Chemical deashing method for coal

Abstract

The invention discloses a chemical deashing method for coal, belonging to the technical field of clean coal. A novel deashing acid solution is adopted for deashing coal and is a mixed acid of hydrofluoric acid and at least one other inorganic acid, wherein the mass percentage content of the hydrofluoric acid is 5-30%, the mass percentage content of other inorganic acids is 10-40%, and total acid concentration is 10-40%; during acid leaching, the mass ratio of the deashing acid solution to the raw material coal is (1-6):1, reaction temperature is 10-80DEG C, and the process of acid leaching lasts for 4-24 hours; and meanwhile, after exhaust gas and scouring water, generated in a defluorination processing, are graded and reused and a waste mixed acid solution is repeatedly reused, a lime solution is adopted for absorption. The method provided by the invention is suitable for deashing larger coal particles of which the diameter is 1-5mm, and can achieve a better deashing effect. A moderate reaction condition is adopted to ensure that the deashing mixed acid containing hydrofluoric acid is difficult to volatilize, so that energy consumption and cost are lowered and environmental pollution is lightened at the same time.

Description

technical field [0001] The invention relates to a preparation method of high-purity coal, in particular to a chemical deashing method of coal. Background technique [0002] my country's coal resources are rich and complete, but the content of inorganic minerals (ash) is relatively high, which limits the wide application in industry to a certain extent. In particular, the application of coal in the fields of carbon electrode manufacturing, graphite products, activated carbon, high-temperature lubrication, and oil substitution for internal combustion engines has put forward higher requirements for the ash content of coal. The storage and transportation of high ash coal also has the problem of high cost consumption. Therefore, the development of coal deashing technology for a long time has become a widely studied clean coal technology. [0003] At present, the methods of coal deashing to prepare high-purity coal and ultra-pure coal are mainly divided into three categories: ph...

AI Technical Summary

Problems solved by technology

However, grinding coal to a certain extent will increase energy consumption, and will also bring difficulties to subsequent treatments such as filtration and washing, resulting in large loss of raw materials and reduced production efficiency.

At the same time, due to the fine particle size of deashed coal, its application range is limited.