A method for preparing expandable graphite or graphene by utilizing waste cathode carbon formed in electrolytic aluminum production

Abstract

A method for preparing expandable graphite or graphene by utilizing waste cathode carbon formed in electrolytic aluminum production is disclosed. The method includes (1) a step of crushing, adding a strong oxidant and water into the crushed product, stirring, rolling or wet-grinding the mixture, and performing a hydrothermal oxidation reaction; (2) a step of controlling the temperature, pressurizing, feeding supercritical or liquid carbon dioxide, mixing the mixture by stirring the mixture, allowing the mixture to stand, adjusting the temperature and pressure, performing separation to obtain aqueous slurry and graphite oxide slurry fluid, and washing the graphite oxide slurry fluid with water to remove impurities; and (3) a step including 1) a manner of performing atomization, expansion and stripping to remove the carbon dioxide; or 2) a manner of adding a reactant for reduction, and then performing atomization, expansion and stripping to remove the carbon dioxide, or further performing denitrification and deoxygenation; or 3) a manner of adding a fluorinating agent, heating the mixture, performing a fluorinating reaction, and performing atomization, expansion and stripping to remove the carbon dioxide. Expanded graphite powder, graphene powder, denitrified deoxygenated graphene powder or fluorinated graphene powder which are prepared by the method have excellent properties. The method is simple, efficient, clean, free of secondary pollution, low in energy consumption and suitable for industrial production.

Description

technical field [0001] The invention relates to a method for preparing expanded graphite or graphene, in particular to a method for preparing expanded graphite or graphene by using electrolytic aluminum waste cathode carbon. Background technique [0002] At present, the output of electrolytic aluminum in my country and the world is developing rapidly. According to statistics, by the end of December 2016, the aluminum smelting enterprises of electrolytic aluminum in my country had built a production capacity of 43.698 million tons, and the operating production capacity had reached 36.739 million tons. With the increase of electrolytic aluminum production, the solid waste produced in the electrolysis process, such as waste cathode carbon, waste anode carbon particles, waste refractory bricks, waste insulation bricks, and waste insulation slag, has also increased rapidly, of which only my country's electrolytic aluminum The annual waste cathode produced by the industry has reac...

AI Technical Summary

Problems solved by technology

However, due to the high energy consumption, high cost and secondary pollution of these existing treatment methods, the environmental pollution of the waste cathode carbon blocks of electrolytic aluminum has not been effectively solved, and most of the waste cathode carbon blocks of aluminum electrolytic cells are still discarded.

At present, although the treatment of electrolytic aluminum waste cathode carbon blocks has long been a common problem in the industry, and regeneration research has been carried out in many technical fields, there has not been any report on the research or practice of using electrolytic aluminum waste cathode carbon blocks to produce graphene