Method of extracting aluminum oxide by leaching flyash with hydrochloric acid

A technology of fly ash and alumina, applied in chemical instruments and methods, inorganic chemistry, aluminum compounds, etc., can solve the problems of large and complex impurity removal system, high cost, high energy consumption, etc., to overcome the high energy consumption of crystallization, Reduced energy consumption and simple process

Inactive Publication Date: 2017-10-24
青岛海山环保工程有限公司
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Problems solved by technology

However, there are still some problems in the extraction of alumina from fly ash by alkaline method, mainly ① the calcium-silicate slag produced by sintering method can only be used as cement raw material, and the production of 1 ton of alumina will produce several times the silicon content of fly ash Calcium slag, while cement has its corresponding sales radius, if there is no large-scale cement industry support in the local area, it will cause secondary pollution; ②The sintering method only extracts the alumina in the fly ash, and the use value of its silica is low
③ The sintering method for processing fly ash equipment requires large investment, high energy consumption and high cost
The amount of residue in the acid process of the prior art is small, and while alumi

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  • Method of extracting aluminum oxide by leaching flyash with hydrochloric acid

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Embodiment 1

[0041] A method for extracting alumina by leaching fly ash with hydrochloric acid, comprising the following steps:

[0042](1) High-alumina active fly ash (40% alumina content) and hydrochloric acid (31%) are mixed according to the ash-acid ratio of 0.9, and the alumina in the ash is dissolved by reacting at 130°C and 1.2Mpa for 2h.

[0043] (2) step (1) reacts and obtains slurry to form the leaching residue that does not contain floating matter and the leaching residue of high silicon after settling, washing and filtering, and the leaching liquor is used for extracting crystalline aluminum chloride, and leaching residue can be Harmless landfill or further extraction of silicon oxide.

[0044] (3) Pass into the leaching liquid that step (2) obtains and be that 95% HCl gas of dry purity, make the aluminum chloride crystallization in the leaching liquid form aluminum chloride hexahydrate crystal and separate out, through solid-liquid separation Obtain crude aluminum chloride an...

Embodiment 2

[0051] (1) High-alumina activated fly ash (60% alumina content) and hydrochloric acid (29%) are mixed according to the ash-acid ratio of 1, and the alumina in the ash is dissolved by reacting at 150°C and 1.5Mpa for 1 hour.

[0052] (2) step (1) reacts and obtains slurry to form the leaching residue that does not contain floating matter and the leaching residue of high silicon after settling, washing and filtering, and the leaching liquor is used for extracting crystalline aluminum chloride, and leaching residue can be Harmless landfill or further extraction of silicon oxide.

[0053] (3) Pass into the leaching liquid that step (2) obtains and be that 95% HCl gas of dry purity, make the aluminum chloride crystallization in the leaching liquid form aluminum chloride hexahydrate crystal and separate out, through solid-liquid separation Obtain crude aluminum chloride and residual liquid, when the concentration of hydrogen chloride in the leaching liquid reaches 30%, stop feeding ...

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Abstract

The invention discloses a method for extracting alumina by leaching fly ash with hydrochloric acid. By passing hydrogen chloride gas into the leaching solution of fly ash and hydrochloric acid, the aluminum chloride in the leaching solution crystallizes to form aluminum chloride hexahydrate The crystals are precipitated, omitting the complicated iron removal process in the purification process of aluminum chloride and the defects that other impurity ions (sodium, potassium, magnesium, calcium, etc.) cannot be removed, and realize the separation, purification and crystallization of aluminum chloride in one step; at the same time The crystallization process is realized at room temperature, the process is simple, and the energy consumption is low. The impurity metal ions in the residual liquid can be further enriched for recovery. While extracting alumina, other metal salts and silicon oxide in the leaching residue can be recovered. The field of alumina extraction from coal ash has broad application prospects.

Description

technical field [0001] The invention belongs to the field of high-value utilization of fly ash, in particular to a method for preparing alumina by treating fly ash with hydrochloric acid. Background technique [0002] In recent years, the rapid development of my country's coal power industry has brought about a sharp increase in the discharge of solid waste fly ash. At present, the annual discharge of fly ash in my country is over 100 million tons, and the total stockpile of fly ash in my country is more than one billion Ton. The discharge of a large amount of fly ash not only occupies a large amount of land, but also seriously pollutes the environment, which constitutes a double damage to the ecology and the environment. Therefore, the comprehensive utilization of fly ash has great practical and long-term strategic significance. Similarly, my country is a country that is not rich in aluminum resources. According to the current growth rate of alumina production and the wast...

Claims

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Application Information

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IPC IPC(8): C01F7/22
CPCC01F7/22C01P2006/80
Inventor 孙起毛维彬
Owner 青岛海山环保工程有限公司
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