SU565882A1 - Method of obtaining magnesium chromite - Google Patents

Description

one

This invention relates to the production of magnesium chromite used in the manufacture of refractories.

A known method for producing magnesium chromite is based on the interaction of an alkali metal bichromate, for example, sodium bichromate with magnesium sulphate, followed by thermal decomposition of the resulting magnesium dichromate. Thermal decomposition is carried out in the presence of alkali metal sulfate, for example, sodium sulfate l.

As a by-product of this method, alkaline uletallic sulfate is obtained, but this method has a complex technology.

There is also known a method for producing magnesium chromite, consisting in the thermal decomposition of magnesium dichromate, which is formed as a result of the interaction of chromic anhydride solution and magnesia with subsequent filtration of the pulp (stage 1) and acidification of the filtrate with chromium anhydride (stage II) to pH 1, O-1 , 2 which corresponds to the pH of the dichromate solution

magni. The magnesium sinter obtained during the thermal decomposition of bichromate is repulped in water, the pulp is filtered, magnesium chromite is washed and dried at 1OO - to obtain the desired product with the minimum content of impurities 2.

However, according to this method, the process is conducted in an acidic environment, which aggressively affects the equipment and creates an adverse) and good working conditions when conducting the technological process.

The goal has been achieved: the described procedure is to obtain chromate mat 1i, including the interaction of xpostoBoro aphydride with magnesium oxide, the separation of the sludge from the chromium-containing solution, the treatment of the latter with an oxygen-containing chromium compound — chrochromates, and the thermal decomposition of chromates. The preferred amount of INPUT x x yugi otoma is 40-6% of the amount of magnesium oxide.

Distinctive features of c; g (x; both are kak; garad-containing compounds xf: j t-i. X, amix) imats in the amount of 40-60% of the amount of magnesia.

Example. 10 kg of chromic anhydride is dissolved in 500 p of water. The resulting solution is heated to 50 ° C with stirring, 51.8 kg of magnesium oxide containing weight is added. %: 78.0 3.0 SO; j 0.85 CaOi 3.1 SiO and 3.8,

After stirring for 15 minutes, the mixture is filtered, the slurry is washed with 10 liters of hot water (70 ° C) and removed from the process.

To the resulting chromium-containing solution, 116.5 kg of chromochromates are added, containing by weight: 11.4 Cj-O, 68.1 Pg-3 total. and 0.4504.

The resulting mixture of chromates is subjected to thermal decomposition in a spray calcining furnace at 850 ° C;

1 chromite magnesium (192 kg) contains weight. %: 77 Cr20j, 21.3 Mg-0,0,46

0,

0.02 Ge

Claims (2)

1. A method for the production of magnesium Magnesium, including the interaction of chromic anhydride with starch oxide, separation of the slime from the chromium-containing solution, treatment of the latter with an oxygen-containing chromium compound and thermal decomposition of chromates, characterized in that, in order to improve working conditions and eliminate corrosion of the equipment, to process the chromium-containing solution chromium chromates are used as the oxygen-containing chromium compound. 2. The method according to claim 1, that is, that chromichromates serve in the amount of 40-60% of the amount of magnesium oxide.