Side stream causticization method and apparatus of Bayer process alumina production

An alumina and Bayer process technology, applied in alumina/aluminum hydroxide and other directions, can solve the problems of increased energy consumption, the impact of decomposition speed, complex process flow, etc., to reduce energy consumption, reduce investment and operating costs, and simplify the process. Effect

Active Publication Date: 2014-06-11
SHENYANG ALUMINIUM MAGNESIUM INSTITUTE
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] The sodium carbonate causticization process is an indispensable process in the alumina production process, because if the sodium carbonate accumulated in the production process cannot be discharged in time, it will crystallize and precipitate on the heating surface of the stripper and evaporator, forming scaling, thus Reduce heat transfer efficiency and increase energy consumption
Moreover, when the accumulation of sodium carbonate exceeds 30g / L, it will also have a certain impact on the decomposition rate
[0003] In view of the above unfavorable factors, at present, in domestic Bayer process alumina plants, the process of causticizing and desalting is added in the mother liquor evaporation workshop. This process is complicated and consumes a lot of energy

Method used

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  • Side stream causticization method and apparatus of Bayer process alumina production
  • Side stream causticization method and apparatus of Bayer process alumina production

Examples

Experimental program
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Effect test

Embodiment 1

[0023] This embodiment is causticizing step by step, such as figure 1 As shown, the secondary or tertiary washing liquid from the red mud separation and washing process is used as the causticizing raw liquid 7 and entered into the first tank 1 of the causticizing tank, and the lime milk 8 is added to the first tank 1 of the causticizing tank, and the material is fed to the causticizing tank. Pass into compressed air 5 to make the causticizing solution 12 enter the secondary causticizing tank 102, stay in the secondary causticizing tank for at least 2 hours and stir evenly, after causticizing, the solution 9 enters the settling tank 2 for solid-liquid separation, and the settling tank The overflow 10 is the causticized liquid pumped to the red mud separation and washing process by the causticized liquid pump 3 for one or two washing settling tanks, and the bottom flow of the settling tank 11 is the causticized slag pumped to the red mud separation and washed by the causticized s...

Embodiment 2

[0028] This embodiment is simultaneous causticization

[0029] Such as figure 2 As shown, the difference between this embodiment and embodiment 1 is that the secondary or tertiary washing liquid from the red mud separation and washing process enters each causticizing tank 103 as the causticizing stock solution 7 and lime milk 8, and the others are the same as in the embodiment 1. .

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Abstract

The invention discloses a side stream causticization method and an apparatus of Bayer process alumina production. According to the side stream causticization method, the causticization raw solution is a secondary or tertiary washing solution from a red mud separation washing step, and the side stream causticization method is adopted to replace the evaporation salt-emission process. According to the present invention, the side stream causticization method can replace the evaporation salt-emission process at the early stage of factory construction, has characteristics of simple process, investment reduction, easy operation and energy consumption reduction, and is especially for Bayer process alumina plants adopting gibbsite as the raw material.

Description

technical field [0001] The invention belongs to the technical field of alumina production, and mainly relates to a causticizing method and device for sodium carbonate, and is especially suitable for a method for producing alumina from gibbsite. Background technique [0002] The sodium carbonate causticization process is an indispensable process in the alumina production process, because if the sodium carbonate accumulated in the production process cannot be discharged in time, it will crystallize and precipitate on the heating surface of the stripper and evaporator, forming scaling, thus Reduce heat transfer efficiency and increase energy consumption. Moreover, when the accumulation of sodium carbonate exceeds 30g / L, it will also have a certain impact on the decomposition rate. [0003] In view of the above unfavorable factors, at present, in domestic Bayer process alumina plants, a causticizing salt discharge process is added in the mother liquor evaporation workshop, whic...

Claims

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Application Information

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IPC IPC(8): C01F7/02
Inventor 郭英姿张佰永李志国
Owner SHENYANG ALUMINIUM MAGNESIUM INSTITUTE
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