Method for volatilizing and removing fluoride from aluminum electrolytic cell waste carbon material

An aluminum electrolytic cell and carbon material technology, which is applied in the field of hazardous substances disposal and utilization produced in the aluminum electrolysis process, can solve the problems of the failure of effective and harmless utilization of waste cell lining carbon blocks, and achieve the elimination of harmful components of hydrogen cyanide. , the effect of reducing investment costs and recycling costs

Active Publication Date: 2015-12-02
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Aiming at the common problem that waste tank lining carbon blocks cannot be effectively and harmlessly utilized in the production process of aluminum electrolysis, the present invention provides a method for volatilization and defluorination of waste carbon materials in aluminum electrolysis tanks

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] The method for volatilization and defluorination in the waste carbon material of the aluminum electrolytic cell, its specific steps are as follows:

[0026] (1) 100g of aluminum electrolyzer waste carbon material containing fluoride salt (C75.10wt%, F4.70wt%, Al 2 o 3 5.40wt%, SiO 2 0.39wt%) crushed to 0.3~5mm, the powder less than 0.3mm is bonded with 1% asphalt of the powder mass to make a 0.5~1mm ball;

[0027] (2) Pass the material obtained in step (1) into moist air with a velocity of 0.80m / s, and control the mass ratio of water and air in the moist air with water to 0.10:1 (kg / kg). Volatile flue gas containing fluoride salt was obtained by volatilization at 750°C for 2 hours; after volatilization, the fluorine in the aluminum electrolytic cell waste carbon material containing fluoride salt was reduced to 0.078wt%, and the fluorine removal rate was 98.34%;

[0028] (3) The volatile flue gas obtained in step (2) containing fluoride salts is blown into air at a te...

Embodiment 2

[0030] The method for volatilization and defluorination in the waste carbon material of the aluminum electrolytic cell, its specific steps are as follows:

[0031] (1) 100g of aluminum electrolyzer waste carbon material containing fluoride salt (C88.60wt%, F4.00wt%, Al 2 o 3 3.14wt%, SiO 2 0.10wt%) is crushed to 0.3-5mm, and the powder less than 0.3mm is bonded with 1% asphalt of the powder mass to form a 0.5-1mm ball;

[0032] (2) Pass the compressed agglomerated material obtained in step (1) into moist air with a flow rate of 0.20m / s, and control the mass ratio of water and air in the moist air with water to 0.04:1 (kg / kg) , volatilized at a temperature of 750°C for 1 hour to obtain volatile flue gas containing fluoride salts; after volatilization, the fluorine in the aluminum electrolytic cell waste carbon material containing fluoride salts was reduced to 0.064wt%, and the fluorine removal rate was 98.40%;

[0033] (3) Put the volatile flue gas obtained in step (2) at a ...

Embodiment 3

[0035] The method for volatilization and defluorination in the waste carbon material of the aluminum electrolytic cell, its specific steps are as follows:

[0036](1) 100g aluminum electrolyzer waste carbon material containing fluoride salt (C80.12wt%, F4.14wt%, Al 2 o 3 4.04wt%, SiO 2 0.21wt%) is crushed to 0.3-5mm, and the powder less than 0.3mm is bonded with 1% asphalt of the powder mass to form a 0.5-1mm ball;

[0037] (2) Pass the compressed agglomerated material obtained in step (1) into moist air with a flow rate of 0.40m / s, and control the mass ratio of water and air in the moist air with water to 0.07:1 (kg / kg) , volatilized at a temperature of 900°C for 2 hours to obtain volatile flue gas containing fluoride salts; after volatilization, the fluorine in the aluminum electrolytic cell waste carbon material containing fluoride salts was reduced to 0.08wt%, and the fluorine removal rate was 98.07%;

[0038] (3) The volatile flue gas obtained in step (2) containing fl...

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Abstract

The invention relates to a method for volatilizing and removing fluoride from an aluminum electrolytic cell waste carbon material and belongs to the technical field of proposal and utilization of hazardous substances produced in the aluminum electrolytic process. The aluminum electrolytic cell waste carbon material containing fluorinated salt is crushed to 0.3-5mm, and an asphalt adhesive occupying one percent by mass of a powder material is added into the powder material which is smaller than 0.3mm so as to prepare 0.5-1mm pellets. The obtained material is introduced into wet air containing water, and is volatilized at 750-1100 DEG C for 1-2h so as to obtain volatile smoke containing fluorinated salt. The volatile smoke containing the fluorinated salt is blown into the air and burnt at 700-1050 DEG C, CO and HCN are thoroughly burnt, the burnt volatile smoke containing the fluorinated salt is cooled to a room temperature and then connected with a purifying device so as to obtain fluorinated alumina, the fluorinated alumina is used for aluminum electrolysis production, and the purified gas meets national GB28661-2012 emission requirements. The method for volatilizing and removing the fluorinated salt through utilizing the wet air containing water as carrying gas, provided by the invention, realizes the purpose of removing the fluorinated salt from a spent potliner carbon block containing the fluorinated salt.

Description

technical field [0001] The invention relates to a method for volatilization and defluorination of waste carbon materials in an aluminum electrolysis cell, and belongs to the technical field of disposal and utilization of hazardous substances produced in the aluminum electrolysis process. Background technique [0002] The initial main materials for the lining of aluminum electrolytic cells are carbonaceous materials, alumina and mullite. During the production process of aluminum electrolysis, due to the penetration and corrosion of the lining material by the electrolyte at high temperature, the lining structure of the electrolytic cell will be deformed or broken, and the aluminum liquid and electrolyte in the electrolytic cell will leak from the cracks. In severe cases, production must be stopped and carried out overhaul. Generally, the electrolyzer needs to be overhauled after 3 to 6 years of use. Overhaul is to take out all the lining material, that is, the waste tank lin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25C3/06
Inventor 朱云施哲李艳陈仕鸿陈顺智
Owner KUNMING UNIV OF SCI & TECH
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