Study On The Process Of Leaching Gold By Novel Non-cyanide Leaching Agent

Cyanidation is a mature method of immersion gold,which is widely used in China's gold industry.However,the cyanidation process will produce a large amount of cyanide-containing wastewater in the production process.Because cyanide is highly toxic,cyanide-containing wastewater can cause serious environmental pollution if handled improperly,and some gold-bearing minerals are not suitable for cyanidation.Therefore,the development of clean and efficient non-cyanide leaching process has became the focus research which being studied in some industries.In this paper,the new non-cyanide leaching agent for its universal and leaching kinetic process were studied,the results obtained for the type of non-cyanide leaching agent for industrial applications to provide theoretical basis and reference.Taking the multi-metal flotation gold concentrate and the carbonate type refractory gold as raw materials,a novel non-cyanide leaching agent was used for gold-leaching researches.The effects of leaching agent dosage,leaching time,liquid-solid ratio,blowing volume,pH on gold leaching process were investigated.The best non-cyanide leaching process conditions were determined,and compared with cyanide leaching.When using multi-metal flotation gold concentrate as raw material,the optimal leaching process parameters of the non-cyanide leaching agent were as follows:the size of the ore-200 mesh accounting for 96%,25? of the leaching temperature,25 kg/t of the leaching agent,3:1 of liquid-solid ratio,1500 r/min of stirring speed,12 of pulp pH value and 10 h of leaching time.The leaching rate of gold could reach 97.6%.When carbonate refractory raw ore was used as raw material,the better leaching rate could be obtained by roasting pretreatment.The best leaching conditions were as follows:mineral particle size-200 mesh accounted for 93%,roasting at 800? for 3 h,25? of the leaching temperature,6 kg/t of the leaching agent,3:1 of liquid-solid ratio,1500 r/min of stirring speed,12 of pulp pH value and 11 h of leaching time.The leaching rate of gold could reach 91.2%.The results show that leaching rate of this non-cyanide leaching agent was close to that of cyanidation leaching.The non-cyanide leaching agent has a good selectivity for gold and silver,with the advantages of fast leaching rate,environmental friendly and low cost,which has a good practical application prospect.A novel non-cyanide leaching agent was used to study the leaching kinetics of gold concentrate and ore.The results show that the leaching process of both ores can be described by the shrinking unreacted nuclear model.Considering the effects of stirring speed,liquid-solid ratio,leaching temperature,leaching agent dosage and mineral particle size on the leaching process,the factors influencing leaching rate,activation energy,reaction order and limiting steps were obtained.The related mathematical model of leaching process was established,the macroscopic reaction kinetic equations of two kinds of ore were deduced as follows.Leaching kinetic equation of gold concentrate:#12Leaching kinetic equation of raw ore:(?)...