Technologies Salt and Marine Chemicals

Process for the preparation of refractory grade magnesia of >97% purity and requiring less water in the process

IPR Status: 12/400512 and 11/376707

The present invention provides an improved process for the preparation of MgO of high purity >99% from salt bitterns via intermediate formation of Mg(OH)2 obtained from the reaction of MgCl2 and lime, albeit indirectly, i.e., MgCl2 is first reacted with NH3 in aqueous medium and the slurry is then filtered with ease. The resultant NH4Cl-containing filtrate is then treated with any lime, to regenerate NH3 while the lime itself gets transformed into CaCl2 that is used for desulphatation of bittern so as to recover carnallite and thereafter MgCl2of desired quality required in the present invention. The crude Mg(OH)2is dried and calcined directly to produce pure MgO, taking advantage of the fact that adhering impurities in the Mg(OH)2 either volatilize away or get transformed into the desired product, i.e., MgO.

Advantages of the invention:

The main advantage invention is that Mg(OH)2 obtained from the reaction of MgCl2 and ammonia in aqueous medium, which is very easy to filter, requires no further purification and can directly yield MgO of high purity, thereby largely eliminating the tedious nature of work up encountered in the conventional process of preparation of MgO from purified Mg(OH)2.


Technology licensed to:

Yet to be licensed