In the established technologies, the use of classic depressants of pyrite, such as lime represents one of the main problems in the flotation of gold-bearing copper (Cu) ores. Lime addition leads to the depression of the noble metals - gold (Au) and silver (Ag) that end up in tailings. Thus, the operator incurs economic losses. The current paper presents research aimed at replacing in flotation of copper pyrite ore, bearing gold and silver, the classical depressor lime with catholyte, i. e. with solution obtained during the electrolysis of water (pure or aqueous solutions) using a diaphragm electrolyser. Data from the conducted research show an increase in the content of precious metals in the obtained copper concentrate - from 148. 04 g/Mg Au and 112. 8 g/Mg Ag achieved by classical process to 216.45 g/Mg Au and 174.03 g/Mg Ag obtained by the proposed treatment. At the same time the Cu recovery increased by 3 % and the grade of Cu concentrate was 27.5 % Cu (compared to 16.2 % in the classical process). It seems that the main parameter influencing the selection separation process is the catholyte pH value.