Device for calcining aluminum oxide clinker by directly utilizing coal powder and method thereof

Abstract

The apparatus for calcining alumina clinker with coal powder includes one hearth with one temperature measuring thermocouple connected to the first temperature controlling instrument to measure the temperature in the upper part of the hearth and one temperature controlling thermocouple connected to the second temperature controlling instrument to control the temperature rise in the hearth, one coal feeder in the inlet of the hearth, one coal powder mixer with burner connected to the coal feeder, one cyclonic separator and one induced draft fan connected to the outlet of the hearth, one flowmeter and one air flow rate regulating valve connected between the coal powder mixer and one air tank, and one air compressor connected to the air tank. During calcining alumina clinker proper amount ofcalcium containing material is added into high aluminum coal powder, and the present invention has low power consumption for extracting alumina from coal powder.

Description

technical field [0001] The invention belongs to the technical scope of high-efficiency pulverized coal combustion and high-efficiency and low-energy utilization of low-grade resources, and particularly relates to a device and method for preparing pulverized coal, high-efficiency pulverized coal combustion, pneumatic transportation, high-temperature separation of fly ash, and calcining alumina clinker. In particular, a device and method for directly using coal powder to calcinate alumina clinker. Background technique [0002] With the super-rapid development of thermal power plants, the amount of coal burned by power plant boilers reaches 1.2-1.4 billion tons every year, and the amount of fly ash discharged every year reaches 200-400 million tons, especially in major cities such as Ningxia, Inner Mongolia, Shanxi, and Shaanxi. Coal-producing areas produce a large amount of high-alumina coal every year, of which the amount of fly ash with an alumina content higher than 30% is ...

AI Technical Summary

Problems solved by technology

The operation of this kind of pulverized coal boiler brings two more serious problems. One is that a large amount of fly ash by-product will cause serious pollution problems to land and water sources.

Second, the sulfur dioxide and a small amount of fly ash in the flue gas also bring environmental pollution to the atmosphere

[0013] In 2001, Rayalu et al studied the synthesis of zeolite from flyash after burning bituminous coal and lignite (S.S.Rayalu, J.S.Udhoji, K.N.Munshi, M.Z.Hasan. Highlycrystalline zeolite-a from flyash of bituminous and lignite coalcombustion[J].Journal of Hazardous Materials, 2001, 88(1): 107-121), the test shows that SiO 2 / Al 2 o 3 When the ratio is 3.47, it is most beneficial to the synthesis of porous zeolite, which shows that it is feasible to synthesize different materials using fly ash; this document describes the utilization of fly ash in India (R.H.Matjie, J.R.Bunt, J.H.P. .Extraction of alumina from coal fly ash generated from a selected low rank bituminous South African coal[J].Minerals engineering.2004, 18:299~310), India is similar to China, 75% of electricity comes from thermal power generation, India currently pulverized coal The ash utilization rate also reaches 27% (the world's average level reaches 33%), which is much higher than that in China. The article also mentions the extraction of alumina in fly ash, but there is no good way

[0014] R.H.Matjie et al. (P.Asokan, Mohini Saxena, Shyam R.Asolekar.Coalcombustion residues-environmental implications and recycling potentials[J].Resources Conservation and Recycling.2005,43:239~262) on high-aluminum coal (coal ash contains 30% Aluminum, 1.5% titanium, 2.5% alumina, 9.5% calcium oxide, 60% silicon dioxide) were extracted and studied. The fly ash was mixed with calcium oxide and calcined at 1000°C to 1200°C to generate acid or alkali soluble Calcium aluminate, then washed with sulfuric acid to produce a solution containing iron, aluminum and titanium, at 80°C, the concentration is 6.12mol / m 3 Immersed in acid for 4 hours, the final aluminum recovery efficiency reached 85%, and the extracted aluminum-containing substances contained 99.4% of high-purity alumina. It has application value, but the method in this article is still re-calcination method, and the energy consumption is very high

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