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Recovery of magnesium from Uyuni salar brine as high purity magnesium oxalate
Abstract
Containing 10.2 Mt Li, Salar de Uyuni is known to be the richest resource of Li in the world. A high Mg/Li mass ratio of 21.2:1 of the Uyuni salar brine used in this study is a significant factor hindering the effective lithium recovery. Stabcal modelling was first conducted to study the conditions and chemical speciation of various species involved in the selective precipitation of Mg and Ca oxalate. Along with the addition of oxalic acid, the effect of pH was then studied in order to determine optimal conditions to selectively remove Ca and achieve high Mg yield subsequently. At an Oxalate/Ca molar ratio of 6.82:1 and pH < 1, ~ 80% of Ca could be removed from brine without co-precipitation of Mg oxalate. A NaOH/Mg/Oxalate molar ratios of 1.95:1:1 to 3.21:1:1.62 in the range of pH 3-5.5 was used for the Mg precipitation. A recovery of > 95% Mg was obtained (precipitate containing mostly Mg oxalate) together with the K and Li losses of up to 35% from the original brine. Washing would remove Li, K contaminants and the co-precipitated sodium sulphate and oxalate. Their absence from the final precipitate was confirmed by XRD analysis. The high purity (99.5% grade) Mg precipitate obtained could be used as a precursor for MgO production.
... The precipitation technique is widely employed in large-scale industrial processes to extract lithium from brine, particularly when the brine has a low Mg/Li mass ratio [124]. When the Mg/Li ratio is below 6, separating lithium and magnesium using precipitation is effective. ...
... Under optimal reaction conditions, it was discovered that both ammonium oxalate and sodium carbonate are efficient in precipitating 98% of Mg [135]. Oxalic acid was discovered to effectively precipitate over 95% of magnesium as magnesium oxalate in brine, even at a high magnesium-to-lithium ratio of 21 [124]. ...
The escalating demand for lithium has intensified the need to process critical lithium ores into battery-grade materials efficiently. This review paper overviews the transformation processes and cost of converting critical lithium ores, primarily spodumene and brine, into high-purity battery-grade precursors. We systematically examine the study findings on various approaches for lithium recovery from spodumene and brine. Dense media separation (DMS) and froth flotation are the most often used processes for spodumene beneficiation. Magnetic separation (MS) and ore gravity concentration techniques in spodumene processing have also been considered. To produce battery-grade lithium salts, the beneficiated-concentrated spodumene must be treated further, with or without heat, in the presence of acidic or alkaline media. As a result, various pyro and hydrometallurgical techniques have been explored. Moreover, the process of extracting lithium from brine through precipitation, liquid–liquid extraction, and polymer inclusion membrane separation employing different organic, inorganic, and composite polymer sorbents has also been reviewed.
... The Salar de Uyuni in Bolivia however has nearly ten million tons worth of lithium resource but due to the high magnesium content (Mg 2+ /Li + mass ratio approx. 21:1), conventional lithium extraction complicated [36]. This is because an elevated amount of the Mg 2+ ion-precipitating reagent is required. ...
... Brines with a high Mg 2+ /Li + mass ratio are prevalent in industrial settings [36]. Intriguingly, solvent extraction may be used to recover lithium from such brines with significant quantities of magnesium and even calcium [72,73]. ...
The increasing adoption of lithium in clean energy technologies has promoted significant development of novel and environmentally sustainable techniques for lithium extraction from secondary sources. In this review, we evaluate seawater and geothermal brines as potential secondary lithium resources for supplementing the rising demand. The review examines relevant literature to understand key aspects pertaining to lithium extraction from these systems in which the fundamental chemistry, the efficacy of different potential extraction techniques, and the associated impacts of each technique are critically reviewed. The extensive research in conventional closed basin brines is utilized as a baseline to demonstrate the current research progress, providing guidelines for future research direction in lithium extraction from seawater and geothermal brines. Based on the literature, it is suggested that sorption and ion-exchange will have high potential for prospective lithium extraction from aqueous resources like salars, seawater, and geothermal brines, and that the integration of activated carbon materials or microorganisms with these techniques will enhance the selectivity of lithium extraction from aqueous resources.
... Previous studies [28,29] Thus, a molar ratio of 1:1 was used as the lower bound. An upper bound of molar ratio of 1:2 was selected to ensure high removal rate of Ca 2+ in the reject brine. ...
... Based on Eq. (12), the purity of the synthesized MgC 2 O 4 ⋅2H 2 O can be calculated according to Eq. (16), where M MgC2O4⋅2H2O was the molecular weight of MgC 2 O 4 ⋅2H 2 O (148.4) and M H2O was the molecular weight of H 2 O (18.0). According to the results, the purity of the synthesized MgC 2 O 4 ⋅2H 2 O was estimated to be 99.6 %, which was comparable to the findings of previous studies[28]. ...
... The precipitation process is the simplest separation process because it does not require expensive chemicals or complicated equipment. Generally, the chemical reagents used for precipitation processes are based on aluminum [9,10], oxalic acid [11,12], ammonium phosphate [13], and sodium metasilicate [14]. Hai (2018) used sodium silicate to separate lithium and magnesium [15]. ...
... Resources 2022,11, 89 ...
Potential natural resources of lithium in Indonesia from brine water and bittern generally have low lithium and high magnesium levels, which need to be separated before further extraction. This research investigates the separation process of magnesium from brine water and bittern using a sodium silicate solution. The experimental results showed that the magnesium precipitation efficiency using sodium silicate was better in brine water than in bittern. A separation selectivity ratio of magnesium to lithium (Mg/Li) below 1 was obtained in brine water of 0.59 and bittern of 0.11 with the addition of a 1.25 mole fraction of sodium silicate solution to magnesium ions. After the precipitation at optimum addition of sodium silicate and water leaching process using distilled water, lithium’s recovery in the brine water and bittern filtrate was 84% and 35%, respectively. In brine water, water leaching increased lithium and magnesium ions in the filtrate. However, in bittern, the water leaching increased lithium recovery without dissolving magnesium ions into the filtrate. The precipitation products from the bittern were identified as complex lithium compounds in the forms of Li2MgO4SiLi2(MgSiO4) and LiMg4Na3O30Si12 phases, while the precipitation products in brine water mostly had a phase of CaO·MgO·Si2O5 (Diopside) and LiCl.
... The conventional method of Mg(OH) 2 recovery from seawater brine is through the addition of lime, however, one of the major problems of this method is a relatively low Barba et al. (1980). Tran et al. (2013), Dong et al. (2018) product purity of below 80% (Gong et al. 2018). An optimized response surface methodology was introduced for the recovery of magnesium from desalination brine based on the precipitation of Mg(OH) 2 by the reaction of MgCO 3 with ammonium hydroxide. ...
... With the addition of an alkali source (NaOH, NH 4 OH), the recovery of MgO from desalination reject brine can be achieved through the precipitation and further calcination of Mg(OH) 2 (Dong et al. 2018). Tran et al. (2013) recovered Mg oxalate with a purity of 99.5% from Uyuni salar brine via the use of oxalic acid. They found that calcium could be removed from brine without co-precipitation of Mg oxalate when pH is less than 1, which also provides a suitable method to produce MgO. ...
In order to address freshwater scarcity, seawater desalination technologies have been widely studied in recent years. However, the disposal of desalination brine which contains an even higher concentration of salts than seawater can potentially damage the surrounding environment. Therefore, alternative approaches aiming to recover valuable resources from desalination brine have been conducted. Three resources that can be recovered have been studied in this paper, which are minerals, freshwater and energy. The techniques to recover minerals can be divided into pressure-driven techniques, thermal-driven techniques, electro-driven techniques and other techniques. The water recovery techniques employ mainly membrane/thermal integrated hybrid processes, while the energy recovery techniques such as pressure retarded osmosis (PRO) and reverse electrodialysis (RED) utilize the salinity gradient energy (SGE) to generate energy. The valuable mineral products have also been reviewed in this paper in terms of recovery methods, performance of processes and product quality. The reviewed products are sodium salts (NaCl, NaOH, Na2SO4), lithium salts (LiCl, Li2CO3), magnesium salts (struvite, Mg(OH)2, MgSO4, MgO), calcium salts (CaSO4, CaCO3) and other minerals (U, Rb, Cs). Based on the cost and revenues of each technique, an economic comparison has been conducted along with the cost analysis of operating desalination plants.
... Lithium carbonate (Li 2 CO 3 ), as the fundamental material for lithium application industry, 1−3 is mainly obtained by the reactive crystallization of Na 2 CO 3 with LiCl/Li 2 SO 4 derived from the salt lake brines by a variety of methods, such as solvent extraction, 4−9 membrane separation, 10,11 calcination, 12,13 adsorption, 14,15 and chemical precipitation. 16,17 The reaction, however, generates a large amount of the alkali mother solution containing 1.4−2.0 g·L −1 Li + and 55−62 g·L −1 Na + during the Li 2 CO 3 production. ...
... CA and S denote IL and TRPO, respectively. Based on eqs 11 and 13, the extraction equilibrium constant of Li + , K e,Li , is obtained by eq 14. (17) where D Na is the distribution coefficient of Na + . Based on these results, in the following experiments, [A336]TTA was economically selected to extract Li + from the high-Na/Liratio alkali solution. ...
