Co-combustion characteristics of electrolytic aluminum waste and coal

The electrolytic aluminum waste, which would inevitably be produced from the electrolytic process in the aluminum industry, is harmful to environment and human body. Sending it to the coal-fired boiler seems to be an eco-friendly scheme to dispose the waste. In this study, the co-combustion characteristics of the electrolytic aluminum waste (cathode carbon blocks (CCB) and hardened material (HM)) and the bituminous coal (BC) are investigated. During the thermogravimetric experiment, the char combustion of CCB shows the similar trend as that of BC before 800 & DEG;C. A series of oxidization reactions of carbon in anthracite and graphite (both are the raw materials of CCB) could be observed at relatively high temperature. The mass of HM changes smoothly as the temperature rises. Both CCB and HM could promote the ignitability of the blends efficiently, in which the ignition point comes to 517.33 & DEG;C when the mass proportion of HM is 30%. The addition of CCB brings out the second peak in DTG curves of the blends. The burnout performance is weakened as the increase of mass proportion of HM. Remarkable synergy happens during the co-combustion process between BC and CCB/HM, because the pre-exponential factors of the blends increase abruptly compared with that of BC in the early stage of the char combustion. Compared with the activation energy, the pre-exponential factor changes more intensely, which plays a more important role in the co-combustion process.