WAY TO REDUCE THE QUANTITY OF ZINC (Zn) AND LEAD (Pb) IN MATERIALS CONTAINING IRON (Fe)

摘要

The application describes a method for reducing the amount of zinc and lead in raw materials containing iron, which includes the following steps: selective leaching of Zn and Pb contained in the starting materials while mixing the starting materials with hydrochloric acid and an oxidizing agent, comprising at least 5 wt.% manganese dioxide, in one or more reactors at a temperature of 35 ° C or more, and at a pH in the range from 0.5 to 3.5; filtering the resulting mixture to separate the solid and filtrate; washing the solid with water, the resulting solid mainly containing Fe and a reduced amount of Zn and Pb compared to the starting materials; returning the filtrate obtained in stage b) and the aqueous wash fractions obtained in stage c) containing chloride and solubilized Zn and Pb to one or more reactors; sedimentation of solubilized Zn and Pb in the return filtrate and wash water fractions when mixed with a neutralizing agent; filtering and washing the solid residues obtained in step d) to remove the chloride in solution from the solid residues that contain at least Pb and Zn. The application also describes the use of processed materials obtained after processing in the sintering plant and in a blast furnace or in all pyrometallurgical plants in which iron matters, such as an electric arc furnace, a self-leveling cupola, a cupel furnace (closed-arc furnace) , plasma oven, carousel oven.