THE EFFECT OF INJECTION PARAMETERS ON SLAG FUMING

Many slag treatment processes use injection of solid reductants into slag baths to recover metal values. In the present laboratory study, the effect of selected injection parameters such as lance diameter, gas flowrate, coal particle size and slag bath temperature have been investigated, and the behaviour of different types of reductant in slag fuming has also been considered. Coal laden gas discharge through a lance into a slag bath has been monitored by a pressure transducer. The pressure traces have revealed that the slag bath viscosity changes as fuming progresses. High momentum coal injection, a thin wall lance, intense bath agitation and increasing temperature all improve the fuming rates. Natural gas was found to be a better reductant than coal and brown coal char.