Defluorination of Waste Cathodic Carbon Through Steam Under Conventional High-Temperature Roasting

With the development of the electrolytic aluminum industry, a large number of waste cathode carbons (WCC) of electrolytic aluminum remain, which are typical harmful solid wastes and cause serious harm to the environment. The harmless treatment of WCC is extremely important. Conventional heating and steaming is a good treatment method for WCC blocks. Fluoride has good selective heating characteristics, which promote the transformation of fluoride to escape in the form of gas, and realizes the separation of carbon and fluorine in the WCC of electrolytic aluminum. The characterization of WCC under steam high-temperature calcination was compared with that under traditional high-temperature calcination and chemical leaching. Tests show that, under the condition of water vapor, the carbon layer of WCC is larger, which is more conducive to the separation of carbon and fluorine. In this paper, the effects of different temperatures, heating times, and water flow rates on the defluorination rate were studied. The results showed that, when the WCC was heated at 950 degrees C for 3 h, and the flow rate was 3.5 g/min, the defluorination effect of cathode carbon was the best, reaching 93%.