Spent cathode carbon (SCC) blocks of aluminum electrolytic cell were hazardous waste produced in the production of electrolytic aluminum. In this present work, a facile, rapid, and economical strategy was proposed to remove fluoride and other toxic substances in the SCC block by the flash joule heating method. SCC after flash joule heating (F-SCC) were prepared in different flash voltages and number of passes; the chemical composition, microscopic morphology and carbon configuration of the SCC and F-SCC were described in detail. The results show that the purification efficiency depends upon the flash voltages and pass number. In terms of flash voltage, 150 V (5.62 kJ/g) is the optimal voltage to maintain the micro-expansion characteristics of the cathode carbon. Multiple flash joule heating can not only maintain its high-graphitization carbon, but also improve its micro-expansion characteristics. In addition, the electrochemical performance of F-SCC was characterized, and F-SCC displayed excellence capacitance performance. The low-cost, rapid -regeneration method based on the flash joule heating provides an effective method for the clean recycling and high-value utilization of carbonized solid waste.
Keywords: Spent cathode carbon; capacitance performance; flash joule heating; purification.