Process for stabilizing fluorine in electrolytic aluminum spent pot lining by roasting method
Wang Dongyue, Wang Haibin, Chunlei Li, Yongrong Qi, Liting Fan, Peng Li
Abstract
Abstract Electrolytic aluminum Spent Pot Lining (SPL) contains excess soluble fluoride, which can cause harm to the environment and human body when it seeps into the ground with rainwater. Therefore, it is necessary to convert the soluble fluoride into a chemically stable insoluble substance. In order to stabilize the fluoride ions of soluble fluoride, a roasting process is adopted. Through thermodynamic calculations and experiments, four factors of suitable calcium salt, calcium salt to SPL ingredient ratio, roasting temperature and time are determined to obtain the best operating conditions. The experimental results show that when the calcium salt is CaCl 2 , the ingredient ratio is m(CaCl 2 )/m(SPL)=0.5, the roasting temperature is 750°C and the roasting time is 5h, the amount of F - leaching is 10.64ppm, meeting the national requirements for the amount of F - leaching in electrolytic aluminum solid waste. Finally, the process route of roasting stable fluorine was determined according to suitable operating conditions.