Method for subsequent treatment of aluminum sulfate generated in technical process of extracting alumina from fly ash

A technology of process and treatment method, applied in alumina/aluminum hydroxide and other directions, can solve the problems of high investment cost, equipment corrosion, difficulty in realizing continuous production, etc., and achieve the effect of reducing costs and improving economic benefits.

Inactive Publication Date: 2012-07-11
西安航天科技工业有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In the process of extracting alumina, if hydrochloric acid is used to dissolve and participate in the reaction, the problem of equipment corrosion will be serious, it will be difficult to realize continuous production, and the investment cost will be high.
And when sulfuric acid is used for stripping (during stripping reaction) in the technological process, although the equipment corrosion problem is solved and...

Method used

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  • Method for subsequent treatment of aluminum sulfate generated in technical process of extracting alumina from fly ash
  • Method for subsequent treatment of aluminum sulfate generated in technical process of extracting alumina from fly ash
  • Method for subsequent treatment of aluminum sulfate generated in technical process of extracting alumina from fly ash

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Step 1: adding aluminum chloride hexahydrate washing solution to dilute the aluminum sulfate solution obtained in the process of extracting alumina from fly ash.

[0036] Step 2: Under the temperature condition of 30° C., HCl gas is passed into the mixed solution obtained in Step 1 to make it saturated while stirring, and aluminum chloride hexahydrate crystals are precipitated;

[0037] Its reaction equation is as follows:

[0038] Al 2 (SO 4 ) 3 18H 2 O +6HCl=2(AlCl 3 ·6H 2 O)+3H 2 SO 4 +6H 2 o

[0039] Step 3: filter and wash the aluminum chloride hexahydrate crystal;

[0040] Step 4: Calcining aluminum chloride hexahydrate crystals to obtain alumina, HCl gas and water.

[0041] In step 1, the acid used in the process of extracting alumina from fly ash is sulfuric acid, and the extracted intermediate product is aluminum sulfate solution or aluminum sulfate crystals.

[0042] In step three, the aluminum chloride lotion obtained when washing the aluminum chl...

Embodiment 2

[0045] Step 1: Concentrate and crystallize aluminum sulfate crystals from the aluminum sulfate solution obtained in the process of extracting alumina from fly ash, add 20% hydrochloric acid solution for dilution, and the mass percentage of aluminum sulfate and hydrochloric acid is 1:5.

[0046] Step 2: Under the temperature condition of 30° C., HCl gas is passed into the mixed solution obtained in Step 1 to make it saturated while stirring, and aluminum chloride hexahydrate crystals are precipitated;

[0047] Its reaction equation is as follows:

[0048] Al 2 (SO4 ) 3 18H 2 O +6HCl=2(AlCl 3 ·6H 2 O)+3H 2 SO 4 +6H 2 o

[0049] Step 3: filter and wash the aluminum chloride hexahydrate crystal;

[0050] Step 4: Calcining aluminum chloride hexahydrate crystals to obtain alumina, HCl gas and water.

[0051] In step 1, the acid used in the process of extracting alumina from fly ash is sulfuric acid, and the extracted intermediate product is aluminum sulfate solution or alu...

Embodiment 3

[0054] Step 1: Concentrate and crystallize aluminum sulfate crystals from the aluminum sulfate solution obtained in the process of extracting alumina from fly ash, add 28% hydrochloric acid solution for dilution, and the mass percentage of aluminum sulfate and hydrochloric acid is 1:3.

[0055] Step 2: Under the temperature condition of 55° C., HCl gas is passed into the mixed solution obtained in Step 1 to make it saturated while stirring, and aluminum chloride hexahydrate crystals are precipitated;

[0056] Its reaction equation is as follows:

[0057] Al 2 (SO 4 ) 3 18H 2 O +6HCl=2(AlCl 3 ·6H 2 O)+3H 2 SO 4 +6H 2 o

[0058] Step 3: filter and wash the aluminum chloride hexahydrate crystal;

[0059] Step 4: Calcining aluminum chloride hexahydrate crystals to obtain alumina, HCl gas and water.

[0060] In step 1, the acid used in the process of extracting alumina from fly ash is sulfuric acid, and the extracted intermediate product is aluminum sulfate solution or a...

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Abstract

The invention relates to a method for the subsequent treatment of aluminum sulfate generated in the technical process of extracting alumina from fly ash. According to a process for extracting the alumina from the fly ash, when hydrochloric acid is used for dissolving out, the corrosion of equipment is serious, and the continuous production is difficult to realize; and when sulfuric acid is used for dissolving out, the content of crystal water in prepared aluminum salt crystals is high, and the thermal loss of roasting decomposition is relatively high. The method comprises the following steps of: adding a subsequent aluminum chloride lotion or a solution of hydrochloric acid into a solution of aluminum sulfate generated in the technical process or aluminum sulfate crystals obtained after crystallization, diluting, introducing HCl gas into the mixed solution at the temperature of between 30 and 85 DEG C to ensure that the solution is saturated, and precipitating aluminum chloride hexahydrate crystals; and roasting to obtain the alumina. By the method, the problems about equipment corrosion caused by using the hydrochloric acid for dissolving out in the process for extracting the alumina from the fly ash, and overhigh energy consumption caused by roasting aluminum sulfate salt crystals after the sulfuric acid is used for dissolving out are solved; and the HCl gas which is brought into the production process can be obtained from smoke produced by roasting aluminum chloride hexahydrate, and can be recycled without any conversion, so that the cost is effectively reduced.

Description

technical field [0001] The invention relates to a process for treating fly ash, in particular to a subsequent treatment method for aluminum sulfate in the process of extracting alumina from fly ash. Background technique [0002] Fly ash is the fine ash collected from the flue gas after coal combustion, and its main composition is SiO 2 、Al 2 o 3 , FeO, Fe 2 o 3 , CaO, TiO 2 wait. The whole world emits a huge amount of fly ash every year. In 2010, the domestic emission exceeded 300 million tons. Air and water pollution, land desertification, alkalization and other environmental pollution problems caused by its accumulation and loss of land are problems that plague the world. All countries are actively looking for ways to reuse fly ash. [0003] The technical research on extracting alumina from fly ash began in the 1980s. To obtain alumina from fly ash with a higher extraction rate, it is necessary to try to destroy SiO 2 -Al 2 o 3 bond, raise Al 2 o 3 activity. ...

Claims

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Application Information

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IPC IPC(8): C01F7/02
Inventor 郭新锋曾伟杨超郭坤高璇梁兴国
Owner 西安航天科技工业有限公司
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