Dissolution technology of high alumina fly ash by method of sulphuric acid

Abstract

The invention discloses a dissolution technology of high alumina fly ash by a method of sulphuric acid, comprising the following steps: mixing high alumina fly ash with dilute sulfuric acid in proportion to obtain an original pulp A; sending the original pulp A into a dissolution unit through a dissolution charging pump, preheating through grade 1-3 sleevings to obtain a preheat pulp B; heating the sleevings to heat the preheat pulp B to obtain a heating pulp C; sending the heating pulp C in a digester for carrying out insulation dissolution to obtain a dissolved pulp D under the conditions of insulation and pressure maintaining; and carrying out 3-level self-evaporation cooling on the dissolved pulp D, and then sending the cooled dissolved pulp D and an acid sludge washing liquor E into a dilution trap to obtain a mixed pulp F. According to the invention, alumina is dissolved out from the high alumina fly ash and enters in the solution, and the dissolution rate of alumina is 85-90 %, so that the preparation for subsequent production process is made; the high alumina fly ash is utilized reasonably, the cost is low, the advantage of economic rationality is achieved, and the problem of corrosion of devices in the dissolution process is solved.

Description

technical field [0001] The invention relates to the field of alumina industry, in particular to a high-aluminum fly ash dissolution process. Background technique [0002] At present, more than 70 million tons of alumina are produced every year in the world, and almost all alumina plants use bauxite as raw material. my country is the largest alumina producer in the world, with an annual output of about 30 million tons of alumina, accounting for about 40% of the world's total output. However, my country's bauxite resources are relatively poor. Bauxite reserves only account for about 6% of the world's total reserves. The ore grade is low. The ore type is mainly difficult to handle diaspore. , and the production cost is also higher. Due to the serious shortage of bauxite resources in our country, we can only rely on importing ore from abroad to solve the problem of raw materials. my country imports about 30 million tons of bauxite ore annually, accounting for about 50% of the d...

AI Technical Summary

Problems solved by technology

The disadvantage is that aluminum chloride solution is difficult to remove iron and impurities, hydrochloric acid is very corrosive to equipment at a temperature of 80-160 ° C, and some technical and material problems need to be further studied and solved

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