Abstract: As the result of theoritical and experimental investigations in laboratory and industrial scale physico-chemical models for optimal conditions of copper, zinc and iron sulphides flotation and depression have been derived, verified and proved. Physico-chemical models derived are based on the mechanism of reagents action and represent themselves determined quantitative relationships between concentrations of reagents ions in pulp. They can be used ay plants, firstly, for examination and imperfection of technological processes of copper or zinc flotation at depression of iron sulphides by lime and, secondly, as the criteria for functional units of automation systems in optimization of these process.