Specification of William Edward Newton : preparing hydrate of magnesia.

  • Newton, William Edward.
Date:
1874
Catalogue details

Licence: Public Domain Mark

Credit: Specification of William Edward Newton : preparing hydrate of magnesia. Source: Wellcome Collection.

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    Specification. A.D. 1874.—N° 1810. Newton’s Improved Process for Preparing Hydrate of Magnesia. 5 Or instead of using liquor ammoniae as the means of forming the hydrate of magnesia, the carbonate of sesqui-carbonate of ammonia may he substituted therefor, in which case enough must be taken to entirely precipitate the magnesia. Prom sixty to eighty pounds will be found 5 sufficient for the purpose for every one hundred and twenty-five pounds of the sulphate of magnesia taken. And as the most of the ammonia can be reclaimed, whether as a sulphate or carbonate, or as ammoniacal gas, by subjecting the clear liquor when drawn off to any of the well- known processes for its manufacture in a condensed form it may (at 10 little cost) be used in excess so as to insure a perfect precipitation of the whole of the magnesia. When the carbonate is used it is better to use a moderate degree of heat at first to effect the precipitation of the magnesia, after which it may be brought to the boiling point and continued for a few minutes, 15 which will effect a thorough chemical dissolution of the sulphate of magnesia, resolving it into a hydrate and forming simultaneously there¬ with a sulphate of ammonia, and setting free the carbonic acid with which the ammonia was previously charged. If desired the boiling process may be prolonged sufficiently long to 20 expel all the sulphate of ammonia, after which the magnesia may be allowed to settle as before, the liquor drawn off, and the magnesia then washed twice or three times with distilled water, either cold or with heat, and with agitation, each time allowing it to settle, and then drawing off the liquor, until it has been sufficiently washed to remove all trace 25 of the ammonia or other impurities with which it may have been charged or mixed. When the ammonia is driven off by boiling directly from the magnesia after the reaction has taken place, the vat or boiler in which the mixture is contained should be provided with a suitable cover and worm through 30 which the products of distillation may be conducted into the receiver in which the ammonia is to be reclaimed. The boiling need not con¬ tinue longer than is absolutely necessary to expel the ammonia. The sulphate and excess of other kinds of ammonia thus driven off may be condensed in any known way, and afterwards treated with soda or 35 other suitable material to set free the ammoniacal gas, and which being again condensed in water will form the necessary liquor ammoniae for