Method for preparing ammonium sulfate and sodium bicarbonate from sodium sulfate

Abstract

The invention provides a method for preparing ammonium sulfate and sodium bicarbonate from sodium sulfate, which adopts an ammonium source as a conversion medium for preparing ammonium sulfate and sodium bicarbonate from sodium sulfate. The ammonium source comprises any one or a mixture of at least two of diammonium hydrogen phosphate, ammonium formate or ammonium nitrate. The method is simple inprocess and low in cost, the utilization rate of sodium sulfate is larger than 85%, the purity of sodium bicarbonate is larger than or equal to 90%, and the purity of the ammonium sulfate product meets the requirements of GB535-1995.

Description

technical field [0001] The invention belongs to the field of chemical technology, in particular to a method for preparing sodium bicarbonate, in particular to a method for preparing ammonium sulfate and sodium bicarbonate from sodium sulfate. Background technique [0002] Sodium bicarbonate is an important chemical and an intermediate in the preparation of soda ash. Sodium bicarbonate is generally produced from sodium chloride through the Solvay method or combined alkali-making method, while the raw material sodium chloride is mostly obtained by drying and refining seawater or obtaining it through salt wells. With the substantial increase in the demand for soda ash in industrial production, the raw material of sodium chloride is in a tense situation. At the same time, my country produces a large amount of sodium sulfate. According to statistics, my country's annual by-product sodium sulfate reaches more than 10 million tons, while the sales volume of sodium sulfate is less...

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 the ammonium sulfate with pure phase cannot be obtained, and the cost is high, so that the technology of sodium sulfate to prepare soda ash is at a standstill

Disclosed in CN101544385A is a kind of method that takes sodium sulfate as raw material and supplements organic amine to prepare sodium carbonate to co-produce calcium sulfate, and this method can realize that the conversion rate of sodium reaches more than 90%; High consumption; the entrainment of organic amines in sodium bicarbonate and calcium sulfate is more, the recovery is difficult, the loss is more, and the production cost will be relatively high

[0007] CN104355326A, CN102198953A and CN202016881U all disclose a kind of method that double decomposition method prepares sodium bicarbonate co-production ammonium sulfate, it uses sodium sulfate and ammonium bicarbonate as raw material, obtains sodium bicarbonate by double decomposition reaction, and the mother liquor that separates obtains is decomposed by high temperature. Ammonia, evaporated and concentrated at 130°C to obtain sodium sulfate crystals, after separation, the mother liquor was cooled and crystallized to obtain the double salt of sodium sulfate and ammonium sulfate, and the mother liquor was evaporated and crystallized to obtain ammonium sulfate product. 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

The cooling temperature of this method is too low, the optimal cooling temperature is -5°C to -2°C, the energy consumption is high, and the overall yield is low, the utilization rate of sulfate is only about 25%, the material circulation is large, and the production and operation cost is high , so far failed to achieve industrialization

[0009] Disclosed a kind of precipitation method among CN105000579A and CN105712382A, this kind 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 the recovery rate of this process ammonia Only about 50%, resulting in waste of resources and increased operating costs, and the calcium sulfate produced has large output, low value, poor quality, difficult sales, and easy to cause secondary pollution

[0010] Disclosed in CN103754898A is a method of utilizing sodium sulfate and calcium chloride to prepare sodium chloride and combining the joint alkali-making method to produce sodium carbonate. The method uses sodium sulfate and calcium chloride as raw materials, and obtains sodium chloride solution and sulfuric acid by double decomposition reaction Calcium solids, and then produce sodium carbonate through the combined soda production method. This method is simple and easy to implement, and the process is mature, but it still does not bypass the generation of new solid waste calcium sulfate, and has not been popularized and applied.

[0011] From the above studies, it can be seen that the current technology for preparing sodium bicarbonate from sodium sulfate has problems such as complicated process, low sodium utilization rate, and low purity of ammonium sulfate.

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