Processing Of Gold-containing Slag From Sulfuric Acid Production Using Sulfatizing Roasting Followed By Chlorine Salt Leaching

With the reduction of the gold resourese which can be easy processed,peoplepayed more attention to the comprehensive development and utilization of therefractory gold resourese. Gold-containing slag was industrial waste residue whichwas discharged followed by producing sulfuric acid by sulphide ore contains pyrite,white iron ore, non-ferrous metal sulfide ore, etc.Traditionally called itgold-containing slag when there were some gold and silver enriched by roasting.Effectively using gold-containing sulfate slag and other secondary resources not onlycould expanded the scope of available gold resources,turned waste to wealth,but alsoalleviated the burden of the environment.The raw material was the waste residue from sulfuric acid production fromHunan province.The gold leaching technique would be done. The study of propertiesshowed that the grade of gold was16.23g/t.The particle size was fine,with-0.074mmcontent accounted for84.14%. the distribution of gold and iron was almostunanimously in each fraction. The XRD pattern showed that the main minerals ofgold-containing sulfate slag were hematite, magnetite, quartz, mica. The chemicalphase analysis results of iron showed that hematite accounted for75.24%, magnetiteaccounted for22.30%, carbonate iron accounted for1.54%, pyrite accounted for0.21%and ferrosilite accounted for0.71%.The direct leaching experiment for gold-containing sulfate slag indicated that theleaching rate was under20%no matter by any leaching methods,it belonged torefractory gold resourese.The reason why the leaching rate was so low was that theexposure rate of gold was too low,most of the iron mineral were wrapped that unableto touch with leaching drug.Compared with the results of direct leachingexperiment,the paper choosed chlorine leaching as the main leaching method.In order to expose as more as gold mineral from iron ores,the pretreatment wasdone.The paper choosed sulfatizing roasting as the pretreatment method.The singlefactor experiment showed that when the dosage of sulfuric acid was1.6t/t,the strengthof sulfuric acid solution was60%,the roasting temperature was500℃,the dosage of RS-1was50kg/t, the roasting time was80min,gold exposure rate reached the top.Thethermomechanical analysis proved the feasibility of the sulfatizingroasting.Compared with the results of oxidizing roast proved that the superiority ofthe sulfatizing roasting.The single factor experiment of chlorine leaching was done.The result showedthat when the dosage of NaClO3was100kg/t, the dosage of NaCl was70kg/t,theleaching temperature was80℃, the liquid-solid ratio was3.5:1,the leaching time was3h,the effect of leaching was the best,the leaching rate reached95.01%. The leachingthermomechanical analysis explained how the dosage of drugs and leaching timeinfluenced the leaching rate.The paper choosed Sulfatizing Roasting followed by Chlorine Leaching as theprocess for gold-containing slag.Under the optimum condition of roasting andleaching,the gold leaching rate can reached95.01%,the effect was obvious.Comparedwith the traditional cyanide leaching,it’s advantage was the speed,easy to operate andthere were little pollution to the environment.But those gold which are wrapped bysilicate minerals cannot been exposed restricted improving the leaching rate, and thedosage of drug was big,process cost was high.It need to be done more resrach.