The Study On The Combined Process For The Recovery Of Pb, Zn, Ag And Ge In Leaching Residues Of Znic Hydrometallurgy

Leaching residue from the electrolytic Zinc industries was a kind of hazardous waste (HW48) with various heavy metals and valuable metals. It was also made a large contribution to the pollution by rotary kiln processes. In this thesis, it was mainly discussed the current status on the residue treatment of hydrometallurgical industries in our country. According to the availability of heavy metals in the residues, a series of researches have been taken to study the leaching characteristics and of heavy metals (Lead, Zinc, Cadmium, Silver, Germanium, Indium, i.e.). It was proposed a combined process that combine the rotary kiln, silver floatation and Ge/In extraction which applied on a case in recycling and reusing project of a in hydrometallurgical industry in Liangshan District, Sichuan Province. It was of great environmental benefits and of technological&economic availability.Rotary kiln treatment was a mature process for leaching residues from hydrometallurgical manufactures. The calcination of leaching residues in rotary kiln at1100~1300℃, and then Pb、Zn、Ge and In in solid phase could be reduced and transformed to gas phase to reacted with oxygen to generate the oxic state heavy metals. These ash contained heavy metals was collected by bag dust collector, and subsequently to extracted Oxic Zinc, Al and so on. The As and Fe was directly preconcentrated in residues in rotary kiln, and then treated by silver floatation. The final kiln residue can extracted for Ag to produce Ag minerals for comerical product.The Results was shown as follows:①The annual treated residues could be increased to50.000t/a. and recoverd oxic zinc about3500t/a;②The leaching residues could be recycled and undergo a harmless treatment by subsequent calcination in rotary kiln.This combined process would eliminate the leaching residues polution to the environment, and solve the paradox between residues (HW48) and production of hydrometallurgical Zinc manufactures. Furthermore, it was a process of great significance for renovation of cleaner production and development of circular economy for smelting enterprises.