Study On The Processing Technology Of A Complex Refractory Carlin Gold Mine

With the large-scale mining of gold resources,the number of gold mines that are easy to be smelted is becoming less and less,and complicated and difficult to be selected has become the main resource of gold at present.This kind of gold deposits exists in complex forms such as inclusion and symbiosis,adopt the conventional method of dressing,the recovery rate of gold is generally low.Therefore,how to improve the recovery rate of gold and comprehensively recover other valuable elements in ore has become an important research topic for this kind of mining enterprises.This study,taking the Carlin type of gold ore in Gansu as the research object,analyses why it is difficult to handle the gold ore with arsenic and antimony,and analyses its advantages and disadvantages of common pretreatment method,have been put forward the mineral separation process that pre-gravity-concentration after-flotation for the raw ore,put forward the smelting process that preprocessing-two-stage roasting-grinding-cyanide leaching for the gold concentrate.On the basis of this process,this paper optimized the type and quantity of the mineral processing agents,optimized the process of roasting and cyaniding,and obtained good experimental results.From the study of technological mineralogy,the ore contains Au 5.92 g/t,among which 1.42 g/t gold occurs in the form of sub-microscopic gold or micro inclusions in pyrite,toxic sand,stibnite and other sulfide minerals,and its share is 23.99%.0.50 g/t gold occurs in the form of a fine inclusion in the gangue minerals such as lignite,antimony ore and quartz,with a share of 8.45%.The remaining 4.00 g/t gold exists in the form of bare gold,with a share of 67.57%.The occurrence state of gold in ore is complex and recovery is difficult.It is difficult to obtain ideal gold recovery index by single recovery method.According to the occurrence status and output characteristics of gold,the flotation of Nielsen centrifuge of raw ore and the regrinding process of ore in the gravity separation was adopted to obtain the gold recovery rate of 86.03%and the grade of 50.05 g/t.The leaching rate of gold concentrate was 90.23%after pretreatment-two-stage roasting-grinding-cyanide leaching,and 56.25%after direct cyanidation of flotation tailings.The final comprehensive recovery rate of gold reached 85.48%after the raw ore was leached by gravity separation-flotation-each product(roasting).