Method for removing iron in process of preparing aluminum oxide by Bayer process

A technology of alumina and Bayer method, applied in chemical instruments and methods, preparation of alkali metal aluminate/alumina/aluminum hydroxide, inorganic chemistry, etc., can solve problems such as small particles cannot be eliminated, and achieve the best practical value, The effect of high feasibility and simple operation

Pending Publication Date: 2022-04-19
YUNNAN WENSHAN ALUMINUM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the production of alumina by the Bayer process, most of the iron minerals in the bauxite are discharged through sedimentation in the form of red mud, but there are still some very small particles of iron compounds that cannot be excluded and enter the solution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] This embodiment provides a method for removing iron in the Bayer legal alumina process, which includes:

[0028] S1. After the bauxite is crushed, it is added to the circulating mother liquor for wet grinding and stripping to obtain stripping pulp.

[0029] S2. Dilute the stripping pulp and then separate it by settling to obtain crude sodium aluminate liquid and red mud slurry.

[0030] S3. The active dissolution slag and the crude sodium aluminate solution were mixed according to the mass volume ratio of 1 g / L, and then settled at 100°C for 3 minutes to separate the sodium aluminate semen.

[0031] Among them, the active dissolution slag is the solid residue remaining after the decomposition mother liquor in the alumina production process of the Bayer method is mixed with aluminum ash and dissolved at 150°C. The mass volume ratio of aluminum ash to decomposition mother liquor is 270g / L. The alkali ratio of the decomposition mother liquor is 2.50.

[0032] Active dis...

Embodiment 2

[0037] This embodiment provides a method for removing iron in the Bayer legal alumina process, which includes:

[0038] S1. After the bauxite is crushed, it is added to the circulating mother liquor for wet grinding and stripping to obtain stripping pulp.

[0039] S2. Dilute the stripping pulp and then separate it by settling to obtain crude sodium aluminate liquid and red mud slurry.

[0040] S3. The active dissolution slag and the crude sodium aluminate liquid were mixed according to the mass volume ratio of 3 g / L, and then settled at 80°C for 10 min to separate the sodium aluminate semen.

[0041] Among them, the active dissolution slag is the solid residue remaining after the decomposition mother liquor in the alumina process produced by the Bayer method is mixed with aluminum ash and dissolved at 120°C. The mass volume ratio of aluminum ash and decomposition mother liquor is 250g / L. The alkali ratio of the decomposition mother liquor is 2.50.

[0042] Active dissolution ...

Embodiment 3

[0047] This embodiment provides a method for removing iron in the Bayer legal alumina process, which includes:

[0048] S1. After the bauxite is crushed, it is added to the circulating mother liquor for wet grinding and stripping to obtain stripping pulp.

[0049] S2. Dilute the stripping pulp and then separate it by settling to obtain crude sodium aluminate liquid and red mud slurry.

[0050] S3. The active dissolution slag and the crude sodium aluminate solution were mixed according to the mass volume ratio of 5 g / L, and then settled at 90°C for 6 minutes to separate the sodium aluminate semen.

[0051] Among them, the active dissolution slag is the solid residue remaining after the decomposition mother liquor in the alumina production process of the Bayer method is mixed with aluminum ash and dissolved at 130°C. The mass volume ratio of aluminum ash to decomposition mother liquor is 270 g / L. The alkali ratio of the decomposition mother liquor is 2.75.

[0052] Active dis...

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PUM

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Abstract

The invention provides a method for removing iron in a Bayer process aluminum oxide process, and relates to the technical field of aluminum oxide preparation, the method comprises the following steps: mixing a sodium aluminate crude solution obtained after separation of dissolved slurry with active dissolved slag, and carrying out settling separation to obtain a sodium aluminate fine solution. According to the method, on one hand, positive and negative ions in the active dissolution residues are utilized to destroy the electrical structure of iron sol, so that iron is easier to precipitate and separate out; on the other hand, non-coagulated iron sol is adsorbed by utilizing the porous structure of the active dissolution residue. And under the dual action, a better iron removal effect is achieved. In addition, the active dissolution slag is an intermediate product in the aluminum ash treatment process, the utilization of the active dissolution slag better realizes the resource recycling of the aluminum ash, and the method has certain environmental protection significance. The method is easy to operate, high in feasibility and good in practical value.

Description

technical field [0001] The invention relates to the technical field of alumina preparation, in particular to a method for removing iron in the Bayer alumina process. Background technique [0002] The iron in the sodium aluminate solution mainly comes from bauxite, and equipment corrosion will also increase the iron content in the solution. In the production of alumina by the Bayer process, most of the iron minerals in the bauxite are discharged through sedimentation in the form of red mud, but there are still some very small particles of iron compounds that cannot be excluded and enter the solution. When the iron content in the sodium aluminate solution is too high, aluminum hydroxide enters during the seed separation process, causing the alumina iron content to exceed the standard, and enters the aluminum ingot during electrolysis. At present, the first-grade product of domestic metallurgical grade alumina requires Fe 2 o 3 Less than 0.020%, but with the development of e...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/0646C01F7/066C01F7/14
CPCC01F7/0646C01F7/066C01F7/14
Inventor 晏华钎戴静卞磊熊德芬王花孔令丽朱杨昆罗俊松杜银江王治国
Owner YUNNAN WENSHAN ALUMINUM
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