Method for producing aluminum oxide and co-producing active calcium silicate through high-alumina fly ash

Abstract

The invention provides a method for producing alumina and co-producing active calcium silicate with high-alumina fly ash. The steps include: first reacting high-alumina fly ash with sodium hydroxide solution to perform pre-desilication to obtain liquid-phase desiliconization liquid and Desiliconized fly ash in solid phase; add milk of lime to the desiliconized liquid for causticization reaction, the solid phase is active calcium silicate, and the finished product is obtained by pressure filtration and flash drying; add limestone and carbonic acid to the desiliconized fly ash The sodium solution is formulated into a qualified raw slurry, and then the qualified raw slurry is roasted into clinker, and the liquid phase dissolved in the clinker is sodium aluminate crude solution; the sodium aluminate crude solution is desiliconized, carbonized, and seeded in the first and second stages. Metallurgical grade alumina that meets the requirements can be obtained after processes such as calcination and roasting. The invention overcomes the defects in the prior art, realizes less material flow and slag formation, relatively low energy and material consumption and production costs, high alumina extraction rate, and co-produces active calcium silicate with high added value, which can be used Widely used in chemical industry.

Description

technical field [0001] The invention relates to high-tech resource utilization of fly ash, in particular to a method for producing alumina and co-producing active calcium silicate from high-alumina fly ash. Background technique [0002] With the increasing shortage of bauxite resources, the use of fly ash, coal gangue and other industrial solid wastes to extract alumina has attracted more and more attention. The extraction of alumina from high-alumina fly ash and other aluminum-containing resources has attracted more and more attention. For example, the Late Paleozoic coal seams and gangue in the Ordos Basin are rich in boehmite and kaolinite and other minerals, and the alumina content in the fly ash produced after combustion is as high as 50%, which is the same as that in medium-grade bauxite. Rather, it 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 Inn...

AI Technical Summary

Problems solved by technology

Although these patents have considered the phase characteristics of fly ash and adopted the idea of ​​extracting silicon first and then aluminum to reduce energy consumption and improve element utilization, the white carbon black produced after silicon extraction currently has a small market share in China. , the disadvantage of limited dosage, and the production of white carbon black by the carbon separation method is difficult to control compared with the traditional acid method to produce white carbon black, the equipment is more complicated, and the cost is higher

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