An overview of the composition of wolframite ores of the Akchatau deposit and the technologies for processing concentrates using NaOH and Na₂CO₃ by hydro- and pyrometallurgical methods is given, and the disadvantages associated with both the technology and the equipment are noted. To develop a technology for processing Akchatau wolframite concentrates, samples of ore materials were taken, the chemical and mineralogical composition of the samples was studied, and enrichment was carried out to obtain rich concentrates. The kinetics of the sintering of the wolframite concentrate with soda was investigated, the dependences of the degree of transformation of the tungsten minerals into sodium tungstate were obtained, and the rate constants, the order of the reaction, and the values of the apparent activation energy were calculated. The results of sintering an enlarged sample of wolframite concentrate with soda in a muffle furnace are presented. After the subsequent leaching, studies were carried out to purify the obtained solutions of sodium tungstate from the impurities while eliminating the operations of the neutralizing solutions through the use of electrodialysis with an MK-40 cation-exchange membrane. The scheme of processing the wolframite ores of Akchatau is proposed.

This study presents the results of an investigation into the effectiveness of microwave (MW) treatment (1) as a preconditioning method for technogenic raw materials (2) to enhance zinc (3) leaching (4) efficiency. Selective dielectric heating facilitates phase transformations (5), converting sphalerite (ZnS) into zinc oxide (ZnO), which exhibits significantly improved acid leachability. The response surface methodology (RSM) was utilized to evaluate critical operational variables, encompassing sulfuric acid concentration, leaching period, slurry density, and thermal conditions. The obtained results confirm the potential of MW treatment in hydrometallurgical processes, offering a sustainable and energy-efficient alternative for processing technogenic raw materials.

Industrial technologies for processing tungsten concentrates using soda roasting or autoclave leaching are based on the production of alkaline sodium tungstate solutions that contain impurities such as silicon, phosphorus, arsenic, and others. The purification of these solutions from impurities requires the neutralization of excess soda or alkali with inorganic acids, which leads to the formation of chloride and sulfate effluents that are subsequently discharged into waste repositories. An analysis was carried out on existing methods for the production and processing of sodium tungstate solutions using HNO₃ and NH₃, as well as extraction and sorption techniques involving anion exchange resins. Currently, processes such as nanofiltration, reverse osmosis, and electrodialysis are being applied for water purification and the treatment of sulfate and chloride effluents. These processes employ various types of industrially manufactured membranes. For the purpose of electrodialysis, a two-compartment electrodialyzer setup was employed using cation-exchange membranes of the MK-40 (Russia) and EDC1R (China) types. The composition and structure of sodium tungstate, used as the starting reagents, were analyzed. Based on experiments conducted on a laboratory-scale unit with continuous circulation of the catholyte and anolyte, dependencies of various parameters on current density and process duration were established. Stepwise changes in the anolyte pH were recorded, indirectly confirming changes in the composition of the Na₂WO₄ solution, including the formation of polytungstates of variable composition and the production of H₂WO₄ via electrodialysis at pH < 2. The resulting tungstic acid solutions were also analyzed. The conducted studies on the processing of sodium tungstate solutions using electrodialysis made it possible to obtain alkaline solutions and tungstic acid at a current density of 500–1500 A/m², without the use of acid for neutralization. Yellow tungstic acid was obtained from the tungstic acid solution by evaporation.

Focuses on the processing of tungsten raw materials through various operations, including sintering, leaching, purification, and the production of technical tungstic acid. Modern research aims to enhance these processes, particularly the sintering of wolframite concentrates with alkali metal compounds and the leaching of concentrates and cakes. Experiments revealed that reactions between tungsten minerals and sodium carbonate from Akchatau ores commence at temperatures above 520–550 °C, intensifying between 750 and 850 °C. The concentrates were sintered at 750, 800, and 850 °C with a sodium carbonate excess coefficient of 1.05 to 1.2 to evaluate the effect on sodium tungstate extraction. Water leaching was conducted under a probabilistic–deterministic experimental design, analyzing five factors at four levels. Tungsten extraction was assessed based on solution density and the composition of the insoluble residue. Data processing established polynomial trends for tungsten trioxide extraction, and a material balance for sinter leaching was calculated from experiments using 100 g samples with a liquid-to-solid ratio of 2:1. The findings can be applied to improve tungsten processing technologies.

The article focuses on the study of the processes intended for copper smelting slag processing, in order to extract such valuable components as copper, zinc, iron and silica. Various options for slag leaching with the use of sulfuric acid as one of the most promising approaches are considered. Preliminary thermodynamic calculations confirmed the high probability of dissolution of metal oxides when interacting with sulfuric acid. High-temperature leaching resulted in higher recovery rates for copper and other valuable metals. The use of sulfuric acid at the concentration of 50 g/dm3 in combination with the optimization of leaching parameters provided the high efficiency of valuable metal extraction—copper up to 76%, zinc up to 94% and iron in the form of oxide up to 92%. Acceleration of pulp filtering was achieved through two-stage re-pulping with hot water. The study results confirm the prospects of hydrometallurgical methods of slag processing. It opens up opportunities for the development of more efficient technologies for processing copper smelting waste, aimed at maximum extraction of useful components at minimal costs. The study was supported the Committee of Science of the Ministry of Science and Higher Education of the Republic of Kazakhstan, Grant No. BR21881939.

The increasing demand for non-ferrous, precious, and rare metals necessitates more comprehensive and efficient use of mineral raw materials, such as gold-antimony ores and concentrates. A promising approach is the use of pyrometallurgical processing in a fluidized bed, which offers more efficient heat and mass transfer than conventional technologies. This study aims to investigate the evaporation kinetics of antimony sulfide (Sb2S3) from gold-antimony ores and concentrates in a fluidized bed under various conditions. The experiments involved varying temperature (923-1223 K), particle size (0.09-2.0 mm), and layer thickness (5-15 mm) to determine the evaporation rate of Sb2S3. The experimental setup consisted of a laboratory-scale fluidized bed reactor equipped with a controlled gas flow of nitrogen mixed with sulfur vapor. The evaporation rates were measured using a gravimetric method and confirmed by X-ray diffraction and microscopic analysis of samples. The results show that the evaporation rate of Sb2S3 in a fluidized bed is 7-9 times higher than in a fixed bed. This is due to significantly improved heat and mass transfer in the fluidized system. At 1023 K, the overall evaporation rate increased with decreasing grain size. This is associated with an increase in the total surface area of the material, but the specific evaporation rate normalized to unit surface area was independent of particle size. The process was not significantly affected by bed height in the range of 5-15 mm. Antimony recovery into sublimates improved by 2-3% compared to conventional technology. It reached 98-99% due to suppression of Sb2O5 formation. These findings confirm the efficiency of supplying an inert gas with sulfur vapors into the fluidized bed. This reduces harmful gas emissions and minimizes dust entrainment. It also allows for effective distillation of volatile components at lower temperatures.