A method for producing alumina without evaporation based on the calcification-carbonization method

A technology of alumina and carbonization, which is applied in the preparation of alumina/hydroxide, alkali metal aluminate/alumina/aluminum hydroxide, calcium carbonate/strontium/barium, etc. Problems such as energy consumption in the production process of mud containing alkali, to achieve the effect of solving the pollution of the environment caused by red mud occupying land, reducing energy consumption, and reducing mine consumption

Active Publication Date: 2016-01-20
DONGDA NONFERROUS SOLID WASTE TECH RES INST LIAOLING CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The above-mentioned patented technologies are all aimed at energy saving and consumption reduction in the alumina production process and the harmless utilization of red mud, but none of them have achieved the goal of completely solving the alkali content in red mud and greatly reducing the energy consumption in the production process.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0055] The bauxite is crushed to -250μm and then mixed with calcium aluminate and primary circulation mother liquor. Calcification slag and primary dissolution mother liquor are obtained under the conditions of 280°C and 15min of calcification transition dissolution. Calcium aluminate and bauxite during calcification transition dissolution The mass ratio of ore is 1.2:1, the sodium oxide content in the primary cycle mother liquor used is 170g / L, and the molar ratio of sodium oxide to alumina in the primary cycle mother liquor is 3.5:1;

[0056] The molar ratio of sodium oxide and alumina in the primary dissolution mother liquor obtained by calcification transformation dissolution is 1.5:1. After the dissolution mother liquor is refined with milk of lime and added with aluminum hydroxide seed crystals to decompose and precipitate aluminum hydroxide, aluminum hydroxide and aluminum hydroxide are obtained respectively. The content of aluminum hydroxide and sodium oxide is 170g / L, ...

Embodiment 2

[0063] The bauxite is crushed to -250 μm and then mixed with calcium aluminate and primary circulation mother liquor. Calcification slag and primary dissolution mother liquor are obtained under the conditions of 100°C and 60 minutes of calcification transition dissolution. During the calcification transition dissolution process, calcium aluminate and lime are mixed with The mass ratio of bauxite is 0.2:1, the sodium oxide content in the primary circulating mother liquor is 100g / L, and the molar ratio of sodium oxide to alumina in the primary circulating mother liquor is 2.5:1;

[0064] The molar ratio of sodium oxide and aluminum oxide in the primary dissolution mother liquor obtained by calcification transformation dissolution is 2:1. The content of aluminum and sodium oxide is 100g / L and the molar ratio of sodium oxide to alumina is 2.5:1. The primary decomposition mother liquor is used as a cycle mother liquor and returned to the calcification transformation dissolution proc...

Embodiment 3

[0071] The bauxite is crushed to -250μm and then mixed with calcium aluminate and primary circulation mother liquor. Calcification slag and primary dissolution mother liquor are obtained under the conditions of 240°C and 45min reaction for calcification transition dissolution. Calcium aluminate and bauxite during calcification transition dissolution The mass ratio of ore is 0.5:1, the sodium oxide content in the primary circulating mother liquor is 160g / L, and the molar ratio of sodium oxide to alumina in the primary circulating mother liquor is 3.0:1;

[0072] The molar ratio of sodium oxide and aluminum oxide in the primary dissolution mother liquor is 1.55:1. After the dissolution mother liquor is purified by lime milk and aluminum hydroxide seed crystals are decomposed, and the aluminum hydroxide in the mother liquor is precipitated, the contents of aluminum hydroxide and sodium oxide are obtained respectively. The primary decomposition mother liquor is 160g / L and the molar...

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Abstract

The invention relates to the field of alumina production, in particular to a method for producing alumina without evaporation based on a calcification-carbonization method. The steps are to mix the crushed bauxite, calcium aluminate and a circulating mother liquor, and then carry out a calcification transformation dissolution at 100-280 ° C. The mother liquor after dissolution is refined and decomposed by crude liquid, and then directly returned to the dissolution process for recycling. After the calcified slag undergoes carbonization transformation, it dissolves aluminum at a second low temperature. The sodium aluminate solution dissolved in the second time is precipitated by calcium-containing minerals to obtain calcium aluminate. The calcium aluminate returns to the primary calcification transformation dissolution process and is recycled as a calcium source. The main components of the tailings obtained from the secondary low-temperature melting of aluminum are calcium silicate and calcium carbonate, which can be directly used in the cement industry. This method cancels the evaporation process of the existing alumina production process of bauxite, greatly reduces the energy consumption of the production process, and realizes the harmless utilization of tailings while improving the recovery rate of alumina, which is an energy-saving method. Environmentally friendly alumina production method.

Description

technical field [0001] The invention relates to the field of alumina production, in particular to a method for producing alumina without evaporation based on a calcification-carbonization method. technical background [0002] Aluminum is a pillar industry in my country's non-ferrous metallurgical industry. As of 2013, my country's primary aluminum production capacity reached 18 million tons, and its alumina production capacity was close to 40 million tons, ranking first in the world. Compared with my country's rapidly developing aluminum industry, my country's bauxite resource reserves are not large, and most of them are diaspore-type bauxite with high aluminum, high silicon, and low aluminum-silicon ratio. The energy consumption of alumina production process using diaspore type bauxite is much higher than that of foreign gibbsite production process. The reasons for this are: [0003] (1) The temperature (generally above 260°C) and caustic alkali concentration (about 240g / ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/30C01F7/04C01B33/24C01F11/18
CPCC01B33/24C01F7/04C01F7/30C01F11/18
Inventor 张廷安吕国志张子木刘燕豆志河
Owner DONGDA NONFERROUS SOLID WASTE TECH RES INST LIAOLING CO LTD
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