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Method for producing aluminum oxide from fly ash

A technology for fly ash and alumina, applied in the removal of alumina/aluminum hydroxide and solid waste, can solve the problems of strong acid, large consumption of soda ash, large amount of slag, large amount of clinker, etc. The effect of less phase residue, small material flow, mature and reliable technology

Active Publication Date: 2012-02-15
河南华慧有色工程设计有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The acid method uses H 2 SO 4 Or acidic materials such as HCl put forward higher requirements on the corrosion resistance of production equipment. In order to solve the problem of corrosion resistance of production equipment, more expensive corrosion-resistant materials have to be used; The energy consumption is too high, and the amount of slagging after alumina extraction is large
[0011] The consumption of strong acid and soda ash (or caustic soda) in the acid-base mixing method is too large, and AlCl needs to be removed 3 solution or Al 2 (SO 4 ) 3 Impurities such as Fe in the solution are unfavorable factors that limit the industrialization of this technology

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] The raw material is fly ash from a thermal power plant, the main chemical composition is Al 2 o 3 38%, SiO 2 45.2%, the ground fineness is -80 mesh limestone powder and sodium carbonate and evaporated carbonation decomposition mother liquor according to CaO and SiO 2 The molar ratio is 1.0 control, sodium carbonate (including the Na in the carbonation decomposition mother liquor after evaporation 2 O) The amount added is in accordance with Na 2 O and Al 2 o 3 + Fe 2 o 3 The molar ratio is 1.1 to control the batching to prepare raw slurry; burn the raw slurry at a temperature of 1110°C to obtain qualified clinker; use the adjusting liquid to leach the clinker under the condition of 80-90°C, The leaching rate of alumina can reach 68.95%, and the leaching rate of sodium oxide in clinker can reach 69.98%. The clinker leachate is desiliconized and decomposed by carbonation to obtain aluminum hydroxide, which is roasted to obtain metallurgical grade alumina products. ...

Embodiment 2

[0042] The raw material is fly ash from a thermal power plant, the main chemical composition is Al 2 o 3 42%, SiO 2 46%, the ground fineness is -80 mesh limestone powder and sodium carbonate and evaporated carbonation decomposition mother liquor according to CaO and SiO 2 The molar ratio is 1.3 control, sodium carbonate (including the Na in the carbonation decomposition mother liquor after evaporation 2 O) The amount added is in accordance with Na 2 O and Al 2 o 3 + Fe 2 o 3 The molar ratio is 1.0 to control the batching to prepare raw slurry; burn the raw slurry at a temperature of 1200°C to obtain qualified clinker; use the adjusting liquid to leach the clinker under the condition of 80-90°C, The leaching rate of alumina can reach 78.68%, and the leaching rate of sodium oxide in clinker can reach 83.95%. The clinker leachate is desiliconized and decomposed by carbonation to obtain aluminum hydroxide, which is roasted to obtain metallurgical grade alumina products.

Embodiment 3

[0044] The raw material is fly ash from a thermal power plant, the main chemical composition is Al 2 o 3 46%, SiO 2 44%, the ground fineness is -80 mesh limestone powder and sodium carbonate and evaporated carbonation decomposition mother liquor according to CaO and SiO 2 The molar ratio is 1.5 control, sodium carbonate (including Na in the carbonation decomposition mother liquor after evaporation 2 O) The amount added is in accordance with Na 2 O and Al 2 o 3 + Fe 2 o 3 The molar ratio is 1.2 to control the batching to prepare raw slurry; burn the raw slurry at a temperature of 1120°C to obtain qualified clinker; use the adjusting liquid to leach the clinker under the condition of 80-90°C, The leaching rate of alumina can reach 84.64%, and the leaching rate of sodium oxide in clinker can reach 92.51%. The clinker leachate is desiliconized and decomposed by carbonation to obtain aluminum hydroxide, which is roasted to obtain metallurgical grade alumina products.

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Abstract

The invention relates to a method for producing aluminum oxide from fly ash, particularly a technique for producing metallurgical-grade aluminum oxide or non-metallurgical-grade aluminum oxide by comprehensively utilizing fly ash resources. The method is characterized by comprising the following steps: (1) adding fly ash and limestone powder or lime powder into an alkaline solution to obtain a raw slurry; (2) firing the raw slurry into clinker; (3) carrying out alkaline leaching on the clinker; (4) after carrying out desiliconizing treatment on the leach solution, carrying out liquid solid separation; (5) carrying out carbonating decomposition on the desiliconized solution subjected to liquid solid separation, thereby obtaining aluminum hydroxide; and (6) roasting the aluminum hydroxide to obtain the aluminum oxide product. The method provided by the invention can be used for treating the fly ash raw materials, which have different sources, different chemical compositions and different mineral compositions, to produce the aluminum oxide; the technology is mature and reliable; compared with the existing acid-process production technique, the invention does not need expensive corrosion-resistant equipment; and compared with the existing alkali-process production technique, the invention has the advantages of low material flow rate and low solid-phase slag amount, and is beneficial to environmental protection.

Description

technical field [0001] A method for producing alumina from fly ash relates to a process for producing metallurgical-grade alumina or non-metallurgical-grade alumina by comprehensively utilizing fly ash resources. Background technique [0002] Fly ash is a finely powdered material collected from the flue gas of coal combustion. The mineral composition and chemical composition of fly ash are related to the source of coal. Its phase composition is mainly vitreous, and it also contains mullite, quartz, hematite, magnetite, anhydrite, tricalcium phosphate and yellow feldspar, etc. Powdery material; the chemical composition is mainly Al 2 o 3 , SiO 2 , Fe 2 o 3 , CaO, MgO, etc., and also contains a small amount of rare elements. Fly ash storage will occupy a large amount of land, and will also cause a certain degree of pollution to the surrounding environment. Therefore, it is of great significance to study the comprehensive utilization of fly ash, turn waste into treasure,...

Claims

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Application Information

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IPC IPC(8): C01F7/02B09B3/00
Inventor 李旺兴尹中林杨志民
Owner 河南华慧有色工程设计有限公司
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