SU1211219A1 - Method of producing high-silica cryolite - Google Patents

Description

This invention relates to TexHOiKS of the preparation of a cryolite.

The purpose of the invention is to control the process

Simplification of the process occurs by eliminating the use of soda, speeding up the filtration process and the drying temperature.

Example 1, K 20 wt.h, aluminum fluoride suspensions,. containing 50% of the main substance, add 100 weight of HH. a solution of sodium metascate containing 18%, the content of the reaction mass is 7, t 7.5; Af 3; SiO 7.0; F 7.0; The reaction mass is stirred at 30 minutes; the precipitate is separated from the mother liquor by filtration; the filtration rate is 3.1 m / m -h. The resulting product, cryolite, is dried for 2 hours. As a result, 20 wt.% Of dry matter is obtained, which contains, wt.%: Na 16.2; AF 11.2 SiO 29.7; F 33.7; humidity 4.2.

Example 2 To 20 parts by weight, a suspension of aluminum fluoride containing 55% of the basic substance is added to 100% by weight, per hour, of sodium metasupaccate solution containing 22% NajSiO. The total content of the reaction mass is% : NajO 9.0; Af 3.8; SiO 9.0; F 7.5. The reaction mass is stirred at 20 minutes. The precipitate is separated from the mother liquor by filtration, the filtration rate is 3.1 m / m h. The resulting product, cryolite, is dried at 100 ° C for 2 h. The result is 23 weight, h, dry substance, which contains by weight,%; Na 14.5; AF.13.2; SiO 30.0; F 38.6 humidity 3.7,,

Example 3, K 20 weight, h, sus

Thorns of aluminum fluoride containing 50% of the basic substance, 100 weight, h of sodium metasilicate solution containing 25% is added. The total content of the reaction mass is,%: NagO 10.3; A 3,0; Sic2 10.0; F 7.0, The reaction mass is stirred at a temperature of 75 ° C for 20 minutes. The precipitate is separated from the mother liquor by filtration, and the filtration rate in this case is 3.1 .h. The resulting product, cryolite, is dried at a temperature of 2 hours, as a result

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they get 28 weight, h, dry matter, in which wt.% 18.2% is contained; AF 12.8; SiO 33.0; F 31.0; moisture content 4.6 and 68 weight parts, filtrate, with the content of NajO 5.12 At - 6.05 SiOt - 4.4 and F - 0.4 wt.%, to which was added 36 weight, h, dev. sodium metasilicate and sent to a new treatment of aluminum fluoride. As a result, a new portion of cryolite of Example 1 is obtained,

Thus, the introduction of aluminum metasilicate solution in the range of 18-25% into a suspension of aluminum fluoride leads to the formation of a well-filtered precipitate. Going beyond these limits are not advisable. At low concentrations, the yield of the final product decreases and an increase in concentration leads to the formation of a difficult to filter sediment, i.e., the filtration process becomes more complicated, which consequently leads to unnecessary expenses and complicates the process,

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The process introduction temperature is also optimal, as it simplifies the process by allowing the desired product to be obtained at lower temperatures. Its lowering is impractical, so (at a temperature below 50 ° C, the reaction of the formation of cryolite He proceeds, and above leads to an increase in the cost of the process and additional energy costs)

The disappearance time of 20–30 min with continuous stirring ensures that the desired product is obtained. When shortened for 20 min, the reaction proceeds partially, since the complete interaction of the components does not occur. Aging for more than 30 minutes does not lead to special changes in the composition of the final product.

Drying of the obtained precipitate at retr. 100-120 ° C is optimal, (the temperature below 100 ° C does not lead to complete separation of water and the precipitate is obtained with a moisture content of 7%) at a temperature of 120 ° C, a very dry product is obtained, and additional energy is consumed.

The proposed method allows to speed up the filtering process up to J 3.1 (2.2-2.5 by pro31211219

totipu} to reduce the amount of production by using reagents, to reduce the temperature of the filtrate to obtain new drying of cryolite, to create waste-free cryolite.

Claims (1)

METHOD FOR PRODUCING HIGH SILICON CRYOLITE, including mixing aluminum-containing and silicon-containing substances during heating, separating the obtained precipitate from the solution by filtration and drying the precipitate, characterized in that, in order to simplify the process, aluminum fluoride is used as aluminum-containing substance, as silicon-containing 25-25% solution of sodium metasilicate, heating is carried out to 50-75 ° C, and drying is carried out at 100-120 ° C.