Method for extracting alumina from fly ash based on ammonium sulfate activation process

Abstract

The invention relates to a method for extracting aluminum oxide from fly ash based on an ammonium sulfate activation process. By adopting roasting of the fly ash and ammonium sulfate, combined impurity removal and a two-section fluidized roasting system, the problem of high corrosion of equipment in the background technology is solved; a process chain of a main flow is shortened; through the roasting system, the roasting process is low in energy consumption, economic and low in cost by using methods such as two-section cyclic fluidized roasting and dense phase transportation; and the technical problem of material melting, wall sticking, caking or ring forming is solved.

Description

technical field [0001] The invention relates to a method for extracting alumina from fly ash based on an ammonium sulfate activation process. Background technique [0002] Thermal power generation occupies a dominant position in my country's power generation structure, and coal-fired thermal power generation occupies an absolute proportion in thermal power generation. Fly ash is a solid waste discharged from coal-fired power plants. [0003] In recent years, with the development of the power industry, the emission of fly ash has increased sharply. According to the report of China Coal Industry Association in January 2009, the total coal production in my country in 2008 was 2.716 billion tons, most of which were used for power generation , the annual discharge of fly ash in my country has exceeded 200 million tons, and the cumulative stockpiles have exceeded 2.5 billion tons, occupying a large amount of arable land and polluting the environment on a large scale. Therefore, ca...

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Problems solved by technology

[0008] In the process of extracting alumina by acid leaching or sintering alkali fusion, in order to remove impurities in the solution, the Bayer method in the alumina industry is basically used to remove impurities, resulting in a long process chain, large equipment investment, and energy consumption. At the same time, whether it is the mixing of fly ash and activating material at high temperature or the calcination of aluminum salt to produce alumina, it needs to be roasted. During the roasting process, the energy consumption is high, and it is very easy for the material to melt and stick to the wall, agglomerate or agglomerate. Phenomena such as circles

Therefore, due to the above reasons such as high cost and difficult process operation, the extraction of alumina from fly ash has not been able to realize industrial production for a long time.

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