Method for recycling slag slurry of overhauling groove slag of electrolytic cell

Abstract

The invention discloses a method for recycling slag slurry of overhauling groove slag of an electrolytic cell. The method is characterized by comprising the following steps of a. sorting the overhauling groove slag of the electrolytic cell and selecting waste slag slurry; b. carrying out powder grinding on the waste slag slurry and carrying out floating selection to select carbon powder; drying and then calcining at a high temperature being 1700-1900 DEG C; and gasifying sodium fluoride and sulfur to obtain a high-purity carbon material. According to the method disclosed by the invention, fluoride salts which are difficult to remove in the waste slag slurry of the overhauling groove slag of the electrolytic cell are separated, so that the recycling value of the overhauling groove slag of the electrolytic cell is improved, and wastes are changed into valuable things; and the economical and pollution-free recycling of the overhauling groove slag of the electrolytic cell is realized and the hidden danger of pollution is radically eliminated.

Description

[0001] technical field [0002] The invention relates to a paste recovery and utilization method of electrolyzer overhaul slag, and belongs to the technical field of electrolyzer overhaul slag treatment. Background technique [0003] Aluminum electrolytic cells generally need to be overhauled after 4 to 5 years of use. The average cell life of most enterprises in my country is about 1500 days. The waste lining removed during the overhaul is the overhaul slag of the electrolytic cell, which contains soluble fluoride. Overhaul slag mainly includes waste cathode carbon blocks, waste refractory bricks, paste, waste insulation bricks, refractory powder, refractory mortar and waste insulation boards, etc. The production amount is about 30kg / t·Al (relative number, which varies with the age of the tank). At present, the national electrolytic aluminum production capacity exceeds 9 million t / a, and the overhaul slag production is about 270,000 t / a. [0004] Aluminum electrolysis is p...

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Problems solved by technology

However, the disadvantages of this method are also very obvious: fluorine is harmful to refractory bricks, and fluorine is easily discharged into the air with flue gas to cause air pollution; the sodium content in waste cathode carbon blocks is extremely high, which will affect the later strength of cement

[0009] 3. As early as 1982, Shandong Aluminum Plant began to use waste carbon blocks to add alumina clinker to kilns to replace part of anthracite coal. Although it has passed the national appraisal and achieved good results, it cannot achieve large quantities and high added value. use

[0010] 4. Research on waste SiC-Si3N4 waste refractory brick treatment technology is basically blank at home and abroad

[0011] 5. Research on the recycling of production water for electrolytic aluminum fluorine-containing waste treatment is basically blank at home and abroad

[0012] The above-mentioned methods for dealing with electrolytic cell overhaul slag cannot be used in large quantities and with high added value, so there are not many industrial applications. As a result, most of the aluminum electrolytic cell overhaul slag is still discarded

[0013] Whether the slag from the overhaul of the electrolytic cell is stored or landfilled, huge investment costs and operation and management costs will be invested, and there will be long-term potential pollution hazards

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