Method for recycling carbon and electrolytes from waste cathode carbon block of aluminum electrolytic cell

A technology for waste aluminum electrolysis cell and cathode carbon block, which is applied in the electrolysis process, electrolysis components, calcium/strontium/barium halide, etc., can solve the problems of large dosage of chemicals and many flotation stages, and achieves less dosage of chemicals , The effect of simplifying the processing process and reducing the impact

Inactive Publication Date: 2016-08-03
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 milling:

[0054] First use a jaw crusher to crush the cathode carbon block of 1kg of the waste cathode carbon block of the electrolytic aluminum tank to -30mm, then use a fine crusher to crush it to -2mm, and finally use a ball mill to grind it to a particle size of 200 mesh, of which -200 mesh 80%.

[0055] Step (2): Alkali immersion filtration:

[0056] Take 1 kg of waste cathode carbon powder that has been ground in step (1), add 4 mol / L of sodium hydroxide solution to form a slurry (the mass ratio of solid to liquid is 1: 6), and put it under a temperature of 50 ° C and a rotating speed of 100 r / min. Under the condition, leaching is carried out in a stirring leaching tank, and after stirring and leaching for 45 minutes, filter to obtain filter cake A1 and filtrate B1; add CaO equivalent to 105% of soluble fluoride content (or substance amount) to filtrate B1 until the precipitation ends , and filtered to obtain filter cake A2 and filtrate B...

Embodiment 2

[0067] Compared with Example 1, the difference is that the water in the step (3) is replaced by the flotation medium in the process of preparing the slurry, and the flotation medium filtrate B2 is diluted 0.6 times with water. After the flotation, the upper carbon powder and the CaF 2 It is the lower layer 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 milling:

[0070] First use a jaw crusher to crush the cathode carbon block of 1kg of the waste cathode carbon block of the electrolytic aluminum tank to -30mm, then use a fine crusher to crush it to -2mm, and finally use a ball mill to grind it to a particle size of 200 mesh, of which -200 mesh 85%.

[0071] Step (2): Alkali immersion filtration:

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

[0073] Step (3): Flotation:

[0074] The filter cake (f...

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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 recovery, and in particular relates to a method for recovering carbon and electrolyte from waste cathode carbon blocks of an aluminum electrolytic cell. Background technique [0002] Metal aluminum has become an important basic material for the development of the national economy. However, in the process of aluminum smelting, due to the erosion of 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 electrolytic aluminum output in 2015 has reached 31.41 million tons, and more than 300,000 tons of waste cathode carbon blocks have been 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 fluorid...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25C3/08C25B15/08C01B31/02C01F11/22
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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