Search

CN-122013202-A - Treatment method of aluminum electrolysis waste cathode

CN122013202ACN 122013202 ACN122013202 ACN 122013202ACN-122013202-A

Abstract

The application provides a treatment method of an aluminum electrolysis waste cathode. The treatment method comprises the steps of carrying out first electrolysis on an aluminum electrolysis waste cathode and an aluminum electrolysis waste anode in molten salt in inert gas to obtain a graphitized cathode material. The application carries out first electrolysis on the aluminum electrolysis waste cathode and anode in molten salt, the first electrolysis is carried out at a relatively mild temperature, and graphitization is realized by electrochemical reforming of amorphous carbon materials in the molten salt. The treatment method of the application obviously reduces the energy consumption required by the traditional high-temperature graphitization, avoids the severe requirements of equipment on high temperature, effectively removes impurities such as fluoride, sulfur and the like, and improves the graphitization degree of the waste cathode. In addition, the method has simple process flow and lower cost, and the prepared graphitized cathode material can be applied to the fields of structural materials, energy storage and the like.

Inventors

  • GUAN WEI
  • QI LIJUAN
  • SUN YAN
  • WANG QIAO
  • Mo Yongda
  • WAN DA
  • Jia Yekai
  • DU TINGTING

Assignees

  • 中铝科学技术研究院有限公司

Dates

Publication Date
20260512
Application Date
20241112

Claims (10)

  1. 1. The treatment method of the aluminum electrolysis waste cathode is characterized by comprising the following steps of: and in inert gas, carrying out first electrolysis on the aluminum electrolysis waste cathode and the aluminum electrolysis waste anode in molten salt to obtain a graphitized cathode material.
  2. 2. The method of claim 1, wherein the molten salt is at a temperature of 500-1000 ℃.
  3. 3. The method according to claim 1 or 2, wherein the voltage of the first electrolysis is 2.5v to 3.0v; And/or the time of the first electrolysis is 2-6 hours.
  4. 4. A treatment method according to any one of claims 1 to 3, wherein the mass ratio of the aluminium electrolysis waste cathode to the molten salt is 1:200-500.
  5. 5. The processing method according to any one of claims 1 to 4, characterized in that the processing method further comprises: And immersing the aluminum electrolysis waste cathode in the molten salt, and then carrying out the first electrolysis, wherein the immersing time is 1-5 h.
  6. 6. A treatment method according to any one of claims 1 to 5, characterized in that the treatment method comprises: step S1, crushing the aluminum electrolysis waste cathode to obtain aluminum electrolysis waste cathode powder; And S2, wrapping the aluminum electrolysis waste cathode powder by using a current collector, and carrying out first electrolysis with the anode in the molten salt to obtain the graphitized cathode material, wherein the current collector is selected from one or more of a graphite net, a graphite column, graphite paper, metal foam and a metal net, and more preferably, the current collector is graphite paper and/or foam nickel.
  7. 7. The process of any one of claims 1 to 6, wherein the molten salt preparation method comprises: and sequentially carrying out water removal and second electrolysis on the solid salt to obtain the molten salt.
  8. 8. The method according to claim 7, wherein the temperature of the water removal is 200-250 ℃, and/or the time of the water removal is 24-28 hours; And/or the voltage of the second electrolysis is 2.0-3.0V, and/or the time of the second electrolysis is 8-24 h, and/or the temperature of the second electrolysis is 500-1000 ℃.
  9. 9. The method according to any one of claims 1 to 8, characterized in that the molten salt is a water-soluble molten salt, preferably the water-soluble molten salt is selected from any one or more of NaCl, KCl, caCl 2 and BaCl 2 , further preferably the water-soluble molten salt is CaCl 2 ; And/or the inert gas is argon or helium; and/or the anode is a graphite rod.
  10. 10. The treatment method according to any one of claims 1 to 9, wherein the aluminum electrolysis waste cathode comprises, by mass, 72.25% of carbon element, 5.95-6.80% of fluorine element, 4.46-5.05% of sodium element, 0.62-0.83% of sulfur element, and the balance of other impurity elements, and/or the graphitization degree of the graphitized cathode material is 93.0-98.0%.

