SU623827A1 - Method of obtaining magnesium oxide - Google Patents

Description

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The invention relates to the field of production of magnesium oxide used in rubber, cable and tire nroindustry.

Soda methods for producing magnesium oxide are known, based on precipitation of magnesium sulphate from magnesium carbonate soda solution with subsequent thermal decomposition to magnesium oxide 1J, | 2J, 3J.

A method of producing magnesium oxide is known, according to which aqueous solutions of magnesium sulphate and sodium carbonate are reacted by continuously feeding them into the reactor and moving them. The precipitated magnesium carbonate precipitate formed is filtered, washed, dried and calcined, for example at 800-900 ° C, in a muffle furnace 2.

The disadvantage of the known method is the poor filterability of the magnesium trihydrocarbonate precipitate due to the presence of a significant amount of amorphous substance in it. To sufficiently wash it, a large amount of wash water is required.

The aim of the invention is to accelerate the filtering process and reduce the amount of flush water.

The goal is achieved by the proposed method of obtaining magnesium oxide by mixing aqueous solutions of magnesium sulphate and sodium carbonate, followed by filtering the precipitate formed, washing it, drying and calcining at 800-900 ° C, the difference being that 5-8 v / v of another initial solution and mix it for 10-15 minutes.

The proposed method allows to increase the filtration rate by more than 2.5 times compared with the known method and reduce the consumption of wash water by about 2 times.

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Example 1. In 240 ml of an aqueous solution of sodium carbonate with a concentration of 160 g / l, 10 ml of magnesium sulphate of concentration 215 g / l, having a pH of 9.2 at 40 ° C, are added with stirring.

The resulting silicate solution is stirred for 15 minutes and fed for 4 minutes to a reactor containing 190 ml of magnesium sulphate with a concentration of 215 g / l. At the end of the sodium carbonate supply, the resulting suspension is stirred for 3 minutes and

45 minutes. Then the suspension is filtered at a rate of 90 ml / min, sprinkled with 1.2 l of water, dried, calcined for 40 min and calcined for 4 hours while in a muffle furnace.

Get the product of the following chemical composition, weight./about: MgO 93.0, CaO 0.84, Pe, Ol 0.07, SO; 2-0.35 and Mp 0.0028.

Example 2. A 200 ml aqueous solution of sodium carbonate with a concentration of 160 g / l was introduced into a 200 aqueous solution of sulphate magic with a concentration of 215 g / l at pH 9.2 and 40 ° C. After 15 minutes, do not mix. This solution is iodized into a reactor containing 220. Ml of carbonic acid at a concentration of 160 g / l for 4 minutes.

At the end of the feeding of the solution of magnesium sulfate, the resulting suspension is stirred for 3 minutes and settled for 45 minutes. Then the suspension is filtered at a speed of 105 ± 10 ml / min, about 1.2 liters of water are added, dried, calcined, and calcined at 4 hours.

The result is magnesia c.ie its chemical composition, weight. / ,,: MgO 94.2, CaO 0.81, Fe.Os 0.075, 0.32, Mn 0.0025.

The proposed method is quite economical, since r; in addition to reducing the filtering time and water consumption for washing, contributes to an increase in the productivity of the process at the expense of h, s –..P (when working, reactor volume, flow is not necessary Part of the reactor was left: the reaction suspension, serving as a seed.

Claims (3)

1. Author's certificate of the USSR AO 439477, cl. C 01 F 5/02, 10.03.72. 2.Pozin, ME, Technologists of Mineral Salts, Vol. 1. 296–29. 3. Authors certificate of the USSR .Nb 277752, cl. From 01 F 5/24, 07/03/67.