Comprehensive utilization method of aluminum electrolytic carbon residue

Abstract

The invention relates to the technical field of aluminum electrolysis, in particular to a comprehensive utilization method of aluminum electrolytic carbon residue. According to the comprehensive utilization method, the aluminum electrolytic waste carbon residue is crushed, screened and ball-milled, then floatation is conducted, water glass is treated as a depressor, kerosene is treated as a capture agent, and carbon is obtained; an electrolyte discharged from the bottom of a floatation tank is filtered, and a filter-out material is obtained; a mixed solution containing HNO3 and Al(NO3)3 is added in the filter-out material, a reaction is conducted under 60-65 DEG C for 1-1.5 h, and a solid-liquid mixture is obtained; and solid-liquid separation is conducted on the solid-liquid mixture, filter residue is obtained, the filter residue is leached with a high concentration hydrofluoric acid solution, solid-liquid separation is conducted, and AlF3 is obtained. According to the comprehensive utilization method, carbon powder and the electrolyte in the aluminum electrolytic wasted carbon residue are effectively separated, and environment pollution caused by fluorine emission is avoided. Therecycled carbon powder and aluminum fluorine can be returned to be used for aluminum electrolysis, raw material consumption of aluminum electrolysis is lowered, and the environmental benefits and theeconomic benefits are remarkable.

Description

technical field [0001] The invention relates to the technical field of aluminum electrolysis, in particular to a comprehensive utilization method of aluminum electrolysis carbon slag. Background technique [0002] Modern large-scale prebaked aluminum electrolytic cells usually use carbon products as anodes for electrolytic production. The carbon anode working in the electrolyte sometimes has different degrees of particle shedding, resulting in the formation of carbon residue, which will greatly affect the performance of the electrolyte and production indicators. [0003] As the production capacity of aluminum electrolysis continues to increase, the demand for carbon anodes continues to increase, resulting in a gradual decline in the quality of carbon anodes. During aluminum electrolysis, due to the selective oxidation of the carbon anode, the aggregate particles are not completely burned, but enter the electrolyte solution, and carbon slag is thus produced. Normally, the c...

AI Technical Summary

Problems solved by technology

When a large amount of carbon slag floats on the surface of the aluminum electrolyte, a current path will pass through, and the carbon slag will form between the carbon anode and the cathode, resulting in current loss; when the carbon slag content in the electrolyte exceeds a certain range, the alumina dissolution rate will slow down. Slow, deposits on the bottom of the furnace, leading to deterioration of tank conditions

When the carbon residue is fished out, a large amount of electrolyte and heat will be taken away, and due to incomplete recovery, some fluoride salts will be lost

[0004] In addition, a large number of carbon slag piles are placed in the open air, flying with the wind, and the dissolved fluorine in the carbon slag slowly enters below the surface under the action of rainwater, which brings huge pressure to the environment