Four diketonate-based functional ionic liquids (ILs) with trialkylmethylammonium ([A336]+) cation were synthesized, and the synergistic extraction systems containing IL and thetrialkylphosphineoxide (TRPO) were developed to separate Li+ from the solution generated during the Li2CO3 production by the reaction of LiCl and Na2CO3. Compared to their precursors 1,3-diketones, over the wide pH range from 1.26 to 10.17, ILs showed higher Li+ extractability from the solution with high Na to Li mass ratio. Among the four ILs, the IL with 2-thenoyl-trifluoroacetonate (TTA-) anion showed the best Li+ separation ability. Under the optimized conditions, [A336]TTA was up to 83.26%, which was much higher than that of its precursor (71.50%). The results of slope analysis and characterizations indicated that the extracted Li+ species using the extraction systems with or without TRPO were Li2CO3·2[A336]TTA·TRPO and Li2CO3·4[A336]TTA, respectively. Finally, a three stages extraction process was validated, and the recovery efficiency of Li+ from the solution provided by Qinghai CITIC Guoan Science and Technology Development Co. Ltd (CITIC) was up to 97.16%, indicating that the extraction system of [A336]TTA + TRPO was efficient for separating lithium from the alkaline aqueous solution.
... It is the world's second largest nutritional supplement for crops after nitrogen (Adnan et al., 2017). Mg and its compounds are widely used in a number of high-value industrial applications such as in the production of certain alloys and catalysts, and in the chemical, electronic, pharmaceutical and agricultural industries (Tran et al., 2013;Tran et al., 2016;Kong et al., 2017). ...
... To summarize, our findings have provided further light on potential fungal roles in struvite solubilization, element release and biomineralization which may be important in fertilizer and other soil management applications, but are also of possible significance for other biotechnological purposes such as metal or element biorecovery through oxalate or phosphate bioprecipitation. Mg is a very important metal in technology and its numerous applications have led to increasing Mg metal production across the world (Tran et al., 2013;Tran et al., 2016). Mg-oxalate has also been used for the synthesis of nanoparticulate magnesium oxide. ...
Struvite (magnesium ammonium phosphate - MgNH4 PO4 ·6H2 O), which can extensively crystallize in wastewater treatments, is a potential source of N and P as fertilizer, as well as a means of P conservation. However, little is known of microbial interactions with struvite which would result in element release. In this work, the geoactive fungus Aspergillus niger was investigated for struvite transformation on solid and in liquid media. A. niger was capable of solubilizing natural (fragments and powder) and synthetic struvite when incorporated into solid medium, with accompanying acidification of the media, and extensive precipitation of magnesium oxalate dihydrate (glushinskite, Mg(C2 O4 ).2H2 O) occurring under growing colonies. In liquid media, A. niger was able to solubilize natural and synthetic struvite releasing mobile phosphate (PO43- ) and magnesium (Mg2+ ), the latter reacting with excreted oxalate resulting in precipitation of magnesium oxalate dihydrate which also accumulated within the mycelial pellets. Struvite was also found to influence the morphology of A. niger mycelial pellets. These findings contribute further understanding of struvite solubilization, element release and secondary oxalate formation, relevant to the biogeochemical cycling of phosphate minerals, and further directions utilizing these mechanisms in environmental biotechnologies such as element biorecovery and biofertilizer applications. This article is protected by copyright. All rights reserved.
... Recently, scientists have proposed to extract lithium from brines using sorption, extraction, and electrodialysis methods to eliminate the loss of water, a valuable resource for the population. Another disadvantage of natural evaporation is the production of magnesium salts (carnallite and bischofite) and lithium salts, which require further separation [128,129]. ...
Rapid global electrification, nuclear power expansion, and nuclear energy in general will undoubtedly increase the demand for lithium. This article provides a detailed analysis of existing technologies for extracting lithium from various natural resources: spodumene, lepidolite, and sea salt, among other minerals. The technologies are summarised by the feedstock processing method. The article evaluates the various methods' economic feasibility, complexity, and technological viability. It also discusses promising methods for extracting lithium from low-grade resources that may transition from off-balance to on-balance categories. This article also presents a “future outlook”, highlighting research gaps, possible technological improvements, and sustainability considerations.
... Several studies were focused on improving purification processes removing major impurities such as Na, K, Ca, and Mg. In the removal of divalent ions, Tran et al. [24] employed a chemical precipitation method to purify a LiCl brine sourced from the Uyuni salt flat, with Mg/Li and Ca/Li ratios of 21 and 0.7, respectively. In this method, Ca and Mg compounds were precipitated by adding oxalic acid under conditions of an oxalate/Ca molar ratio of 6.82 at a pH below 1 and an oxalate/Mg ratio of 1.62 within a pH range of 3 to 5.5. ...
Direct lithium extraction (DLE) is emerging as a promising alternative to brine extraction although it requires further processing to obtain high-quality products suitable for various applications. This study focused on developing a process to concentrate and purify complex LiCl solutions obtained through direct lithium extraction (DLE). Two different chemical compositions of complex LiCl solutions were used, dividing the study into three stages. In the first part, lithium was concentrated to 1% by mass by evaporation. In the second, electrodialysis was used to alkalinize the LiCl solution and remove magnesium and calcium impurities under different current densities. The best results obtained were magnesium and calcium removals of 99.8% and 98.0%, respectively, and lithium recoveries of 99% and 96%. In the third stage, the selectivity of two different commercial cationic membranes (Nafion 117 and Neosepta CMS) was evaluated to separate Li⁺, K⁺, and Na⁺ cations under different current densities and volumetric flow rates. The Neosepta CMS membrane demonstrated higher lithium recovery. This study evaluated the quality of the purified lithium-rich solution and its potential use both in the production of Li2CO3 as well as in the electrochemical production of LiOH.
... In commercialized processes, such as the chemical precipitation method currently used for lithium mining, reducing the concentration of the divalent cations is the costliest step as they can prevent high lithium recoveries from some brines. 18,41,42 Studies in membrane systems have also shown that calcium and magnesium are significant causes of flux declines due to inorganic scaling. 24,43 One previous study investigated the solar evaporation performance of a box-like structure in concentrated seawater solutions. ...
In this work, we analyzed the effects of mineral scaling on the performance of a 3D interfacial solar evaporator, with a focus on the cations relevant to lithium recovery from brackish water. The field has been rapidly moving toward resource recovery applications from brines with higher cation concentrations. However, the potential complications caused by common minerals in these brines other than NaCl have been largely overlooked. Therefore, in this study, we thoroughly examined the effects of two common cations (calcium and magnesium) on the long-term solar evaporation performance of a 3D graphene oxide stalk. The 3D stalk can achieve an evaporation flux as high as 17.8 kg m–2 h–1 under one-sun illumination, and accumulation of NaCl on the stalk surface has no impact. However, the presence of CaCl2 and MgCl2 significantly reduces the evaporative flux even in solutions lacking scale-forming anions. A close examination of scale formation during long-term evaporation experiments revealed that CaCl2 and MgCl2 tend to precipitate out within the stalk, thus blocking water transport through the stalk and significantly dropping the evaporation rates. These findings imply that research attention is needed to modify and optimize the internal water transport channels for 3D evaporators. Additionally, we emphasize the importance of testing realistic mixtures—including prominent divalent cations— and testing long-term operations in interfacial solar evaporation research and investigating approaches to mitigate the negative impacts of divalent cations.
... More information on initial lithium concentration and other operating parameters can be found in the Supplementary Sheet (Table S3). (Brown and Beckerman, 1990;Bukowsky et al., 1991;Galli et al., 2014;Hamzaoui et al., 2007;Han et al., 2020;Hawash et al., 2010;Heidari and Momeni, 2017;Taminura et al., 2014;Tran et al., 2013;Um and Hirato, 2014;Zhang et al., 2019 precipitants on geothermal brine extracted from the Hatchobaru power plant in Ohita, with a low initial lithium concentration of 10 mg/L. Li-ions were recovered as lithium aluminate in a coprecipitation process with aluminium hydroxide. ...
Lithium has been a critical metal for energy transition, mainly because of its application as an energy storage matrix, which has seen its demand increasing exponentially in the last decades. To supply the current demand chain and overcome the geographical and technological limitations of lithium extraction from Salt Lake brines, the present article investigates the possibility of lithium extraction from non-conventional resources, such as Oilfields and Geothermal brines. Thus, our investigation seeks to answer the following research questions: (1) Are there identified lithium-rich subsurface brine resources? (2) Could the conventional lithium extraction precipitation method be successfully applied to those resources? (3) What are the state-of-the-art of alternative technologies that can economically be applied for efficient lithium recovery from those subsurface brine re-sources? First, our investigation identifies and distributes geographically lithium-rich subsurface brine resources worldwide, with the American continent being abundant on Oilfield brine. Europe, on the other hand, was much more abundant in Geothermal water. The UK possesses lithium-rich oilfields at relatively low concentrations and highly enriched geothermal brine, with an abundance of other lithium-rich brine sites possible across Africa and Asia. Secondly, it was established through a critical evaluation that conventional precipitation methods are insufficient for lithium extraction when applied to subsurface brines. Thus, it leads us to survey the state-of-the-art of novel extraction technologies with data from 1960 to the present, with the highest information density covering the last 22 years. Out of the reviewed extraction technologies, ion-sieve adsorbent and nanofiltration were found to be the best ally for lithium extraction from subsurface brine in the present and near future with low energy consumption, excellent lithium recovery, high extraction rate, outstanding selectivity, and forming adaptability.
