关键词: 氰化贫液, 硫化法, 硫酸根富集, pH调控

Abstract: Aiming at common issues in the gold smelting industry，such as the complex composition and high toxicity of cyanidation barren solution and the tendency of traditional treatment methods to cause sulfate accumulation，this paper systematically investigated the purification efficiency and resource recovery potential of the sulfurization process（sulfurization-acidification-recovery-recycling process）using high and low concentration cyanidation barren solutions from an enterprise as the subjects. By examining key control parameters（pH value，sodium hydrosulfide dosage，etc.）during the zinc and copper precipitation stages，the optimal process conditions were determined: for low-concentration barren solution，pH=7.0~7.3 in the zinc stage and pH=4.1~4.3 in the copper stage；for high-concentration barren solution，pH=6.0~6.8 in the zinc stage and pH=3.8~4.1 in the copper stage. The sodium hydrosulfide dosage was 105% of the mo⁃ lar amount of the target metal ions in both cases. The results showed that this process enables efficient selec⁃ tive recovery of copper and zinc. The recovery rates for zinc and copper in low-concentration cyanidation barren solution reached 92.5% and 98.2%，respectively，while those in high-concentration cyanidation barren solution were 72.7% and 97.8%，respectively. The resulting zinc sludge had a zinc grade >40%， and the copper sludge had a copper grade >45%，both of which could be directly sold to generate econom⁃ ic benefits. The core innovation of the process lies in the reaction pathway design，which effectively precip⁃ itates the sulfate ions introduced during the acidification stage as gypsum during the neutralization stage， thereby reducing the net sulfate increment in the system from 40 g/L in conventional acidification processes to 5 g/ L，fundamentally suppressing sulfate accumulation. This study provides an innovative solution for treating complex cyanidation barren solutions that simultaneously achieves resource recovery and system sa⁃ linity balance，offering significant engineering application value.

Key words: cyanide-depleted solution, sulfidation method, sulfate accumulation, pH control