Recycle of Spent Potlining with Low Carbon Grade by Floatation

Abstract

Spent potlining (SPL) from Hall-Heroult cells is a kind of toxic solid waste with recyclable carbon and electrolyte. The recycle of SPL by floatation, which can meet environment requirements and bring economic profits, is focused on presently because of its great potential to be industrialized and spread. However, it is difficult to get a good floatation index in floatation of SPL with carbon content lower than 50%. Therefore, the dressing of SPL with 36.1% of carbon has been investigated in the paper with the interesting potential to improve the quality of floatation products by optimizing floatation conditions, such as grinding size, pulp density and agitation speed of floatation machine. And the comparative experiment has been performed. The results show that quality of both carbon product and electrolyte product were improved under optimized conditions of grinding size of 90% of the particle sizes less than 0.74mm, pulp density of 25% and agitation speed of 1700r/min. The carbon content in carbon product was raised by 5.40 and carbon content in electrolyte product decreased by 0.26 while electrolyte recovery of electrolyte product increased by 4.58.