氧化剂对氰化体系下黄铁矿溶解行为的影响及机理

Influence of oxidant on pyrite dissolution behavior in cyanide leaching systems and its mechanics

本文针对氰化过程金精矿中黄铁矿与氰化物作用特性,对比研究次氯酸钠、过氧化氢和过硫酸钠对黄铁矿的预氧化处理效果,并对黄铁矿溶解特性、氰化物消耗、硫氰酸根离子浓度及氧化渣表面物质组成变化进行了分析。结果表明:3种氧化剂均能抑制黄铁矿的氰化溶解,当以过硫酸钠为氧化剂时,氰化物的消耗量减少51.72%,硫氰酸根离子的生成量减少75.97%,同时氰化体系中的氧环境得到改善。但以次氯酸钠为氧化剂时,氯化物的释放导致氰化物的消耗量增加10.34%。SEM-EDS及XPS分析结果表明,氧化剂的使用导致黄铁矿表面形成了不与氰化物作用的FeO、FeSO_(4)和Fe_(2)(SO_(4))_(3),从而抑制了黄铁矿氰化溶解,优化了氰化提金系统的浸出环境。

This paper examined the effects of sodium hypochlorite,hydrogen peroxide and sodium persulfate on the pre-oxidation treatment of pyrite.The study analyzed the dissolution characteristics of pyrite,cyanide consumption,thiocyanate ion concentration and the surface composition of oxidized residues resulting from treatment with various oxidants.The results indicate that all three oxidants inhibit cyanide dissolution of pyrite.When the sodium persulfate is used as the oxidant,the cyanide consumption is reduced by 51.72%,the thiocyanate ion generation decreases by 75.97%,and the oxygen environment in the cyanide leaching system is improved.In contrast,using sodium hypochlorite as an oxidant releases chloride ions,which increase cyanide consumption by 10.34%.SEM-EDS and XPS analyses results reveal that the application of oxidants results in the formation of FeO,FeSO_(4) and Fe2(SO_(4))_(3) on the pyrite surface.These compounds are non-reactive with cyanide,thereby inhibiting pyrite cyanidation and improving the leaching environment in the cyanide gold extraction system.