... The presence of impurities, notably MgHPO 4 ⋅3H 2 O in Co-loaded MSHP (Fig. S10b), necessitates further purification to isolate Co 2+ . For example, a series of acid digestions of Co-loaded MSHP, cobalt oxalate precipitation with oxalic acid [50] or ammonium oxalate [48,51,52], filtration, calcination [53], and subsequent dispersion of cobalt oxide in HCl produce a highpurity CoCl 2 solution, a vital source of 60 Co [54]. However, these known methodologies are open to refinement or modification to meet the needs of specific applications such as sterilization and medical therapy. ...
... The χFD result cannot identify the metal element, so the XRF test obtained the results of any elements contained in the sample. (Sulistiyono et al. 2018;Sumarno, Ratnawati & Nugroho 2012;Tran et al. 2013). Mud and brine water samples produced the same element, calcium. ...
Mud volcano material is generally rich in oxides, while oxides are the main compounds forming rare earth elements. Bledug Kuwu, Central Java, Indonesia, is one of the active mud volcanoes, so there may be rare earth elements. This research is the characterization of rare earth elements (REE) in the Bledug Kuwu mud using magnetic and geochemical methods. Magnetic characterization uses magnetic susceptibility measurements. The geochemical characterization of the mud samples consisted of the XRF (X-Ray Fluorescence), XRD (X-Ray Diffraction), ICP-EOS (inductively coupled plasma) test, and the SEM-EDS (Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy) test. The results of the geochemical analysis of the Bledug Kuwu mud sample were the content of quartz, kaolinite, and calcite with an average concentration of 42.26%, 23.67%, and 33.96%. The susceptibility of Kuwu's mud is 0 because the concentration of metal elements is low; according to the results of XRF, XRD, and SEM tests identified the main mud elements as C, O, Si, Ca, and Al. The rare earth elements in Kuwu's mud are Ce, Dy, Eu, Gd, Ho, La, Nd, Pr, Sm, Tb, Y, and Sc. The highest concentrations were Ce 52.22 ppm and La 47.95 ppm.
... The calcium oxalate precipitate is calcined to CaO and reused in the first precipitation stage. The next stage is purifying by precipitation in order to remove contaminants, such as Fe, Al, and base metals, before lithium is concentrated via evaporation and recovered as 99.5% Li 2 CO 3 at 80-90 • C by carbonation using Na 2 CO 3 [31][32][33]. ...
The objective of this study is to describe primary lithium production and to summarize the methods for combined mechanical and hydrometallurgical recycling of lithium-ion batteries (LIBs). This study also aims to draw attention to the problem of lithium losses, which occur in individual recycling steps. The first step of hydrometallurgical treatment is leaching, which is an effective method capable of transferring over 99% of the present metals to the leach solutions. Extraction of metals after leaching can be conducted using various methods, with precipitation being the most commonly used. The precipitation of other metals can result in the co-precipitation of lithium, causing total lithium losses up to 30%. To prevent such losses, solvent extraction methods are used to selectively remove elements, such as Co, Ni, Al, and Mn. Solvent extraction (SX) is highly effective, reducing the losses to 3% per extraction stage and reducing overall lithium losses to 15%. After the refining, lithium is precipitated as lithium carbonate. High lithium carbonate solubility (1.5 g/L) and high liquid to solid leaching ratios require costly and avoidable operations to be implemented in order to enhance lithium concentration. Therefore, it is suggested that more studies should focus on multistage leaching with lower L/S ratios.
... For typical salt lake brines, the Mg 2+/ Li + ratio is usually unfavorable (6, 20 and 133 for Salar de Atacama in Chile, Uyuni in Bolivia and Great Salt Lake in USA, respectively [22,46]). Separation of lithium from divalent cations can be achieved by simple precipitation using various precipitants such as Ca(OH) 2 , Na 2 C 2 O 4 , Na 2 CO 3 , oxalic acid and NaOH [68,69]. Xu et al. [70] and Sun et al. [71] reviewed magnesium and lithium separation methods including precipitation, adsorption, solvent extraction, nanofiltration and electrochemical methods. ...
Oil (and natural gas) field brines can be considered promising sources of lithium for the sustainable supply of a growing market. To date, many materials have been developed for direct lithium recovery from brines, but most often these materials have been tested under various conditions, what makes it impossible to compare them. The aim of this research is to provide knowledge that would enable the comparison and selection of effective sorbents for different types of brines. For this purpose, an eight-step experimental protocol was employed. The recovery tests started with a pure lithium solution (300 mg/kg), and then other salts were gradually added, resulting in a brine containing Li⁺ (220 mg/kg), Na⁺ (7.21 wt%), Ca²⁺ (3.0 wt%) and Mg²⁺ (1000 mg/kg). For selected cases, the effect of pH was also investigated. Fifty materials (including ion exchange resins, organophosphate extractants, mineral adsorbents) were examined, for which the distribution coefficient and lithium recovery were determined. Moreover, for the most promising materials, lithium over magnesium selectivity and lithium ion capacity were determined. Only γ-Al2O3, TiO2 and MnOx-based powders keep their effectiveness in ultra-high salinity ranges and in the presence of high concentrations of Ca²⁺ and Mg²⁺ in alkaline solution.
... The thermal decomposition analysis identified by the TG/DTA were consistent with earlier research that confirmed the decomposition of CaC 2 O 4 .H 2 O to CaO [52][53][54][55]. The detected peak at 750 • C was generated by the transformation of CaC 2 O 4 .H 2 O to CaCO 3 . ...
Reject desalination brine is a rich source of salts and valuable materials. But, its disposal into the external environment generates a major source of pollution. This paper investigated the production of reactive CaO from reverse osmosis (RO) reject brine and its use as adsorbent for phosphate removal from contaminated seawater and RO industrial waste. This study was realized via two steps. Firstly, the recovery of Ca-phase from reject brine via oxalic acid at optimized conditions resulting clcium oxalate monohydrate, and its calcination at 900°C for 2 h to produce the reactive CaO. Secondly, the produced reactive CaO was doped by Fe3O4 via co-precipitation method to produce reactive [email protected]3O4 composites. The reactive [email protected]3O4 was explored as a potential adsorbent with enhanced capacity for phosphate ions (PO4³⁻) removal. The estimated maximum reactive [email protected]3O4 uptake capacity for PO4³⁻ (106.3 mg/g) is comparatively higher than the identified values for the reactive CaO (72.8 mg/g) and Fe3O4 (41.6 mg/g). The kinetics of the PO4³⁻ uptake reaction via reactive [email protected]3O4 obey the Pseudo-Second order model (R² > 0.98) and the equilibrium time was determined after 450 minutes. The equilibrium study of the demonstrated reaction exhibited excellent agreement with the isotherm assumption of the Freundlich model implying multilayer and heterogeneous adsorption processes. The thermodynamic aspect of PO4³⁻ adsorption reaction is favorable and exothermic. The adsorbent selectivity, reusability experiments and realistic study were also discussed . Furthermore, the computational study using DMs was applied to better understand the interaction for {PO43−/CaO(111)&CaO@Fe3O4(111)} systems. The simulation results demonstrate favorable, more stable, spontaneous adsorption and exothermic for PO43−/CaO@Fe3O4(111) than PO43−/CaO(111)complex. Overall, CaO@Fe3O4(111) could serve as a effective and reusable adsorbent for phosphate ions recovery from aqueous solutions.
... Ammonium oxalate and sodium carbonate were found to be effective in precipitating 98% of Mg under optimal reaction conditions [41]. Oxalic acid was also found to be effective in precipitating more than 95% of Mg as Mg oxalate in brine with Mg/Li ratio as high as 21 [42]. Researchers have shown that integrated and multi-step methods are effective for precipitating and separating 99% of Mg from brines with a high Mg/Li ratio. ...
Brine, in the form of seawater, salt lakes and geothermal water, holds massive amounts of valuable minerals. Among the variety of metallic and non-metallic elements that are recovered from brine at varying scales, Lithium (Li) has received immense interest in recent years due to its exponentially rising demand. Concentrated brine, which is the by-product of desalination, holds an even higher concentration of valuable minerals in comparison to other brine sources – thereby making it a ‘resource’ for Li extraction. Tremendous progress has been made in recent years in the development of novel technologies to concentrate brine faster and efficiently to cope up with the rising production needs for Li. This review aims to highlight the recent developments in this field starting from the significance of extracting Li from brine followed by discussing recent advancements in the various non-evaporative technologies proposed in the literature. Finally, major challenges associated with these technologies in terms of sustainability, cost and technology are also presented. It can be concluded that rather than stand-alone technologies, research must be focused on hybrid technologies for efficient utilization of desalination brines to improve the overall efficiency of the process. Moreover, comprehensive techno- and socio-economic analyses are essential to make these novel technologies commercially viable.
... Reject brine has a high cation concentration especially calcium ion and magnesium ion (around 1700ppm) than normal seawater (around 1300ppm). [5]. Through the chemical reaction between reject brine and certain additives (e.g. ...
... Reject brine has a high cation concentration especially calcium ion and magnesium ion (around 1700ppm) than normal seawater (around 1300ppm). [5]. Through the chemical reaction between reject brine and certain additives (e.g. ...
