A milliseconds flash joule heating method for the regeneration of spent cathode carbon.

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.