Experimental Study In Pretreatment Of High-sulfur And High-arsenic Refractory Gold Concentrate By Ozone And Ferric Chloride

With the increasingly exhausting of easily leach able gold ores,Developments of refractory gold ores containing high-sulfur and high-arsenic have attracted extensive attention around the world.According to statistics,the gold reserves in the refractory gold ore in the world accounted for 60 percents of the total gold reserves.At present about 1/3 of world gold production is from refractory gold ores.In our country,30 percents of gold reserves proven is from refractory gold ores.It is practically meaningful to explore better use of refractory gold ores at present and in the future of China.The most important thing of developing this type of mineral is the choice and application of pretreatment method.This will directly relate to leach rate of gold,cost, environment protection etc.This article is studying in the pretreatment approach of high-sulfur and high-arsenic refractory gold concentrate(HHRGC).It must be pre-oxidation to break the parcel layer so that gold in the refractory gold concentrate(RGC)which was wrapped in sulfide minerals can contacting with the leaching agent.Based on the characteristics of the HHRGC of interest,our study looked into the method that ferric chloride and ozone pretreatment of RGC.Include:1)Ferric chloride pretreatment of RGC,in which the effects of the ratio of liquid to solid,reaction temperature,reaction time and the quantity of FeCl₃ on the leaching rate of iron were discussed.2)ozone and ferric chloride pretreatment of RGC,in which the effects of the velocity of ozone,the ratio of liquid to solid,reaction temperature,reaction time and the quantity of FeCl₃ on the leaching rate of iron and sulfur were conducted.The results show that ferric chloride has some effect in pretreatment of HHRGC. However,it has been prevented the ferric chloride from the further contacting with sulfide minerals due to the experiment produced a large number of element sulfur,and the highest iron leaching rate being up to 50.2 percent.Ozone and ferric chloride pretreatment show improvement of the leaching of iron and sulfur,which was related to the velocity of ozone,the ratio of liquid to solid,reaction temperature,reaction time and the quantity of FeCl₃.The availability of ozone was verified to obtain the higher leaching rate of iron and sulfur,the iron leaching rate was up to 83.96 percent and the sulfur leaching rate was up to 72.56 percent.There is no element sulfur in the slag after pretreatment by ozone and ferric chloride method.This paper research's ozone and ferric chloride to leaching refractory gold ores can effectively increase the leaching rate of iron and sulfur,and the reaction product are non-toxic,which meets the environmental protection requirement.However,the leaching rate of pyrite and arsenopyrite still has room for improvement;it is necessary to further technical research and improve the laboratory equipment and conditions.