UN METODO DE RECUPERAR MAGNESIA DE MATERIAS PRIMAS QUE CON- TIENEN CARBONATO DE MAGNESIO.

摘要

This invention is concerned with the recovery of relatively pure magnesia from magnesite which is normally contaminated with too much silica and silicates to permit the magnesite simply to be calcined for the recovery of refractory grade magnesia. The magnesite in its raw uncalcined state is treated with SO2 at elevated temperatures preferably between 50 DEG and 60 DEG C. thereby rapidly dissolving a high proportion of magnesium as bisulphite without the cost of initial calcination and without dissolving above about 1% of SiO2 present in the magnesite. The solution of magnesium bisulphite can thus be purified by filtration and magnesia may be recovered in known manner from the purified solution.