Process Study On Iron And Gold Recovery From Cyanide Tailings

Abstract:With the continuous development of the gold industry in China, a large amount of cyanide tailings are produced every year. These cyanide tailings haven’t been utilized effectively, taking up massive land, and causing serious environment pollution. The cyanide tailings contains a lot of valuable metals, but there is no reasonable and effective method of comprehensive utilizing the cyanide tailings, therefore, looking for a reasonable and effective method for recycling these valuable metals in the cyanide tailings comprehensively is very urgent, which has considerable economic benefit and environment benefit, which has addressing the relevance of environmental pollution. According to the ancient experience of comprehensive utilization of cyanide tailings, the paper advances the process of recovering iron by the way of reduction roasting and acid leaching, and recovering gold by the way of cyanide leaching from cyanide tailings which was produced after leaching gold calcine by the way of cyanide leaching in a goldmine factoryThe material of the experiment is cyanide tailings in which the gold grade is5.6g/t, the iron grade is29.55%, and the main iron ore is hematite which is disseminated parcel, mosaic and other complex relationship with the gangue. Iron was extracted from cyanide tailings by the way of reduction roasting and acid leaching, the effect of mixing mode, roasting temperature, roasting time, the dosage of coal, ball milling on leaching rate of iron were researched. And the leaching rate of iron was91.26%under the suitable conditions of uniform mixing, roasting temperature800℃, roasting time100min, the mass ratio of coal and cyanide tailings13%, at least95%of roasting ore reaching the size of-300mesh the concentration of sulfuric acid50%, leaching temperature105℃, leaching time3h, the theoretic dosage sulfuric acid1.0.Gold was extracted from roasting ore which has leaching by acid by the way of cyanide leaching, the effect of the dosage of sodium cyanide, the ratio of liquid to solid, leaching time on leaching rate of gold were researched. And the leaching rate of gold was71.43%under the suitable conditions of sodium cyanide dosage4kg·t-1, leaching time28h, the ratio of liquid to solid2:1.FeSO4·7H2O was produced from acid liquor after reduced by pyrite which was treated by ball milling, when the pyrite which was treated by ball milling reduce the acid liquor, the effect of the ratio of liquid to solid, reaction temperature, reaction time on reduction rate of iron were researched. The reduction rate of iron was96.27%under the suitable conditions of liquid to solid100:20, reaction temperature80℃, reaction time6h, and FeSO4·7H2O which was produced after the reduction liquor treating by freezing crystallization has reached the standard of the first kind of product of GB10531-2006, FeSO4·7H2O which was produced after the mother liquor treating by evaporation crystallization has reached the standard of the second kind of product of GB10531-2006, the output rate of FeSO4·7H2O are48.08%and65%after the twice crystallized.