Description

Treatment method of aluminum electrolysis waste cathode Technical Field The invention relates to the technical field of solid waste treatment of aluminum electrolysis, in particular to a treatment method of an aluminum electrolysis waste cathode. Background Along with the improvement of high-performance technology of industrial materials, lightweight aluminum and aluminum alloy are widely applied to important fields such as aviation, aerospace, ships and the like. However, in the current industrial electrolytic aluminum process production process, the solid hazardous waste amount of the waste cathode carbon is increased year by year, and if the waste cathode carbon contains a certain amount of fluoride, the waste cathode carbon can cause great harm to the life and the environment of human beings if the waste cathode carbon is piled for a long time. At present, scholars develop a series of processes such as aqueous solution chemical method, physical method, high temperature method and the like to treat fluoride in waste cathodes. Among them, the high temperature heat treatment process is the most commonly used graphitization process, and is usually performed at a high temperature of 2000 ℃ or higher, and the calcined spent cathode is subjected to a long-term treatment at a high temperature (usually between 2000 ℃ and 3000 ℃) and a specific atmosphere (such as inert gas or vacuum). During this process, the carbon atoms rearrange to form an ordered graphite crystal structure, which may take several hours to several days, resulting in the problem that the apparatus needs to have a capacity to withstand high temperatures and consumes high energy. Aiming at the processes of fluoride removal and the like by a waste cathode chemical leaching method, fluoride can be removed by an aqueous solution method, but the treated fluorine-containing wastewater can cause a large amount of aqueous solution to generate secondary dangerous wastes, and meanwhile, the corrosion of equipment can be increased. The high-temperature combustion method is to heat the waste cathode to about 1000 ℃ and add a certain chemical reagent to perform chemical reaction so as to remove impurities, but the method can inhibit the reaction of fluoride by the combustion of carbon under the condition of oxygen. The physical floatation method is to add a certain amount of capturing agent for floatation, recover carbon at the upper part and deposit fluoride at the lower part, and has low conversion efficiency and more secondary harm of wastewater. Graphitization is an effective way for changing the structure of the carbonaceous material, so that the carbonaceous material has excellent properties such as high temperature resistance, conductivity, lubricity, chemical stability and the like, and realizing high added value and efficient utilization of carbonaceous resources. At present, the method for improving graphitization mainly comprises a catalytic graphite method, a chemical vapor deposition method, a microwave heating method, a high-temperature high-pressure method and the like, wherein a large amount of catalyst is coated in graphite obtained by the catalytic graphite method and is difficult to completely remove, the graphite obtained by the chemical vapor deposition method has lower production efficiency and is difficult to realize industrialized low-cost production, the crystallinity of the graphite obtained by the microwave heating method is not high, the catalyst is difficult to remove later, and graphitization can not be realized even at the temperature higher than 2000 ℃ for a porous carbon material with a disordered layer structure by the high-temperature high-pressure method. Therefore, the graphitization methods have the defects of high energy consumption, large pollution, high requirement on carbon materials, high purity and the like to different degrees. Disclosure of Invention The invention mainly aims to provide a treatment method of an aluminum electrolysis waste cathode, which aims to solve the problems of high energy consumption and high pollution in the treatment method of the aluminum electrolysis waste cathode in the prior art. In order to achieve the aim, according to one aspect of the invention, a treatment method of an aluminum electrolysis waste cathode is provided, which comprises the steps of carrying out first electrolysis on the aluminum electrolysis waste cathode and an anode in molten salt in inert gas to obtain graphitized cathode materials. Further, the temperature of the molten salt is 500-1000 ℃. Further, the voltage of the first electrolysis is 2.5V-3.0V, and/or the time of the first electrolysis is 2-6 h. Further, the mass ratio of the aluminum electrolysis waste cathode to the molten salt is 1:200-500. Further, the treatment method further comprises the steps of immersing the aluminum electrolysis waste cathode in the molten salt, and then carrying out the first electrolysis, wherein the immersing time is 1-5 hours