Method for treating spent cathodes of spent potlinings of aluminum electrolysis cells

An aluminum electrolytic cell and treatment method technology, applied in chemical instruments and methods, aluminum fluoride, aluminum halide, etc., can solve the problems of secondary pollution sources, long process, inability to effectively realize comprehensive utilization of waste cathode resources, etc. The effect of production costs

Inactive Publication Date: 2017-03-22
GUIZHOU BRANCH CHINA ALUMINUM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, these methods have the disadvantage of long process, and some methods will also bring problems such as secondary pollution sources

Method used

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  • Method for treating spent cathodes of spent potlinings of aluminum electrolysis cells
  • Method for treating spent cathodes of spent potlinings of aluminum electrolysis cells

Examples

Experimental program
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Effect test

Embodiment 1

[0022] Crush the waste cathode and semi-coke, the particle size is 0.5-8mm; mix and mix the broken waste cathode, semi-coke and quartz sand in proportion, the ratio is: waste cathode 30%, semi-coke 20%, quartz 50% %. The above mixed raw materials were placed in a reaction furnace, the temperature was raised to 2000°C, and the heat treatment was carried out for 20 h to obtain the SiC product, and the cyanide was removed at the same time. During the heating process, the molten cryolite is separated from the raw material through the horizontal partition at the lower part of the furnace, and the fluoride-containing gas generated enters the fluoride collector through the exhaust pipe, and the fluoride in the gas is collected after cooling, and discharged through the lye. null.

Embodiment 2

[0024] The waste cathode and metallurgical coke are crushed, and the particle size is 1-3mm. Mix the crushed waste cathode, metallurgical coke and quartz sand in proportion and mix evenly, the ratio is: 40% of waste cathode, 15% of metallurgical coke, and 45% of quartz. Put the above mixed raw materials in the reaction furnace, raise the temperature to 2400 ° C, and heat-treat for 15 h to obtain SiC products, and remove the cyanide in them at the same time. During the heating process, the molten cryolite is separated from the raw materials through the lower partition of the furnace, and the generated fluoride-containing gas enters the fluoride collector through the pipeline, and the fluoride in the gas is collected after cooling, and emptied through the lye.

Embodiment 3

[0026] The waste cathode and petroleum coke are crushed, and the particle size is 1-3mm. Mix the crushed waste cathode, petroleum coke and quartz sand in proportion and mix evenly, the ratio is: 55% of waste cathode, 10% of petroleum coke, and 35% of quartz. Put the above mixed raw materials in a reaction furnace, raise the temperature to 2500°C, and heat-treat for 15 hours to obtain the SiC product, and remove the cyanide in it at the same time. During the heating process, the molten cryolite is separated from the raw materials through the lower partition of the furnace, and the generated fluoride-containing gas enters the fluoride collector through the pipeline, and the fluoride in the gas is collected after cooling, and emptied through the lye.

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Abstract

The invention relates to a method for resource utilization of solid wastes of aluminum electrolysis cells, in particular to a method for treating spent cathodes of spent potlinings of aluminum electrolysis cells. The method includes adding a carbon material and quartz sand into the spent cathodes of the spent potlinings of the aluminum electrolysis cells, conducting high-temperature carbothermic reduction in a high-temperature reacting furnace to obtain SiC, enabling cryolite to form melts to sink, making the melts and the generated SiC to undergo solid-liquid separation, and subjecting a fluoride salt to furnace gas evaporation prior to gas-solid separation from the generated SiC so as to obtain SiC; collecting the sunk cryolite melts and conducting condensation recovery so as to obtain cryolite; collecting evaporated furnace gas and cooling so as to obtain the fluoride salt. The method has the advantages that the SiC is prepared through a high-temperature carbothermic reduction method, fluoride and electrolytes are recovered, the electrolytes are reused for the aluminum electrolysis industry, and cyanide in the spent potlinings is decomposed and removed, so that comprehensive resource utilization of the spent potlinings of the aluminum electrolysis cells is achieved and electrolysis production cost is reduced.

Description

technical field [0001] The invention discloses a method for treating waste cathodes of waste liners of aluminum electrolytic cells, and relates to a method for resource utilization of solid wastes of aluminum electrolytic cells. Background technique [0002] Aluminum electrolytic cell waste liner waste cathode is an inevitable solid waste produced in the electrolytic aluminum process. Because of its high fluorine content and a small amount of highly toxic cyanide, it has serious environmental hazards and has been listed by many countries. into the list of hazardous waste. At present, there is no effective treatment method for waste cathodes. Domestic electrolytic aluminum production enterprises mainly use open-air stacking or landfill methods for the waste cathodes of aluminum electrolytic cell linings produced. This treatment method not only pollutes the environment, but also wastes resources such as carbon and electrolyte in the waste tank lining. With the rapid developm...

Claims

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Application Information

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IPC IPC(8): C01B32/963C01F7/54C01B9/08
CPCC01B9/08C01F7/54
Inventor 张劲斌罗英涛杨宏杰陈开斌
Owner GUIZHOU BRANCH CHINA ALUMINUM IND
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