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Method for improving production efficiency of aluminium oxide produced with Bayer process

A technology of Bayer method and alumina, which is applied in the field of improving the efficiency of alumina production by Bayer method, can solve the problems of not economically and effectively improving the medium circulation efficiency, high production cost, and difficult industrial application, so as to improve the medium circulation efficiency and equipment The effect of low requirements and increased production capacity

Inactive Publication Date: 2018-10-16
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Use aliphatic alcohol or alkylphenol as the extractant to extract the alkali component in the sodium aluminate solution, or separate the alkali component and high molecular ratio sodium aluminate solution through the electrolysis process, or carry out the process by introducing a third component such as methanol The method of dissolution and crystallization has disadvantages such as high production cost or high energy consumption, and the introduction of organic components irrelevant to the Bayer system, which makes it difficult for industrial application.
[0008] Therefore, the existing method cannot economically and effectively improve the medium circulation efficiency of the existing Bayer process alumina production process

Method used

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  • Method for improving production efficiency of aluminium oxide produced with Bayer process
  • Method for improving production efficiency of aluminium oxide produced with Bayer process

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Embodiment 1

[0060] This embodiment provides a method for improving the efficiency of alumina production by the Bayer process. The mother liquor of a certain Bayer process alumina plant is used as a raw material. The main composition of the mother liquor of the alumina plant (g / L, the same below) is shown in Table 1 mentioned.

[0061] Table 1

[0062]

[0063] Its production process includes the following steps:

[0064] (1) Mix the seed separation mother liquor with solid NaOH to prepare a liquid phase NaOH 2 o k Concentration is 400g / L, the slurry that molecular ratio is 5.5, discharge salt with sodium carbonate seed crystal at 100 ℃ for 3 hours, filter to obtain sodium carbonate filter cake and Na 2 o k Concentration is 400g / L, molecular ratio is the liquid before crystallization of 5.5;

[0065] (2) Na 2 o k The pre-crystallization solution with a concentration of 400g / L and a molecular ratio of 5.5 was cooled to 45°C and crystallized for 15 hours to obtain a sodium aluminat...

Embodiment 2

[0070] This embodiment provides a method for improving the efficiency of alumina production by the Bayer process, using the evaporated mother liquor of a certain Bayer process alumina plant described in Table 1 as a raw material, and the production process is as follows:

[0071] (1) Mix the A-effect evaporation mother liquor with solid NaOH to form a liquid phase NaOH 2 o k With a concentration of 500g / L and a molecular ratio of 7.7, use sodium carbonate seed crystals to discharge salt for 3 hours at 100°C, and filter to obtain sodium carbonate filter cake and Na 2 o k Concentration is 500g / L, the liquid before crystallization that molecular ratio is 7.7;

[0072] (2) Na 2 o k The pre-crystallization solution with a concentration of 500g / L and a molecular ratio of 7.7 was cooled to 60°C and crystallized for 5 hours to obtain a sodium aluminate hydrate filter cake and a crystallization mother solution with a caustic concentration of 492g / L and a molecular ratio of 37;

[...

Embodiment 3

[0077] This embodiment provides a method for improving the efficiency of alumina production by the Bayer process, using the evaporated mother liquor of a certain Bayer process alumina plant described in Table 1 as a raw material, and the production process is as follows:

[0078] (1) Mix the B-effect evaporation mother liquor with solid NaOH to form a liquid phase NaOH 2 o k Concentration is 600g / L, the slurry that molecular ratio is 10.6, discharge salt with sodium carbonate seed crystal at 100 ℃ for 3 hours, filter to obtain sodium carbonate filter cake and Na 2 o k Concentration is 600g / L, the liquid before crystallization that molecular ratio is 10.6;

[0079] (2) Na 2 o k The pre-crystallization solution with a concentration of 600g / L and a molecular ratio of 10.6 was cooled to 50°C and crystallized for 10 hours to obtain a sodium aluminate hydrate filter cake and a crystallization mother solution with a caustic concentration of 583g / L and a molecular ratio of 42;

...

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Abstract

The invention relates to a method for improving production efficiency of aluminium oxide produced with the Bayer process. According to the method, caustic soda flakes required to be supplemented for an aluminium oxide plant are subjected to a reaction with Bayer-process seeded precipitation spent liquor or evaporation mother liquor, a sodium aluminate solution with high alkali and high molecular ratio is formed, and carbon alkali removal and causticizing of Bayer mother liquor can be realized without forced effect evaporation and other processes; by means of efficient crystallization of sodiumaluminate hydrate as an intermediate product, circulating efficiency of dissolution media and production capacity of the conventional equipment can be improved. Synchronous salt elimination and causticizing and improvement of medium circulating efficiency can be realized on the premise that other substances or energy are or is not input; the newly added sodium aluminate hydrate crystallization process is mild in condition, equipment investment is low, industrial controllability is high, and economic benefit is obvious. The aluminium oxide product prepared with the method is identical to thatof the aluminium oxide product produced with the Bayer process, no new waste gas, waste liquor or solid waste is produced, and energy conservation and environmental protection are realized.

Description

technical field [0001] The invention relates to the technical field of alumina production, in particular to a method for improving the efficiency of alumina production by Bayer process. Background technique [0002] The metal aluminum and alumina industry is an important basic raw material industry for the development of the national economy. More than 90% of the total output of industrial alumina is used for electrolytic production of metal aluminum, and the rest is used in the fields of electronics, refractory materials, petroleum, chemical industry, ceramics, environmental protection and pharmaceuticals. [0003] In 2017, my country's alumina output was 69.02 million tons, accounting for 56.2% of the world's output. At present, the industrial production method of alumina is basically alkali method, mainly including Bayer method, sintering method and Bayer-sintering combined method. Thanks to the advancement of technology and equipment, and subject to economic constraint...

Claims

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Application Information

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IPC IPC(8): C01F7/04C01F7/06C01F7/14
CPCC01F7/04C01F7/06C01F7/14
Inventor 曹绍涛张毅张芳芳
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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