BigPatents India

The present invention reports an improved process for the recovery of refractory grade magnesium from marine bittern through desulphation route comprising formation of magnesium chloride during the process of desulphation by the addition of stoichiometric quanitiy of calcium chloride to bittern. As a result, sulfate ions are removed in the form of gypsum which is filtered out. The desulphated bittern is again treated with stoichiometric amount of ammonia and ammonium carbonate thus forming magnesium carbonate. The purity of MgO is 99.3% and CaO/SiO2 ratio is also favourable. There is no boron contamination and the bulk density is 3.355 gm/cc. The process is not energy intensive and does not involve any boron removal steps. The high pure magnesia thus obtained in this process is suitable for manufacturing high quality magnesia bricks for industries.