Dealkalization method of Bayer process red mud

Abstract

The invention relates to the field of aluminum smelting, in particular to a dealkalization method of red mud by the Bayer process, comprising: a, taking red mud; b, taking calcium oxide-containing materials, strong oxidants, and fluorides and putting them into enhanced diffusion of red mud slurry In the container, control the CaO in the calcium oxide-containing material and the Na in the solid phase of the red mud 2 The weight ratio of O is 2 to 6, the addition of strong oxidant is 0 to 0.1% of the content of sodium oxide in red mud, and the addition of fluoride is 0 to 0.1% of the content of sodium oxide in red mud to obtain mixed pulp residue; c, Atmospheric pressure dealkalization reaction, put the mixed pulp slag obtained in step b into a stirred atmospheric pressure dealkalization reactor for dealkalization reaction, the reaction temperature is 50-102°C, the liquid-solid ratio is 3-8, and the reaction time is greater than 3h ; d, 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, which can reduce the alkali content in the discharged red mud to less than 1%, and does not produce other hazardous waste.

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...

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 benefit is poor, or the process is complicated, the energy consumption is high, and it is difficult to realize industrialization