Experimental Study on the Collecting Agent for Spent Potlining Flotation Index Optimization

Abstract

Froth flotation is a low-cost SPL recycling technique, which separates carbon in spent potlining (SPL) from other components. The carbon is enriched in the flotation concentrate since it has outstanding hydrophobicity, and cryolite is enriched in the flotation tailing. During the process, NaF in SPL dissolves in water and can be recovered by evaporation and crystallization, whilst cyanides are decomposed. The recycling efficiency is evaluated by flotation index which is greatly affected by the collecting agent. In this study, the effects of types, dosing times, dosage and emulsification of collecting agent on the flotation index were studied. The optimized collecting agent was adopted in a quadruple-roughing double-cleaning closed-circuit experiment. The results indicated that carbon grade and recovery of concentrate were higher than 80% and 95%, respectively, while the NaAl11O17 and Na3AlF6 were successfully concentrated in the floatation tailing.