of the disulphide ions in marcasite, e.g. S2O2−8 and/or S2O2−7 ions, which are probably formed during grinding in air. Dialkyl dixanthogen is the only alkylxanthate species found on the surfaces of pentlandite and pyrrhotite, but the amounts are substantially smaller than on marcasite. The sulphur in pentlandite and pyrrhotite is most probably mainly oxidised to sulphate ions, but very small amounts of a strong oxidising agent seem to be formed as well. No alkylxanthate species have been found on the surfaces of troilite after treatment with alkylxanthate ions. The relationship between the kind of alkylxanthate species formed on the sulphide mineral after treatment with an aqueous alkali alkylxanthate solution and the structure of the mineral is discussed.
Electrochemical studies were conducted to determine if ions present in the Copper Cliff process water at INCa's Sudbury complex were interactive on pentlandite and pyrrhotite surfaces. It was found that Ca2+, S2O3
2− and SO4
2− were significantly surface active at the normal process pH. From comparisons of other voltammetric traces obtained for xanthate interactions it was concluded that these ions would influence the extent of adsorption of X− by the sulphide minerals as well as control the onset of hydrophobicity. Simple hydrophobicity tests confirmed that S2O3
2− and Ca2+ competed with xanthate for adsorption on the surface of pentlandite whereas only Ca2+ increased the xanthate dosage required to render pyrrhotite hydrophobic. Mechanisms for pentlandite and pyrrhotite flotability arising from xanthate reactions were put forward. Xanthate chemisorption took place on the nickel sites in the case of pentlandite, which was oxidized at the surface to form dixanthogen which enhanced hydrophobicity. No xanthate chemisorption took place on pyrrhotite, the surface being rendered hydrophobic by dixanthogen which was formed as part of a mixed potential reaction involving with the normal pyrrhotite oxidation process.
Electrochemical behavior of chalcopyrite was investigated in the absence and presence of dithiophosphate (DTP) and dithiophosphinate (DTPI), selective thiols against Fe-sulfides in the flotation of sulfide ores, in potentiostatically controlled electrochemical condition. Diffuse reflectance Fourier transformation (DRIFT) spectroscopy was applied to determine the type of adsorbed collector species, and Hallimond tube flotation tests were performed to clarify the role of polarization potential and thiol collectors on the floatability of chalcopyrite. DRIFT spectroscopy study proposed that dithiolate of DTP, (DTP)2, was the major surface compound formed under oxidizing potentials in slightly acidic and neutral conditions. However, DTP species formed on mineral surface in alkaline condition could not be determined possibly due to heavy surface coating of metal oxyhydroxides. DTPI species formed on chalcopyrite was found to be in the form of CuDTPI + (DTPI)2. Additionally, presence of adsorbed DTPI, DTPI0, was also detected. Self-induced floatability was significantly high particularly in slightly acidic condition and decreased by increasing pH due to surface coating of metal oxyhydroxides. Addition of both collectors improved the flotation performance at all pH values. However, the positive effect of DTP at high alkaline pH values was lower than that of DTPI. This was attributed to weak collecting property and lower hydrocarbon chain length of DTP compared to DTPI. Effect of pulp potential could not be observed in slightly acidic condition, but it became apparent at higher pHs. Although better flotation responses were obtained in mildly oxidizing potentials, both collectors enlarged the floatability potential range of chalcopyrite.
Using the criteria of recovery and rate, the flotation of the principal copper sulfides and pyrite with sulfhydryl collectors was found to follow the pattern: xanthate > dithiophosphate = thionocarbamate = xanthogen ethyl formate > dixanthogen. Flotation rate was found to be a more sensitive parameter than recovery; especially as near-ultimate recovery is approached. The differing response of these five minerals to the anionic xanthate or dithiophosphate collectors was found to correspond to the mineral semiconductor type. As the pH increases from pH 5 to 10.5 both recovery and rate were generally found to decrease with all the sulphydryl collectors except dixanthogen.
Historically, the process of reagent selection and optimization has been rather informal, reductionistic and frequently based on extension of personal experience from one mineral system or plant to another, gut feeling, anecdotes, and myths. There is no recognized “standard” practice, and the informal process is fraught with pitfalls. The complexity and variability in mineralogy and the complex interactions between chemical, physical-mechanical and operational factors in the plant are invariably ignored in such an approach, and the selected reagent will have a narrow, un-optimized window of performance. Thus the chemical solution to a plant’s demand will not be robust. This approach is also very costly in the long run and adds little to our knowledgebase. In this paper an expanded holistic view of the flotation system is described, and a rational, holistic process is discussed for reagent selection, optimization, and profitable implementation in the plant, using base metal sulfide flotation system as an example. Although such an approach in the flotation system may, at first glance, imply impracticality, an attempt is made in this paper to show that a manageable holistic approach can be practiced and that it is necessary in order to develop robust solutions to metallurgical needs in the plant.
