Dealkalization method for Bayer process red mud

A Bayer process red mud and dealkalization technology, which is applied to chemical instruments and methods, alkali metal oxides, and solid waste removal, can solve problems such as difficulty in industrialization, poor economic benefits, and low dealkalization rate, and achieve improved Solubility, calcium ion activity increase, and the effect of improving dealkalization efficiency

Active Publication Date: 2019-08-16
河南镁联铝基材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The defects of the above-mentioned patent applications are that either the dealkalization rate is low, the economic...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] A kind of dealkalization method of red mud of Bayer process, the process of recovering alkali is operated according to the following steps, comprising:

[0031] a, Intensified diffusion pretreatment, take calcium oxide-containing materials, potassium permanganate, and sodium fluoride and put them into an enhanced diffusion container equipped with red mud slurry, stir for 10 minutes, and obtain mixed pulp residue;

[0032] b, atmospheric pressure dealkalization reaction, put the pulp slag obtained in step a into a stirred atmospheric pressure dealkalization reactor for dealkalization reaction, the reaction temperature in dealkalization reaction is 80 ° C, the liquid-solid ratio is controlled to 7, and the reaction time for 4h;

[0033] c. Separation and washing, the separated alkali-containing solution is returned to the alumina production process, and the separated low-alkali red mud is sent to the storage yard for storage.

[0034] The results obtained are shown in Ta...

Embodiment 2

[0036] A kind of dealkalization method of red mud of Bayer process, the process of recovering alkali is operated according to the following steps, comprising:

[0037] a, Intensified diffusion pretreatment, take calcium oxide-containing materials, potassium permanganate, and hatching sodium into an enhanced diffusion container equipped with red mud slurry, stir for 10 minutes, and obtain mixed pulp slag;

[0038] B, normal pressure dealkalization reaction, put the pulp slag obtained in the step a into a stirred normal pressure dealkalization reactor and carry out dealkalization reaction, the reaction temperature in the dealkalization reaction is 80 ℃, the liquid-solid ratio is 6.8, and the reaction time is 4h;

[0039] c. Separation and washing, the separated alkali-containing solution is returned to the alumina production process, and the separated low-alkali red mud is sent to the storage yard for storage.

[0040] The results obtained are shown in Table 1.

Embodiment 3

[0042] A kind of dealkalization method of red mud of Bayer process, the process of recovering alkali is operated according to the following steps, comprising:

[0043] a, Intensified diffusion pretreatment, take calcium oxide-containing materials, potassium permanganate, and sodium fluoride and put them into an enhanced diffusion container equipped with red mud slurry, and stir for 11 minutes to obtain mixed pulp residue;

[0044] B, normal pressure dealkalization reaction, put the pulp slag obtained in step a into a stirred normal pressure dealkalization reactor and carry out dealkalization reaction, the reaction temperature in dealkalization reaction is 80 ℃, the liquid-solid ratio is 6.7, and the reaction time is 4h;

[0045] c. Separation and washing, the separated alkali-containing solution is returned to the alumina production process, and the separated low-alkali red mud is sent to the storage yard for storage.

[0046] The results obtained are shown in Table 1.

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Abstract

The invention relates to the field of aluminum smelting, and particularly relates to a dealkalization method for Bayer process red mud. The method comprises the following steps: a, taking red mud; b,feeding a calcium oxide-containing material, a strong oxidant and a fluoride into a reinforced diffusion container filled with red mud slurry to obtain mixed slurry, wherein the weight ratio of CaO inthe calcium oxide-containing material to Na2O in the red mud solid phase is controlled to be 2-6, the adding amount of the strong oxidant is 0-0.1% of the content of sodium oxide in the red mud, andthe adding amount of the fluoride is 0-0.1% of the content of the sodium oxide in the red mud; c, carrying out a normal-pressure dealkalization reaction, namely feeding the mixed slurry obtained in the step b into a normal-pressure dealkalization reactor with a stirring function to carry out the dealkalization reaction, wherein the reaction temperature is 50-102 DEG C, the liquid-solid ratio is 3-8, and the reaction time is more than 3 hours; and d, carrying out separating and washing, returning a separated alkali-containing solution to an aluminum oxide production process, and piling separated low-alkali red mud in a storage yard, wherein the alkali content in the discharged red mud can be reduced to 1% or less, and no other harmful wastes are generated.

Description

technical field [0001] The invention relates to the field of aluminum smelting, in particular to a dealkalization method of Bayer process red mud. Background technique [0002] Red mud is the waste residue discharged during the alumina production process. It is reddish-brown because it contains a certain proportion of iron oxide, so it is called red mud. At present, the vast majority of alumina production adopts alkaline process, mainly including sintering process, Bayer process, and the hybrid and serial production processes derived from the above two processes. The raw material used in the Bayer process is bauxite. The silica contained in the bauxite is converted into sodium silicate slag in the alumina production process and enters the red mud, resulting in the loss of alumina and sodium oxide along with the red mud. The sodium oxide taken away not only causes alkali loss and increases production costs, but also makes comprehensive utilization of red mud difficult and po...

Claims

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Application Information

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IPC IPC(8): C01D1/02C01F7/02B09B3/00
CPCC01D1/02C01F7/02B09B3/80
Inventor 薛小成周辉放
Owner 河南镁联铝基材料有限公司
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