Control Technology for Tailings Pond Water Expansion in Copper Hydrometallurgy Based on High-concentration Gravity-flow Ball Mill System

Tailings pond water expansion is a core safety and environmental challenge faced by the copper hydrometallurgy industry, which directly triggers major hazards such as dam failure risks and acidic wastewater leakage. Aiming at the problem that the traditional ball mill-cyclone classification process, restricted by pulp concentration (45–60%), results in excessive system water supplement and continuous rise of water level in tailings ponds, an innovative technical scheme of "wet semi-autogenous mill + wet ball mill series connection with high and low positions + high-concentration gravity flow" was proposed. By eliminating gravity cyclones, optimizing equipment layout and regulating process parameters, the targets of stabilizing pulp concentration at 70% (by ore weight percentage) and achieving minus 200 mesh particle size accounting for ≥70% were realized. Industrial practice shows that the system can reduce external water supplement by more than 28% from the source, significantly alleviate the water expansion pressure of tailings ponds, avoid the terminal treatment cost of acidic wastewater, and simplify the process flow. This scheme provides a water expansion control path of "source water reduction + process water control" for the copper hydrometallurgy industry, which has both safety guarantee and environmental benefits, and possesses remarkable engineering application value.