A clean process for preparing activated alumina from fly ash

Abstract

The invention discloses a clean process for preparing activated aluminum oxide by using pulverized fuel ash. The clean process comprises the following steps that 1, pulverized fuel ash is activated; 2, leaching with a mixed alkaline liquor and solid-liquid separation are performed; 3, carbonating disintergration and wash-drying are performed; 4, calcination is performed. The red sludge from an aluminum oxide enterprise is used for replacing limestone, the pulverized fuel ash is activated by adopting a low-temperature sintering process, and then Al2O3 is dissolved out of the mixed alkaline liquor. Waste residues are modified, waste water is treated, energy is recovered, the resource utilization rate and waste recovery rate are high, and the cleaning degree of the process meets the requirement for three-level clean production in the domestic aluminum oxide industry.

Description

technical field [0001] The invention relates to a process for preparing activated alumina, in particular to a clean process for preparing activated alumina from fly ash. Background technique [0002] Fly ash is solid waste discharged from thermal power boilers in coal-fired power plants and manufacturing enterprises, with an annual discharge of nearly 300 million tons. Fly ash is generally stacked in the open air, and after sun exposure, rain, weathering, and decomposition, a large amount of acidic water or ionized water carrying heavy metals is produced, which infiltrates and damages groundwater quality, and the outflow leads to surface water pollution, weathered particles pollute the atmosphere, and landslides and natural disasters such as landslides. γ-Al 2 o 3 As a kind of activated alumina, due to its high temperature resistance, wear resistance, oxidation resistance and porous characteristics, it has become the catalyst carrier with the best performance and is widel...

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Problems solved by technology

The soda lime sintering method and the acid-dissolved precipitation method are seriously polluted, the utilization rate of the residue is low, and it is easy to cause secondary accumulation; the fluoride fluxing method is toxic, and the operation risk is high. The process is complicated due to the removal of fluorine in the later stage, and the cost of water treatment is high; Although the limestone sintering method has the advantages of cheap and easy-to-obtain raw materials, high utilization rate of the residue (red mud), and self-pulverization of the sintered material, the energy consumption is too high (sintering temperature is above 1200°C), and the leaching section in the later stage is due to Na is used 2 CO 3 A single lye will lead to secondary reactions in the leaching process, greatly increasing the silicon content in the eluate, and producing a large amount of silicon slag after desiliconization. The process is complicated and the cost is high, so it is difficult to popularize and apply

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