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Photo of ore sample made on SEM, maps and EDS analysis for section 1 (a, b) with 800 times and section 2 (c, d) with 600 times magnification.
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The present study is devoted to the extraction of rare-earth metals (REMs) from a high-silica ore found in one of the deposits in Kazakhstan. The total content of rare-earth elements (REE) in the ore was found to be 340 ppm. The ore and the silicon-containing cake were studied using a scanning electron microscope (SEM) and XRD analysis. The Gibbs e...
Citations
... As terbium is always accompanied by other REEs, it is challenging to separate terbium from others. The conventional method for recovering terbium generally includes beneficiation followed by hydrometallurgical processes such as roasting/cracking, leaching, precipitation, crystallization, solvent extraction (SX), and ion exchange (IX) (Karshigina et al. 2018). The ores containing these minerals are mostly processed by physical separation/beneficiation techniques to recover the rare earth containing minerals. ...
... For rare earth elements extraction and separation, diverse extractants, including D2EHPA [7][8][9][10], Cyanex 272 [11][12][13][14], Cyanex 921 [15][16], PC88A [17][18][19][20], TBP [21][22][23][24], EHEHPA [25][26][27][28], and various ionic liquids [29][30][31][32], have been utilized in operational conditions and different aqueous sulfate, chloride, and nitrate mediums. All trivalent lanthanide ions have extremely similar properties owing to the coverage of 4f electrons. ...
The twofold extraction behavior of light and heavy rare earth elements transforms into a more selective extraction of heavy rare earth elements when Di-(2-ethylhexyl) phosphoric acid (D2EHPA), one of the commonest cation exchange extractants, is employed. However, why this phenomenon has not been fully investigated from the quantum perspective yet. To confirm and interpret the laboratory-observed selectivity results in the extraction of Y(III) over than La(III), this study utilized the Density Functional theory (DFT) connected with Born Haber thermodynamic besides importing the solvent effect through the Conductor-Like Screening Model (COSMO). The hydration reaction energies of La(III) and Y(III) were estimated at -383.7 kcal/mol and -171.83 kcal/mol according to the cluster solvation model. It was observed that, among other influential factors, hydration energy is a critical one in the rate of the extraction free energy of every rare earth element and its tendency to be transferred to the organic phase in reacting to the extractant ligand. It was shown that the experimental ∆∆G ext results (2.1 kcal/mol) enjoyed a proper consonance with the ∆∆G ext results of DFT calculations (1.3 kcal/mol). In the pursuit of discovering the reasons for this phenomenon, the orbital structure of every aqueous and organic complex was studied, and the significant differences in energy magnitudes were discussed. The current comprehensive design of experimental studies and calculations can give birth to a deeper understanding of the interactions of the D2EHPA extractant with La(III) and Y(III).
... In 2019, global mining production of rare earth oxide (REO) equivalent was 210,000t (USGS, 2022). Phosphatic rocks contain 0.046 wt.% REEs, on average, correspond to approximately 125kt of REEs probable yearly production and a relatively high value owing to increased HREEs % (Karshigina et al. 2018;Wu et al. 2017). A potential resource of REEs that must be taken into account is the by-product of phosphatic fertilizer i.e. phosphogypsum. ...
In general, the phosphatic rock contains around 0.05 wt% rare earth elements (REEs). The global commercial phosphatic rock output is anticipated to obtain 250 million tons per year, making phosphate rocks a significant source of REEs. The review discusses the geological aspects of phosphate rocks, their availability, and methodologies to convert them to phosphoric acid and ultimately to phosphogypsum. Phosphogypsum (PG) is a high-volume by-product of phosphate-based chemical industries that produce phosphoric acid. Because of the low radioactivity of radionuclide contaminants, roughly 85% of PG is stored in open fields. These PG stacks require enormous land areas, cause substantial upkeep expenses, and may create major environmental damage. Apart from the detailed analysis of metal worth in phosphogypsum, the efforts put forth by researchers in recovering valuable rare earth elements from PG have been discussed. Additionally, the processes for metal separation and purification are also discussed in vogue.
... Bastnaesite and fluorite have similar properties. The effective separation of fine bastnaesite from fluorite has always been a difficult problem in the field of mineral processing [11][12][13][14]. Salicylhydroxamic acid (SHA) is highly selective to bastnaesite and is usually used as a collector in the bastnaesite flotation process. ...
During the flotation separation process of bastnaesite, it is difficult to separate bastnaesite from fluorite effectively. In this present study, sodium silicate (SS) can effectively improve the flotation separation effect of bastnaesite and fluorite in salicylhydroxamic acid (SHA) systemasa. Through relevant analyses, such as Zeta potential measurements, adsorption capacity tests, Fourier transform infrared (FTIR) spectroscopic analyses and X-ray photoelectron spectroscopy (XPS) tests, the selective suppressor of SS on fluorite was proven. At pH 10, the single mineral flotation results show that with the increase of SS dosage, the flotation recovery of fluorite rapidly decreases from 61.5% to 35.31%, while the flotation rate of bastnaesite is still high (recovery is 80.02%). Then, the experiment of artificial mixed ore proved that the flotation separation of fluorite and bastnaesite was effective under the appropriate dosage of inhibitor. The results of potentiodynamic measurement and an adsorption capacity test showed that the structure of SS more easily reacted with fluorite, which further prevented the adsorption of SHA on the fluorite surface. FTIR test results and XPS analysis further showed that SS had a strong binding effect with the Ca site on the fluorite surface, but a weak binding effect with the Ce site on the bastnaesite surface. Consequently, SS can be used as an effective inhibitor in the flotation separation of fluorite and bastnaesite.
