Bauxite dissolving out method for reducing caustic alkali combined in prepared red mud

A bauxite and caustic alkali technology, applied in alumina/aluminum hydroxide and other directions, can solve the problems of difficult industrial realization, cumbersome synthesis process, increased cost burden, etc., to broaden the scope of resource utilization, simple process, and production cost. low effect

Inactive Publication Date: 2010-11-17
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, a large amount of synthetic calcium ferrite is required in the process, and the synthesis process is cumbersome and difficult; liquid-solid separation is also a huge process, which will increase the cost burden
[0020] In summary, although various methods have been proposed to reduce red mud binding alkali, the processes are cumbersome and industrially difficult to realize. Therefore, a simple and easy-to-achieve industrialized method for reducing bauxite dissolution and red mud binding is needed. Alkaline method

Method used

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  • Bauxite dissolving out method for reducing caustic alkali combined in prepared red mud
  • Bauxite dissolving out method for reducing caustic alkali combined in prepared red mud
  • Bauxite dissolving out method for reducing caustic alkali combined in prepared red mud

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0056] Bauxite 115g, lime 14.5g and 41.25g sodium hydroxide and 150mL water (lye N K 213.1g / L) mixed to form a slurry, added to the autoclave, stirred, reacted at 100°C for 10h, raised the temperature to 260°C, and then supplemented the decomposition mother liquor at 260°C with a high-pressure plunger pump (the composition is N T =176g / L,N k =164g / L, Al 2 o 3 =108g / L, pre-concentrated from 585mL to 200mL), dissolved at 260°C for 60min. The chemical compositions of the liquid and solid phases produced by dissolution are shown in Table 4.

[0057] Table 4

[0058]

[0059] The N / S of red mud is 0.28.

Embodiment 2

[0061] Bauxite 115g, lime 14.5g and high a K Solution 200mL (N T =101.1g / L, N k =96.0g / L, Al 2 o 3 =5.1g / L, a K =30.8) mixed to form a slurry, added to the autoclave, stirred, reacted at 100 ° C for 10 h, raised the temperature to 260 ° C, and then replenished the circulating mother liquor (concentrated from 438 mL to 150 mL in advance) at 260 ° C with a high-pressure plunger pump, at 260 ° C Dissolution at ℃ for 60min. The chemical compositions of the liquid and solid phases produced by dissolution are shown in Table 5.

[0062] table 5

[0063]

[0064] The N / S of red mud is 0.23.

Embodiment 3

[0066] Bauxite 115g, lime 14.5g and high a K Solution 150mL (N T =134.2g / L, N k =128.0g / L, Al 2 o 3 =25.6g / L, a K =8.1) Mix to form a slurry, add to the autoclave, stir, react at 100°C for 10h, heat up to 260°C, then replenish the circulating mother liquor (concentrated from 438mL to 200mL in advance) at 260°C with a high-pressure plunger pump, Dissolution under 60min. The chemical composition of red mud produced by dissolution is shown in Table 6.

[0067] Table 6

[0068]

[0069] The N / S of red mud is 0.32.

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Abstract

The invention discloses a bauxite stripping method, and the bauxite can make the caustic alkali combined in produced red mud be lowered. The stripping method is as follows: (A) anterior stage: a boehmite type bauxite, lime and sodium aluminate solution are mixed, and the mixed pulp is heat preserved for long enough time between 90 DEG C and 260 DEG C so that silica in the bauxite is transformed into hydrogarnet as much as possible; (B) posterior stage: then concentrated circulating mother liquid is supplemented to the pulp under such temperature, or the concentrated circulating mother liquid is supplemented to the pulp after the temperature of the pulp is raised between 230 DEG C and 290 DEG C, and finally, the bauxite is stripped for half an hour to three hours under the raised temperature. The molecular ratio aK is more than 4 of the caustic alkali of the sodium aluminate solution mixed with the boehmite type bauxite and the lime in the anterior stage to alumina. The bauxite stripping method has the advantages of simple process, being easily industrialized and low production cost.

Description

technical field [0001] The invention relates to a method for leaching bauxite that reduces the combined caustic in the output red mud, in particular to a method for leaching bauxite with high silicon content that reduces the combined caustic in the output red mud . Background technique [0002] The production of alumina by the Bayer method is to directly use the circulating mother liquor containing a large amount of free caustic to treat the bauxite, and dissolve the alumina to obtain a sodium aluminate solution. Add aluminum hydroxide seeds to the sodium aluminate solution and stir for a long time. Decomposition and separation of aluminum hydroxide crystals. The decomposed mother liquor is evaporated and then used to dissolve the next batch of bauxite. [0003] A significant portion of the production cost of alumina (approximately 15-25%) is due to the price of sodium hydroxide added to the Bayer cycle to replace sodium hydroxide lost in the cycle. Therefore, reducing ca...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/02
Inventor 陈文汨黄伟光陈学刚李云峰谢巧玲彭秋燕
Owner CENT SOUTH UNIV
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