Method for producing superfine white carbon black, ferric hydroxide and aluminum oxide by using coal ash

Abstract

The invention belongs to a resourceful, economic and fine utilization method of coal ash, and relates to a method for producing superfine white carbon black, ferric hydroxide and aluminum oxide by using coal ash. The method comprises the following steps of: with the coal ash as a raw material and a sulfuric acid and caustic soda solution as a solvent, grinding the coal ash, heating to assist in dissolving the coal ash, carrying out acid leaching on the coal ash, and then, filtering and cleaning the coal ash to obtain a filtrate, wherein the filtrate is used for preparing the ferric hydroxide and the aluminum oxide, a filter cake obtained through leaching and filtering is used for preparing the superfine white carbon black, and a fluoride-contained gas generated through leaching is used for absorbing and preparing an AlF3 product. By using the method, the problem that the industrial application can not be realized because the traditional coal ash leaching way is low in useful substance leaching rate is better solved fundamentally, and the total useful substance dissolution rate of the coal ash can be increased from 15-20% to 75-85%, so that resourceful utilization, economic and fine utilization, product diversification and higher additional value of the coal ash can be realized.

Description

technical field [0001] The present invention belongs to the method of fly ash resource utilization and economic refinement; in particular, it uses fly ash produced in thermal power generation and heat supply production as raw material to produce ultrafine hydrated silica (i.e. ultrafine white carbon black ), ferric hydroxide, alumina and aluminum trifluoride products. Background technique [0002] Fly ash is the product of pulverized coal combustion in thermal power generation and heating production. Its main available substances are Al, Fe, Si. Of which SiO 2 The highest content is 40% to 60%, which is 20% to 30% of alumina and 4% to 20% of iron oxide. According to the test results, it is not difficult to see that it can be used as a good product resource. my country is a big country of thermal power generation and heating supply. With the rapid development of thermal power generation and heating industry, the annual production of fly ash is also increasing day by day; ...

AI Technical Summary

Problems solved by technology

Even so, although certain results have been achieved, its development and utilization level is limited to the building materials industry, and the utilization of fly ash is very low, less than 5%, which is only in the initial stage of development and utilization; Compared with the United States, which has a high level of development and utilization, there is a big difference

Due to problems such as the inability to open Al~Fe~Si bonds during leaching, the output of water treatment agents is low, the product cost is too high and the developed products are single, resulting in the inability to carry out industrial production.

It can be seen from this that the low leaching rate of Al and Fe substances in the utilization of fly ash and the high single cost of the developed material are the key difficulties that lead to the promotion and application of the comprehensive utilization technology of the chemical composition of fly ash.

[0003] People in the industry know that fly ash has the following characteristics from the analysis of its chemical composition: first, the content of silicon, aluminum, and iron is high and the output is huge, which can be used as a rich product resource; The low leaching rate of useful substances in the conventional liquid phase leaching method has become a key and difficult problem

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