A Chemical Treatment Method for Improving the Sedimentation and Separation Effect of Red Mud

Abstract

The invention relates to the technical field of sedimentation and separation of red mud, in particular to a chemical treatment method for improving the effect of sedimentation and separation of red mud, which is characterized in that the steps of the treatment method are as follows: When the iron oxide content in the solid phase is ≥ 20%, use a non-ionic sedimentation accelerator combined with the first synthetic flocculant for treatment. For the dissolved red mud with a low iron oxide content, when the iron oxide content in the solid phase of the dissolved red mud is < 20%, the combination of cationic sedimentation accelerator and the second synthetic flocculant is used for treatment, which has the advantages of simple method, high sedimentation efficiency, good sedimentation effect, low treatment cost, and improved red mud sedimentation separation with improved recovery rate of alumina and caustic alkali Effect of chemical treatment methods and other advantages.

Description

technical field [0001] The invention relates to the technical field of sedimentation and separation of red mud, in particular to a chemical treatment for improving the sedimentation and separation effect of red mud with simple method, high sedimentation efficiency, good sedimentation effect, low treatment cost, high recovery rate of alumina and caustic method. Background technique [0002] As we all know, in the alumina production process, the bauxite ore is pulverized and enters the dissolution stage, and the dissolved ore pulp needs to be settled by red mud to separate insoluble ore impurities and red mud from the sodium aluminate solution. There are two types of flocculants commonly used in alumina plants at home and abroad, one is synthetic flocculants (based on acrylic acid or / and hydroxamic acid polymers containing acrylamide groups, such as the Flomin AL series products of Aisen Company, Cyfloc HX series products from Cytec, Alclar series products from BASF, Superflo...

AI Technical Summary

Problems solved by technology

[0005] However, due to the preparation of high-molecular-weight polysaccharides, especially polysaccharides of several million to tens of millions, most of them are still in the laboratory stage at home and abroad, and the cost of large-scale production is extremely expensive, so it is difficult to apply them on a large scale in the red mud sedimentation process In addition, low-molecular-weight polysaccharides, generally thousands to hundreds of thousands of polysaccharides, are added in a particularly large amount in the red mud sedimentation process, and will be enriched in the mother liquor to affect the growth of subsequent crystal seeds

Secondly, cross-linking low-molecular-weight polysaccharides can increase the molecular weight of polysaccharides, but because the cross-linking agent is a chemical agent, it will degrade in the alkaline mother liquor and increase the organic content of the mother liquor, affecting the subsequent process, so it is not practical

[0006] For the dissolved red mud with low iron oxide content, cationic polymers are mostly self-polymers of quaternary ammonium salts, which cannot maintain a stable structure and increase the sedimentation velocity in a high-concentration lye environment, and have limited removal effect on floating matter. It is difficult to meet the higher requirements below 0.10g / L. Moreover, the current high-molecular-weight and easily soluble polysaccharide agents are either expensive or remain in the laboratory research and development stage, while natural polysaccharides such as cassava flour and starch have dissolution costs. time, easy residue, low molecular weight, dust pollution, large dosage, and affecting the decomposition of seed crystals, etc., for the dissolution red mud mud with low iron oxide content, the existing cationic polymers are unstable and the supernatant has poor clarity And other issues

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