Leaching of Willemite Concentrate in Sulfuric Acid Solution at High Temperature

The technical practicability of high temperature leaching process using willemite concentrate as the materials was developed in the study for extracting base metals. The factors affecting the leaching rates of zinc, iron, and silica from willemite concentrate were investigated, and optimized for maximum zinc extraction and minimum iron and silica dissolution to meet the needs of solution purification. Under the studied conditions (413 K, 0.81 mol/L sulfuric acid, duration 60 min, liquid to solid ratio (L/S) 10 mL/g, agitation speed 550 rpm, particle size of −250 + 300 mesh and 1.4 MPa pressure), up to 97% zinc was leached into lixivium together with approximate 5.72% SiO2 and 21.11% Fe. The performance of liquid-solid separation was also improved with decreasing silica dissolution under the experimental conditions used.