... As Tran et al. have shown in previous studies with brines from the "Salar de Uyuni", the removal of calcium from a magnesium rich brine with oxalic acid was the most effective at a pH ≤ 1 with an Oxalic acid/ Ca molar ratio of 6.82:1 using 5 M NaOH (molar ratio NaOH/Oxalate of 1.41:1) to adjust the pH of the solution. It is reported in the same study that after four hours of reaction 80% of calcium could be precipitated as calcium oxalate (Tran et al., 2016;Tran et al., 2013;An et al., 2012). A significant difference in the reaction kinetics would be expected given the differences in concentrations of lithium and magnesium between the Uyuni brine and the Atacama refined brine used in this investigation. ...
Ongoing research to develop a new generation of materials to achieve a more reliable and higher energy density lithium-ion batteries has attracted working groups attention worldwide in academia and industry. Products like lithium carbonate or lithium hydroxide are fundamental as the main feedstock for future materials. Recently, metal-atom substituted cathode materials with various metals has proved to improve the life-time, stability and performance of cathodes and consequently of the batteries. In this regard, this publication describes an approach to remove calcium impurities from industrial Lithium-rich brines with oxalic acid. Moreover, the present magnesium is reduced by the precipitation of magnesium hydroxide in a controlled manner in order to obtain a Lithium-enriched brine with a well-defined magnesium concentration in the absence of calcium. Finally, a process is presented to produce high purity lithium carbonate with controlled concentrations of magnesium between 1% to 3% as magnesium hydroxide. The magnesium hydroxide containing lithium carbonate is produced in a co-precipitation step, where initially the magnesium hydroxide is precipitated and subsequently the lithium carbonate is precipitated in a one-pot process.
... For example, there are roughly 30 saline in the Qaidam Basin, which account for 81% of the total lake saline [7,8]; and the total lithium resources in the lakes are about 3.3 m [9]. Most salt lake brine in China, however, has a high mass ratio of Mg/Li of 40:1 in a majority of salt lake brine, and the highest mass ratio of Mg/Li is roughly 1,837:1 [10][11][12][13]. Moreover, the ionic radius of lithium is similar to that of magnesium. ...
... The high-purity lithium carbonate product can then be obtained by further treatment. The Uyuni Salar de brine (3600 m altitude) in Bolivia is considered as one of the richest lithium-bearing brines (10.2 Mt) [38], with a relatively high Mg 2? /Li ? mass ratio of 16-22 [28]. ...
Rapid developments in the electric industry have promoted an increasing demand for lithium resources. Lithium in salt lake brines has emerged as the main source for industrial lithium extraction, owing to its low cost and extensive reserves. The effective separation of Mg2+ and Li+ is critical to achieving high recovery efficiency and purity of the final lithium product. This paper summarizes Mg2+/Li+ separation materials and methods in the field of lithium recovery from salt lake brines. The review begins with an introduction to the global distribution and demand for lithium resources, followed by a description of the materials used in various separation techniques, including precipitation, adsorption, solvent extraction, nanofiltration membrane, electrodialysis, and electrochemical methods. A comparison, analysis, and outlook of such methods are comprehensively discussed in terms of principles, mechanisms, synthesis/operation, development, and industrial applications. We conclude with a presentation of challenges and insights into the future directions of lithium extraction from salt lake brines. A combination of the advantages of various materials is the most logical step toward developing novel methods for extracting lithium from brines with high separation selectivity, stability, low cost, and environmentally friendly characteristics.
... However, the high Mg 2+ concentration in salt lake brine will make it more difficult to extract lithium. To separate Mg 2+ and Li + , several methods have been developed, including precipitation [8][9][10], solvent extraction [11][12][13][14], adsorption [15][16][17][18] and membrane separation [5,7]. Traditional precipitation has been widely used for extracting lithium from salt lakes with low mass ratio of Mg 2+ /Li + . ...
To improve the efficiency during the process of Mg²⁺/Li⁺ separation, a novel nanofiltration (NF) membrane was optimized by doping graphene oxide (GO) additives into the ultrafiltration (UF) base membrane. The effects of GO doping content on the morphology, structure and surface properties of UF membrane and the final NF membrane were studied comprehensively. The hydrophilic GO acted as a “bridge” between UF membrane and polyamide layer due to the “anchor effect”, which significantly enhanced the interaction between base membrane and polyamide layer. The results revealed that with ultra-low GO doping content of 0.05 wt%, the final NF005 membrane exhibited a high selective separation capacity for Mg²⁺ and Li⁺ (SMg,Li≈0.062), and the flux increased by about 119% compared with the pure NF0 membrane. Additionally, due to the high stability of membrane, the excellent separation capacity of NF005 membrane only changed slightly after 7-day cycle filtration test. Importantly, a small amount of GO doping greatly improved the permeability of both UF and NF membranes, which correspondingly improved the separation efficiency and accelerated the filtration rate. This work provides a new direction for designing membrane with high efficiency for Mg²⁺/Li⁺ separation, which is potential in the field of lithium extraction.
... Their cleavage is a reflection of the minerals crystal structure that consists of aluminium silicate sheets that are weakly bound together by layers of positive ions (Yu et al., 2004;Ma et al., 2014). This positive ion in biotite is dominantly potassium and iron with only minor magnesium (Xiong et al., 2014;Tran et al., 2013). Because the chemical bonds between the aluminium silicate sheets are much weaker than those within the sheets, both of these mica minerals can be easily separated into thin sheets that are both flexible and elastic. ...
... Chemical oxalate precipitation is also widely used for the recovery of actinides (Abraham et al. 2014). High purity magnesium oxalate was obtained from Uyuni salar brine via chemical oxalate precipitation (Tran et al. 2013). Nickel is a primary co-existing element in Co minerals (Hazen et al. 2017), while industrially, cobalt, and nickel are also normal elements used in several kinds of batteries (Lupi et al. 2005;Rodrigues and Mansur 2010;Chen et al. 2011). ...
In this research, the capabilities of culture supernatants generated by the oxalate-producing fungus Aspergillus niger for the bioprecipitation and biorecovery of cobalt and nickel were investigated, as was the influence of extracellular polymeric substances (EPS) on these processes. The removal of cobalt from solution was >90% for all tested Co concentrations: maximal nickel recovery was >80%. Energy-dispersive X-ray analysis (EDXA) and X-ray diffraction (XRD) confirmed the formation of cobalt and nickel oxalate. In a mixture of cobalt and nickel, cobalt oxalate appeared to predominate precipitation and was dependent on the mixture ratios of the two metals. The presence of EPS together with oxalate in solution decreased the recovery of nickel but did not influence the recovery of cobalt. Concentrations of extracellular protein showed a significant decrease after precipitation while no significant difference was found for extracellular polysaccharide concentrations before and after oxalate precipitation. These results showed that extracellular protein rather than extracellular polysaccharide played a more important role in influencing the biorecovery of metal oxalates from solution. Excitation–emission matrix (EEM) fluorescence spectroscopy showed that aromatic protein-like and hydrophobic acid-like substances from the EPS complexed with cobalt but did not for nickel. The humic acid-like substances from the EPS showed a higher affinity for cobalt than for nickel.
... Therefore, salt lakes with a much larger lithium resources, low exploitation cost, and less environmental pollution have been increasing emphasized [14]. However, most salt lake brine in China has a high magnesium-to-lithium mass ratio [15][16][17][18]. Furthermore, the ionic radius of lithium is similar to that of magnesium, thereby limiting the development of technologies for lithium extraction from salt lake brine. ...
In the current study, the applicability of nanofiltration membrane for recovering lithium from salt lake brine with a high magnesium-to-lithium mass ratio was evaluated under different operating pressure, temperature, multi-ion presence, and concentration ratio conditions. The results showed that the yield of lithium and its separation from magnesium increase with pressure, with the rejection of magnesium reaching 92% at 3.5 MPa. The maximum membrane flux of 50 L/m² h is achieved at 313 K, while the separation efficiency decreases with increasing temperature. Furthermore, the existing sodium and potassium compete with lithium to pass through the nanofiltration membrane. The yield of lithium reaches 99% when the concentration ratio is 4. However, membrane flux and separation efficiency decrease with increasing concentration ratio. Ionic fractionation is found to be governed by the special properties of the ions, dielectric exclusion, and steric hindrance. Our results indicate that DK membrane shows considerable promise as a means to separate magnesium and lithium and to recover lithium from salt lake brine with high magnesium-to-lithium mass ratios.
Lithium will continue to be in high demand for electric vehicle battery applications over the next few decades. Countries try to remain competitive in this emerging industry by contributing to the lithium raw material supply chain. Lithium from oilfields and geothermal brines is an important source of extracted lithium, but it needs to be concentrated before it can be recovered. This paper reviews the concentration stages during lithium recovery from brines and proposes using polyelectrolyte complex nanoparticles to improve or replace traditional concentration techniques, such as nanofiltration and solvent extraction. Key factors for optimizing nanoparticle performance, including charge density, pH, polyelectrolyte mass ratio, ionic strength, shear rate, order of addition, and multi-layer deposition, are discussed. In the proposed workflow to replace solvent extraction, release mechanisms such as pH or ionic strength-induced release are also presented to strip complexed lithium into the solution. Several cationic and anionic polymers have been compiled and screened based on criteria such as charge density, solubility, toxicity, selectivity, and their ability to form complexes with lithium through electrostatic interactions. The screening process has led to the recommendation of a specific polycation and polyanion to achieve an optimum nanostructure architecture for lithium extraction from brines containing high Mg2+ impurity. Polyelectrolyte complex nanoparticles could enhance positively charged nanofiltration membranes or enable lithium extraction from brines without needing organic solvents, as used in solvent extraction.
