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针对低品位高硫高粘土含砷含碳卡林型金精矿矿石性质特殊,直接氰化金浸出率仅为10.01%,且常规生物预氧化方法无法有效脱除金精矿中的硫、砷等有害杂质,开展了分步生物预氧化试验研究。通过充气搅拌浸出条件试验,考察了磨矿细度、接种量和矿浆浓度对预氧化效果的影响,结果表明三者均对预氧化效果影响很大。当工艺参数为:浸矿温度45℃,磨矿细度-37μm占90%,矿浆浓度10%,接种量10%,搅拌速度120 r·min-1,浸矿体系2 L,采用分步预氧化方法,共氧化9 d,金精矿中硫、砷脱除率分别可达82.96%和92.01%,后续金的氰化浸出率为79.91%。预氧化渣XRD图谱,SEM分析以及氰化试验表明,金精矿中有机碳物质具有严重劫金作用,同时预氧化5~9 d期间黄铁矿表面形成的大量黄钾铁矾膜对后续金的氰化浸出也具有严重的抑制作用。
In view of the special nature of low-grade, high-sulfur, high-clay arsenic-containing Carlin-type gold concentrate, the leaching rate of direct cyanide gold is only 10.01%. Conventional biological pre-oxidation can not effectively remove sulfur and arsenic from gold concentrate And other harmful impurities, carried out a step-by-step biological pre-oxidation test. By aeration agitation leaching conditions test, the effects of grinding fineness, inoculum size and pulp concentration on the pre-oxidation effect were investigated. The results showed that all three had a great influence on the pre-oxidation effect. When the process parameters are as follows: leaching temperature 45 ℃, grinding fineness -37μm 90%, pulp concentration 10%, inoculation 10%, stirring speed 120 r · min-1, leaching system 2 L, Oxidation and co-oxidation for 9 days, the removal rates of sulfur and arsenic in gold concentrate reached 82.96% and 92.01%, respectively. The cyanidation leaching rate of the subsequent gold was 79.91%. XRD pattern of pre-oxidation slag, SEM analysis and cyanidation test show that the organic carbon in gold concentrate has a serious effect on robbing gold. At the same time, a large amount of jarosite film formed on the surface of pyrite during 5 ~ 9 d pre- Cyanide leaching also has a serious inhibitory effect.