| 摘要 |
<p>A method for producing high grade magnesium oxide (magnesia) from crude magnesite or from other crude magnesium-containing compounds such as magnesium hydroxide, magnesium carbonate, basic magnesium carbonate etc., all of which can be thermally decomposed to crude magnesium carbonate, and which contain an iron impurity. The method comprises calcining the crude magnesium-containing compounds to crude magnesium oxide (2), forming a slurry of the crude magnesium oxide (3) and reacting the slurry with carbon dioxide (4). The unreacted solid is removed from the iron-containing pregnant magnesium bicarbonate solution at (5). A water-soluble aluminium salt is added to the pregnant solution (6) to precipitate out the iron (7) and the solution is air sparged (8) and/or heated after clarification to produce a precipitate of hydrated magnesium carbonate and/or basic magnesium carbonate. The precipitate is separated out (9) and decomposed (10) to produce substantially pure magnesium oxide.</p> |
