| 摘要 |
The magnesium hydroxide contained in the exhausted precipitate obtained by purifying liquids with activated magnesia is reactivated by converting it into the carbonate and thence to the oxide. The magnesium hydroxide may either be converted into the bicarbonate by passing carbon dioxide, preferably under pressure, into a suspension of the precipitate until the pH is 6.5, boiling the solution and calcining the separated carbonate at 500 DEG to 950 DEG C., or be converted into the carbonate by carbonating a slurry of the precipitate until the pH is 9.0 and calcining the resulting carbonate. The Specification as open to inspection under Sect. 91 comprises also washing the precipitate free from sugar, dewatering under vacuum and heating the resulting cake to 550-900 DEG C. This subject-matter does not appear in the Specification as accepted. |
