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, relating to a method comprising the steps of in the production of aluminum oxide, introducing SO4<2-> by adding one or a mixture of more of sodium sulfate, aluminum sulfate (basic aluminum sulfate) and an alunite ore into seeded precipitation evaporation liquor, converting potassium oxide into potassium sulfate, and performing precipitation and separation in a form of sodium aphthitalite, wherein the precipitation is implemented under high-causticizing alkali and low-temperature conditions, so that residual sodium sulfate in the solution can be avoided, and the solution can be purified; sodium aphthitalite can be used for dissolving and separating out a potassium sulfate product by virtue of variable temperature, and sodium sulfate can be recycled; or a high-potassium low-sodium ore is used for generating a pure potassium aluminate solution by using a limestone sintering method, and then the pure potassium aluminate solution is subjected to a replacement reaction with sodium aphthitalite to generate potassium sulfate and sodium aluminate; potassium chloride also can be used for converting sodium aphthitalite into pure potassium sulfate. The method disclosed by the invention can be used for producing aluminum oxide and potassium sulfate by adopting nepheline and the alunite ore by virtue of a multiple process technology, and also can be used for producing chemicals namely aluminum oxide and potassium sulfate by adopting high-silicon ores such as potassium feldspar, lepidolite and illite by virtue of an acid-alkali combination method.

Description

technical field [0001] The invention relates to a method for separating potassium oxide from potassium-containing sodium aluminate solution, relating to a method for separating potassium oxide from potassium-containing species evaporation mother liquor in the process of 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 re...

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, all the mother liquor of carbon fraction 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 Russian industry

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