Study On New Technology Treating Lead Anode Slime By Hydrometallurgical Process

A novel hydrometallurgical process treating lead anode slime is developed.It includes acid leaching, alkaline leaching, amine leaching and electric potential control of chlorination leaching process. when the electric potential is controlled at 380⁴00mv, and L/S is 5: 1, materials are chloridized and leached by chlorine in 4N HC1 medium for about 1 hr at normal temperature, more than 98% As, Sb, Bi and Cu, 85% Te, 1.4% Ag and 2.6-36% Au enter solution, where 99% Au and Ag may be recoveried in Te concentrate. The leaching residue cantains 28—30% Ag,40% Pb, <0.3%Cu, <0.05%Bi, <0.9% Sb, and <0.08% As, from which Au and Ag can be recoveried by the current technology. A new technology of arsenic removal for treating arsenic-rich lead anode slime by use of adding a small quantity of KI and SO₂ gas to reduce As(V) to As(III), meanwhile 99% Te is recoveried in the form precipitation. And then 90% As is removed by distillation at <107℃ and Sb, Bi and Cu are recoveried from the remanent solution by hydrolyzation-neutralization method, where the direct recovery of Sb, bi and Cu are higher than 96%.The influence of reacting atmosphere, roasting temperature, and roasting time on the volatilization rate of As was studied systematically .The results of roasted sand experiments under the optimal conditions showedthat the volatilization rate of As was more than 87% and the arsenic content in the roast was below 3%in steam condition .The phase transformation and reaction mechanism in the process of roasting for arsenic removal was also discussed by means of XRD. The silver can be recovered from lead anode slime from Luoding by chlorination. Direct and total recovery rates of silver and Au are 96.52% and higher than 99%, respectively, Sb is 42.9%, Bi is 72.24%, and Cu in Copper concentrate and BI-Cu concentrate are 77.79% 89.2%, respectively. All valuable metals can be recovered effectively .The practice proves that this process is low power consumping, short period of production, high metal recovery rate, no pollution to environment and high economic benefit.