Harmless treatment method of electrolytic aluminum waste cathode carbon block

The invention relates to the technical field of electrolytic aluminum in the aluminum industry, in particular to a harmless treatment method for electrolytic aluminum waste cathode carbon blocks. The method comprises the following steps: crushing and screening electrolytic aluminum waste cathode carbon blocks to be treated to obtain waste cathode carbon block powder with target granularity; the waste cathode carbon block powder and alkali-doped molten salt are put into a reactor to be mixed; wherein the temperature of the molten salt is 500 to 700 DEG C; adding a medium block into the reactor, and carrying out microwave heating and ultrasonic vibration on the mixture in the reactor in an inert atmosphere so as to separate cryolite and electrolyte in the carbon block from cathode carbon; wherein the dielectric block is used for providing vibration conditions of microwaves and ultrasonic waves; and grinding the cathode carbon, and immersing the cathode carbon into an alkaline solution to remove fluoride and cya