Processing method for aluminum electrolysis waste cathode carbon block

Abstract

The invention belongs to the technical field of recycling of electrolytic aluminum industrial wastes and specifically discloses a processing method for an aluminum electrolysis waste cathode carbon block. The processing method comprises the following steps: breaking the waste cathode carbon block and then adding water for ball-milling, performing decyanation treatment, leaching with hot water, leaching with concentrated sulfuric acid, washing and performing flotation, thereby acquiring a first-level carbon powder product and a second-level carbon powder product; reacting a primary acid leaching solution with a sodium hydroxide solution and filtering, thereby acquiring solid aluminum hydroxide; mixing the reaction filtrate with lime and filtering, thereby acquiring calcium sulfate; using water for absorbing the mixed gas formed by the primary washing gas and the acid leaching gas, thereby acquiring a hydrofluoric acid solution; mixing the prepared hydrofluoric acid solution with a ball-milling separating liquor and a hot water leaching separating liquor; adding aluminum hydroxide into the mixed liquor; filtering and separating the reactants; filtering, thereby acquiring the liquid phase of reusable water and the solid phase of fluorine-containing aluminum hydroxide; and roasting, thereby acquiring a fluorine-containing aluminum hydroxide product. According to the method providedby the invention, the harmless comprehensive recycling of the aluminum electrolysis waste cathode carbon block is realized.

Description

technical field [0001] The invention relates to the technical field of recycling and utilization of waste in the electrolytic aluminum industry, in particular to a comprehensive treatment and utilization method for waste cathode carbon blocks of aluminum electrolysis cells, that is, a processing method for aluminum electrolysis waste cathode carbon blocks. Background technique [0002] Aluminum electrolysis waste cathode carbon blocks, also known as electrolytic cell waste cathode carbon blocks, are wastes produced in the aluminum electrolysis industry. It is estimated that about 800,000 to 1,500,000 tons of spent cathode carbon blocks are discarded in my country every year. The main components of waste cathode carbon blocks are carbon, alumina, cryolite, fluoride, cyanide, etc., and the two substances of fluoride and cyanide are harmful to the environment. The carbon, alumina, and Cryolite, sodium fluoride, etc. are necessary substances in aluminum electrolysis and are val...

AI Technical Summary

Problems solved by technology

[0003] However, although the waste cathode carbon block of the electrolyzer has been listed as a hazardous solid waste by the country, it is required to undergo harmless treatment before it can be discharged.

But until now, the waste cathode carbon blocks of domestic electrolyzers have basically not been harmlessly treated, but are disposed of by landfill, or stored in the open air, or even discarded at wil