Дана характеристика отвальным медным шлакам, рассчитан их рациональный состав. Для эффективной переработки подобных шлаков предложено применение процесса выщелачивания растворами серной кислоты, не требующего затрат тепловой энергии извне, вследствие экзотермичности протекающих реакций. Выполнен расчет термодинамических характеристик реакций, возможных при выщелачивании отвальных медных шлаков растворами серной кислоты. Проведен анализ фазового равновесия процесса выщелачивания шлака при различных расходах серной кислоты, оценено влияние температуры на изменение состава фаз, построены диаграммы фазового равновесия. Выполнены исследования по сернокислотному выщелачиванию отвальных медных шлаков при комнатной температуре и при 80 °С. Выявлены проблемы сгущения и фильтрования пульпы после выщелачивания, связанные с образованием кремниевой кислоты.

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.

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 rapid advancement of high-technology industries critically depends on the supply of rare earth elements (REEs), which constitute strategic raw materials for knowledgeintensive sectors. This study proposes an integrated methodological framework for the development of the Kundybay REE deposit, combining geomechanical substantiation of open-pit slope stability with beneficiation optimization of weathering-crust ores. The novelty of the research lies in the justification of rational pit-wall parameters based on a coupled 3D geological–geotechnical model implemented in the Micromine environment. Structurally disturbed zones were identified and subjected to detailed stability analysis using numerical modeling techniques. Particular emphasis was placed on the delineation of geotechnical domains and factor-of-safety evaluation in Slide2, which enabled refinement of design solutions and optimization of slope geometry. Simultaneously, the study addresses processing challenges of refractory weathering-crust ores through the application of ultrasonic aerohydraulic desliming combined with a vibro-centrifugal separation device. Optimization of slope parameters resulted in a 30 Mt reduction in stripping volume, corresponding to a 16.7% economic gain. The proposed flowsheet achieved a concentrate grade of 948.89 g/t REEs with an overall recovery of 45.66%. The results confirm that integrating geomechanical design with process engineering provides a technically robust and economically efficient basis for REE deposit development.

The article presents experimental data on the electrochemical oxidation of vanadium-bearing ore with the aim of increasing the efficiency of vanadium extraction during subsequent hydrometallurgical processing. Three different charge compositions were studied during the preliminary oxidative roasting stage, differing in the type of oxidizers used: calcined soda, sodium chloride, and their mixture in a mass ratio of 9:1. Electrochemical oxidation was carried out in a sulfuric acid medium using a membrane electrolysis cell equipped with an MK-40 type diaphragm. Experimental studies were conducted by varying key technological parameters: H2SO4 concentration (5–15%), solid-to-liquid phase ratio (1:2–1:5), temperature (25–85 ◦C), process duration (0.5–3 h), and current density (100–1000 A/m2 ). It was found that preliminary roasting promotes the conversion of vanadium into higher oxidation states, predominantly V5+, which significantly increases its solubility during subsequent electrochemical treatment. For the first time, the kinetic patterns of electrochemical vanadium leaching were identified, as well as the limiting mechanism of the process, associated with the formation of poorly soluble oxide films on the ore surface. Optimization of the electrochemical oxidation parameters allowed us to achieve vanadium extraction into solution up to 92%.

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 cationexchange 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.

Rapid development of high-tech industries is due to the rare and rare-earth metals used in instrumentation and radio electronics. Their materials are used primarily in the military-industrial and aerospace industries and are of strategic importance for the state. Purpose. To develop a technology of enrichment of difficult-to-enrich rare-earth ore of weathering crust on the basis of combined gravity and flotation enrichment scheme. Methodology. Studies on processing of this mineral raw material were carried out on the basis of gravity-flotation enrichment with obtaining rare-earth concentrate. The enrichment studies were carried out on a selected sample of ore from the deposit. On the basis of sieve and sedimentation analyses, the distribution of the sum of rare-earth elements (∑REE) in ore size classes and enrichment products was studied. Gravity enrichability of ore was determined by fractional analysis. Findings. The method of gravity enrichment using the developed gravity apparatus and flotation enrichment of sand and clay fraction of the studied ore has been developed. Gravity enrichment produced a concentrate containing 1053.76 g/t of rare-earth elements (∑REE), flotation enrichment of the clay fraction of the ore produced a concentrate containing 590.0 g/t of rare-earth elements (∑REE). Originality. The developed ultrasonic aerohydrodeslimator was used for ore desliming. The gravitational technology of processing of hard-to-enrich rare-earth ore of weathering crust with the use of vibrocentrifugal frequency apparatus, which allows to intensify the extraction of fine ore particles, is developed. Rare earth ore of size class -0.045 + 0 mm (clay fraction) and class -2.5+0.045 mm (sand fraction) was subjected to flotation beneficiation.

A hierarchical surface that includes objects with different sizes, as a result of creating local fields, initiates a large number of effects. Micropores in the composition of macropores, as well as nanoclusters of the substance, were detected by scanning electron and atomic force microscopies on the surface of ZnO/Por-Si samples. An identical fractal dimension for all levels of the hierarchy was determined for these structures, which is associated with the same response to external excitation. Photoluminescence studies have shown the presence of localized levels in the band gap, with the probability of capturing both electrons and holes, which ensures charge transitions between energy bands. Decomposition of the electron paramagnetic resonance (EPR) signal into components made it possible to determine the manifestations of various types of interaction between paramagnetic particles, including the hyperfine structure of the spectrum. The ordering of the structure of the substance as a result of sequential annealing in the range from 300 to 500 °C was revealed in the EPR spectrum. This fact, as well as photo- and gas sensitivity for all types of samples studied, confirms the prospects of using these structures as sensors.

The asbestos wastes were exploited for extraction of magnesium by agitation leaching process in atmospheric conditions, using hydrochloric acid as the leaching agent. The study was focused on investigating the kinetics of magnesium leaching. The effects of some variables, including stirring speed (150−300 r/min), leaching temperature (25−90 °C), leaching duration (10–60 min), the concentration of hydrochloric acid (150–300 g/L) and the solid - liquid ratio (1:2–1:5), on the leaching rate were carefully evaluated. It was found that increasing the stirring speed, leaching temperature, and concentration of hydrochloric acid can significantly increase the rate at which magnesium is leached. A comprehensive kinetic scrutinization was performed by fitting the experimental data with exponential kinetic equation, Yander diffusion equation, Drozdov-Rotinyan equation, and Prout-Tompkins equation. Amongst all these tested kinetic equations, the diffusion-controlled process showed a higher goodness-of-fit with experimental data. Thermodynamic aspects were also appraised carefully. The apparent activation energy for the process was calculated to be 19.8 kJ/mol, indicating a relatively low-level energy needed to initiate the process efficiently. Overall, the current study provided insight into how changing certain parameters can affect the overall performance when attempting to extract magnesium from the asbestos wastes by leaching process.