Method for production of alumina, joint product of cement and joint product of 4A zeolite molecular sieve with high aluminum fly ash

Abstract

The invention provides a method for production of alumina, a joint product of cement and a joint product of 4A zeolite molecular sieve with high aluminum fly ash. The production of alumina with high aluminum fly ash comprises the steps of: pre-desilication, raw slurry preparation, clinker calcination, clinker leaching, first and second stage deep desilication, carbon dioxide decomposition, seed precipitation, aluminum hydroxide calcination, thus obtaining alumina. Part of the sodium aluminate crude liquor generated from pre-desilication can be used to synthesize a 4A zeolite molecular sieve with desilication liquor, and residues from clinker leaching can be used for cement production after desilication. Characterized by simple process, low energy consumption, low cost and high utilization rate of raw material, the method of the invention is suitable for industrial application.

Description

technical field [0001] The invention relates to fly ash resource utilization technology, in particular to a method for co-producing alumina, cement and 4A zeolite molecular sieve from high-alumina fly ash. Background technique [0002] With the increasing shortage of bauxite resources in our country, the extraction of alumina from other aluminum-containing resources including high-alumina fly ash has attracted more and more attention. Moreover, there are a large number of high-alumina fly ash resources in my country. For example, due to the special geological background, the Late Paleozoic coal seams and gangue in the Ordos Basin are rich in minerals such as boehmite and kaolinite. The alumina content is as high as about 50%, which is equivalent to that of medium-grade bauxite, and is a very valuable raw material for alumina production. According to statistics, the potential reserves of high-aluminum fly ash in the central and western regions of Inner Mongolia are as high as...

AI Technical Summary

Problems solved by technology

The disadvantages of this process are: the raw material consumption is high, 5 tons of limestone is required to produce 1 ton of alumina, resulting in high energy consumption; and 8 tons of slag are produced, and the amount of slag is too large; the silicon element in the fly ash is all formed into cement, and there is no High value-added utilization possible

In this method, the aluminum and silicon elements contained in the fly ash have been utilized with high technology, but the disadvantages are: the reaction temperature is too high, the time is long, the energy consumption is high, and industrial grade alumina and sodium silicate are added, resulting in The production cost is too high, and the quality of the prepared zeolite molecular sieve is poor, so it is difficult to promote and apply on a large scale

This method is relatively simple in process and low in synthesis temperature, but the disadvantage is that it uses kaolin and expensive active alumina and active silica as raw materials, and the production cost is high.

[0004] In summary, the existing high-alumina fly ash utilization technology is still immature and perfect, and there are problems such as large material consumption, high waste residue output, low added value, high cost and difficulty in industrial production to varying degrees.

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