In this study, we investigate the reduction smelting of antimony concentrate, where sodium antimonate is the primary antimony-bearing component, in alkaline melts. This study aims to reduce the carbon footprint of metallic antimony production. It is shown that traditional carbon reduction is accompanied by significant formation of carbon-containing gases and sodium losses due to volatilization. Based on thermodynamic analysis and experimental investigations, carbon monoxide is established as the key active gaseous reducing agent for antimonate compounds, predominantly operating in the temperature range of approximately 320–900 °C, which corresponds to the stages of coke oxidation and sodium antimonate decomposition. The authors propose introducing sodium hydroxide into the charge to form an alkaline melt with a lowered melting point when mixed with the antimony concentrate, ensuring the sequestration of carbon dioxide through the formation of sodium carbonate. Experiments confirmed the possibility of chemically fixing up to 75.5% of CO₂ into the slag phase at the laboratory stage and up to 87% of CO₂ during pilot tests of reduction smelting under a flux layer. Crude metal with an antimony content of 94–96.2% Sb was obtained, while coke consumption was reduced by 16–20%. The proposed approach ensures a simultaneous increase in the degree of antimony recovery, the utilization of carbon-containing gases, and the formation of a stable eutectic slag melt. This allows the process to be considered an element of carbon-neutral pyrometallurgical technology for processing antimony concentrates.

Lead cake forms from dust as a result of the gas cleaning process during copper smelting. The objective of this study was to develop equipment and technology for a continuous hydrometallurgical method for extracting osmium from the lead cake. In this method, leaching is carried out using an aqueous solution of hydrogen peroxide and sulfuric acid. During the leaching, rhenium is converted into an acidic solution from which rhenium can be easily extracted into a marketable product. Osmium is predominantly converted into a solution, the processing of which, including the extraction of osmium into a marketable product, will be published later. A unit for leaching osmium–rhenium-containing cake with continuous loading for leaching, continuous feeding of leaching solutions, and continuous discharge of the leaching slurry was created. Using the simplex experimental design method, the dependence of osmium recovery on the consumption rates of hydrogen peroxide and sulfuric acid and the leaching duration was studied. Near-optimal leaching conditions were as follows: 68–70 mL of 30% hydrogen peroxide and 7 mL of concentrated sulfuric acid per 100 g of cake, 55 min of leaching, and a specific column throughput of 100 g of cake per 55 min. Nine experiments achieved 96.5% osmium recovery.

The paper presents the results of studies of fine-grained tungstic acid synthesis and research of tungsten trioxide obtained from it. A literature analysis was performed and the direction of the study was formulated. A method of precipitation of tungstic acid from sodium tungstate solutions by hydrochloric acid solution has been proposed. To produce tungstic acid, a continuous operation unit that provided the required draining rates of sodium tungstate and hydrochloric acid solutions, the temperature of draining solutions and their concentrations, was created. The dependence of the specific surface of the obtained tungstic acid on the concentration of the used hydrochloric acid was investigated, and the optimum concentration of hydrochloric acid at 430 grams per liter was determined. Using the mathematical method of simplex-planning experiments, the effect of three parameters on the specific surface area of tungstic acid — the concentration of sodium tungstate solution, the ratio of volume rates of drained solutions, and the temperature of drained solutions, was investigated. The following, close to optimum parameters have been received: concentration of sodium tungstate solution of 35–40 grams per liter, ratio of concentrated (430 g/l) hydrochloric acid to the volume of sodium tungstate solution is (1.9–2.0):1, temperature of solutions is 15–20 °С. Tungstic acid with a specific surface area of 60 m2/gram was obtained. It is determined that for the preparation of tungsten trioxide with a high specific surface area, the heating rate of tungsten acid in its drying must be 40–50 degrees per hour and the final drying temperature must be equal to 400 °C. Figures illustrating the dependence of the specific surface of the obtained tungstic acid on the concentration of sodium tungstate solution, the ratio of the volume velocities of the drained solutions and the temperature of the drained solutions are presented.

The article presents the results of a comprehensive investigation into the extraction of high-purity zinc from condensates formed during the electric smelting of low-grade, hard-to-enrich polymetallic raw materials from the Shalkiya deposit, accompanied by the production of ferrosilicon. The relevance of the research lies in the growing need to develop technologies for processing industrial waste containing valuable metals, particularly in light of the depletion of easily accessible rich ore reserves. The aim of the work was to develop a pyrometallurgical method for extracting zinc and lead using controlled atmospheric and vacuum processes. It was established that at temperatures up to 1100°C in an inert atmosphere, zinc distillation is negligible due to the low vapor pressure of its oxides. However, secondary distillation in a reducing atmosphere at the same temperature resulted in more than 95% recovery of zinc, though still contaminated with lead. A final purification step conducted under vacuum conditions (10 Pa, 800°C, 1 hour) yielded high-purity zinc with a residual impurity level below 0.01%. The results obtained dismantle the technological possibility of efficient extraction and purification of zinc from storage facilities formed during the processing of poor raw materials, which opens up prospects for the industrial implementation of this technique for the integrated use of manmade resources.

The processing of lead cakes containing osmium and rhenium is complicated by the significant variability in their elemental and phase compositions. The aim of this study was to determine the effects of lead cake composition on acid consumption and the recovery of Os and Re during oxidative leaching in a continuous-flow reactor. The leaching of 15 industrial cakes derived from copper production—containing 440–4260 g/t Re and 23–63 g/t Os—was investigated in a sulfuric acid medium, using sodium hypochlorite as the oxidizing agent. The experimental results showed that increasing contents of PbCO₃, PbO, and metallic Pb in the cake reduce Os and Re recovery at a fixed reagent dosage. It is established that variations in H₂SO₄ consumption are primarily driven by the cake’s phase composition; in particular, the acid is consumed through reactions with acid-neutralizing matrix components (PbCO₃ and PbO), thereby altering the effective pulp acidity and oxidative leaching conditions. Thermodynamic modeling indicated that pH changes primarily affect the chemical state of matrix components, whereas Os and Re remain predominantly in the forms OsO₄(aq) and ReO₄⁻, respectively. Under near-optimal conditions, recoveries of up to 95–96% for Os and 99–100% for Re were achieved. The kinetic study results demonstrated a faster extraction rate for Re compared with Os. In summary, the results show that the phase composition of the cake is a key parameter influencing acid and oxidant consumption; furthermore, adjusting the reagent regime based on the composition of industrial lead cakes enhances the stability and efficiency of Os and Re recovery.