Smelting reduction of bottom ash in presence of liquid steel bath for recovery of aluminium

Abstract

For the recovery of aluminium from industrial waste bottom ash, a new concept was developed for smelting reduction in presence of metal solvent bath. Nitrogen plasma arc was generated by passing current and nitrogen gas through a hollow graphite electrode. Nitrogen plasma generated heat for reduction as well as melting under inert atmosphere inside the furnace. Pellets containing 50%bottom ash, 50% iron slime and charcoal were fed in the plasma zone above the liquid steel bath which was acted as for the absorption of reduced metals after reduction of oxides present in the wastes. Due to the immediate absorption of aluminium in the liquid steel bath after subsequent reduction from waste, vaporization loss of aluminium metal got minimized. The percent recovery of aluminium were determined in case of different exposure time, types of arcing and plasma gas etc. Maximum recovery of aluminium was recovered upto 21% with 30 minute exposure of pellets containing 50% bottom ash and 50% iron slime. It was observed that aluminum, could be recovered effectively from the wastes. © 2016 by The Minerals, Metals & Materials Society.