METHOD FOR RECYCLING WASTE CATHODE CARBON BLOCKS OF ALUMINUM ELECTROLYSIS

摘要

A method for recycling waste cathode carbon blocks of aluminum electrolysis, comprising the following steps: (1) crushing and screening the waste cathode carbon blocks, so as to obtain carbon particles; (2) mixing the carbon particles with a sulfuric acid solution, so as obtain a slurry A, and then performing pressure leaching, so as obtain a slurry B; (3) evaporating and concentrating the slurry B until the mass percentage of water is lower than 8%, so as to obtain a slurry C; (4) adding concentrated sulfuric acid into the slurry C, so as to obtain a slurry D, then baking same at 150-300°C for 0.5-10 h, and then baking at 300-600°C for 0.5-8 h, so as to obtain a baked carbon; and calcining the baked carbon at an elevated temperature, so as to obtain a purified carbon, or mixing same with a leaching agent and leaching, filtering and washing same, so as to obtain the purified carbon. In the treatment process, a high-temperature fluorine-containing flue gas and fluorine-containing waste water are not produced, and fluorine, aluminum and carbonaceous materials can be recycled, thereby achieving the comprehensive recycling and cleaning treatment of the waste cathode carbon blocks of aluminum electrolysis.