In the quest for environmental sustainability, the rising demand for electric vehicles and renewable energy technologies has substantially increased the need for efficient lithium extraction methods. Traditional lithium production, relying on geographically concentrated hard-rock ores and salar brines, is associated with considerable energy consumption, greenhouse gas emissions, groundwater depletion and land disturbance, thereby posing notable environmental and supply chain challenges. On the other hand, low-quality brines-such as those found in sedimentary waters, geothermal fluids, oilfield-produced waters, seawater and some salar brines and salt lakes-hold large potential owing to their extensive reserves and widespread geographical distribution. However, extracting lithium from these sources presents technical challenges owing to low lithium concentrations and high magnesium-to-lithium ratios. This Review explores the latest advances and continuing challenges in lithium extraction from these demanding yet promising sources, covering a variety of methods, including precipitation, solvent extraction, sorption, membrane-based separation and electrochemical-based separation. Furthermore, we share perspectives on the future development of lithium extraction technologies, framed within the basic principles of separation processes. The aim is to encourage the development of innovative extraction methods capable of making use of the substantial potential of low-quality brines.
Energy storage plays a crucial role in the modern energy landscape, with its applications spanning from renewable energy integration to the electrification of transportation and microgrids. Lithium is a key component of lithium-ion batteries at the core of energy storage technologies. Increasing demand for lithium has challenged supply chains and required a rethinking of how we source it. This comprehensive review presents a critical and holistic assessment of the opportunities and challenges of sourcing lithium from diverse feedstocks, such as seawater, geothermal, produced water (oilfield), and salt lake brines. We assess various lithium extraction technologies (precipitation, extraction, electrochemical techniques, and membrane processes) considering these three feedstocks. A quantitative comparative analysis is conducted across all technologies, considering factors such as cost, commercial maturity, operation duration, and other relevant parameters to determine the most promising technologies for each feedstock while identifying remaining research and technological gaps. Our analysis reveals that Direct Lithium Extraction (DLE) technologies, characterized by higher selectivity and lower environmental impact, demonstrate significant promise for enhancing lithium yields from geothermal brines. In contrast, membrane processes are identified as more suited for seawater and salt lake brines, offering cost-effective scalability despite challenges with selectivity and membrane fouling. Ultimately, the efficient integration of these technologies is illustrated for harvesting lithium from each unconventional resource. The analysis shows that adsorption and chemical precipitation are the commercial technologies for lithium recovery from geothermal, salt lake, and oilfield brine.
The unbalanced supply and demand of lithium (Li) has elevated the urge for its extraction owing to the accelerated surge of battery and electric vehicle (EV) industries to meet the carbon emission reduction target. As the cost of extracting Li from brine is typically 30–50% lower than conventional hard-rock sources, this work intends to critically analyze the evolution of direct lithium extraction (DLE) methods employed in Salt Lake brine with various magnesium/lithium (Mg/Li) mass ratios whereas the lithium brine concentration (LBC) methods seek to concentrate the Li brine and eliminate contaminants without isolating the Li from the brine. Solvent extraction, precipitation, adsorption, membrane technology, and electrochemical extraction are the developed methods for Li extraction from Salt Lake brine. This review focuses on the mechanism, workflow, and comparative analysis of different methods. Moreover, recent technological advancements to handle the high Mg/Li ratio, such as modification of adsorption using ion sieves, liquid-membrane electrodialysis, and efficient multicomponent doping electrode materials, have also been discussed in depth. Although it was previously believed that solvent extraction was only feasible for low Mg/Li ratio brines, it has recently been commercially applied for high Mg/Li ratio brines in China. Precipitation is more ecology-friendly and economically favorable because of its low cost. Li extraction from brines with high Mg/Li ratios also shows promising performance using aluminate (Al) precipitants and novel Mg precipitants. However, during Mg precipitation, there is a significant loss of Li. On the other hand, in the cost-effective adsorption method, aluminium salt adsorbents are industrially used, yet low adsorption capacities limit their application. Recently, ion-exchange methods have gained popularity, as ‘Li sieves’ exhibit remarkable selectivity and adsorption towards Li-ions and are effective at high Mg/Li ratios. Powdered ionic sieves have low fluidity and solution permeability despite their strong affinity and adsorption capacity. Membrane technology is promising because of the benefits of improved energy consumption, simple controls, high separation rates, and the continuity of the process, yet as an emerging technology, its commercial viability is not proven. Nevertheless, a coupled “adsorption-membrane” technique has been developed and used in China for Salt Lake brines with low Li grades. Furthermore, exceptional selectivity, low energy demand, and minimal impact on the environment of electrochemical methods make Li extraction from brine promising. Being a recent technology, there is ample scope for improving electrode materials and understanding the process mechanism and cell configuration. Lastly, perspectives on the future Li extraction from brines are conferred in this article. By combining the methods (i.e., adsorption and ion exchange, membrane technology, and electrochemical process), the growth potential exists for an efficient, cost-effective, green, and sustainable extraction technology for Li from Salt Lake brine with a high Mg/Li ratio.
Under the Paris Agreement, established by the United Nations Framework Convention on Climate Change, many countries have agreed to transition their energy sources and technologies to reduce greenhouse gas emissions to levels concordant with the 1.5°C warming goal. Lithium (Li) is critical to this transition due to its use in nuclear fusion as well as in rechargeable lithium-ion batteries used for energy storage for electric vehicles and renewable energy harvesting systems. As a result, the global demand for Li is expected to reach 5.11 Mt by 2050. At this consumption rate, the Li reserves on land are expected to be depleted by 2080. In addition to spodumene and lepidolite ores, Li is present in seawater, and salt-lake brines as dissolved Li ⁺ ions. Li recovery from aqueous solutions such as these are a potential solution to limited terrestrial reserves. The present work reviews the advantages and challenges of a variety of technologies for Li recovery from aqueous solutions, including precipitants, solvent extractants, Li-ion sieves, Li-ion-imprinted membranes, battery-based electrochemical systems, and electro-membrane-based electrochemical systems. The techno-economic feasibility and key performance parameters of each technology, such as the Li ⁺ capacity, selectivity, separation efficiency, recovery, regeneration, cyclical stability, thermal stability, environmental durability, product quality, extraction time, and energy consumption are highlighted when available. Excluding precipitation and solvent extraction, these technologies demonstrate a high potential for sustainable Li ⁺ extraction from low Li ⁺ concentration aqueous solutions or seawater. However, further research and development will be required to scale these technologies from benchtop experiments to industrial applications. The development of optimized materials and synthesis methods that improve the Li ⁺ selectivity, separation efficiency, chemical stability, lifetime, and Li ⁺ recovery should be prioritized. Additionally, techno-economic and life cycle analyses are needed for a more critical evaluation of these extraction technologies for large-scale Li production. Such assessments will further elucidate the climate impact, energy demand, capital costs, operational costs, productivity, potential return on investment, and other key feasibility factors. It is anticipated that this review will provide a solid foundation for future research commercialization efforts to sustainably meet the growing demand for Li as the world transitions to clean energy.
In this study, a struvite-precipitation method that uses triammonium phosphate trihydrate was introduced to separate Mg²⁺ from Li⁺ in a salt-lake brine. The precipitation experiments in the simulated brines exhibited excellent Li/Mg separation efficiency. The Mg²⁺ recovery in the precipitates, Li⁺ recovery in the solution, and Mg/Li mass ratio in the solution reached 99.71%, 4.88%, and 0.1%, respectively, under optimum condition. The relevant separation and adsorption mechanisms were investigated using solution-chemistry calculations, first-principle density functional theory (DFT) calculations, X-ray diffraction (XRD) analysis, scanning electron microscope (SEM) analysis, Brunauer–Emmett–Teller (BET) analysis, and zeta-potential measurement. The solution-chemistry calculations, first-principle DFT calculations, and XRD analysis demonstrated selective Li/Mg precipitation separation. The XRD analysis illustrated that the precipitates were struvite and dittmarite. The SEM, BET, and zeta-potential measurement results demonstrated that Li⁺ in the solution could adsorb on the magnesium precipitates and suffered from a significant loss during the aging process. Therefore, performing a quick and direct filtration after the precipitation process is necessary to eliminate the Li⁺ loss in the precipitates. The triammonium phosphate trihydrate also exhibited excellent performance in the simulated salt-lake brines with a broad range of initial Li⁺ and Mg²⁺ concentration and actual salt-lake brines.
