Abstract:Based on fratures that hematite can not dilute into sulfuric acid, dissolution of other elements of two-stage calcine was studied in dilute sulfuric acid to reduce purification burden of process iron chemical products prepared using acid solution. The results show that zinc can be completely removed, removal rate of As and Mg is 91.06% and 96.09% above respectively, and the leaching rate of Al, Cu and Ni is 45.59%, 48.11% and 18.11% respectively in two-stage calcine under the conditions including sulfuric acid concentration of 12%, leaching temperature of 90 ℃, leaching time of 120 min, and L/S=4/1. Sulfuric acid concentration has a big influence on the leaching rate of impurities, at the same time, iron dissolution rate is 14.38%. The higher the sulfuric acid concentration is, the higher the leaching rate of impurity metals is.