Two-stage digestion process of boehmite-gibbsite hybrid bauxite

A gibbsite and boehmite technology, applied in the direction of alumina/aluminum hydroxide, etc., can solve the problems of the decrease of alumina recovery rate, the increase of red mud amount and the high concentration of solution, so as to reduce the energy consumption of dissolution and reduce the Loss, volume reduction effect

Inactive Publication Date: 2012-12-19
长沙瑞德新材料科技发展有限公司 +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In this process, due to the addition of lime, the recovery rate of alumina decreases and the amount of red mud increases. The concentration of the solution in the underflow of the dissolved ore pulp is high, the caustic ratio is low, and the filtration is difficult.

Method used

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  • Two-stage digestion process of boehmite-gibbsite hybrid bauxite

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] The boehmite-gibbsite mixed type bauxite with an aluminum-silicon ratio (A / S) of 6 is used as a raw material, wherein the boehmite mineral weight percentage accounts for 20%. The molecular ratio of most of the circulating lye to this mixed bauxite is 1.38, and the concentration of lye is Na 2 O 130g / L, eluted at 110°C for 20min, the caustic molecular ratio of the first-stage eluate is 1.40. Add caustic soda and the remaining circulating lye to the underflow of a section of dissolved ore pulp settling and separation, according to the concentration of ore pulp Na 2 O 183g / L, and the molecular ratio of boehmite dissolved in the underflow is 1.37 for pulp preparation. The prepared pulp is pre-desiliconized at 100°C for 6 hours, and the pre-desiliconization rate is 50%. The pre-desilication slurry is directly subjected to the second-stage high-temperature dissolution, the dissolution temperature is 230°C, the dissolution time is 20min, the caustic molecular ratio of the se...

Embodiment 2

[0022] The processing of raw materials and a section of low-temperature stripping are the same as in Example 1. Add caustic soda and the remaining circulating lye to the underflow of a section of dissolved ore pulp settling and separation, according to the concentration of ore pulp Na 2 O 150g / L, and the molecular ratio of boehmite dissolved in the underflow is 1.33 for pulp preparation. The prepared pulp was pre-desiliconized at 100°C for 6 hours, and the pre-desiliconization rate was 46%. The pre-desilication slurry is directly subjected to the second-stage high-temperature dissolution, the dissolution temperature is 230°C, the dissolution time is 20min, and the caustic molecular ratio of the second-stage dissolution liquid is 1.35. The second-stage high-temperature dissolution slurry is mixed with the overflow of the first-stage low-temperature dissolution pulp sedimentation separation, and is diluted and desiliconized at 100°C for 2 hours, and then the slurry is separated...

Embodiment 3

[0024] Processing raw material is with embodiment 1. The molecular ratio of circulating lye and mixed bauxite according to the complete dissolution of gibbsite is 1.38, and the concentration of lye is Na 2 O 180g / L, dissolved at 100°C for 20 minutes, the caustic molecular ratio of the eluate in the first stage is 1.40. Add caustic soda to the underflow of a section of dissolved ore pulp settling and separation, according to the concentration of Na in the pulp 2O 240g / L, and the molecular ratio of boehmite dissolved in the underflow is 1.30 for pulp preparation. The prepared pulp is pre-desiliconized at 95°C for 8 hours, and the pre-desiliconization rate is 40%. The pre-desilication slurry is directly subjected to the second-stage high-temperature dissolution, the dissolution temperature is 230°C, the dissolution time is 10min, and the caustic molecular ratio of the second-stage dissolution liquid is 1.32. The second-stage high-temperature dissolution slurry is mixed with th...

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Abstract

The invention relates to a two-stage digestion process of boehmite-gibbsite hybrid bauxite. The process is characterized in that soluble gibbsite of the boehmite-gibbsite hybrid bauxite is dissolved under a normal pressure and in short time without adding lime during the digestion process; and that insoluble boehmite is treated by a high temperature. The method can not only ensure full recovery of alumina but also reduce energy consumption of the digestion greatly. By performing predesilicification of ore pulp under a condition of high solid content after a first bottom flow is added to a systemized supplement with alkali, heating surface scar of a second high-temperature digestion slows down; and pulp liquid volume of predesilicification can be reduced. Loss of alumina and red mud amount can be reduced because no lime is added in the digestion process. With the two-stage digestion process of the boehmite-gibbsite hybrid bauxite, problems of low alumina recovery rate or large investment, high energy consumption and the like existing in a process of Bayer digestion process of the boehmite-gibbsite hybrid bauxite can be solved; and objects of economically producing alumina with the two-stage digestion process by employing the boehmite-gibbsite hybrid bauxite as raw materials are realized.

Description

technical field [0001] The invention relates to a two-stage dissolution process of boehmite-gibbsite mixed type bauxite, which belongs to the technical field of alumina production in light metal metallurgy. Background technique [0002] The types of bauxite mainly include gibbsite ore, boehmite ore and diaspore ore, and boehmite-gibbsite mixed ore. When the Bayer method is used to dissolve bauxite in the alumina industry, the appropriate dissolution process system is usually selected mainly according to the type of ore. When the Bayer method is used to dissolve bauxite to produce alumina, the dissolution performance of gibbsite ore is the best. In industry, low temperature (145-175°C) and low caustic concentration (Na 2 O 120-140g / L) for 30-60min, the alumina in the ore can be fully dissolved; the dissolution performance of diaspore ore is the worst, and usually requires high temperature (245-280°C), concentrated alkali (> 220g / L) under the condition of 60-90min, the al...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02
Inventor 李小斌彭志宏刘桂华周秋生齐天贵杨毅
Owner 长沙瑞德新材料科技发展有限公司
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