Studies of hydrometallurgical processes of complex processing of polymetallic sulphide industrial products were carried out. Thermodynamic models of the behavior of individual components of the studied raw materials in complex heterogeneous systems are constructed. Researches of nitric acid leaching of the studied sulfide materials of JSC Svyatogor are carried out. The optimal parameters and parameters of the process of copper electroextraction from sulfate-nitrate solutions were obtained.