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Synergistic defluorination method of microwave-ultrasonic-alkali leaching of waste cathode carbon blocks in aluminum electrolysis

A waste cathode carbon block, aluminum electrolysis technology, applied in the preparation/purification of aluminum fluoride, aluminum halide, carbon, etc., can solve the problems of incomplete reaction, large amount of waste liquid, difficult to handle, long processing time, etc.

Active Publication Date: 2021-02-05
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The purpose of the present invention is to provide a microwave-ultrasonic-alkali leaching method for synergistic fluorine removal of waste cathode carbon blocks in aluminum electrolysis. Immersion ultrasonic treatment comprehensively treats waste cathode carbon blocks, which greatly shortens the production efficiency and can be used in large-scale continuous production. It has an important guiding role in saving resources, reducing energy consumption and obtaining usable carbon blocks and their subsidiary products.

Method used

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  • Synergistic defluorination method of microwave-ultrasonic-alkali leaching of waste cathode carbon blocks in aluminum electrolysis
  • Synergistic defluorination method of microwave-ultrasonic-alkali leaching of waste cathode carbon blocks in aluminum electrolysis
  • Synergistic defluorination method of microwave-ultrasonic-alkali leaching of waste cathode carbon blocks in aluminum electrolysis

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Effect test

Embodiment 1

[0036] In the composition of waste cathode carbon blocks used in the present embodiment, according to weight percentage, carbon 58.4%, oxygen 14.7%, fluorine 12.7%, sodium 9.37%, calcium 0.8%, and the balance is aluminum oxide and its trace elements.

[0037] Break the waste cathode carbon block into a particle size of 1-3cm, break it again if it is larger than 3cm, and enter the grinding stage if it is less than 1cm, then put the cathode carbon block into the crucible, the crucible is a quartz crucible, and the sample is placed on the isolation net. The volume of the sample accounts for 2 / 3 of the volume of the crucible, and the crucible is placed in a high-temperature microwave device.

[0038]When the temperature of the waste cathode carbon block rises to 300°C, a small amount of oxygen is introduced to oxidize and remove most of the cyanide. After the temperature reaches 400°C, the oxygen supply is stopped and argon is continuously introduced as a protective gas, and the ca...

Embodiment 2

[0043] In the composition of waste cathode carbon blocks used in the present embodiment, according to weight percentage, carbon 58.4%, oxygen 14.7%, fluorine 12.7%, sodium 9.37%, calcium 0.8%, and the balance is aluminum oxide and its trace elements.

[0044] Break the waste cathode carbon block into a particle size of 1-3cm, break it again if it is larger than 3cm, and enter the grinding stage if it is less than 1cm, then put the cathode carbon block into a crucible, which is a corundum crucible, and place the sample on the isolation net. The volume of the sample accounts for 2 / 3 of the volume of the crucible, and the crucible is placed in a high-temperature microwave device.

[0045] When the temperature of the waste cathode carbon block rises to 300°C, a small amount of oxygen is introduced to oxidize and remove most of the cyanide. After the temperature reaches 400°C, the oxygen supply is stopped and argon is continuously introduced as a protective gas, and the cathode carb...

Embodiment 3

[0050] In the composition of waste cathode carbon blocks used in the present embodiment, according to weight percentage, carbon 58.4%, oxygen 14.7%, fluorine 12.7%, sodium 9.37%, calcium 0.8%, and the balance is aluminum oxide and its trace elements.

[0051] Break the waste cathode carbon block into a particle size of 1-3cm, break it again if it is larger than 3cm, and enter the grinding stage if it is less than 1cm, then put the cathode carbon block into the crucible, the crucible is a quartz crucible, and the sample is placed on the isolation net. The volume of the sample accounts for 2 / 3 of the volume of the crucible, and the crucible is placed in a high-temperature microwave device.

[0052] When the temperature of the waste cathode carbon block rises to 300°C, a small amount of oxygen is introduced to oxidize and remove most of the cyanide. After the temperature reaches 400°C, the oxygen supply is stopped and argon is continuously introduced as a protective gas, and the c...

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Abstract

The invention discloses a microwave-ultrasonic-alkali leaching synergistic method for removing fluorine from aluminum electrolysis waste cathode carbon blocks, and relates to the treatment technology of aluminum electrolysis waste cathodes. The method mainly includes five steps of crushing, microwave roasting, grinding, ultrasonic water bath alkali leaching, and filtration and separation. Firstly, the waste cathode carbon block is crushed, and the particles are obtained by screening, which are put into a crucible and placed in a high-temperature microwave reactor. During the heating process, oxygen is introduced to remove cyanide, and then protective gas is introduced to carry out microwave high-temperature roasting; the roasted cathode carbon block is finely ground, and the finely ground carbon powder is poured into the lye, and ultrasonically assisted. Alkali leaching treatment; after the leaching is completed, it is separated and filtered, and the solid material is dried to obtain regenerated carbon powder with a purity of more than 90%. The method of the invention can effectively remove the fluoride in the cathode carbon block, so that the carbon block can be reused, the method is simple and efficient in operation, and can realize the harmless utilization of aluminum electrolysis solid waste.

Description

technical field [0001] The invention relates to a treatment technology for aluminum electrolysis waste cathodes, in particular to a method for synergistically removing fluorine by microwave-ultrasonic-alkali leaching of aluminum electrolysis waste cathode carbon blocks. Background technique [0002] In the production process of electrolytic aluminum, the new electrolytic cell will be replaced after 5 to 8 years of use, and the replaced cathode is the used cathode. The main reason for the replacement is that the aluminum electrolytic cell was infiltrated by impurities such as sodium fluoride, which caused it to rupture, and the liquid in the cell leaked from the crack, which made the production unable to continue. In recent years, with the sharp increase in demand for aluminum, the aluminum electrolysis industry has also developed rapidly, and the scale of the production line has increased rapidly. Every time the cathode is replaced, a large number of waste cathode carbon blo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B32/05C01F7/54
CPCC01F7/54C01B32/05
Inventor 许磊朱知刘建华韩朝辉彭金辉巨少华田时泓代林晴夏仡任义尧
Owner KUNMING UNIV OF SCI & TECH