A method for recovering carbon and electrolyte from waste cathode carbon blocks of aluminum electrolytic cells

An aluminum electrolytic cell waste and cathode carbon block technology, which is applied in the electrolysis process, electrolysis components, carbon preparation/purification, etc., can solve the problems of large dosage of chemicals and many flotation stages, and achieves less dosage of chemicals and simplification Treatment process, effect of reducing influence

Inactive Publication Date: 2018-01-16
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to solve the technical problems such as the large dosage of chemicals and the large number of flotation stages in the flotation process of existing waste cathode carbon blocks, the present invention provides a method for recovering carbon powder and electrolyte from the waste cathode carbon blocks of aluminum electrolytic cells. To achieve the purpose of ensuring the purity and recovery rate of good carbon powder with less dosage of chemicals and fewer flotation stages

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0053] Step (1): crushing and grinding:

[0054] First use a jaw crusher to crush the cathode carbon block to -30mm, then use a fine crusher to crush it to -2mm, and finally use a ball mill to grind to a particle size of 200 mesh, of which -200 mesh Accounted for 80%.

[0055] Step (2): Alkaline leaching filtration:

[0056] Take 1kg of the ground waste cathode carbon powder in step (1), add 4mol / L sodium hydroxide solution to make a slurry (solid-liquid mass ratio is 1:6), at a temperature of 50℃, rotating speed 100r / min Under the conditions, leaching in a stirring leaching tank, stirring and leaching for 45 minutes and then filtering to obtain filter cake A1 and filtrate B1; add CaO equivalent to 105% of the soluble fluoride content (or substance amount) to the filtrate B1 until the precipitation is complete , Filter to obtain filter cake A2 and filtrate B2.

[0057] Step (3): Flotation: Add the filter cake (filter cake A1 and filter cake A2) in step (2) into water at a solid-liqu...

Embodiment 2

[0067] Compared with Example 1, the difference is that the flotation medium is used to replace the water in step (3) in the process of preparing the slurry, and the flotation medium filtrate B2 is a liquid diluted 0.6 times with water. After flotation, the upper layer of carbon powder and CaF are separated 2 It is the lower electrolyte of the main body. By calculation, the electrolyte recovery rate is 91.44%, the carbon powder purity is 86.64%, and the recovery rate is 93.21%.

Embodiment 3

[0069] Step (1): crushing and grinding:

[0070] First use a jaw crusher to crush the cathode carbon block to -30mm, then use a fine crusher to crush it to -2mm, and finally use a ball mill to grind to a particle size of 200 mesh, of which -200 mesh Accounted for 85%.

[0071] Step (2): Alkaline leaching filtration:

[0072] Take 1kg of the ground waste cathode powder in step (1), add 6mol / L sodium hydroxide solution to make a slurry (solid-liquid mass ratio is 1:7), at a temperature of 40℃, rotating speed 90r / min conditions Next, leaching in a stirring leaching tank, stirring and leaching for 60 minutes and then filtering to obtain filter cake A1 and filtrate B1; add CaO equivalent to 107% of the soluble fluoride content (or amount of substance) in the filtrate B1 until the precipitation is complete. Filter cake A2 and filtrate B2.

[0073] Step (3): Flotation:

[0074] Add the filter cake (filter cake A1 and filter cake A2) in step (2) into water at a solid-liquid mass ratio of 1:1...

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Abstract

The invention discloses a method for recycling carbon and electrolytes from a waste cathode carbon block of an aluminum electrolytic cell. The method comprises the following steps that 1, the cathode carbon block is crushed and grinded; 2, cathode carbon powder obtained from the cathode carbon block subjected to crushing and grinding in the step 1 is stirred and leached in alkali liquor and then filtered, so that a filter cake A1 and filtrate B1 are obtained; and a precipitating agent is added into the filtrate B1, so that a filter cake A2 and filtrate B2 are obtained after filtering is conducted; and 3, the filter cake A1, the filter cake A2, a flotation medium and flotation reagents are subjected to mixing and pulp conditioning, and thus the carbon and electrolytes are obtained through flotation and separation; the flotation reagents comprises the collecting agents, the foaming agents and the conditioning agents; the collecting agents are composed of the collecting agent C1 and the collecting agent C2 at the mass ratio of 0.65-0.75:0.25-0.35; the collecting agent C1 is selected from at least one of coal tar, heavy oil, kerosene and diesel oil; and the collecting agent C2 is selected from at least one of dodecylamine, sodium dodecyl benzene sulfonate, sodium oleate and sodium dodecyl sulfate. According to the method for recycling the carbon and the electrolytes from the waste cathode carbon block of the aluminum electrolytic cell, the carbon powder and the electrolytes are effectively separated and recycled from the waste cathode carbon block.

Description

Technical field [0001] The invention belongs to the field of carbon waste recycling, and specifically relates to a method for recycling carbon and electrolyte from waste cathode carbon blocks of aluminum electrolytic cells. Background technique [0002] Metal aluminum has become an important basic material for the development of the national economy. However, in the aluminum smelting production process, due to the erosion of the electrolyte, about 10kg of waste cathode carbon blocks will be produced for every ton of electrolytic aluminum produced, which has become the main solid pollutant in the aluminum electrolysis industry. According to this calculation, the domestic production of electrolytic aluminum in 2015 has reached 31.41 million tons, and more than 300,000 tons of waste cathode carbon blocks are produced, which is huge and cannot be ignored. [0003] In the waste cathode carbon block produced by aluminum electrolysis, the main components are carbon, cryolite, sodium fluo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C25C3/08C25B15/08C01B32/05C01F11/22
CPCC01F11/22C25B15/08C25C3/08
Inventor 田忠良杨凯肖劲袁杰郭伟昌赖延清李劼
Owner CENT SOUTH UNIV
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