Method for preparing sodium bicarbonate and co-producing ammonium sulfate and calcium carbonate from glauberite

Abstract

The invention provides a method for preparing sodium bicarbonate and co-producing ammonium sulfate and calcium carbonate from glauberite, which specifically comprises the following steps: (1) introducing carbon dioxide into salting-out mother liquor to carry out calcification reaction, and carrying out solid-liquid separation to obtain sodium bicarbonate and sodium bicarbonate mother liquor; (2) introducing ammonia gas into the sodium bicarbonate mother liquor for ammoniation reaction to obtain ammoniated mother liquor; (3) mixing the glauberite raw material, sodium sulfate and the ammoniated mother liquor, carrying out salting-out reaction, and carrying out solid-liquid separation to obtain first double salt, calcium carbonate and salting-out mother liquor; (4) carrying out reaction on the mixed double salt and water, and carrying out solid-liquid separation to obtain sodium sulfate and separated mother liquor; (5) carrying out cooling crystallization on the mixed ammonium sulfate mother liquor and the separation mother liquor, and carrying out solid-liquid separation to obtain second double salt and crystallization mother liquor; and (6) carrying out evaporative crystallization on the crystallization mother liquor, and carrying out solid-liquid separation to obtain ammonium sulfate and ammonium sulfate mother liquor. According to the method, sodium bicarbonate is prepared from glauberite as a raw material, high-valued conversion of sodium sulfate and calcium sulfate is achieved, and the problem of stockpiling of glauberite tailings is solved.

Description

Technical field [0001] The present invention belongs to the field of chemical technology and environmental protection, relates to a process for preparing sodium bicarbonate, particularly to a method of ammonium sulfate and calcium carbonate by-produced Glauberite a sodium bicarbonate preparation. Background technique [0002] Glauberite as a sodium enriched calcium sulfate and mineral resources, it is an important feedstock preparation over anhydrous sodium sulfate. Chinese Glauberite abundant, conventional mining methods are dissolved in water by way of extraction in which the sodium sulfate, thereby producing anhydrous sodium sulphate, and calcium sulphate which can not be effectively utilized in the main stockpiling. In addition, due to the smaller anhydrous sodium sulfate applications, and by the impact of industrial by-product sodium sulfate and reduce the impact of the downstream industry demand, the market shrinking demand. Glauberite to achieve efficient utilization, appl...

AI Technical Summary

Problems solved by technology

However, due to the low conversion rate of sodium sulfate metathesis reaction, the utilization rate of sodium sulfate is less than 60%, and it is impossible to obtain ammonium sulfate with pure phase, the cost is high, so the technology of sodium sulfate to prepare soda ash is at a standstill

Some studies have added organic amines to the reaction system of sodium sulfate to prepare sodium carbonate to promote the metathesis reaction. This method can increase the conversion rate to more than 90%, but because the organic amine is easily soluble in water, it is extremely difficult to separate, and Due to the residue of organic matter in ammonium sulfate and sodium carbonate, the loss of organic amine is large, the cost is high, and the product quality is low

[0005] CN101544385A discloses a kind of method that takes sodium sulfate as raw material and supplements organic amine to prepare sodium carbonate to co-produce calcium sulfate, described method can realize the conversion rate of sodium reaches more than 90%, but organic amine has high boiling point, high viscosity, evaporation recovery energy The consumption is high, and the entrainment of organic amine in sodium bicarbonate and calcium sulfate is much, the recovery is difficult, the loss is large, and the production cost is high

[0006] CN104355326A, CN102198953A and CN202016881U all disclose a method for preparing sodium bicarbonate and co-producing ammonium sulfate by metathesis. Using sodium sulfate and ammonium bicarbonate as raw materials, sodium bicarbonate is obtained through metathesis, and the separated mother liquor is deaminated at high temperature. Evaporate and concentrate at 130°C to obtain sodium sulfate crystals. After separation, the mother liquor is cooled and crystallized to obtain the double salt of sodium sulfate and ammonium sulfate. The mother liquor is then evaporated and crystallized to obtain ammonium sulfate products. However, the process of the method is complicated and requires multiple high temperatures, cooling, etc. process, high energy consumption, low utilization rate of sodium ions and sulfate radicals, large evaporation depth, large material circulation, high production cost, and no industrialized precedent at present

[0007] CN105000579A and CN105712382A all disclose a kind of precipitation method, and this method prepares sodium bicarbonate by double decomposition reaction of ammonium bicarbonate and sodium sulfate, then adds lime in sodium bicarbonate mother liquor, reclaims wherein ammonia, but in this process ammonia The recovery rate is only about 50%, resulting in waste of resources and increased operating costs, and the by-product calcium sulfate has a large output, low value, and poor quality, which makes it difficult to sell and easily causes secondary pollution

Images