The Direction And Distribution Of Sliver In The Kivcet Collocation Zinc Leaching Residue Lead Smelting Process

The sintering-blast furnace reduction smelting techniques is mostly used in lead smelting at the present day. The disadvantages of the process are complexity of raw materials preparation, easily leakage of lead dust and pollution of sulfur dioxides and so on. The leaching residue produced by zinc hydrometallurgy can only be stockpiled because of lack of appropriate treatments, which causes a waste of land and mineral resources and leads to heavy metal leakage and pollution. Due to wide range of adaptability of the raw materials, with the processing of zinc leach residues and efficient recovery of noble metals, the Kivcet lead smelting process is the most successful and perfect method of direct lead smelting technology. To increase the recovery rate of silver, conserve resources and improve of corporate efficiency, when process zinc leaching residue. This paper uses the lead concentrate and zinc leaching residue as the experimental materials, by oxidizing roasting them to prepare restore materials, makes a simulation of the carbothemic reduction stage of the Kivcet with handle zinc leaching residue lead smelting process and studies the distribution of silver in lead and slag.The main component of the product obtained which by oxidative roasting the lead concentrate is PbSO4and ZnO. The product of oxidizing roasting the zinc leaching residue contains PbSO4, ZnSO4, Fe2O3and Fe3O4. The content of silver in lead concentrates is500g/t, which reduce to460g/t after oxidizing roasting the lead concentrate. However, the content of silver from230g/t increases to320g/t after oxidizing roasting the zinc leaching residue.Thermodynamic studies indicate that PbS can be more easily oxidized to PbSO4than PbO, When the temperature is below1100K. The stable region of ZnS oxidation generated ZnSO4is narrow, raising the temperature or reduce the SO2concentration can make the product contains more ZnO. When the temperature is1073K, PbS and ZnS in the air oxidation products are PbSO4and ZnO. This is consistent with the oxidizing roasting experimental results. It makes a simulation of the carbothemic reduction stage of the Kivcet with handle zinc leaching residue lead smelting process and study the distribution of silver in lead and slag under different temperatures and reducing. The results indicate that when the reduction temperature is1200℃and use the coke reduction restores the material, the crude lead containing silver is1250g/t, silver in slag is94g/t, the maximum distribution ratio is22.11; When use the graphite as the reductant, the maximum distribution ratio of silver between lead and slag is30.13. At this time, the silver in the crude lead is1280g/t, silver in the slag is80g/t. when the reduction temperature is1230℃、1250℃、1270℃and1300℃, the maximum distribution ratio is28.59、28.75、20.06and19.17. It shows that the lead can catch silver well. To make more silver into the lead and improve the recovery of silver, the temperature of carbothemic reduction of lead oxide melt should be controlled within the range of1200-1250℃.