Preparation of metal zinc from hemimorphite by vacuum carbothermic reduction with CaF2 as catalyst

Zn reduction was investigated by the vacuum carbothermic reduction of hemimorphite with or without CaF2 as catalyst. Results indicate that CaF2 can catalyze the carbothermic reduction of zinc silicate, decrease the reaction temperature and time. The lower the reaction temperature and the more the amount of CaF2, the better the catalytic effect. The optimal process condition is obtained as follows: the addition of about 10% CaF2, the reaction temperature of 1373 K, the molar ratio of C to ZnTotal of 2.5, the pressure of system lower than 20 kPa, the reaction time of about 40 min. Under the optimal process condition, the zinc reduction rate is about 93% from hemimorphite.