Linear sweep voltammetry has been used to study the electrochemical properties of platinum, copper and copper sulfide electrodes in the absence and in the presence of potassium diethyldithiophosphate. The influence of several variables, namely, sweep rate, solution pH, dithiophosphate concentration, etc. has been studied. Oxidation-reduction reactions at platinum, copper and copper sulfide electrodes are postulated to explain the observations. In the absence of any dithiophosphate in solution, the initial oxidation reaction is probably the discharge of hydroxyl ions. Dithiophosphate ions inhibit the oxidation reaction. Under suitable conditions, bis(diethoxythiophosphoryl)disulfide forms at platinum, whereas cuprous and cupric dithiophosphates form at copper and copper sulfide. The oxidation products can be reduced at the respective electrodes, however, the reactions are generally irreversible.
Electroflotation tests were conducted with a chalcopyrite fines-sodium diethyldithiocarbamate system with normal variables such as effect of concentration, pH of the collector and conditioning time, separately with oxygen and hydrogen bubbles generated electrolytically. Studies were attempted to check the effect of pH changes and electrolyte gases on the surface products. The surface products were extracted with carbon tetrachloride and analysed by UV-visible and I.R. spectrophotometric methods. It was found from the results that the qualitative nature of the surface product was unaffected by the above parameters.
On the basis of an analysis by spectrophotometric methods, it is concluded that, when xanthate reacts with a sulfide mineral surface, in general either dixanthogen or the metal xanthate is formed and not a mixture of the two. Exceptions are covellite and molybdenite. The nature of the reaction products does not vary with pH of the solution nor with the chain length of the xanthate homologue used. The results agree with rest potential measurements in showing that dixanthogen is formed on those minerals that assume a rest potential greater than the equilibpotential for the reduction of dixanthogen or xanthate.
Thermochemical measurements were made of the reactions between sodium cyclohexyl dithiocarbamate, potassium n-butyl xanthate and mixtures thereof with pyrite at pH = 4. The initial steady state heat of adsorption for the potassium n-butyl xanthate and sodium cyclohexyl dithiocarbamate was −67 kJ/mole. When a mixture of these reagents was used this increased to −90 kJ/mole. In all cases the pH increased during the experiments. When FeS04 replaced the pyrite the ΔH for the xanthate decreased to −43.9 kJ/mole. The results indicated that for the xanthate, the metal thiolate was formed and subsequently oxidised to dixanthogen. The latter reaction did not occur in the case of the dithiocarbamate, however the extent of the first reaction between the dithiocarbamate and pyrite was controlled by proton availability. For the mixture of reagents it is proposed that the dithiocarbamate adsorbs preferentially due to its faster adsorption kinetics and the more stable nature of the surface complex. The dixanthogen species formed then aggregates around the “anchors” and results in enhanced hydrophobicity. This will contribute towards the enhanced flotation performance obtained when mixtures collectors are used [1].
The adsorption of ethyl xanthate on pyrite, pyrrhotite, chalcopyrite and sphalerite has been studied using FTIR-ATR techniques and microflotation. Non-activated minerals and minerals activated with copper sulfate have been investigated at different pH values and xanthate concentrations. Diethyl dixanthogen is formed on non-activated pyrite, pyrrhotite and chalcopyrite. Iron xanthate co-exists with diethyl dixanthogen as a monolayer form on pyrite and a copper xanthate surface compound co-exists with diethyl dixanthogen on chalcopyrite. After copper sulfate activation a copper (I) type xanthate compound exists on all of the minerals studied. Acidic pH favours the adsorption of ethyl xanthate on non-activated minerals, whereas the neutral pH range is most favourable for xanthate adsorption on activated minerals.
Adsorption of diethyldithiocarbamate (DTC) on covellite, cuprite and tenorite was investigated under different experimental conditions. The qualitative nature of surface species formed at the interface was examined by selective solvent extraction and UV—visible spectrophotometric techniques. The presence of surface species such as [Cu(DTC)]+, Cu(DTC)2 and Cu(I) DTC at different concentrations of the reagent and pH of the suspension was investigated. The results of this study indicate a surface reaction between DTC ligand molecules and surface copper sites. As a result of interaction with DTC, cations on the mineral surface are dislodged from the lattice and precipitated on the surface as copper dithiocarbamate complexes. Depending on the concentration of DTC, two types of copper complexes, i.e. [Cu(DTC)]+ at low concentration and Cu(DTC)2 at higher concentration, are noted on copper(II) substrates, whereas on cuprite Cu(I) DTC was formed along with [Cu(DTC)]+ and Cu(DTC)2. From the kinetic study, the overall adsorption was found to be mainly controlled by diffusion processes.
