Method for producing xonotlite and aluminum oxide according to coal ash sintering hydrothermal method

Abstract

The invention relates to a method for producing xonotlite and aluminum oxide according to a coal ash sintering hydrothermal method. The method provided by the invention comprises the following steps: putting coal ash in an ingredient of a chemical beneficiation solvent for chemical beneficiation and then separating and washing so as to prepare concentrate of coal ash; (2) preparing raw slurry; (3) sintering to prepare a clinker; (4) dissolving out the clinker and separating and washing the clinker; (5) preparing xonotlite precursor original slurry; (6) hydrothermally synthesizing to prepare an xonotlite precursor; (7) hydrothermally synthesizing to prepare an xonotlite filter cake. The method provided by the invention can be used for effectively solving the problem and defect in the prior art that the consumption of limestone is great, the consumption of energy resources is great and the quantity of slag is great. Coal ash is comprehensively utilized to produce xonotlite and aluminum oxide, so that the silicon mineral source is replaced, the bauxite resource is replaced, and resources such as land are saved; moreover, large-scaled economic production can be realized.

Description

technical field [0001] The invention relates to a comprehensive utilization method of fly ash, in particular to a method for producing xonotlite and alumina by a fly ash sintering hydrothermal method. Background technique [0002] Some coal fields in central and western Inner Mongolia and northern Shanxi are rich in high-alumina coal resources, with prospective reserves of nearly 100 billion tons, equivalent to about 15 billion tons of high-alumina fly ash, which is equivalent to the current reserves of bauxite in my country More than 8 times of that, and the alumina content in some fly ash can reach 40~50%. This kind of fly ash is generally called high aluminum fly ash. Fly ash is the main solid waste from the perspective of power generation in power plants, but the alumina content in the high-alumina fly ash produced by the combustion of high-alumina coal can reach 35-45%, some even as high as 50%, and the silicon content is generally 35%. %above. High-alumina fly ash is ...

AI Technical Summary

Problems solved by technology

Except for the pre-desilication-soda lime sintering method to achieve industrial demonstration production capacity, most of the other technological levels are still at the stage of expansion or semi-industrial testing. Utilization and other issues; the pre-desilication-soda lime sintering method is currently a process that can realize industrial production, but this process still has problems such as large consumption of limestone, high energy consumption for burning lime, large amount of tailings, and difficulty in utilization.

[0007] The traditional process produces xonotlite and its products, and its siliceous raw material is generally produced by using diatomite or quartz sand and alkali under melting conditions to generate industrial water glass. In the preparation process of raw materials, it is necessary to use a large amount of high-quality silicon ore such as quartz sand and diatomaceous earth to co-melt with soda ash or sodium sulfate in a melting kiln, and then cool, pulverize and dissolve to make it; this makes the selection of silicon raw materials require mining and Consume a large amount of non-renewable silicon mineral resources such as quartz and diatomaceous earth; at the same time, calcareous raw materials generally need to use high-quality fuels such as coke or white coal to separately burn lime and refined milk of lime, which consumes a lot of energy and costs, and is harmful to resources and the environment. Great impact

[0008] Existing various processes for producing aluminum hydroxide or aluminum oxide with high alumina fly ash all produce a large amount of silicon-calcium slag or silicon slag, a large amount of silicon-calcium slag or The large-scale rational utilization of silicon slag has become a huge bottleneck in various processes

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