Method for separating potassium oxide from potassium-containing sodium aluminate solution

Abstract

The invention discloses a method for separating potassium oxide from a potassium-containing sodium aluminate solution, and relates to a method for separating potassium oxide from an evaporated sodium aluminate solution in an aluminum oxide production process. Potassium oxide is converted into potassium sulfate by adding sodium sulfate (or alunite for reaction to produce sodium sulfate) into the sodium aluminate solution and introducing SO4<2->, and is precipitated and separated in a form of aphthitalite, sodium sulfate and a little sodium carbonate mixture. The precipitation is performed under the condition of high caustic alkali and low temperature, and the residual of sodium sulfate in the solution can be avoided. A separation product can separate a potassium sulfate product according to a phase diagram, and sodium sulfate is recycled, or potassium chloride converts the mixture into pure potassium sulfate. The method achieves the output of sodium sulfate, and aluminum oxide and potassium sulfate can be co-produced by employing nepheline and alunite by a parallel serial method, and can be produced by employing high silicon ore such as nepheline and illite by an acid-alkali combined method.

Description

technical field [0001] A method for separating potassium oxide from potassium-containing sodium aluminate solution relates to a method for separating potassium oxide from evaporated potassium-containing sodium aluminate solution during alumina production. Background technique [0002] Potassium salt is an important chemical raw material and agricultural fertilizer. In industry, potassium chloride is produced through water-soluble potassium-containing resources such as salt lake water and potash mines, and then a part of it is converted into other potassium salt products such as potassium sulfate. Water-insoluble potassium ore is another potassium-containing resource. A lot of research has been done on its utilization internationally, but large-scale industrial production has not been realized because the production cost is higher than that of water-soluble potassium salt. my country's water-soluble potassium resources are scarce, and the reserves of insoluble potassium ore a...

AI Technical Summary

Problems solved by technology

Although potassium oxide is beneficial to the process, its price is much higher than that of sodium oxide, and it is a pity to lose it

[0004] When producing alumina by the sintering method of potassium-rich and aluminum-containing raw materials, the potassium-containing sodium aluminate solution is first carbonated and decomposed to convert caustic soda into carbon soda, and then separate the two through evaporation according to the difference in solubility of potassium carbonate and sodium carbonate , because the solubility of potassium carbonate is much greater than that of sodium carbonate, in order to obtain potassium carbonate, the carbon mother liquor needs to be evaporated to dryness, and a large amount of mixture of potassium and sodium carbonate is precipitated during the evaporation process, and the separation cost is high. This method is only used in the former Soviet Union industry

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