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Method for preparing alumina by using power plant fly ash

A technology for power plant fly ash and alumina, applied in the field of non-ferrous metal metallurgy, can solve the problem of high alumina process cost, achieve the effects of high energy utilization rate, low production cost and simplified process steps

Inactive Publication Date: 2013-01-02
李景江
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Aiming at the problem of high cost of the existing process of extracting alumina by using fly ash, the present invention provides a new method for producing alumina by utilizing fly ash of a power plant. The present invention proceeds according to the following steps:

Method used

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  • Method for preparing alumina by using power plant fly ash

Examples

Experimental program
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Effect test

Embodiment 1

[0016] Take 1,000 grams of fly ash, grind it to 100 μm, mix the fly ash with 2,600 ml of sulfuric acid with a mass percentage of 75%, and leach at 100°C for 1 hour; filter the fly ash leached by sulfuric acid to separate the remaining acid from the filter residue . Add 3000ml of water to the filter residue, boil and dissolve at 50°C for 30 minutes to dissolve the reactant, filter to remove the residue, and obtain an aluminum sulfate solution.

[0017] The aluminum sulfate solution was heated and concentrated to 1000ml, 5500ml of 15% hydrochloric acid was added, and then HCl gas was introduced to precipitate aluminum chloride crystals, which were filtered to obtain 1853 grams of aluminum chloride crystals.

[0018] use NH 3 1750ml of 25%wt ammonium hydroxide solution was reacted with aluminum chloride solution to obtain aluminum hydroxide precipitate and ammonium chloride solution. After filtration, aluminum hydroxide crystals are calcined at 1100°C to obtain Al 2 o 3 358.5...

Embodiment 2

[0021] Take 1,000 grams of fly ash, grind it to 125 μm, mix the fly ash with 6,000 ml of sulfuric acid with a mass percentage of 80%, and leach at 150°C for 1.5 hours; filter the fly ash leached by sulfuric acid to separate the residual acid from the filter residue . Add 3500ml of water to the filter residue, boil and dissolve at 60°C for 40 minutes to dissolve the reactant, filter to remove the residue, and obtain an aluminum sulfate solution.

[0022] Evaporate and crystallize the aluminum sulfate solution to obtain 2719 grams of Al 2 (SO4) 3 18H 2 O crystals, aluminum sulfate crystals are mixed with 4500ml of 32% hydrochloric acid, then feed HCl gas, separate out aluminum chloride crystals, filter to obtain 1916 grams of aluminum chloride crystals.

[0023] use NH 3 1750ml of 25%wt ammonium hydroxide solution was reacted with aluminum chloride solution to obtain aluminum hydroxide precipitate and ammonium chloride solution. After filtering, calcining aluminum hydroxide...

Embodiment 3

[0026] Take 1,000 grams of fly ash, grind it to 150 μm, mix the fly ash with 3,500 ml of sulfuric acid with a mass percentage of 90%, and leach at 200°C for 2 hours; filter the fly ash leached by sulfuric acid to separate the remaining acid from the filter residue . Add 4000ml of water to the filter residue, boil and dissolve at 70°C for 45 minutes to dissolve the reactant, filter to remove the residue, and obtain an aluminum sulfate solution.

[0027] The aluminum sulfate solution was heated and concentrated to 1000ml, 3500ml of 25% hydrochloric acid was added, and then HCl gas was introduced to precipitate aluminum chloride crystals, which were filtered to obtain 1911 grams of aluminum chloride crystals.

[0028] Take 400g of liquid ammonia, add aluminum chloride to 2500ml of water to dissolve, and mix the liquid ammonia with the aluminum chloride solution to obtain aluminum hydroxide precipitate and ammonium chloride solution. After filtration, the aluminum hydroxide cryst...

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Abstract

The invention discloses a method for preparing alumina by using power plant fly ash, characterized by: grinding the fly ash, leaching with concentrated sulfuric acid to obtain an aluminum sulfate solution, precipitating aluminum sulfate crystals by concentrating and cooling, dissolving the aluminum sulfate crystals with hydrochloric acid, then letting an HCl gas in the solution to saturate the solution to precipitate AlCl3-6H2O crystals, reacting the AlCl3-6H2O crystals with an ammonium hydroxide solution or liquid ammonia or an ammonium bicarbonate solution or an ammonium carbonate solution to obtain an aluminium hydroxide and ammonium chloride solution, calcining aluminium hydroxide to obtain alumina, displacing ammonium chloride by using magnesium oxide to obtain ammonia gas and magnesium chloride, and hydrolyzing magnesium chloride to obtain magnesium oxide and hydrochloric acid for recycling.

Description

technical field [0001] The invention belongs to the field of non-ferrous metal metallurgy, and relates to a method for preparing alumina by using power plant fly ash. Background technique [0002] Fly ash, as a solid discharge from coal-fired power plants, has an annual output of more than 200 million tons, and a cumulative stockpiling of more than 2.5 billion tons. The stacking of fly ash occupies a large amount of land and poses a threat to agriculture and human health in adjacent areas. harm. The main component of fly ash is Al 2 o 3 , SiO 2 and Fe 2 o 3 etc., where Al 2 o 3 The content is 20-40%. Using fly ash as a raw material to extract alumina and other useful substances solves the environmental pollution caused by fly ash and also solves the problem of shortage of alumina resources, which is of great significance. [0003] So far, the production methods of alumina mainly include alkaline method and acid method. Fly ash is used to extract alumina. Many researc...

Claims

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Application Information

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IPC IPC(8): C01F7/30
Inventor 李瑞冰李鑫吴楠李景江
Owner 李景江
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