SU1404459A1 - Method of producing magnesium hydroxide - Google Patents

Abstract

The invention relates to methods for producing magnesium hydroxide used for producing waterproof magnesia peroxide, as well as producing high purity magnesium oxide used to produce special glass refractories. The method involves the precipitation of magnesium hydroxide from chlorine magnesium solution in ammonia water mixed with sodium bicarbonate and molar 30: (0.63-0.95) o The resulting precipitate of the target product is separated from the solution by filtration, washed first with water and then with 1% hydroxy solution and sodium. The method allows to increase the product yield and significantly speed up the process. 1 hp f-ly, 2 tab. SS

Description

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The invention relates to methods for producing magnesium hydroxide used for the production of waterproof magnesia important for thermal protection coatings of transformer steel, as well as for the production of high purity magnesium oxide used for the production of higher grade periclase, refractories, etc.

The purpose of the invention is to increase the yield of the target product and the degree of purity.

Example. Dn precipitation is used to prepare a solution (p) by dissolving 47.69 g of sodium bicarbonate in 0.238 g of water and adding 1454.0 g of a 25% ammonia solution (molar ratio of components: 0.79: 30). To the prepared solution is poured 1 l of solution (l) containing 280 g / l of magnesium chloride. A loose precipitate is immediately separated from the mixture, which by filtration on a vacuum filter at a pressure difference of 0.08 MPa is separated from the solution, Zrema filtration 45c, the product is 274.99 kg Mg (OH) j, Magnesium hydroxide precipitate is washed on filter 2 , 5l of distilled water. The resulting paste is poured with 1.25 l of 1% sodium hydroxide solution, stirred for 20 minutes at 80 ° C and filtered again under the same conditions. Then the paste is rinsed with 2.5 liters of distilled water. . Get the paste in the amount of 651.56 g, containing

24.3% by weight of magnesium hydroxide, 0.7% by weight of carbon dioxide and 75.0% by weight of water (desired product). The content of ion C in dry magnesium hydroxide is 0.02 wt.%.

The results of the remaining experiments are given in Table 1, and Table 2 shows the dependence of the degree of purity of the product on the type of washing of the precipitate.

The proposed method allows an I0% increase in the yield of the target product as compared with the known one, and also significantly intensifies the process by eliminating the steps of mixing the reagents and settling the magnesium hydroxide precipitate.

Claims (2)

Formula inventions and and I. A method of producing magnesium hydroxide, which includes precipitating it from a chlorine magnesium solution with ammonia water, filtering the precipitate formed and washing it with water, characterized in that, in order to increase the yield of the target product, ammonia water is used in a mixture with sodium bicarbonate at a molar ratio of 30: (0,63-0,95) respectively. 2. The method according to claim 1, which differs from and in order to increase the purity of the product, the precipitate is additionally washed with a 1% sodium hydroxide solution. Tav aw I g, 30,17i M.Z8. 30,775 22, a.076, g 25,50,574.0 -. . Conditions for the preparation of magnesium hydroxide clean water washing solution: known method 14044594 table 2 The content of CI ion in dry magnesium hydroxide, wt.% 0.460 0.020 0.093 0.3 (in pasta)