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Normal pressure low temperature leaching production method for alumina

A production method, alumina technology, applied in chemical instruments and methods, alkali metal aluminate/alumina/aluminum hydroxide preparation, inorganic chemistry, etc., can solve the problems of high energy consumption, difficult operation, high equipment investment, etc. Achieve the effect of reducing production energy consumption, reducing equipment investment, and reducing energy consumption

Inactive Publication Date: 2005-01-19
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

[0004] The purpose of the present invention is to overcome the defects of high equipment investment, high energy consumption and difficult operation caused by high temperature and high pressure operation when processing diaspore bauxite by Bayer process, and propose a low temperature and normal bauxite with industrial operability. A new method of alumina production by pressure-dissolving diaspore-type bauxite and increasing the dissolution rate of alumina

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] With the normal-pressure low-temperature stripping production method of alumina of the present invention, the stripping production of alumina is carried out with Shanxi Yangquan bauxite as raw material, and the composition (wt%) of Shanxi Yangquan bauxite raw material is as follows:

[0027] SiO 2 Fe 2 o 3 Al 2 o 3 CaO TiO 2 A / S

[0028] 8.10 5.61 69.80 1.0 2.15 8.62

[0029] Its stripping steps are:

[0030] 1. Mix bauxite of 120-200 mesh with NaOH solution with a concentration of 70% by weight, and the ratio of parts by weight is bauxite: NaOH solution = 1:2, then put it in the reaction kettle, and heat up to 170°C , reacted for 0.5 hours under a pressure of 0.55Mpa to obtain a mixed reaction product containing lye, sodium aluminate, aluminosilicate and iron slag; after the mixed reactant was cooled to 90°C, water was added to adjust the weight percentage concentration of NaOH solution to Dilute to 40%, heat-preserve and filter at 40°C, and separate t...

Embodiment 2

[0036] After the NaOH solution of Example 1 is returned to the reaction kettle to remove part of the water (the weight percent concentration of the NaOH solution is 60% at this time), the temperature is raised to 200 ° C, the bauxite of Example 1 is added, and the mixture is completely mixed. The reaction was carried out for 3 hours, wherein the weight ratio of NaOH solution to ore was 1.5:1, and a mixed reaction product containing lye, aluminate and red mud (slag) was obtained; the dissolution rate of aluminum was 96.4%. Dilute the reaction solution with the red mud washing solution of Example 1, filter and separate at 90°C to obtain sodium aluminate alkali solution and red mud; concentrate the sodium aluminate alkali solution and crystallize at 105°C to obtain hydrated sodium aluminate crystals; Dissolve it, then desiliconize and sort the products to obtain aluminum hydroxide products, and then sinter the aluminum hydroxide to obtain alumina (in line with the standard of firs...

Embodiment 3

[0038] With the normal-pressure low-temperature dissolution production method of alumina of the present invention, the dissolution production of alumina is carried out with Henan bauxite as raw material, and the composition (wt%) of Henan bauxite raw material is as follows:

[0039] SiO 2 Fe 2 o 3 Al 2 o 3 CaO TiO 2 A / S

[0040] 6.33 4.07 71.50 0.80 4.31 11.3

[0041] Its stripping steps are:

[0042] 1. Mix 120-200 mesh bauxite with NaOH solution with a concentration of 67% by weight, and the proportion by weight is bauxite: NaOH solution = 1: 1.5, then put it in the reaction kettle, and heat up to 150°C , reacted for 7 hours under a pressure of 0.3Mpa to obtain a mixed reaction product containing lye, sodium aluminate, aluminosilicate and iron slag; add water to dilute the weight percent concentration of NaOH solution to 50%, and keep it warm at 40°C Filtrate, heat-preserve and filter at 100°C, and separate the alkali solution containing sodium aluminate and...

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Abstract

The invention relates to a normal pressure low temperature leaching production method for alumina comprising the steps of, (1) subjecting the bauxite to extraction reaction in alkaline solution, filtering to obtain queous alkali and slags containing sodium aluminate, (2) subjecting the queous alkali to compression and cooling down for crystallization, filtering to obtain hydrated sodium aluminate coarse-grain and the filtrated stock solution, dissolving the hydrated sodium aluminate coarse-grain with water or diluted alkaline liquor, obtaining aluminum hydroxide through desiliconization operation, and calcining the obtained aluminum hydroxide.

Description

technical field [0001] The invention relates to the field of production methods of alumina, in particular to a method for producing alumina at normal pressure and low temperature for processing insoluble diaspore bauxite. Background technique [0002] Alkali process is used in the existing production of alumina, mainly including Bayer process, sintering process and its combined process. The sintering method is mainly used to process bauxite with a low aluminum-silicon ratio. When dealing with bauxite with a high aluminum-silicon ratio, its benefit is much lower than that of the Bayer process. The Bayer process mainly uses 200-300g / L NaOH aqueous solution to dissolve bauxite and then directly dilutes and desilicates the seeds to obtain aluminum hydroxide. However, when it is used to process the diaspore type bauxite that accounts for more than 98% of my country's bauxite resources, high temperature (235-280°C) and high pressure (3.5-6.0MP) operati...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/04C01F7/06C01F7/44
Inventor 张亦飞郑诗礼张懿
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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