This work examines the possibility of incorporating borate-containing materials in order to improve the granule strength and reduce the copper losses to slag. A phase diagram of the Fe-S-Cu system was constructed, and a mathematical model with a numerical calculation program were created. Using complete thermodynamic modeling, the influence of the boric anhydride and borate ore on the pelletizing, drying, roasting, and matte production was analyzed. B2O3 enhanced the wet granule strength by forming crystalline hydrates (H2O∙B2O3), which dehydrated at 285 K and melted at 723 K, creating a strong sinter upon cooling. During smelting, boron-containing materials increased process efficiency and they decreased matte losses, creating low-melting, mobile slags. Additionally, borate ore containing montmorillonite ensured sufficient wet granule strength for transport, and its low-melting nature led to liquid phase formation during firing, producing a strong sinter upon cooling.

The aim of the research is the studying the electrochemical reduction of the refractory copper mineral malachite from oxidized ores in the presence of sodium sulfite, a sulphidizing agent, and formation of easily floatable copper (I) sulfide under voltammetric polarization conditions. The studies were conducted using a special electrode assembly design for voltammetric studies and microelectrolysis at a controlled potential of both dispersed ore monominerals and depolarizer solutions. Electrode mechanisms for the monovalent copper sulfide formation during combined cathodic reduction of malachite and sodium sulfite were established. A sulfite ion is easily reduced in an acidic medium to highly active colloidal elemental sulfur, making it an effective sulphidizer for malachite. Copper sulfide was synthesized from malachite under microelectrolysis conditions, and the sulphidizing effect of sulfite was confirmed. The effect of the electrode material on the cathodic decomposition of the synthesized Cu2S was observed.

The aim of the research is the use of electrochemical sulfidizing to increase the degree of copper recovery from refractory oxidized copper ore, in which malachite is the main mineral. The object of research is oxidized copper ore of the Zhezkazgan deposit in the Republic of Kazakhstan that contains 0.70 wt.% of total copper, 0.64 wt.% of which is oxidized minerals. The electrode mechanisms of cathodic reduction of the malachite mineral and the chemical reaction of elemental colloidal-dispersed sulfur formation from sodium thiosulfate established by the voltammetry method were used for preliminary electrochemical sulfidizing of oxidized copper ore for flotation. Electrochemical sulfidizing was carried out by electrolysis under galvanostatic conditions. The results of electrolytic sulfidizing of oxidized copper ore and conversion of refractory minerals into an easily floatable sulfide form are presented. A multifactor model of copper recovery was obtained, according to which a specified high degree of recovery of ≥ 96.0% can be achieved with current densities of 50–150 A m ^− 2 with the addition of sodium thiosulfate sulfidizer of 2–3 g L ^− 1 , the sulfuric acid concentration of 20–24 g L ^− 1 and the electrolysis duration of 60 minutes. The kinetic parameters of the process were studied, and the diffusion mode of sulfidizing was established. Under optimal conditions of electrochemical sulfidizing of oxidized copper ore, the degree of copper recovery into concentrate reaches 96.5%, which exceeds the indicators of direct flotation by 30%.