A method for preparing prebaked anode using aluminum electrolysis waste cathode carbon block

A technology of waste cathode carbon blocks and prebaked anodes, which is applied in the field of reuse of waste cathode carbon blocks in aluminum electrolysis, and can solve problems such as aggravating anode slag drop, limited purification effect, and deterioration of cell conditions

Active Publication Date: 2021-08-10
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, the purification adopts the wet method, the process is complicated, and a large amount of waste water will be generated during the production process, which is not conducive to environmental protection.
And limited by the purification effect, the purified carbon block contains more fluoride, and fluoride such as sodium fluoride and calcium fluoride will greatly promote the prebaked anode and CO 2 The reactivity of the anode will aggravate the slag drop of the anode and deteriorate the tank condition
Because the unpurified carbon block contains more ash, adding a large amount will definitely make the anode ash content exceed the national standard requirement, so it can only be added in a small amount in the form of additives, which limits the use efficiency of waste cathode carbon blocks

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] (1) The raw materials are mixed according to the mass ratio of aluminum electrolysis waste cathode carbon block: electric calcined anthracite: pitch equal to 80:5:15; among them, the particle size of electric calcined anthracite is 13-6mm, and the particle size of aluminum electrolysis waste cathode carbon block is divided into 6 ~3mm, 3~1mm, and -0.15mm are three grades, and the carbon blocks of each grade account for 25%, 25%, and 50% of the total mass of aluminum electrolysis waste cathode carbon blocks, respectively.

[0035] (2) Mix and knead the materials prepared in step (1) at 170° C., and then extrude to obtain the raw carbon block.

[0036] (3) The carbon block raw material is roasted in the carbon monoxide atmosphere according to the following heating system: room temperature ~ 300 ° C heating rate 11 ° C / h, 300 ~ 700 ° C heating rate 3 ° C / h, 700 ~ 1200 ° C heating rate 10 ° C / h , 1200-1900°C heating rate 5°C / h, heat preservation at 1900°C for 30 hours...

Embodiment 2

[0043] (1) The raw materials are mixed according to the mass ratio of aluminum electrolysis waste cathode carbon block: electric calcined anthracite: coal tar: pitch equal to 75:5:2:8; among them, the particle size of electric calcined anthracite is 13 ~ 6mm, and the aluminum electrolysis waste cathode carbon block The particle size is divided into three grades: 6-3mm, 3-1mm, and -0.15mm, and the carbon blocks of each grade account for 25%, 35%, and 40% of the total mass of aluminum electrolysis waste cathode carbon blocks respectively.

[0044] (2) Mix and knead the material prepared in step (1) at 120° C., and then mold it to obtain a raw carbon block.

[0045] (3) The carbon block raw meal is roasted in a helium atmosphere according to the following heating system: room temperature to 300 ° C heating rate 9 ° C / h, 300 ~ 700 ° C heating rate 2 ° C / h, 700 ~ 1200 ° C heating rate 9 ° C / h , 1200-1700°C heating rate 4°C / h, 1700°C heat preservation for 35 hours, 1700°C-700°...

Embodiment 3

[0052] (1) The raw materials are mixed according to the mass ratio of aluminum electrolysis waste cathode carbon block: electric calcined anthracite: phenolic resin is equal to 70:10:20; the electric calcined anthracite particle size is 13 ~ 6mm, and the aluminum electrolysis waste cathode carbon block particle size is divided into There are three grades of 6-3mm, 3-1mm, and -0.15mm, and the carbon blocks of each grade account for 30%, 15%, and 55% of the total mass of aluminum electrolysis waste cathode carbon blocks, respectively.

[0053] (2) Mix and knead the material prepared in step (1) at 30° C., and then vibrate and form it to obtain raw carbon block.

[0054] (3) The carbon block raw material is roasted in the hydrogen atmosphere according to the following heating system: room temperature to 300 ° C heating rate 7 ° C / h, 300 ~ 700 ° C heating rate 1 ° C / h, 700 ~ 1200 ° C heating rate 8 ° C / h, 1200-1500°C heating rate 4°C / h, 1500°C heat preservation for 40 hours,...

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Abstract

The invention discloses a method for preparing a prebaked anode by using waste cathode carbon blocks for aluminum electrolysis, which comprises the following steps: (1) batching, (2) kneading and molding, (3) primary roasting, (4) primary impregnation, (5) Secondary roasting, (6) second impregnation and (7) third roasting to obtain a prebaked anode carbon block. The invention realizes harmless treatment and comprehensive utilization of waste cathode carbon blocks in aluminum electrolysis, solves the problem of environmental pollution and saves petroleum coke. The anode carbon block prepared by the method has excellent performance, good oxidation resistance and low resistivity, which is beneficial to energy saving in the aluminum electrolysis process.

Description

technical field [0001] The invention relates to the field of recycling waste cathode carbon blocks of aluminum electrolysis, in particular to a method for preparing prebaked anodes by utilizing waste cathode carbon blocks of aluminum electrolysis. Background technique [0002] The aluminum electrolysis cathode is deformed, bulged and broken due to the erosion, erosion and thermal stress of molten salt and aluminum liquid, thus producing waste cathode carbon blocks. Under normal circumstances, for every ton of electrolytic aluminum produced, about 10kg of waste cathode carbon blocks will be produced. In 2018, the global output of electrolytic aluminum was 64.34 million tons, and more than 600,000 tons of waste cathode carbon blocks were produced, which is a huge quantity. [0003] Aluminum electrolysis waste cathode carbon block contains carbon, aluminum fluoride, sodium fluoride, calcium fluoride, cryolite, alumina and cyanide and other substances. Among them, the carbon co...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C25C3/12
CPCC25C3/125
Inventor 田忠良赖延清龚培育仲奇凡杨凯肖劲
Owner CENT SOUTH UNIV
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