塔吉克斯坦某难处理金精矿低温二段焙烧预处理试验研究

Experimental study on pretreatment of refractory gold concentrate by low temperature second stage roasting from Tajikistan

高砷高硫金精矿中的金矿物被毒砂(As_(2)O_(3))和黄铁矿(FeS_(2))包裹,直接氰化浸出浸出率较低,其预处理工艺一直是研究关注的热点。本文以塔吉克斯坦高砷高硫金精矿为研究对象,在热重分析和热力学分析的基础上采用二段焙烧法进行预处理,脱除大部分砷、硫、有机碳等有害杂质,并对工艺参数进行优化。试验考察了添加剂及焙烧温度、时间对金精矿中碳、硫、砷脱除率的影响,并在最终焙烧产物物相分析基础上进行了焙烧-氰化浸出验证试验,得到以下主要结论。一段焙烧采用弱氧焙烧气氛焙烧脱砷,不需使用添加剂,较优工艺参数为焙烧温度500~550℃、焙烧时间2 h;二段焙烧采用富氧气氛焙烧脱硫,较优工艺参数为焙烧温度650~700℃、时间2 h;在上述较优工艺参数下的焙烧-氰化浸出的碳脱除率、硫脱除率和砷脱除率分别为91.16%、96.93%和92.52%,金浸出率达到95.30%。该结果相对于直接氰化浸出,金浸出率提高了20%,一定程度上实现了资源的高值化利用,为难处理金精矿高效提金提供了技术依据。

Gold minerals in high arsenic and high sulfur gold concentrate are coated with arsenopyrite(As_(2)O_(3))and pyrite(FeS_(2)),and the leaching rate of direct cyanide leaching is low.The pretreatment technology of high arsenic and high sulfur gold concentrate has been the focus of research attention.In this paper,Tajikistan gold concentrate with high arsenic and high sulfur is taken as the research object.On the basis of thermogravimetric analysis and thermodynamic analysis,a two-stage roasting method is used for pretreatment to remove most of the harmful impurities such as arsenic,sulfur and organic carbon,and the process parameters are optimized.The effects of additives,calcination temperature and time on the removal rate of carbon,sulfur and arsenic in gold concentrate were investigated.Based on the phase analysis of the final calcination product,the roasting-cyanide leaching test was carried out,and the main conclusions were obtained as follows.The first-stage roasting was carried out in a low oxygen atmosphere without additives,and the optimum process parameters were roasting temperature 500~550℃ and roasting time 2 h.The second-stage roasting was performed in an oxygen-rich atmosphere,and the optimum process parameters were roasting temperature 650~700℃ and time 2 h.Under the above optimal process parameters,the removal rates of carbon,sulfur and arsenic were 91.16%,96.93%and 92.52%,respectively,and the gold leaching rate reached 95.30%.Compared with the direct cyanide leaching,the gold leaching rate is increased by 20%,which realizes the high value utilization of resources to a certain extent,and provides a technical basis for efficient gold extraction from refractory gold concentrate.