China Nonferrous Metallurgy

A new process combining carbon leaching, acidification stripping, neutralization, sulfur dioxide (smelting flue gas) air method, and XJD heavy metal removal was studied using cyanide tailings from a certain smelter as raw materials. A harmless treatment and comprehensive resource recovery system for cyanide tailings was established to achieve harmless treatment and comprehensive utilization of resources.The results showed the optimum process parameters were as follows:pulp concentration 30%, carbon leaching for 2h, acidification with nitric acid-sulfuric acid mixture, pH=1.5~2.0, acidizing and aeration for 30min, after acid stripping, adding alkali for neutralization,controlling neutralization pH at 8.5,reacting with sulfur dioxide in air for 30min;the process had been applied industrially for two years, which had got good effect, the process of cyanide tailing conformed to the standard Technical Specification for Pollution Control of Cyanide Leaching Residue in Gold Industry（HJ 943—2018）, met the exemption conditions for cyanide tailing in the National Hazardous Waste List (2021 Edition), and the harmless post-disposal process is treated as general solid waste.The process is applied for comprehensively recycling cyanide and precious metal from cyanide tailing, with certain economic and social benefits.