Roasting And Self-leaching Process Research Of Arsenic-bearing Gold Concentrate

In view of the problems existing in the traditional cyanidation leaching process of arsenic bearing gold concentrate,such as serious gold inclusion,large consumption of cyanogen ion,low gold leaching rate,and serious harm to the ecological environment,the neutral roasting self leaching process of arsenic bearing gold concentrate is put forward,that is,roasting arsenic-bearing gold concentrate in neutral atmosphere,so that the sulfur in sulfide minerals is produced in the form of single substance,while arsenic is produced in the form of single substance Arsenic or arsenic sulfide can be removed,and the resulting elemental sulfur can be used to synthesize stone sulfur mixture to leach the gold in the calcine and realize the non cyanide self leaching of gold.According to the thermodynamic analysis of neutral roasting,arsenopyrite can decompose to form elemental arsenic at 300℃,pyrite can decompose to form elemental sulfur at 746.06℃,but arsenic reacts easily with oxygen and sulfur to form oxide or sulfide of arsenic.When arsenopyrite and pyrite coexist,the ratio of arsenopyrite and pyrite will determine the starting temperature of neutral roasting reaction,the product form and the removal rate of arsenic and sulfur.The neutral roasting behavior of arsenopyrite and pyrite was studied by means of XRD,SEM and EDS.The results showed that when the ratio of arsenopyrite to pyrite is more than 40%,arsenic mainly exists in the form of gaseous elemental arsenic and As4S3,while only a small amount of arsenic exists in the form of Fe As2 and Fe As or Fe As2;when the ratio of arsenopyrite to pyrite is 40%,arsenic mainly exists in the form of gaseous realgar and As4S3;when the ratio of arsenopyrite to arsenopyrite is less than 40%,arsenopyrite exists in the form of gas realgar and As4S3,accompanied by a large amount of gas elemental sulfur.For arsenic-bearing gold concentrate containing Au 40.12g/t,As 9.15% and S 27.84%,the removal rates of As and S are 98.69% and 25.22% respectively,under the neutral roasting conditions of 800℃ and 60 min.The lime sulfur synthetic solution(LSSS)was synthesized by using the elemental sulfur produced in the roasting process,the calcined was selfleached under the optimum leaching conditions,and the leaching rate of gold was 85.18%.Compared with the direct cyanide leaching and LSSS leaching processes,the leaching rates of gold have increased by 55.06% and 41.93%,respectively.The neutral roasting self leaching process can comprehensively utilize the sulfur element in the arsenic bearing gold concentrate,remove the harmful element arsenic cleanly,improve the leaching rate of gold,and provide a new method and process for the clean and efficient utilization of the arsenic bearing refractory gold ore.Figure54;Table20;Reference80...