High-temperature disposal method for spent cathodes of electrolytic aluminum

Abstract

The invention provides a high-temperature disposal method for spent cathodes of electrolytic aluminum. The method comprises the following steps: spent cathode carbon blocks of electrolytic aluminum are crushed into particles of 3-15 mm; then roasting is carried out by using a super high temperature furnace, fluorides in the spent cathode carbon blocks are volatilized, cyanides in the spent cathode carbon blocks are decomposed, flue gas generated during roasting is absorbed through a water spray absorption mode; then, processes such as filtering, drying and the like are carried out, the fluorides and the like are reused in aluminum electrolysis; and a cathode carbon material is discharged out of the super high temperature furnace after the material is cooled. According to the physical and chemical properties of the fluorides, the cyanides and carbon in the spent cathodes of electrolytic aluminum, the fluorides in the spent cathode carbon blocks are volatilized, the cyanides in the spent cathode carbon blocks are decomposed with the high-temperature method; however, on the condition of primary vacuum, carbon in the cathodes cannot burn, so that effective separation of carbon, the fluorides and the cyanides in the cathodes is achieved, and hazard-free disposal and resource utilization of the spent cathodes of electrolytic aluminum are achieved.

Description

technical field [0001] The invention belongs to the field of solid waste treatment, in particular to a method for high-temperature treatment of waste cathodes of electrolytic aluminum. Background technique [0002] The electrolytic aluminum cathode is made of calcined anthracite, metallurgical coke, graphite, etc. as aggregates, and coal tar pitch and other binders. It is mainly used to make block or paste carbon products for the carbon lining of aluminum electrolytic cells. During aluminum electrolysis, the main reaction that occurs on the cathode is to melt into cryolite (Na 2 AlFeNa 2 AIF 6 AI in ) 3+ It is reduced to liquid metal aluminum, which accumulates on the surface of the bottom of the carbonaceous tank, and the liquid aluminum and the bottom of the carbonaceous tank together serve as the conductive cathode of the electrolytic cell. Due to the various fluorides and impurities in the electrolyte melt, the molten salt produced by electrolysis under the action of...

AI Technical Summary

Problems solved by technology

Due to the lack of advanced electrolytic aluminum waste cathode harmless disposal and resource utilization technology at home and abroad, the landfill treatment method generally adopted by electrolytic aluminum enterprises has caused great environmental pollution and great waste of resources.

[0004] At present, the disposal of electrolytic aluminum waste cathodes in my country and even in the world mainly adopts wet method, combustion method, and landfill method. Among them, the value of carbon powder obtained by wet method is not high, and the fluoride in it cannot be effectively recovered by combustion method, so high-cost methods are mainly used. Landfill method, but because most enterprises cannot carry out harmless landfill according to the disposal method of hazardous waste, the environmental pollution problem of electrolytic aluminum waste cathode has not been effectively solved

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