Experiment Research Of Leaching And Combustion Characteristics Of Spent Potlining In Aluminum Electrolysis

Spent Potlining(SPL) is the byproduct waste of aluminum electrolytsis industry. Its annual production is about 0.12 million tons in China now. Spent potlining is a hazardous solid waste product, and cause serious environmental pollution, and endanger human health. therefore, SPL must be managed carefully. Finding alternatives to landfill disposal has been widely recognized as one of the inevitable challenges facing the global aluminum researchers today.We carried out leaching experiment of fluorides in SPL, and characterized crystal composition of the samples using X-ray diffraction (XRD), and studied the conditions of SPL's leaching by H₂O,NaOH,HCl; We also researched fluorine emission characteristics when combusting in the high temperature tube furnaces, and determined the fluorine quantity in SPL samples and remained samples by the high temperature hydrolyzation-fluorine ion selective electrode; At the same time, we researched effect of fluorine retention using compound additive with Fe and Al and alkali metal during high-temperature tube furnace. The results showed that the quantity of fluorides can be leached by the different medium, and the sequence of leaching ability of different medium is as follows: acid leaching fluoride>alkaline leaching fluoride>water leaching fluoride; acid leaching is 79.51 %, in addition, fluorine element content in SPL after acid and alkali associated with acid leaching is 3.01 % and zero respectively using ESD; The fluorine emission tends to increase with increasing combustion temperature, and fluoride is almost entirely separated out in 1200℃; The fluorine emission increases with increasing retention period, and the fluorine emission rate reached 98.26 % at 1200℃in 30 minutes; fluorine retention rate is increased by 37.07 % additived with Al₂O₃ which was best in compound additive with Fe and Al, and is increased by 41.79 % additived with NaCl which was best in compound additive with alkali metal.Through the research of leaching and Combustion characteristics on SPL, it could provide theoretical basis for recovering of SPL.