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Method for preparing alumina from low-grade bauxite by acid leaching

A low-grade bauxite and alumina technology, applied in chemical instruments and methods, aluminum compounds, inorganic chemistry, etc., can solve the problem of high alumina process cost, and achieve high energy utilization, easy equipment and low production costs. Effect

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

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Problems solved by technology

[0005] Aiming at the problem of high cost of the existing process of extracting alumina by using high-silicon and aluminum-containing minerals, the present invention provides a method for producing alumina by acid leaching of low-grade bauxite, which is carried out according to the following steps:

Method used

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  • Method for preparing alumina from low-grade bauxite by acid leaching

Examples

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Effect test

Embodiment 1

[0022] Take 700 grams of ore sample 1 bauxite, grind it to 100 μm, mix the bauxite with 2600 ml of sulfuric acid with a mass percentage of 98%, and leach at 100 ° C for 1 hour; filter the bauxite leached by sulfuric acid, and make the remaining acid Separate 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.

[0023] The aluminum sulfate solution was heated and concentrated to 1000ml, 3000ml of 38% hydrochloric acid was added, and then HCl gas was introduced to precipitate aluminum chloride crystals, which were filtered to obtain 2057 grams of aluminum chloride crystals.

[0024] Take NH 3 2000ml of 25%wt ammonium hydroxide solution is 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 obtai...

Embodiment 2

[0027] Take 800 grams of ore sample 2 bauxite, grind it to 150 μm, mix the bauxite with 3500 ml of sulfuric acid with a mass percentage of 75%, and leaching at 250 ° C for 1.5 hours; filter the bauxite leached by sulfuric acid, and make the remaining acid Separate 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.

[0028] The aluminum sulfate solution was evaporated and crystallized to obtain 2718 grams of Al 2 (SO4) 3 18H 2 O crystals, aluminum sulfate crystals are mixed with 32% hydrochloric acid 3000ml, then feed HCl gas, separate out aluminum chloride crystals, filter to obtain 2006 grams of aluminum chloride crystals.

[0029] Take NH 3 Content 21%wt ammonium carbonate solution 2000m, aluminum chloride was added into water 2500ml to dissolve, ammonium carbonate solution and aluminum chloride solution were mixed to ...

Embodiment 3

[0032] Take 1,400 grams of kaolin, grind it to 150 μm, mix kaolin with 4,000 ml of sulfuric acid with a mass percentage of 90%, and leach at 200°C for 2 hours; filter the kaolin leached by sulfuric acid to separate the residual 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.

[0033] 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 1929 grams of aluminum chloride crystals.

[0034] Take 400g of liquid ammonia, add aluminum chloride to 2500ml of water to dissolve, and pass liquid ammonia into the aluminum chloride solution to obtain aluminum hydroxide precipitate and ammonium chloride solution. After filtration, the aluminum hydroxide crystals are calci...

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Abstract

The invention discloses a method for preparing alumina from low-grade bauxite by acid leaching, characterized by: grinding the low-grade bauxite, 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 introducing 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 aluminium hydroxide and an ammonium chloride solution, calcining aluminium hydroxide to obtain alumina, carrying out displacement reaction on ammonium chloride and 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 producing alumina by acid leaching of low-grade bauxite. Background technique [0002] The production methods of alumina so far mainly include alkali method and acid method. In the 1960s, Poland used soda-lime sintering to extract alumina from fly ash, and built an experimental plant with an annual output of 5,000 tons of alumina and 350,000 tons of cement. The Commonwealth Scientific and Industrial Research Organization in Melbourne, Australia, proposed the basic aluminum sulfate method, which uses aluminum sulfate solution to dissolve high-silica bauxite to obtain basic aluminum sulfate. The basic aluminum sulfate is calcined at 1150°C to obtain alumina and SO 3 Gas,SO 3 The gas is used to produce sulfuric acid and returned for further use. The French company Bischine invented an acid method that combines concentrated sulfuric acid and hydrochloric acid ...

Claims

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Application Information

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IPC IPC(8): C01F7/26
Inventor 李瑞冰李鑫吴楠李景江
Owner 李景江
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