Technique for rapid separation and red-mud washing of sodium aluminate solution

Abstract

The invention relates to a technique for rapid separation and red-mud washing of a sodium aluminate solution. The technique comprises the steps of desanding, dilution, flocculant pre-preparation, separation, crude liquid filtering, primary washing, secondary washing, tertiary washing, and vacuum filtering. Through the early desanding technique, large-particle materials are filtered out beforehand, so as to eliminate the clogging phenomenon of a settling tank; through dilution, as well as separation and settling with the addition of a flocculant, the separation and settling time is greatly shortened, so as to reduce secondary aluminum oxide loss caused by excessively long separation and settling processes; a washing liquid is recycled for multiple times, so as to greatly reduce the new water consumption, and reduce the aluminum oxide production cost. Therefore, the technique provided by the invention increases the aluminum oxide yield, reduces dissolution loss of aluminum oxide, saves bauxite resources, lowers the production cost, and enhances the market competitiveness without sacrificing the continuous stability of large-scale industrial production.

Description

technical field [0001] The invention relates to a red mud separation and washing process, in particular to a rapid separation of sodium aluminate solution and red mud washing process. Background technique [0002] In the production process of alumina, whether it is sintering method, Bayer method or Bayer sintering combined method, most of the loss of the net dissolution rate of clinker alumina occurs in the separation and settling tank. The separation time is long, and the separation and settling time of the existing process is usually 0.5-2h. During this time, the alumina and sodium oxide that have been dissolved in the slurry will be re-precipitated and lost, resulting in an increase in the content of silicon oxide. Blockage and other phenomena greatly reduce the production capacity of alumina. [0003] With the increase of alumina demand, the total amount of alumina loss in the production process is increasing. Therefore, it is necessary to find an effective rapid separa...

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Problems solved by technology

[0002] In the production process of alumina, whether it is sintering method, Bayer method or Bayer sintering combined method, most of the loss of the net dissolution rate of clinker alumina occurs in the separation and settling tank. The separation time is long, and the separation and settling time of the existing process is usually 0.5-2h. During this time, the alumina and sodium oxide that have been dissolved in the slurry will be re-precipitated and lost, resulting in an increase in the content of silicon oxide. Blockage and other phenomena greatly reduce the production capacity of alumina

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