When obtaining sulfuric acid from pyrite concentrates, a significant amount of waste is generated in the form of pyrite cinders that require disposal. The methods used in processing this raw material are, as a rule, the pyrometallurgical processes of chlorination and chloride sublimation, the disadvantages of which include increased energy consumption and a lack of complexity in the extraction of valuable components. Hydrometallurgical processes are in less demand due to their multi-stage nature and complexity of execution. The method of chemical activation developed at the JSC “Institute of Metallurgy and Ore Beneficiation” makes it possible to isolate iron and non-ferrous metals into separate, middling products and to concentrate noble metals in the cake at the first stage. Physical and chemical studies of the cake found that its basis comprises iron compounds. The silver in the cake is associated with pyrite, while the gold is associated with hematite; it is also possible to find gold in the form of AuCl₃. The content of gold in the cake is 1.5 g/t, and the silver content is 17.7 g/t. Based on physical and chemical studies and data from the literature, various versions of the hydrochlorination method are proposed to open the cake.

This article presents a cutting-edge approach to microwave-assisted processing aimed at enhancing the efficiency of zinc extraction from materials characterized by a high degree of processing complexity. The described technique encompasses two sequential phases: phase transformation under microwave irradiation and leaching in sulfuric acid at ambient temperature. During the phase transformation, implemented through the application of microwave energy, insoluble zinc phases undergo a controlled transition. The experimental results confirm that microwave calcination at 600 °C for 5–7 min is effective for converting ZnS to ZnO without the formation of ZnO∙Fe₂O₃. Zinc extraction from the clinker reached 46.47% after treatment with microwave radiation at a power of 25 kW for the specified duration. Thus, this study opens up prospects for environmentally friendly zinc extraction from challenging-to-process resources.

This article presents the results of cyanide leaching of gold-containing concentrate using the trichlorocyanuric acid (TCCA) oxidizer. Gold-containing concentrate was obtained from a gold tailings sample from a gold recovery factory (GRF) in one of the deposits of Kazakhstan that have not previously been studied for concentrability. According to X-ray phase analysis and energy dispersive spectrometry (DSM) data, the main compounds in the tailings sample under study are pyrite FeS₂, quartz SiO₂, calcite CaCO₃, albite NaAlSi₃O₈, muscovite KAl₂Si₃AlO₁₀(OH)₈, dolomite CaMg(CO₃)₂, and oxidized iron compounds. Microscopic studies of the concentrate have established the presence of ultrafine gold with sizes from Au 0.9 to 10.2 μm in pyrite. Obtaining the gold-containing concentrate with a gold content of 15.95 g/t is possible according to the enrichment scheme, which includes centrifugal separation, classification according to the fineness class −0.05 mm, additional grinding of hydrocyclone sands to a fineness of 90.0–95.0% of the class finer than 0.050 mm, and control centrifugal separation. Since pyrite in technogenic raw materials is the main gold-containing mineral, this paper presents studies on the oxidizability of pyrite with the TCCA oxidizer. The results of studies on the oxidation of pyrite using the TCCA oxidizer show the products of its hydrolysis oxidize pyrite with the formation of various iron compounds on its surface. Pretreatment of gold-containing concentrate with oxidizer TCCA for 3 h before the cyanidation process (20 h) allows for an increase in the recovery of gold in the solution by 5.8%.

This study presents an innovative approach to processing refractory zinc-bearing clinker through the synergistic application of microwave thermal treatment and ultrasonic-assisted leaching. Microwave irradiation induces phase transformations in the clinker, improving its reactivity and facilitating subsequent zinc dissolution, while ultrasonic cavitation enhances mass transfer by disrupting passivation layers. Key process parameters, including acid concentration, temperature, pulp density, and leaching time, were systematically investigated using response surface methodology (RSM) and central composite design (CCD). The results demonstrate that the optimized process conditions led to a significant increase in zinc recovery from refractory materials.

The decrease in the quality of mineral raw materials processed by industry, as well as the increase in requirements for environmental protection, necessitate the development of new directions in the technology of their processing. Biogeotechnology refers to one of the modern areas of scientific and technological progress in the field of processing mineral raw materials. Biologically active additives are increasingly used along with the use of microorganisms in the extraction processes for non-ferrous and precious metals, in particular amino acids which are an integral part of the culture liquid of microorganisms. The processes of sulfuric acid leaching of copper from low-grade ore in the presence of amino acids of different structures and their effect on copper electrolysis were studied. Low-grade ore from one of the Kazakhstan deposits was used as the starting raw material. The copper content in the ore is 0.39%. The diffusion nature of the restrictions was established during the study of the kinetics of the process of sulfuric acid leaching of copper, and the rate constants and value of the effective activation energy were calculated, which amounted to 1.817 kJ/mol. The effect of amino acids with different structures on the leaching process was studied. The positive effect was increased in the glycine - leucine - cysteine - histidine - asparagine series. Depending on the structure of the amino acid, the degree of copper extraction into the solution increases in the range of 1-15%. The effect of aminoacetic acid as a biologically active additive on the process of electrolysis of copper from poor solutions was studied. It was established that the process is inhibited by the reduction of monovalent copper to the metallic state in the presence of glycine.