Developing an effective and sustainable method for the separation of oil and brine mixture is highly necessary for the restoration of environmental pollution caused by the loss of organic solvents during the lithium extraction process from brine. Herein, we report a facile and cost-efficient method to fabricate an underbrine superoleophobic mesh by one-step hydrothermal method. The synthesized CrOx(OH)3-2x/nickel mesh possesses flower-like nanostructure, exhibiting superior superhydrophilicity/underbrine superoleophobicity for different ratios of tributyl phosphate and sulfonated kerosene mixtures. Simultaneously, the CrOx(OH)3-2x /nickel mesh manifests high efficiency for oil and brine separation with an ultrahigh permeation flux (78136 L∙m⁻²∙h⁻¹) and excellent oil rejection efficiency (>99.17%). Furthermore, the as-prepared mesh exhibits high chemical stability, outstanding salt tolerance, and excellent mechanical properties. Importantly, the surface wettability can be changed from superhydrophilicity to superoleophobicity for several times only by ignition the CrOx(OH)3-2x/NM on an alcohol burner for 10 s or modification by OTS. Altogether, the CrOx(OH)3-2x/nickel mesh has tremendous potential in practical oil-brine applications.
With the rapid increase of various electronic products with lithium-ion batteries in our daily life, it is difficult to provide enough supplement to satisfy the growing demand of the market only through exploiting limited lithium resources on land. Consequently, lithium recovery from salt-lake brines, geothermal brines, wastewater from the treatment of wasted batteries, or even sea water has attracted great interest all around the world due to the abundant reserves and low price. Nowadays, various conventional technologies such as solar evaporation-precipitation way have been widely applied to extract lithium from the aqueous solution. Unfortunately, they are always time-consuming, uncontrollable with the secondary pollution generation. Recently, various electrochemical technologies have been received considerable attention for lithium recovery owing to their time-saving, little environmental impact as well as high efficiency. Herein, progresses for lithium recovery using the electrochemical technologies were outlined and discussed based on the previous studies reported in the literatures. The principles, advantages and challenges of electrochemical technologies were critically reviewed. Even though these methods are technically feasible, they are still limited by the poor technical maturity for the large-scale lithium recovery. Thence, more efforts should be made in the future development of electrochemical technologies for improving lithium selectivity as well as material stability, and simultaneously reducing some energy consumption and investing and operating costs. It could provide guidance on the development and design of more attractive electrochemical methods for lithium recovery from liquid resources, which will contribute to achieving the sustainable and renewable society.
Lithium is the principal component of high-energy-density batteries and is a critical material necessary for the economy and security of the United States. Brines from geothermal power production have been identified as a potential domestic source of lithium; however, lithium-rich geothermal brines are characterized by complex chemistry, high salinity, and high temperatures, which pose unique challenges for economic lithium extraction. The purpose of this paper is to examine and analyze direct lithium extraction technology in the context of developing sustainable lithium production from geothermal brines. In this paper, we are focused on the challenges of applying direct lithium extraction technology to geothermal brines; however, applications to other brines (such as coproduced brines from oil wells) are considered. The most technologically advanced approach for direct lithium extraction from geothermal brines is adsorption of lithium using inorganic sorbents. Other separation processes include extraction using solvents, sorption on organic resin and polymer materials, chemical precipitation, and membrane-dependent processes. The Salton Sea geothermal field in California has been identified as the most significant lithium brine resource in the US and past and present efforts to extract lithium and other minerals from Salton Sea brines were evaluated. Extraction of lithium with inorganic molecular sieve ion-exchange sorbents appears to offer the most immediate pathway for the development of economic lithium extraction and recovery from Salton Sea brines. Other promising technologies are still in early development, but may one day offer a second generation of methods for direct, selective lithium extraction. Initial studies have demonstrated that lithium extraction and recovery from geothermal brines are technically feasible, but challenges still remain in developing an economically and environmentally sustainable process at scale.
شورابه پتاس خور ـ بيابانک، منبع غني از منيزيم، کلسيم، پتاسيم و سديم بوده؛ که در اين پژوهش،
تالش شد با استفاده از اکساليک اسيد به عنوان رسوب دهنده به جداسازي و سپس ترسيب کلسيم و منيزيم آن در حضور
ساير کاتيون ها و آنيون ها پرداخته شود . پيش از فاز آزما ي شگاه ي ، شبيه سازي واکنش ها انجام و پيش بيني نتيجه ها به وسيله
نرم افزار استبکال ) modeling Stabcal )صورت پذيرفت . براساس داده پردازي هاي اين نرم افزار و همچنين نتيجه هاي
تجربي به دست آمده ، براي استخراج کلسيم از شورابه بهترين نرخ مولي اکساليک اسيد نسبت به کلسيم و من ي ز ي م به ترت ي ب
1:05 /1و 1:25/1 به دست آمد. آناليز نشان داد با استفاده از اين روش جداسازي کلسيم و منيزيم به ترتيب
87 %و 88 %از شورابه امکان پذير بوده و رسيدن به خلوص 95 %و 94 %به ترتيب براي نمک هاي اکساالت کلسيم و منيزيم
بهدست آمده قابل دستيابي مي باشد
High purity MgO is widely used in various fields as an important magnesium compound. The separation of Mg and Ca is of great importance for the preparation of high purity MgO from dolomite. In this study, the key effects of carbonization temperature and nano-calcium carbonate agglomeration on the separation mechanism of calcium and magnesium have been investigated. The results indicated that the reaction in the carbonization process was stepwise. Precise control of the carbonization temperature was essential for the formation of Mg(HCO3)2 due to its low reaction efficiency at lower temperatures or decomposition markedly at higher temperatures. Meanwhile, there was a common-ion effect in solutions containing Mg2+ and Ca2+. Nano-CaCO3 particles were formed during carbonization and agglomerated with the prolongation of static time. A product with a purity of 99.56% MgO and 0.16% CaO was obtained under the optimized conditions: ratio of liquid–solid 30 L/g, carbonization temperature 22–25 °C, carbonization time 1 h, and refining time 4 h. This work has important guiding significance for the preparation of high purity magnesium oxide from dolomite.
Lithium is one of the most important raw materials for the production of glass, ceramics, nuclear materials, pharmaceuticals, and batteries. Almost 80% of total land-based lithium reserves globally are salt-lake brines. Therefore, lithium should be extracted from salt-lake brines to meet the demand of various industries for lithium resources. Several approaches for lithium extraction have been developed in the past few decades, such as precipitation, ion exchange, adsorption, solvent extraction, and electrolysis. Among these methods, precipitation is the earliest studied and utilized in industrial plants. Furthermore, it has several advantages, such as low cost, green principle, and easy industrialization. This paper reviews the precipitation technology for lithium extraction and the relative mechanism proposed in literature to identify its important parameters. Precipitant dosage, pH value, temperature, and particle size of precipitate are important factors in the process. Economic viability and green principle of various methods are discussed, and potential technologies are suggested. Novel magnesium precipitants appear to be a prospective technology for lithium extraction from brines with high Mg/Li mass ratios. Magnesium precipitation technology also shows great potential in the comprehensive utilization of lithium and magnesium resources. Various precipitation approaches for lithium extraction from brines and perspectives for further investigation are proposed.
Indonesia’s location in the ring of fire gives Indonesia a lot of natural resources such as natural brine water from Ciseeng, West Java. Natural brine contains a lot of minerals such as Na, K, Ca, Mg. and could potentially be the source of those elements. One of the common process for recovering minerals in brine water is through solar evaporation process. This process is ineffective because the evaporation stops in the night time. The purposes of this study are to find another method for concentrating brine, characterize natural brine from Ciseeng, West Java, and investigate the effect of new evaporation method to the brine. In this work, the author conducted the evaporation using electric heater to keep the solution in the desired temperature coupled with blowers to blow air to the surface of the solution for 10 days. The volume of the system was maintained by making up the evaporated water with fresh brine. The results indicate that the evaporation can increase the Mg, Na, and K concentration up to 282%, 283%, and 207%, respectively, while the Ca concentration stays relatively constant compared to the fresh brine. The brine’s °Bé increase from 2.5 to 6. In the process, about 158% of Ca and 51% of Na were recovered as precipitate.
Precipitation of magnesium hydroxide (Mg(OH)2) from bischofite (MgCl2·6H2O) by lime milk, a traditional lime milk method, is featured with its low cost. However, the insoluble impurities such as CaO in the lime limits the purity of magnesium hydroxide. For this reason, a new method has been developed by using the saturated lime supernatant instead of by using lime milk. The insoluble impurities in lime are not able to dissolve in the saturated lime supernatant; thus the purity of magnesium hydroxide is improved. The improved lime method, with a high purity of 99% Mg(OH)2 and 0.094% CaO, has better performance when compares to the traditional lime milk method. Besides, the optimum processing parameters including pH, crystal seed amount, agitation speed, reaction temperature, MgCl2 concentration, reaction time, aging time and PAM addition are reported. High-purity light magnesia (MgO) is obtained from magnesium hydroxide by carbonation and calcination, and its quality fulfills the standard of HG1-324-77. The improved lime method should be a promising way to produce high-purity magnesium hydroxide and light magnesia from bischofite.
Magnesium oxide suitable for the use in basic refractories was prepared from dolomite (CaMg(CO3)2) by hydrochloric acid leaching, precipitation with CO2 and thermal hydrolysis. Leaching of the dolomite ore in aqueous hydrochloric acid solution was investigated with respect to the effects of time on dissolution of the dolomite sample. The dependence of the observed dissolution rate on pH was established. In the carbonation experiments changes in pH, Ca2+ and Mg2+ concentrations versus time in the effluent solution were determined. Effects of the temperature on the precipitation rate of Ca2+ ions as solid CaCO3were studied. Experiments were conducted to determine the kinetics of thermal decomposition of MgCl2.6H2O during pyrohydrolysis process. From high purity magnesium chloride brine magnesium oxide containing 98.86 % MgO was obtained with the thermal decomposition recovery of 98.10 %.
