Method for recycling potassium carbonate from aluminum oxide production process

Abstract

The invention relates to a method for recycling potassium carbonate from an aluminum oxide production process. The method is characterized by comprising the steps that 1, a carbonation decomposition reaction is conducted on mother liquor or a stock solution decomposed through a Bayer process; 2 filtering is conducted; 3, aluminum hydroxide carbon points are washed and then sent to a flash vessel obtained after Bayer digestion for post densification digestion digestion, and a product serves either as aluminum hydroxide seeds of the decomposition procedure or as an aluminum hydroxide product; 4, carbonic acid mother liquor and aluminate hydrate wash liquor are subjected to preliminary vacuum evaporation and preliminary cooling crystallization; 5, preliminary vacuum evaporation mother liquor is subjected to secondary vacuum evaporation and secondary cooling crystallization; 6, generated sodium potassium carbonate double salt crystals are dissolved with the carbonic acid mother liquor and then sent to preliminary vacuum evaporation; 7, generated secondary vacuum evaporation mother liquor is subjected to third vacuum evaporation and third cooling crystallization; 8, obtained third vacuum evaporation mother liquor and secondary vacuum evaporation mother liquor are mixed and then subjected to third vacuum evaporation; 9, obtained potassium carbonate crystals are sintered, and the potassium carbonate is obtained. A potassium carbonate product obtained through the method is high in economic value, and adverse influences generated by K<+> accumulated in the aluminum oxide production process can be eliminated.

Description

technical field [0001] A method for recovering potassium carbonate from an alumina production process relates to a method for recovering potassium carbonate from a sodium aluminate solution rich in potassium. Background technique [0002] Potassium carbonate is widely used in the fields of chemical industry, electronics, glass, ceramics and medicine, and is an important industrial raw material. Most of the foreign potassium ore resources are water-soluble, and the production cost is low; most of the domestic potassium ore resources are nepheline, potassium feldspar and other non-water-soluble potassium-containing minerals, the production process is complicated, and the production cost is high. [0003] The bauxite in some areas of my country contains a relatively high content of potassium, which will gradually accumulate during the alumina production process, and when it accumulates over a certain critical concentration in the alumina production process, it will cause the pa...

AI Technical Summary

Problems solved by technology

Most of the foreign potash resources are water-soluble, and the production cost is low; most of the domestic potash resources are nepheline, potassium feldspar and other non-water-soluble potassium-containing minerals, the production process is complicated, and the production cost is high

[0003] The bauxite in some areas of my country contains a relatively high content of potassium, which will gradually accumulate during the alumina production process, and when it accumulates over a certain critical concentration in the alumina production process, it will cause the particle size of the decomposition product to become finer, etc. At the same time, the obtained alumina product contains a certain amount of potassium, which in turn has an adverse effect on the electrolytic aluminum process.

For example, K in the circulating mother liquor of some alumina plants 2 The concentration of O has exceeded 100g / L after accumulation, and there is a rising trend, which has a negative impact on the alumina production process. At the same time, the alumina product as a raw material for electrolytic aluminum also has a negative impact on the electrolytic aluminum process.

So far there is a lack of effective inhibition of K in the mother liquor 2 The method for the influence of O on the production process of alumina also lacks the method of effectively suppressing the influence of potassium in alumina on the production process of electrolytic aluminum