| 摘要 |
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)<SUB>2 </SUB>obtained from the reaction of MgCl<SUB>2 </SUB>and lime, albeit indirectly, i.e., MgCl<SUB>2 </SUB>is first reacted with NH<SUB>3 </SUB>in aqueous medium and the slurry is then filtered with ease. The resultant NH<SUB>4</SUB>Cl-containing filtrate is then treated with any lime, to regenerate NH<SUB>3 </SUB>while the lime itself gets transformed into CaCl<SUB>2 </SUB>that is used for desulphatation of bittern so as to recover carnallite and thereafter MgCl<SUB>2 </SUB>of desired quality required in the present invention. The crude Mg(OH)<SUB>2 </SUB>is dried and calcined directly to produce pure MgO, taking advantage of the fact that adhering impurities in the Mg(OH)<SUB>2 </SUB>either volatilize away or get transformed into the desired product, i.e., MgO.
|
