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.

The article discusses the interaction in amino acid–gold cyanide systems using amino acids of different structures. The formation of complex compounds of gold cyanide with amino acids with the participation of carboxyl and amino groups is shown. A relationship has been established between the formation of gold complexes with amino acids and the degree of its extraction in the process of leaching from low-grade ore with sodium cyanide together with amino acids: the higher the degree of participation of the amino group in the formation of the complex, i.e., covalent bond, the more pronounced the effect of the amino acid on the degree of gold leaching. The contribution to the formation of the complex of the carboxyl group (ionic bond) and the amino group (covalent donor–acceptor) can be assessed by the intensity of the band at a wave number of 1419 cm⁻¹ of the IR spectra of the systems: gold cyanide–amino acid. This approach makes it possible to predict the effect of amino acid structure on gold recovery during cyanide leaching based on IR spectra.

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.

A complex processing variant for pyrite cinders, i.e., the technogenic waste generated in the production of sulfuric acid, was proposed. This method provided preliminary chemical activation of the initial raw materials that comprised thermal treatment with a sodium bicarbonate solution and resulted in structural and phase changes of separate minerals. Due to chemical activation, it was possible to separate the nonferrous metals into separate products (in addition to the partial extraction of iron) and then concentrate the noble metals in the residue. The noble metals were then able to be extracted through a leaching process with a complex reagent based on sulfur compounds and subsequent cementation with zinc dust. The developed method, unlike pyrometallurgical methods, is less energy-consuming and more easily implemented than the known hydrometallurgical variants, enabling the separation of nonferrous metals and the partial separation of iron into separate middlings at the first stage. Noble metals are concentrated in the residue and extracted from it.

Constantly increasing demand for rare-earth elements contributes to the involvement in the production of ore processing waste, the content of not extracted REE in which is quite large. One of the types of such waste is man-made mineral formations from the processing of phosphate uranium ores, which serve as raw materials for the production of REE concentrate at SARECO LLP. The technology for producing a concentrate includes the following redistribution: opening of raw materials cleaning of productive solutions from impurities; obtaining a concentrate on rare earth elements. One of the main disadvantages of this technology is the coprecipitation of almost 30% REE with ferrous cake when cleaning the most productive solution from impurities. To extract the rare earth elements ferrous cake is leached with sulphuric acid. The article studies the process of sorption from both model solutions that are similar in composition to the productive leaching of ferrous cake and directly from the productive ones, with the aim of further combining the resulting eluates with solutions supplied to precipitate REE.. Considerable attention has been paid to disrupt by ammonium salts.

The depletion of high-grade copper ore reserves in Kazakhstan, coupled with the increasing proportion of refractory ores and the high costs of extraction and processing, necessitates the development of efficient and economically viable technological solutions. In this context, biogeotechnology has gained considerable attention. Recently, alternative approaches based on the use of natural organic compounds—so-called bioreagents—have been introduced into the field of bioleaching. The present study aimed to investigate the effect of amino acids, aliphatic alcohols, and alcohol-based industrial by-products, used as bioadditives, on the bioleaching of copper. The results demonstrated that the influence of amino acids on copper bioleaching decreased in the following order: glycine > leucine > cysteine > histidine > asparagine. Furthermore, the addition of fusel oils, a mixture of aliphatic alcohols, to the bioleaching pulp enhanced copper recovery, achieving extraction efficiencies exceeding 90%.