A method for recycling and utilizing spent cathode carbon blocks from electrolyzer overhaul slag

Abstract

The invention discloses a method for recycling overhauling slag waste cathode carbon blocks of an electrolytic bath. The method is characterized by comprising the following steps: separating the overhauling slag of the electrolytic bath to obtain waste cathode carbon blocks; respectively conducting water leaching to the separated waste cathode carbon blocks, conducting secondary smashing and water leaching to the separated blocks, recycling the separated blocks, grinding and floating the rest powder, and separating carbon powder from the rest powder. According to the method, fluoride salt difficultly removed from the overhauling slag waste cathode carbon blocks of the electrolytic bath can be separated, the recycling value of the overhauling slag waste cathode carbon blocks of the electrolytic bath can be improved, the overhauling slag waste cathode carbon blocks of the electrolytic bath can be changed into valuables, the overhauling slag waste cathode carbon blocks of the electrolytic bath can be economically recycled without pollution, thereby fundamentally removing the hidden pollution hazard.

Description

technical field [0001] The invention relates to a method for recycling waste cathode carbon blocks from overhaul slag of an electrolyzer, and belongs to the technical field of slag treatment from overhaul of an electrolyzer. Background technique [0002] 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. [0003] Alumi...

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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

[0008] 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

[0009] 4. Research on waste SiC-Si3N4 waste refractory brick treatment technology is basically blank at home and abroad

[0010] 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

[0011] 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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