Method for producing low-salt dense soda ash

Abstract

The invention discloses a method for producing low-salt dense soda ash, which comprises steps as follows: a washing tank, a thickening device and a filtrate tank are added after a dense soda ash production technique by solid-phase hydration; in the washing tank, a combined-soda mother solution is used as a solvent to stir and wash alkali monohydrate from a hydrating machine, wherein the solid / liquid volume ratio of the mixed solution during washing is controlled at 30-50%; the solid / liquid volume ratio of the mixed solution is regulated to 60-80% by the thickening device; the thickened mixed solution enters an alkali monohydrate centrifugal machine to carry out solid-liquid separation; the overflow liquid of the thickening device and the filtrate of the centrifugal machine are merged at the filtrate tank and sent to the sodium bicarbonate procedure; and the alkali monohydrate is dried and cooled by a fluidized bed, screened by a double-deck vibrating screen, and packaged to obtain the low-salt dense soda ash of which the sodium chloride mass content is at most 0.3% and the 0.18mm screen tailing content is at least 80%, wherein the content of sodium carbonate in the combined-soda mother solution is 50-85tt, and the mass content of sodium chloride is at most 2.5%. The invention has the advantages of simple technique, stable product quality and no pollution.

Description

technical field [0001] The invention relates to the production technology of heavy soda ash, in particular to a method for producing low-salt heavy soda ash. Background technique [0002] In the soda ash industry, light soda ash is used as raw material to produce low-salt heavy soda ash. In addition to the liquid-phase hydration method, there are two process routes to choose from for the production of low-salt heavy soda ash by solid-phase hydration: the first is to reduce the weight of light soda ash Salt content, low-salt light soda ash is used to produce low-salt heavy soda ash, that is, when heavy alkali is filtered by a rotary drum vacuum filter, the amount of washing water is increased to reduce the salt content of heavy alkali, and heavy alkali is calcined by light ash calciner to produce low-salt Light soda ash, low-salt light soda ash is hydrated by a hydrator, heated and dried in a heavy ash calciner or a fluidized bed, cooled in a soda-cooling furnace, and then en...

AI Technical Summary

Problems solved by technology

The process of producing low-salt heavy soda ash by reducing the salt content of monohydrate alkali requires adding a large amount of washing water to spray and wash monohydrate alkali at the monohydrate alkali centrifuge, which will produce a large amount of salt-containing mother liquor and greatly increase the alkali consumption; even if it is equipped with baking soda production equipment, it cannot completely digest these saline mother liquors, which will eventually lead to the discharge of the combined alkali mother liquor due to expansion, which not only increases material consumption, but also pollutes the environment

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