The subject of inter facing plant grinding and flotation operations is addressed. Use is made of mineral distribution by size in the grinding circuit product combined with size-recovery performance of the flotation circuit. This establishes criteria for defining the economic value of the product from a grinding circuit. A case study is presented for illustration.
The potential beneficial effects of using two or more reagents are widely known and using mixtures of collectors in flotation has shown to increase both the recovery and selectivity simultaneously. In this work, the adsorption behaviour of sodium isopropyl xanthate (SIPX) and dithiophosphinate (DTPI) was investigated. These collectors were selected as strong and selective collectors respectively for the flotation of chalcopyrite. The adsorption behaviour of these collectors, combined in different ratios and order of addition was investigated by electrochemical and adsorption experiments at pH 9.2.The results showed that both the ratio of collectors in mixtures and sequence of addition were important. The maximum synergistic effect was observed at 30:70 (SIPX:DTPI) ratio when DTPI was added initially and at 50:50 ratio when the collectors were added simultaneously.
Physicochemical properties of some flotation reagents and their salts with ions of heavy iron-ferrous metals
- I A Kakovsky
Kakovsky, I.A., 1957. Physicochemical properties of some flotation reagents and
their salts with ions of heavy iron-ferrous metals. In: Proceedings of 2nd
International Congress Surface Activity, London, vol. 4, pp. 225-237.
Personal Communication. Rustenburg. Plaskin, I Investigations of the possible intensification of the flotation process using combinations of collectors. (Mintek translation Feb
- M K N Oertel
- V A Glembotskii
- A M Okolovich
Oertel, M.K., 1981. Personal Communication. Rustenburg. Plaskin, I.N., Glembotskii, V.A. and Okolovich, A.M., 1954. Investigations of the possible intensification of the flotation process using combinations of collectors. (Mintek translation Feb. 1989). Naachnye Soobshcheniya Institut Gonnogo dela Imeni AA Skochinskogo, Akademiya Nauk SSSR, No. 1, pp. 213– 224.
Laboratory testwork of mixed xanthates for the raglan ore
- T Deng
- S Yu
- N O Lotter
- A Di Feo
Deng, T., Yu, S., Lotter, N.O., Di Feo, A., 2010. Laboratory testwork of mixed xanthates
for the raglan ore. In: Proceedings of Canadian Mineral Processors, Ottawa,
January 2010, Paper No. 16, pp. 253-268.
The dithiocarbamates and related compounds
- G D Thorn
- R A Ludwig
Thorn, G.D., Ludwig, R.A., 1962. The dithiocarbamates and related compounds.
Elsevier Publishing Co., Amsterdam, New York.
Plant scale trial of isobutyl xanthate at Raglan concentrator using reference distributions
- N O Lotter
- G Comeau
- L J Kormos
- D Fragomeni
- A Di Feo
Lotter, N.O., Comeau, G., Kormos, L.J., Fragomeni, D., Di Feo, A., 2009. Plant scale trial
of isobutyl xanthate at Raglan concentrator using reference distributions. In:
Proceedings of Canadian Mineral Processors, Ottawa, Paper No. 6, pp. 79-105.
Trial of X-333 Xanthate Mixture at Amplats. South Africa
- N O Lotter
- J Aupiais
Lotter, N.O., Aupiais, J., 1996. Trial of X-333 Xanthate Mixture at Amplats. South
Africa, Personal Communication.
Experiences with computer control of the flotation at Kidd Creek Mines
- P E Thwaites
Thwaites, P.E., 1986. Experiences with computer control of the flotation at Kidd
Creek Mines. In: Proceedings of III Canadian Industrial Computer Society,
Montreal, pp. 56-58.
Principles of Flotation. Australian Institute of Mining and Metallurgy
- K L Sutherland
- I W Wark
Sutherland, K.L., Wark, I.W., 1955. Principles of Flotation. Australian Institute of
Mining and Metallurgy, Melbourne. pp. 95-101.
A quality control model for the development of high-confidence flotation test data
- N O Lotter
Lotter, N.O., 1995. A quality control model for the development of high-confidence
flotation test data. M.Sc. (Chem. Eng.) Thesis. University of Cape Town, South
Africa, June 1995, 188 pp.