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Method for preparing sodium aluminate solid from bayer process red mud

A technology of Bayer process red mud and sodium aluminate, which is applied in the field of preparation of sodium aluminate and can solve the problems of harsh requirements, unsatisfactory morphology, purity and particle size of sodium aluminate

Active Publication Date: 2013-04-10
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] In addition, sodium aluminate crystals, such as CN101607725B and CN101538058B, can also be obtained in the process of recovering alumina and sodium oxide from Bayer process red mud, but these methods have strict requirements on the crystallization process of sodium aluminate, and the morphology of sodium aluminate , purity and particle size are not ideal

Method used

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  • Method for preparing sodium aluminate solid from bayer process red mud
  • Method for preparing sodium aluminate solid from bayer process red mud
  • Method for preparing sodium aluminate solid from bayer process red mud

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Embodiment 1

[0059] Using the method for preparing sodium aluminate hydrate solid from Bayer process red mud of the present invention, the red mud of a certain Bayer process alumina plant in Henan is used as raw material to prepare hydrated sodium aluminate, and the red mud composition of the alumina plant (mass percentage, wt %, the same below) as described in Table 1:

[0060] Table 1

[0061]

[0062] Its production process includes:

[0063] (1) Mix red mud and concentrated sodium hydroxide solution from an alumina plant in Henan to prepare a slurry with a liquid NaOH mass fraction of 45% and a ratio of liquid NaOH mass to dry red mud mass of 2.5:1. And add lime to make CaO and SiO in the solid phase 2 The ratio of the amount of the substance is 1.4:1, and then the slurry is placed in a high-pressure reactor for a stripping reaction, the stripping reaction temperature is 220 ° C, and the stripping time is 0.4 hours, and the stripping solution containing sodium aluminate and red T...

Embodiment 2

[0068] With the method for preparing sodium aluminate hydrate solid from Bayer process red mud of the present invention, the red mud of a certain Bayer process alumina plant in Henan as described in Table 1 is still used as raw material to prepare hydrated sodium aluminate, and the production process is as follows :

[0069](1) The crystallization mother liquor of Example 1 is mixed evenly with the prepared concentrated NaOH solution and the Bayer process red mud, and the ratio of the liquid NaOH mass fraction to the dry base red mud mass is 50%. 3:1 slurry, and add lime to make CaO and SiO in the solid phase 2 The ratio of the amount of the material to the material is 1.6:1, and then the slurry is placed in an autoclave to carry out a dissolution reaction, the dissolution reaction temperature is 230 ° C, and the dissolution time is 0.2 hours. For the solid-liquid mixture of mud and solid slag, the relative dissolution rate of alumina entering the solution is 82.6%;

[0070]...

Embodiment 3

[0075] With the method for preparing sodium aluminate hydrate solid from Bayer process red mud of the present invention, still use the red mud of a certain Bayer process alumina plant in Henan as described in Table 1 to prepare sodium aluminate hydrate as raw material, and its production process is as follows :

[0076] (1) Mix red mud from an alumina plant in Henan with concentrated sodium hydroxide solution to prepare a slurry with a mass fraction of liquid NaOH of 55% and a ratio of liquid NaOH mass to dry red mud mass of 4:1. And add lime to make CaO and SiO in the solid phase 2 The ratio of the amount of the material to the material is 1.3:1, and then the slurry is placed in an autoclave to carry out a dissolution reaction, the dissolution reaction temperature is 260 ° C, and the dissolution time is 0.5 hours. For the solid-liquid mixture of mud and solid slag, the relative dissolution rate of alumina entering the solution is 87.2%;

[0077] (2) After the dissolution, t...

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Abstract

The invention relates to a method for preparing a sodium aluminate solid from bayer process red mud economically and efficiently. In the method, by adopting a high molecular ratio and high alkali concentration sodium aluminate solution, an aluminum extracting reaction can be rapidly carried out under mild operating conditions, so that the recovery rate of alumina in the red mud reaches more than 85%; an efficient crystallization process of hydrated sodium aluminate is realized, the cycle efficiency of a dissolution medium is greatly improved, the granularity and the appearance of a crystal product can be controlled, the purity of the product is high, and the crystal product can transform into an anhydrous sodium aluminate solid under heating conditions of lower than 150 DEG C; and due to secondary sodium removal reaction at low temperature and normal pressure, the sodium oxide component in the red mud can be efficiently recovered, and the sodium oxide content in final red mud is not more than 1%. Therefore, the red mud can be doped in large proportion for preparing building material products, environmental remediation materials, other fillers and the like.

Description

technical field [0001] The present invention relates to the preparation field of sodium aluminate, in particular, the present invention relates to a method for preparing sodium aluminate solid from Bayer process red mud. Background technique [0002] Solid sodium aluminate is an important inorganic compound, its main use is as a water treatment agent to improve the precipitation properties of calcium, magnesium and other ions in industrial water and edible water to reduce water hardness; as a flocculant auxiliary, to Reduce the concentration of soluble silicon in water, etc. In the paper and printing industry, sodium aluminate is used as an additive to improve sizing, filler retention and asphalt coloring properties. In terms of material preparation, sodium aluminate is often used as a raw material to provide a source of alumina for the preparation of molecular sieves and other catalysts. Other uses of solid sodium aluminate include pH adjusters, binders in the ceramic ind...

Claims

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Application Information

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IPC IPC(8): C01F7/04
Inventor 曹绍涛郭涛张亦飞张懿
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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