The recovery of magnesium from magnesite tailings in aqueous hydrochloric acid solutions by acid leaching was studied in a batch reactor using hydrochloric acid solutions. Subsequent, production of magnesium chloride hexahydrate (MgCl2.6H2O) from leaching solution was also investigated. The effects of temperature, acid concentration, solid-to-liquid ratio, particle size and stirring speed on the leaching process were investigated. The pseudo-second-order reaction model seemed to be appropriate for the magnesium leaching. The activation energy of the leaching process was estimated to be 62.4 kJ mol−1. Finally, MgCl2.6H2O in a purity of 91% was produced by evaporation of leaching solution obtained at a temperature of 40 °C, 1.0 M acid, solid-to-liquid ratio of 10 g/L, particle size of 100 µm, stirring speed of 1250 rpm and leaching time of 60 min.
During the brine evaporation it has been determined that 50% of the initial natural brine lithium remains in the residual brine [l]. This phenomenon has been attributed to the retention of lithium by the precipitated salts [1, 2]. The residual brine is highly concentrated with magnesium. Therefore the lithium recovery from this kind of brine becomes more difficult. Indeed the magnesium precipitation as an oxalate or a carbonate decreases the brine magnesium concentration and makes easier the lithium extraction. The calcinations of the oxalate and the carbonate, respectively at 500°C and 900°C produces the magnesia (MgO) which is used as a refractory product. The present study shows that the magnesium rate, in synthetic brines, has been influenced by the following factors: a) the reagents ratio as a function of magnesium concentration; b) the reaction duration; and c) the reaction temperature. By this work we have proved that the lithium retention depends on the formed allotropic variety (α or β) of the magnesium oxalate. When magnesium had been precipitated as a carbonate, all the lithium remained in the solution when the molar ratio CO3/MG was superior to 0.91.
A hydrometallurgical process was developed to recover lithium from a brine collected from Salar de Uyuni, Bolivia, which contains saturated levels of Na, Cl and sulphate, low Li (0.7–0.9 g/L Li) and high Mg (15–18 g/L Mg). Unlike other commercial salar brines currently being processed, the high levels of magnesium and sulphate in Uyuni brine would create difficulties during processing if conventional techniques were used. A two-stage precipitation was therefore first adopted in the process using lime to remove Mg and sulphate as Mg(OH)2 and gypsum (CaSO4.2H2O). Boron (at 0.8 g/L in the raw brine), a valuable metal yet deleterious impurity in lithium products, could also be mostly recovered from the brine by adsorption at a pH lower than pH11.3 in this first stage. The residual Mg and Ca (including that added from lime) which were subsequently precipitated as Ca–Mg oxalate could be roasted to make dolime (CaO ∙ MgO) for re-use in the first stage of precipitation. Evaporation of the treated brine up to 30 folds would produce 20 g/L Li liquors. The salt produced during evaporation was a mixture of NaCl and KCl, containing acceptable levels of sulphate, Mg, Ca, etc. The final precipitation of lithium at 80–90 °C produced a high purity (99.55%) and well crystalline lithium carbonate.
The process of isothermal sintering of magnesium oxide obtained from sea water (by precipitation with 80% and 120% of the stoichiometric quantity of the calcined dolomite and magnesium oxide p.a. (pro analysi purity grade) ) was examined with the addition of SiO2, Al2O3 and TiO2, at temperatures in the range 1300–1800 °C. The process was followed by determining the product density, as well as densification of the compacts. With compacts containing SiO2 or Al2O3 densification was examined in relation to the sintering temperature and quantity of the sintering aid; with compacts containing TiO2 densification was examined in relation to the sintering temperature and pressing pressure. Sample densification and pore removal during isothermal sintering have been shown to be a function of the exponent α in the expression (Δ V/V0) − m = τα. The specific surfaces, chemical compositions and particle size distribution were determined for the magnesium oxide samples examined.
The precipitation of magnesium hydroxide from aqueous solutions by reaction with calcium hydroxide has been studied in agarose gel by electron microscopy and diffraction. The first stage, which dominates at very low Mg2+ concentrations, is the formation of thin single crystals of magnesium hydroxide, some 500 nm or less in diameter. At higher concentrations, these are overgrown to produce larger particles, thicker towards the outside, and generally consisting of several crystallites, with a common c-axis, but imperfectly aligned in the ab plane. The implications for growth mechanisms, and for the production of magnesium hydroxide from seawater, are discussed.
A nanofiltration-based method is presented for selectively separating soluble Mg(II) species from seawater, with the aim of using the Mg-loaded brine for either enriching desalinated water with magnesium ions or for enhancing precipitation of struvite from wastewater steams. Two 2.4″ commercial NF membranes were tested under varying operational conditions. The membrane that was chosen for further investigation (DS-5 DL, Osmonics) showed lower Cl:Mg and Na:Mg concentration ratios in the brine, and improved performance (with respect to the investigated process) at high recovery values. Since the addition of antiscalants was perceived detrimental to the downstream uses of the brine, the aquatic chemistry program PHREEQC was used to simulate the critical (highest) recovery values at which no CaSO4 would precipitate, assuming two concentration polarization factors. To prevent CaCO3 precipitation at the critical recovery values a theoretical calculation was performed (PHREEQC) to determine the required strong acid dosages to the raw seawater. Using the DS-5 DL membrane at 64% recovery, the attained Mg(II) concentration in the brine was 3500mg/l. Therefore, for attaining 12.15mg Mg/l of desalinated water the brine should be dosed to the water at a 1:288 ratio, resulting in additional concentrations of 32.5mg SO4−2/l, 89.3mg Cl−/l, 39.4mg Na+/l, 3.3mg Ca+2/l, and 0.01mg B/l. The overall cost of the proposed process was estimated at 0.00098$/m3 product water, i.e. approximately five times lower than two assessed alternative processes and more than one order of magnitude cheaper than implementing direct dissolution of chemicals, using either MgCl2 or MgSO4.
Magnesium hydroxide is a valuable chemical produced almost in pure form from seawater and its bitterns through precipitation process. Product size distribution of magnesium hydroxide affects the ease of downstream processes of filtration and drying. Therefore, gaining insight into kinetic information in order to improve the size distribution of product particles is essential. In this work, a mechanistic model has been developed for precipitation of magnesium hydroxide from sea bittern. The parameters of model equations based on the population balance concept have been determined using the experimental data of precipitation from a pure synthetic solution containing 3% Mg2+ and a sea bittern from salt production unit of a local petrochemical complex. The model suggests a higher nucleation rate coefficient and a lower growth rate coefficient for precipitation from the sea bittern compared to that from pure synthetic solution. The nucleation increase and growth decrease which were attributed to the effects of impurities in the bittern, would decrease the settling velocity of the product particles and therefore make the filtration process in industrial use more difficult. However, a larger coefficient of agglomeration rate was predicted by the model for precipitation from the bittern favor to product settling.
The thermal decomposition of the magnesium oxalate dihydrate in a static air atmosphere was investigated by TG-DTG techniques. The intermediate and residue of each decomposition were identified from their TG curve. The kinetic triplet, the activation energy E, the pre-exponential factor A and the mechanism functions f(α) were obtained from analysis of the TG-DTG curves of thermal decomposition of the first stage and the second stage by the Popescu method and the Flynn-Wall-Ozawa method.
Endothermically decomposing mineral fillers, such as aluminium or magnesium hydroxide, magnesium carbonate, or mixed magnesium/calcium carbonates and hydroxides, such as naturally occurring mixtures of huntite and hydromagnesite are in heavy demand as sustainable, environmentally benign fire retardants. They are more difficult to deploy than the halogenated flame retardants they are replacing, as their modes of action are more complex, and are not equally effective in different polymers. In addition to their presence (at levels up to 70%), reducing the flammable content of the material, they have three quantifiable fire retardant effects: heat absorption through endothermic decomposition; increased heat capacity of the polymer residue; increased heat capacity of the gas phase through the presence of water or carbon dioxide. These three contributions have been quantified for eight of the most common fire retardant mineral fillers, and the effects on standard fire tests such as the LOI, UL 94 and cone calorimeter discussed. By quantifying these estimable contributions, more subtle effects, which they might otherwise mask, may be identified.
The bromide concentration of sea bittern is 2.0−2.5 g L-1 at 29 0Bé. Evaporation to 34.5−35.0 0Bé increases the bromide concentration to the highest achievable level without significant losses in solid precipitates. Br- and K+ concentrations at this point are ca. 4.0 and 25.0 g L-1, respectively. It is reported herein that bromide concentration in bittern can be enhanced to 8.4 g L-1 with 93% recovery. This is achieved by integrating the process of bromide enrichment with recovery of gypsum, carnallite, magnesium hydroxide, and magnesium chloride. The process revolves around desulfatation of bittern with calcium chloride to promote carnallite (KCl.MgCl2·6H2O) formation. Calcium chloride is generated from the reaction of MgCl2 in carnallite decomposed liquor (CDL) with lime. Recycling of the liquor in this manner enables us to recover the bromide that co-precipitates with carnallite and also the K+ lost in CDL during decomposition of carnallite, leading to high yields of both.
