Method for recycling waste cathode carbon blocks of aluminum electrolysis cell

A technology of waste cathode carbon blocks and cathode carbon blocks, which is applied in the field of aluminum electrolysis, can solve the problems of not being able to completely process waste cathode blocks, and achieve the effect of saving chemical processing raw materials

Inactive Publication Date: 2017-10-24
李立安
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

CN105401169 A discloses a recycling and environmental protection utilization method of waste cathode carbon blocks of aluminum electrolytic cells. The disadvantages are: 1) The method can theoretically incorporate waste cathodes into electrolytic aluminum c...

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0040] 1. Mechanically crush the waste cathode carbon block and grind it to 200 mesh powder; then carry out air separation on the powder to separate and recover the carbon powder from metal aluminum and aluminum carbide. The air separation conditions are 0.5-3m / s. , The collected charcoal powder is reserved.

[0041] 2. Take 30g of carbon powder and place it in a plastic beaker with 125ml of pure water and stir at 25°C for 4 hours to dissolve NaF in water and separate it.

[0042] 3. Keep the separated aqueous solution in a container for later use.

[0043] 4. The filter residue is dried in a vacuum drying oven at 110°C for 4 hours.

[0044] 5. Weigh 24gAl 2 (SO 4 ) 3 .18H 2 O was dissolved in 200ml of pure water to prepare a leachate. The above-mentioned dried filter residue was placed in the leachate and stirred at 25°C for 24 hours, and filtered to obtain the leachate and filter residue.

[0045] 6. A total of 23.1g is collected from the drying of the filter residue, and the content...

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Abstract

The invention discloses a method for recycling waste cathode carbon blocks of an aluminum electrolysis cell. The method comprises the following steps: 1, grinding the waste cathode carbon blocks into powder of 100-200 meshes through superfine grinding, and then winnowing the powder to separate the carbon powder from aluminum and aluminum carbide; 2, adding the fine carbon powder into water, stirring the fine carbon powder, then filtering the obtained solution, and preparing filtrate and filter residues for later use; 3, adding the filter residues in the step 2 into an aluminum sulfate solution, leaving the mixed solution to stand at normal temperature for 20-30 hours, then filtering the mixed solution, washing obtained filter residues to obtain the carbon powder with the carbon content higher than 90% and preparing filtrate for later use; 4, mixing the filtrate obtained in the step 2 and the filtrate obtained in the step 3, adjusting the pH value to be 5.5, increasing the temperature to 90 DEG C, then carrying out reaction for 3 hours to obtain flocculent hydroxyl aluminum fluoride, and carrying out filtering to obtain filter residues; and 5, calcining the filter residues obtained in the step 3 at 485 DEG C to obtain AlF3 and Na5Al3F14 and using AlF3 and Na5Al3F14 as raw materials of aluminum electrolysis. Through the method, the waste cathode carbon blocks of the aluminum electrolysis cell can be efficiently recycled.

Description

Technical field [0001] The invention belongs to the technical field of aluminum electrolysis, and specifically relates to a method for recycling waste cathode carbon blocks of an aluminum electrolysis cell. Background technique [0002] The waste cathode carbon block produced by aluminum electrolysis contains 30-50wt% electrolyte, and its main components are fluoride, cryolite, alumina, calcium fluoride, sodium carbonate, aluminum carbide and cyanide. After the cathode block is exposed to water, the fluorine content of the leaching solution is as high as 6000mg / L, and the cyanide content is 10-40mg / L, which is much higher than the F required in the "Identification Standard for Hazardous Waste-Identification of Extraction Toxicity" - <50mg / L, CN - <1mg / L, belongs to industrial hazardous solid waste. [0003] In the existing waste cathode carbon block treatment method, the graphite is separated from the electrolyte mainly by crushing and various flotation methods, the separate...

Claims

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Application Information

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IPC IPC(8): B09B3/00C25C3/08
Inventor 李丹李立安宋俭
Owner 李立安
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