... Up to now, various methods have been investigated for separating different types of REMs from solution, such as the step-by-step precipitation method, liquid-liquid extraction, membrane separation, solid-liquid extraction, and adsorption [6][7][8][9][10]. Among these, the adsorption method is considered a promising alternative to conventional processes for the effective recovery of REMs, especially from low concentration solutions, due to its simple operation, high recovery efficiency, low cost, and wide applicability [11,12]. ...
The demand for rare earth metal increases rapidly in the modern high-tech industry and therefore the accumulation of rare earth metal ions from an aqueous environment becomes a significant concern worldwide. In this paper, a water-recyclable chitosan-based La3+-imprinted thermoresponsive hydrogel (CLIT) was prepared to accumulate La3+ from solution. The CLIT was characterized by DSC, FITR, Raman spectroscopy, XPS, and SEM, which revealed obvious reversible thermosensitivity and imprinted sites of La3+ ions. An adsorption capacity of 112.21 mg/g to La3+ ions was achieved on CLIT under its optimum adsorption conditions (pH 5, 50 °C, 60 min). The adsorption could be well illustrated by second-order kinetics and Freundlich isotherm models. The La3+-adsorbed CLIT could be recycled only by rinsing with 10 °C cold water, with a desorption rate of 96.72%. After ten cycles of adsorption-desorption, CLIT retained good adsorption capability. In the solution containing six ions, the adsorption coefficients kLa3+/Mn+ of CLIT were 2.04–3.51 times that of non-imprinted hydrogel, with kLa3+/Y3+, kLa3+/Gd3+, kLa3+/Al3+, kLa3+/Fe3+ and kLa3+/Cu2+ being 1.67, 2.04, 3.15, 2.72 and 4.84, respectively.
... Karshigina et. al [82] also reported the recovery of rare earth metals from primary raw material by the process of sulphatization and leaching followed by precipitation. The ore consists of muscovite KAl2(AlSi3)O10(OH, F) 2 , quartz α-SiO 2, and kaolinite Al 2 (Si 2 O 5 ) (OH) 4 . ...
Rare earth elements (REEs) have become an integral part of modern-day technology. REEs such as light rare earth elements (LREEs) are from lanthanum to europium and heavy rare earth elements (HREEs) from gadolinium to lutetium. Rare earth metals are becoming a significant part of modern-day technology and material industry because of their applications in various fields such as hydrogen storage, alloys, batteries, bio-analysis, and nuclear technologies. Due to its multitudinous devotions in various fields, its demand is increasing day by day. This urge leads scientists to work tirelessly to discover novel methods and technologies that are beneficial in the modern era. China has considered a global leader in REE production, and its technological takeover is due to REE reserves. China has limited the supply of REE to other countries. Therefore, scientists are trying to discover low-cost and effective ways of its extraction from primary and secondary sources. Therefore, this is the need of the hour to unearth ores that contain REE and extract them by using a sustainable approach. Factors affecting leaching efficiency are the concentration of lixiviant, temperature, contact time, pulp density, and agitation have also been discussed in detail. This review highlights the leaching mechanism involved in REE extraction from primary sources. The lixiviant used has been discussed in detail. Prospects of the process have also been discussed. This tutorial-based review would be really helpful for the researchers.
... Karshigina et. al [82] also reported the recovery of rare earth metals from primary raw material by the process of sulphatization and leaching followed by precipitation. The ore consists of muscovite KAl2(AlSi3)O10(OH, F) 2 , quartz α-SiO 2, and kaolinite Al 2 (Si 2 O 5 ) (OH) 4 . ...
Rare earth elements (REEs) have become an integral part of modern-day technology. REEs such as light rare earth elements (LREEs) are from lanthanum to europium and heavy rare earth elements (HREEs) from gadolinium to lutetium. Rare earth metals are becoming a significant part of modern-day technology and material industry because of their applications in various fields such as hydrogen storage, alloys, batteries, bio-analysis, and nuclear technologies. Due to its multitudinous devotions in various fields, its demand is increasing day by day. This urge leads scientists to work tirelessly to discover novel methods and technologies that are beneficial in the modern era. China has considered a global leader in REE production, and its technological takeover is due to REE reserves. China has limited the supply of REE to other countries. Therefore, scientists are trying to discover low-cost and effective ways of its extraction from primary and secondary sources. Therefore, this is the need of the hour to unearth ores that contain REE and extract them by using a sustainable approach. Factors affecting leaching efficiency are the concentration of lixiviant, temperature, contact time, pulp density, and agitation have also been discussed in detail. This review highlights the leaching mechanism involved in REE extraction from primary sources. The lixiviant used has been discussed in detail. Prospects of the process have also been discussed. This tutorial-based review would be really helpful for the researchers.