The chemical precipitation of magnesium from sulphate solution, resulting from heap leaching of nickeliferous laterites with sulphuric acid, was studied. Magnesium was removed as hydroxide using calcium hydroxide (Ca(OH)2) and the precipitate produced was a mixture of magnesium hydroxide (Mg(OH)2) and gypsum (CaSO4·2H2O). The variables studied were the temperature and the stoichiometric quantity of Ca(OH)2. The responses measured were magnesium removal and the specific surface of the precipitate. Design of the experiments and statistical analysis of the data were used in order to determine the main effects and interactions of the factors. Scanning electron microscopy (SEM) was also used to investigate the effect of precipitation conditions on the morphological characteristics of the Mg(OH)2–CaSO4·2H2O mixture. Kinetic analysis with the aid of Nielsen theory allowed the determination of the Mg(OH)2 formation mechanism. The use of a magnesium hydroxide–gypsum mixture as a filler material was also examined. The suitability of the precipitate was evaluated by measuring a set of properties that can characterize a material as a filler and by measuring mechanical properties of polymers filled with the precipitate at various addition levels. The magnesium hydroxide–gypsum precipitate proved to be promising for this application, as it was found to have similar properties with other commercial products.
Processes of concentration and separation of calcium and magnesium from artificial and natural sea water by carboxylic ion-exchange resins of acrylic and methacrylic types at different temperatures have been investigated. The values of equilibrium separation factor α for Ca2+Na+, Mg2+Na+ and Ca2+Mg2+ exchanges in ternary systems have been determined in the temperature range of 10°C to 80°C. A significant increase of a values at elevated temperatures has been observed in the first two cases while for Ca2+Mg2+ exchange less remarkable temperature dependence of α can be distinguished. This effect has been shown to allow a selective thermostripping of Ca2+ and Mg2+ from the resins equilibrated at 80°C with sea water in applying cool sea water at 10°C. The thermostripping leads to a selective desorption of both Ca2+ and Mg2+ while Na+ ions remain sorbed, resulting in the increase of Ca2+ and Mg2+ concentration in the eluate up to 50% (in comparison with the initial sea water) and a decrease of 10% for Na+ concentration. These results may be considered as unique in polythermal concentration in comparison with, e.g. conventional evaporation technique. The results of consecutive sorption-thermostripping cycles have shown the possibility to concentrate calcium and magnesium from natural sea water more than three times by applying reagentless (and wasteless as a result) ion-exchange technique. The results of frontal separation of Ca2+ and Mg2+ on acrylic resin in Na+-form from natural sea water and thermostripping solutions obtained are also presented. The novel approach for forecasting temperature dependences of the resin selectivity has been proposed. The approach is based on a thermodynamic interpretation of the results obtained that allows to predict the temperature dependences of both αa (for binary Mg2+Na+ exchange) and the apparent equilibrium constant of ternary Na+Ca2+Mg2+ exchange.
Homogeneous (unseeded) nucleation of Mg phosphate from modified Ca-free seawater solutions was investigated at 20°C and pH of 8. Precipitated solid phase was characterized using chemical analysis, X-ray diffraction, scanning electron microscopy, and IR-spectroscopy. Effect of aqueous phosphate and ammonia concentrations and the intensity of stirring on the induction period time (τ) of Mg phosphates nucleation were studied. A linear relationship between logarithm of bobbierite (Mg3(PO4)2 · 8H2O) saturation index and log τ was established with a slope close to 2. Aqueous NH4+ (up to 0.002 M) has no effect on the nucleation kinetics and does not incorporate in the precipitated solid phase. Stirring of solution has a dramatic effect on nucleation kinetics: the induction period decreases by a factor of 100–10 000 in unstirred solutions compared to stirred ones. The relative diffusion/chemical reaction control mechanism of Mg phosphates precipitation from supersaturated solutions is discussed. It is shown that spontaneous inorganic precipitation of Mg-(ammonium) phosphates (struvite and bobbierite) in modern marine environment is impossible because of very sluggish kinetics.
Among other applications, magnesium hydroxide is commonly used as a flame-retardant filler in composite materials, as well as a precursor for magnesium oxide refractory ceramic. The microstructure of the powder is of prime importance in both technical applications. The influence of synthesis parameters on the morphological characteristics of magnesium hydroxide nanoparticles precipitated in dilute aqueous medium was studied. Several parameters were envisaged such as chemical nature of the base precipitant, type of counter-ion, temperature and hydrothermal treatment. Special attention was given to the obtaining of platelet-shaped, nanometric and de-agglomerated powders. The powders were characterized in terms of particle size distribution, crystal habits, morphology and ability to be re-dispersed in water. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption and laser diffusion analyses were used for this purpose.
Homogeneous (unseeded) nucleation and precipitation kinetics of Ca and Mg phosphates from modified seawater solutions with variable pH, Mg2+, HCO3−, F−, and organic acid concentrations were investigated at 20°C. The induction period of nucleation and the composition of precipitated solid phases were determined as a function of saturation state (6–2000 with respect to octacalcium phosphate (OCP)), Mg2+/Ca2+ activity ratio (0–10) and solution pH (7.2–9.1). The addition of Mg2+, HCO3−, F−, polycarboxylic, aromatic, and amino acids along with variations in pH has a weak effect on the nucleation kinetics of Ca–Mg phosphates in seawater solutions with a 35% salinity. Mg-bearing solutions produce an amorphous precipitate with a Ca : Mg : P molar ratio varying from 6.5 : 1 : 5 to 2.6 : 1 : 2.5 depending on (aMg2+/aCa2+) ratio. The precipitation of this amorphous phase in Mg-bearing solutions corresponds to the formation of a metastable hydrous Ca–Mg phosphate ((Ca,Mg)4H(PO4)3·xH2O) as a precursor of apatite which normally precipitates in Mg-free solutions. Spontaneous inorganic precipitation of Ca phosphate in most natural aquatic systems is kinetically impossible.
Struvite precipitation in wastewater treatment works has caused substantial operational problems since the early 1960s. Struvite, magnesium ammonium phosphate hexahydrate (MgNH4PO4 6H2O), is a white inorganic crystalline mineral that precipitates in places with increased turbulence such as pumps, aerators and pipe bends. Batch experiments were conducted to examine the influence of a number of physical and chemical parameters on struvite crystallisation. This was undertaken by dosing a medium of de-ionised water with varying concentrations of Mg2+, NH4+ and PO4(3-) ions. Preliminary experiments found that struvite could be precipitated out of solution at pH 10 and increasing the ion concentration stoichiometrically could increase crystal yield. Increasing the NH4+ concentration increased purity of the precipitate. As reaction time was increased from 1 to 180 min, crystal size was found to increase from 0.1 to 3mm.
Removal of nitrogen and phosphate through crystallization of struvite (MgNH(4)PO(4).6H(2)O) has gained increasing interest. Since wastewaters tend to be low in magnesium relative to ammonia and phosphates, addition of this mineral is usually required to effect the struvite crystallization process. The present study evaluated the feasibility of using bittern, a byproduct of salt manufacture, as a low-cost source of magnesium ions. High reaction rates were observed; the extent of nitrogen and phosphorus removals did not change beyond 10 min. Phosphorus removals from pure solutions with bittern added were equivalent to those obtained with MgCl(2) or seawater. Nitrogen removals with bittern were somewhat lower than with the alternate Mg(2+) sources, however. Application of bittern to biologically treated wastewater from a swine farm achieved high phosphate removal, but ammonia removals were limited by imbalance in the nitrogen:phosphorus ratio.
Precipitation of Ca phosphates plays an important role in controlling P activity and availability in environmental systems. The purpose of this study was to determine inhibitory effects on Ca phosphate precipitation by Mg(2+), SO(4)(2-), CO(3)(2-), humic acid, oxalic acid, biogenic Si, and Si-rich soil clay commonly found in soils, sediments, and waste streams. Precipitation rates were determined by measuring decrease of P concentration in solutions during the first 60 min; and precipitated solid phases identified using X-ray diffraction and electron microscopy. Poorly-crystalline hydroxyapatite (HAP: Ca(5)(PO(4))(3)OH) formed in control solutions over the experiment period of 24 h, following a second-order dependence on P concentration. Humic acid and Mg(2+) significantly inhibited formation of HAP, allowing formation of a more soluble amorphous Ca phosphate phase (ACP), and thus reducing the precipitation rate constants by 94-96%. Inhibition caused by Mg(2+) results from its incorporation into Ca phosphate precipitates, preventing formation of a well-crystalline phase. Humic acid likely suppressed Ca phosphate precipitation by adsorbing onto the newly-formed nuclei. Presence of oxalic acid resulted in almost complete inhibition of HAP precipitation due to preemptive Ca-oxalate formation. Carbonate substituted for phosphate, decreasing the crystallinity of HAP and thus reducing precipitation rate constant by 44%. Sulfate and Si-rich solids had less impact on formation of HAP; while they reduced precipitation in the early stage, they did not differ from the control after 24 h. Results indicate that components (e.g., Mg(2+), humic acid) producing relatively soluble ACP are more likely to reduce P stability and precipitation rate of Ca phosphate in soils and sediments than are components (e.g., SO(4)(2-), Si) that have less effect on the crystallinity.
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