Method for extracting aluminum oxide from high-alumina coal ash
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A technology of high-alumina fly ash and fly ash, applied in chemical instruments and methods, preparation of alkali metal aluminate/alumina/aluminum hydroxide, aluminum compounds, etc., can solve problems such as refractory metallurgical grade alumina, Achieve the effects of increasing productivity, saving production costs, increasing equipment investment costs and operating difficulty
Inactive Publication Date: 2018-10-09
DATANG INT HIGH ALUMINA COAL R & D CENT
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However, more than 90% of the world's alumina is currently produced by the Bayer process, and the sintering process focuses on the production of v
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Embodiment 1
[0047] This embodiment provides a method for extracting alumina from high-alumina fly ash, such as figure 1 shown, including the following steps:
[0048] 1. Activation treatment
[0049] Put high-alumina fly ash (the ratio of aluminum to silicon is 1.23, the mass content of alumina is 48.6%) and steel balls into the ball mill according to the material-ball ratio 1:1.3 and ball mill for 1.5 hours, so that the average particle size of high-alumina fly ash powder The diameter reaches 3 μm ~ 15 μm.
[0050] The obtained high-aluminum fly ash powder was taken out from the ball mill, and mixed evenly with a sulfuric acid solution with a mass concentration of 13.5% according to the liquid-solid mass ratio of 3.5:1, reacted at 85°C for 100 minutes, and finally filtered and separated the reaction product. Obtain pretreatment fly ash and activation mother liquor.
[0051] 2. Pre-desilication treatment
[0052] Mix the sodium hydroxide solution with a mass concentration of 20% and t...
Embodiment 2
[0072] This embodiment provides a method for extracting alumina from high-alumina fly ash, such as figure 1 As shown, it specifically includes the following steps:
[0073] 1. Activation treatment
[0074] Put high-alumina fly ash (the ratio of aluminum to silicon is 1.23, and the mass content of alumina is 48.2%) and steel balls in a ball mill according to the material-ball ratio of 1:2.5 and ball mill for 1.0 hour, so that the average particle size of high-alumina fly ash powder Reach 3μm ~ 15μm.
[0075] The obtained high alumina fly ash powder is taken out from the ball mill, and mixed with an acid treatment agent (a mixed aqueous solution of sulfuric acid and hydrochloric acid, wherein the mass concentration of sulfuric acid is 5.5%, and the mass concentration of hydrochloric acid is 7.0%) according to the liquid-solid mass ratio of 4:1 Mix evenly, react at 70°C for 120 minutes, and finally filter and separate the reaction product to obtain pretreated fly ash and activa...
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Abstract
The invention provides a method for extracting aluminum oxide from high-alumina coal ash. The method comprises the following steps: activating the high-alumina coal ash, and performing solid-liquid separation to obtain pretreated coal ash and activated mother liquid; performing pre-desiliconization treatment on the pretreated coal ash, and performing solid-liquid separation to obtain desiliconizedcoal ash and desiliconized liquid; performing Bayer dissolution on the desiliconized coal ash, and performing solid-liquid separation on dissolved slurry to obtain a sodium aluminate solution and Bayer dissolved slag; performing hydrothermal reaction on the Bayer dissolved slag and lime milk, and performing solid-liquid separation to obtain silicon-calcium slag and a recycled alkaline solution; performing seed precipitation decomposition on the sodium aluminate solution to obtain aluminum hydroxide and seed precipitation decomposition mother liquid; and calcining the aluminum hydroxide to obtain aluminum oxide. According to the method disclosed by the invention, after the high-alumina coal ash is activated and desiliconized, the aluminum oxide is extracted by adopting a Bayer process, sothat a high-quality metallurgy-level aluminum oxide product can be obtained, and alkali in the Bayer dissolved slag can be recycled; and the method has the process characteristics of low cost, low energy consumption and the like and has the advantage of simplicity in operation.
Description
technical field [0001] The invention relates to resource utilization of high-alumina fly ash, in particular to a method for extracting alumina from high-alumina fly ash. Background technique [0002] Alumina is the main raw material for the production of aluminum ingots. More than 95% of the world's alumina is produced through bauxite. my country is the world's largest producer of alumina, and currently produces more than 30 million tons of alumina per year. But at the same time, my country's bauxite resources are relatively scarce, and the bauxite reserves only account for about 7% of the world's total reserves, and most of them are difficult-to-handle diaspore ores. Due to insufficient bauxite resources, currently about 60% of bauxite depends on imports from abroad. [0003] However, the reserves of high-aluminum fly ash produced by coal power generation in central and western Inner Mongolia and northern Shanxi in my country are abundant. The potential reserves of high-...
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