Method for recovering waste cathode of aluminum electrolytic cell

Abstract

The invention relates to the field of aluminum electrolysis, disclosing a method for recovering a waste cathode of an aluminum electrolytic cell, which comprises the following steps of: 1) cleaning a fireproofing material and a thermal insulation material which are glued to the surface of a carbon block of a waste cathode; 2) smashing the carbon block of the waste cathode into grains with 1-6mm; 3) prebaking an overhauled electrolytic cell with the smashed carbon block grains of the waste cathode through a particle coke baking start-up method; 4) recovering the prebaked residual grains; 5) spearing ash in the residual grains; and 6) taking the recovered residual grains as fluoride salt for the reuse of the aluminum electrolytic cell. The method is suitable for the preheating of the aluminum electrolytic cell and the recovering of the waste cathode; can be directly reused for the aluminum electrolytic cell; has simple operation, high yield, small energy dissipation and low cost; and can effectively recover carbon material and fluoride salt.

Description

technical field [0001] The invention relates to the field of aluminum electrolysis, in particular to a method for recycling spent cathodes of aluminum electrolytic cells. Background technique [0002] For an electrolytic aluminum plant with an annual output of 100,000 tons, the annual discharge of waste cathode carbon blocks is about 2,000 to 3,000 tons. , pollute the water source, do great harm to the surrounding animals and plants, and affect the natural ecological balance. It has become a consensus in the industry to carry out harmless treatment and resource utilization of waste cathode carbon blocks to solve the environmental hazards of waste tank linings, and has become a direction supported by the National Development and Reform Commission and the State Environmental Protection Administration. [0003] The above-mentioned detoxification treatment is the detoxification of electrolytes such as fluoride and cyanide in waste cathodes, and resource utilization refers to th...

AI Technical Summary

Problems solved by technology

However, the carbon content in the waste cathode carbon block is roughly 60-70%. The carbon in the waste cathode carbon block is recovered by the roasting method as fuel, and the heat generated by combustion is difficult to recover, resulting in waste, and the roasting method requires strict temperature control. At present, most of them are in the experimental nature; however, the flotation method cannot be used to process cyanide, and the waste water formed by recovery includes a large amount of organic capture agents, regulators, air bubbles, and cyanide dissolved in it, which is difficult to handle.

At the same time, due to the high carbon content in the waste cathode carbon block, the recovery efficiency is low, and the energy waste is large, so the cost of recovery by roasting and flotation is relatively high.