HYDROMETALLURGICAL TREATMENT FOR THE PURIFICATION OF WAELZ OXIDES THROUGH LIXIVIATION WITH SODIUM CARBONATE

摘要

The hydrometallurgical treatment process provides for the removal of contaminants from waelz oxide, (chlorine, sodium, potassium, sulfur and fluorin, essentially), and comprises the followings steps: lixiviation with soldium carbonate in aqueous alcalin medium, in hot conditions; solid-liquid separation of the effluent and the solid material; purification of the effluent by removing the heavy metals and optionally the undesired anions; washing with water the solid material resulting from the sodic lixiviation; solid/liquid separation of the water and of the purified waelz oxide; recirculation and heating of the effluent obtained in the washing step in order to reuse it in the sodic lixiviation.