Method for reclaiming electrolyte in carbon dross of aluminium electrolysis

An electrolyte and a technology for recovering aluminum, which is applied in the field of electrolyte for recycling aluminum electrolytic carbon slag, can solve the problems of inability to use dense phase transportation, difficult disposal of waste liquid, low recovery rate, etc., and achieve the effect of easy industrial implementation and low processing cost

Active Publication Date: 2008-09-03
GUIZHOU BRANCH CHINA ALUMINUM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The recovery rate of this method is low, and the recovered electrolyte contains high content of carbon powder and other impurities, which cannot be directly returned to the electrolytic cell for use.
The flotation method has the following deficiencies: (1) contains about 9% of the electrolyte in the flotation charcoal powder, and cannot return to the carbon production system; (2) contains high carbon in the flotation electrolyte, reaching more than 5%, and cannot return to the electrolyzer for use; ( 3) The flotation electrolyte is mixed with flotation agent, sticky, and ea

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Weigh 1,000 grams of aluminum electrolytic carbon slag with a particle size of less than 3mm, add 10 grams of clean coal with a particle size of less than 3mm, and 100 grams of industrially pure calcium fluoride, mix the three materials evenly, and roast the mixture at a temperature of 850°C. The calcination time is 1 hour, and the electrolyte with good dispersibility is obtained after calcination. After analysis, the impurity content in the electrolyte is 0.20%, mainly iron and silicon oxides.

Embodiment 2

[0019] Weigh 1,000 grams of aluminum electrolytic carbon slag with a particle size of less than 3 mm, add 50 grams of clean coal with a particle size of less than 3 mm, and 50 grams of industrially pure calcium fluoride, mix the three materials evenly, and roast the mixture at a temperature of 750°C. The calcination time is 2 hours, and an electrolyte with good dispersibility is obtained after calcination. After analysis, the impurity content in the electrolyte is 0.26%, mainly oxides of iron and silicon.

Embodiment 3

[0021] Weigh 1,000 grams of aluminum electrolytic carbon slag with a particle size of less than 3mm, add 100 grams of clean coal with a particle size of less than 3mm, and 10 grams of industrial pure calcium fluoride, mix the three materials evenly, and roast the mixture at a temperature of 650°C. The calcination time is 3 hours, and the electrolyte with good dispersibility is obtained after calcination. After analysis, the impurity content in the electrolyte is 0.31%, mainly iron and silicon oxides.

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Abstract

A method for retrieving electrolyte form aluminum electrolysis carbon residue, characterized in that the aluminum electrolysis carbon residue is mixed with calcium fluoride serving as disperser with a weight of 1 to 10 wt. % of the carbon residue, and coal serving as combustion catalyst with a weight of 1 to 10 wt. % of the carbon residue, and then is roasted for 1 to 3 hours under a temperature of 650 to 850 degree C.. The method has the advantages of low process cost, high retrieving rate of electrolyte, easy implementation. The retrieved electrolyte has little impurity, and can be directly and completely returned to the electrolysis cell for use without negative effect to the quality of the electrolyte and aluminum melt.

Description

technical field [0001] The invention relates to a method for recovering electrolyte in aluminum electrolysis carbon slag. Background technique [0002] At present, about 3-10 kg of carbon slag is discharged for every ton of primary aluminum produced. Due to the immersion and penetration of electrolytes, the electrolyte content in the carbon slag is very high, accounting for about 60% to 70% of the weight of the carbon slag, mainly due to fluorination. Sodium, cryolite, sub-cryolite and a small amount of alumina. Electrolyte is an extremely valuable raw material for electrolysis. If it can be effectively recovered and returned to the electrolytic cell for use, it will be of great benefit to reduce the production cost per ton of aluminum and the consumption of fluoride salt, and can produce obvious economic benefits. [0003] The currently reported technology for processing aluminum electrolytic carbon slag is mainly the flotation method, and the process is complicated. 6 Or...

Claims

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Application Information

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IPC IPC(8): C25C3/06C25C3/18
Inventor 李旺兴陈喜平赵淋
Owner GUIZHOU BRANCH CHINA ALUMINUM IND
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