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Method for preparing graphitized cathode by using waste cathode carbon blocks produced during aluminum electrolysis

A waste cathode of aluminum electrolysis, graphitization technology, applied in the direction of electrodes, electrolysis process, electrolysis components, etc., can solve problems affecting human health, etc., achieve excellent resistance to metal sodium penetration, increase carbon content, and improve carbon purity.

Active Publication Date: 2021-03-23
ZHENGZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, domestic electrolytic aluminum enterprises generally adopt the method of burying or stockpiling solid waste such as waste cathodes, which will affect human health in the long run

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] A method for preparing a graphitized cathode by using aluminum electrolysis waste cathode carbon blocks, comprising the following steps:

[0021] (1) Crush the spent cathode carbon block until the maximum particle size is less than 6mm, of which the content of particle size 3-6mm accounts for 15%, and the content of less than 0.5mm accounts for 40%;

[0022] (2) After one washing, filtering, intercalation acid leaching, filtering, second washing, filtering, and drying, the product of step (1) is purified until the leaching rate of non-carbon impurities exceeds 95%. Among them, the first water washing temperature is 20°C, the solid particle concentration is 20%, and the time is 5h; the intercalation acid leaching uses 80% concentrated sulfuric acid to add 1mol / L nitric acid with a solution volume of 100% and mixes thoroughly for 3 hours; then add spent cathodes to the solid particles Concentration (this invention refers to cathode carbon block particles, the same below) ...

Embodiment 2

[0027] A method for preparing a graphitized cathode by using aluminum electrolysis waste cathode carbon blocks, comprising the following steps:

[0028] (1) Crushing the spent cathode carbon block until the maximum particle size is less than 6mm, of which the content of particle size 3-6mm accounts for 10%, and the content of less than 0.5mm accounts for 50%;

[0029] (2) After one washing, filtering, intercalation acid leaching, filtering, second washing, filtering, and drying, the product of step (1) is purified until the leaching rate of non-carbon impurities exceeds 95%. Among them, the first water washing temperature is 25°C, the solid particle concentration is 15%, and the time is 6h; the intercalation acid leaching uses 98% concentration of concentrated sulfuric acid, and 1mol / L nitric acid with a solution volume of 150% is fully mixed for 6h; then add the spent cathode to the solid particle The concentration is 10%, mixed for 6 hours; then according to the concentratio...

Embodiment 3

[0034]A method for preparing a graphitized cathode using waste cathode carbon blocks for aluminum electrolysis, which is the same as in Example 1, except that in step (2), the primary washing temperature is 10°C, the solid particle concentration is 10wt%, and the time is 0.5h; For layer acid leaching, add 4mol / L nitric acid with a solution volume of 50% to 98% concentrated sulfuric acid and mix thoroughly for 1 hour; then add waste cathodes to a solid particle concentration of 10%, and mix for 1 hour; then add potassium permanganate at a concentration of 10g / L Fully react for 1h. The second washing temperature is 10°C, the solid particle concentration is 5%, and the treatment time is 1h under 100W ultrasonic conditions. The carbon content of the product after drying is 96.17%, the calcium fluoride content is 0.82%, and the sodium fluoride content is 0.38%. In step (3), the coagulation temperature is 120°C for 3 hours; in step (4), the primary roasting temperature is 1100°C fo...

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Abstract

The invention discloses a method for preparing a graphitized cathode by utilizing waste cathode carbon blocks produced during aluminum electrolysis. According to the invention, the waste cathodes of aluminum electrolysis are used for preparing the graphitized cathode, the characteristic of high graphitization of the waste cathodes is effectively utilized, and the purified waste cathodes, calcinedanthracite, metallurgical coke and graphite are used as aggregates to prepare the graphitized cathode; and compared with a traditional preparation mode, the preparation of the graphitized cathode in the invention is easier to realize, and meanwhile, the graphitized cathode prepared by taking the purified waste cathodes as the aggregate has a better characteristic of metal sodium permeation resistance.

Description

technical field [0001] The invention belongs to the technical field of solid waste treatment of aluminum electrolytic cells, and in particular relates to a method for preparing graphitized cathodes by using aluminum electrolysis waste cathode carbon blocks. Background technique [0002] Generally, after 3 to 5 years of production, the electrolytic aluminum tank needs to be overhauled and replaced with a new electrolytic aluminum cathode. The content of old cathode carbon blocks can reach 1 million tons every year due to the replacement of new electrolytic aluminum cathodes. Usually the composition of spent cathodes is: C, NaF, Na 3 AlF 6 , AlF 3 , CaF 2 , Al 2 o 3 etc., the content of each component in different parts of the electrolytic cell is also different. The electrolytes in waste cathode carbon blocks are various and complex in structure. There are many compounds containing sodium element, which is caused by the infiltration of sodium metal into the gap of car...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/532C04B35/64C04B35/622C04B35/626C25C3/08C25C7/02
CPCC04B35/532C04B35/522C04B35/62204C04B35/62605C04B35/64C25C3/08C25C7/025C04B2235/661
Inventor 杨文杰李盼陈昱冉肖宇王立强韩道洋孔亚鹏
Owner ZHENGZHOU UNIV