... In the acid leaching process, monazite is reacted with mineral acids such as sulphuric acid, nitric acid, or hydrochloric acid at elevated temperatures for several hours to decompose ('crack') the phosphate structure. The acid leaching is followed by a series of hydrometallurgical processes for rare earth recovery (Berry et al., 2018;Karshigina et al., 2018). In contrast, the alkaline digestion method is a fusion process that uses caustic soda as the cracking agent for decomposing the monazite at high temperatures (Kumari et al., 2015;Sadri et al., 2017). ...
High-temperature carbothermal reduction experiments with graphite powder were conducted to assess the dephosphorization behaviour of Malaysian monazite concentrate. Thermodynamic analysis of the possible dephosphorization reactions was conducted to evaluate the feasibility of the carbothermal reduction of the monazite phases. The effects of temperature, particle size, and monazite to carbon ratio were then investigated under different conditions. The carbothermal reduction experiments were conducted based on the Taguchi design method, and up to 97% of phosphorous removal was achieved under optimized conditions. The optimal conditions for dephosphorization were determined as; a reduction temperature of 1350 °C, a particle size of -75 μm, and monazite to carbon molar ratio of 0.3. Microstructural and phase characterization of the dephosphorized products revealed that CeO2, Nd2O3, La2O3, and Pr2O3 oxide phases were prominent, and no residual peaks of monazite remained in the reduced products. The information gained from the study can aid in the design of a suitable post-dephosphorization hydrometallurgical treatment for exploiting Malaysian monazite as a local source of REEs.
... In Kazakhstan, where 360-390 thousand tons of refined copper have produced annually, the amount of copper ore flotation waste is growing by 1.8-2 million tons per year, which hurts the environment not only of the urban landscape but also of the entire region. [56][57][58] Thus, based on the current situation, when a huge amount of waste has accumulated in the Balkhash tailings storage facility over the decades of storage of enrichment tailings, which hurts the environment and human health. Tailings from enrichment at the moment still do not have technological methods and methods for their mass utilization. ...
This article presents the results of studies of an analytical review of the possibility of using tailings from the beneficiation of the Balkhash concentration plant as a component of the raw mixture for producing cement clinker. In particular, an analytical review of research was carried out, where the issues of the formation of man-made mineral objects of industrial waste in the Republic of Kazakhstan were considered. The information on the tailings as a large-tonnage man-made waste from the mining and processing and metallurgical industries is presented. The utilization of waste from the beneficiation of non-ferrous metal ores is considered, the characteristics of the beneficiation tailings of the Balkhash beneficiation plant are given, the processes of obtaining Portland cement clinker and its phase compositions are considered. © 2021, Rasayan Journal of Chemistry, c/o Dr. Pratima Sharma. All rights reserved.
... It promotes an enhanced selectivity and processing of pregnant leaching solutions. The principle of the dry digestion method by concentrated sulfuric acid is very similar to the acid-baking technique, which was applied to form water soluble sulfates from minerals and concentrates, including silicon enriched ones [Alkan et al., 2019;Gontijo et al., 2020;Karshigina et al., 2018;Sadri et al., 2017]. In the dry digestion, silicon dissolution was limited to less than 5 wt% SiO 2 from bauxite residue [Rivera et al., 2018]. ...
Storage of red mud – bauxite processing waste – leads to serious environmental problems due to its high alkalinity and particle dispersity. Full or partial utilization or recycling of red mud could reduce the harmful effect on the environment. Scandium is the most valuable ingredient of red mud, yet it's extraction is poorly commercialized due to its high cost. The new efficient extraction technologies promise an ensured supply of scandium and a significant drop in cost. Here, scandium concentrate, extracted from leachate after carbonate treatment of red mud, was subjected to sulfatisation by H2SO4 to separate silica from water-soluble sulfates. To recover and selectively separate scandium from other impurity metals, the crystallization of two complex scandium and ammonium sulfates – NH4Sc(SO4)2 and (NH4)3Sc(SO4)3 – is proposed. The solubilities of these sulfatoscandiates in water, established by isothermal method, are 33.4 and 72.4 g/L, respectively. For the less soluble NH4Sc(SO4)2 a further considerable reduction of solubility has been observed in H2SO4 solutions of concentration above 3.5 М in the presence of 0.5 М NH4Cl at 20 ± 1 °C. More than 99% of scandium in the form of micron-sized NH4Sc(SO4)2 crystals has been recovered from a multicomponent liquid at 5–6 М H2SO4 and 0.5 М NH4Cl. The product contains extremely low levels of impurities. The precipitation of NH4Sc(SO4)2 offers a much higher selectivity in separation of Sc from the other main constituents, as demonstrated by the large separation coefficients between scandium and other metals βSc/M (e.g., for the couple with aluminum βSc/Al = 4280). The recrystallization product after calcination at 1000°С contains 99% Sc2O3.
