Nickel Dissolution in Argon Stirred Steel

Alloys represent a significant production expense, consequently a better understanding of the factors that affect dissolution and recovery could result in substantial cost savings. Argon stirring increases dissolution and mixing rates, which should improve nickel recovery. Gas flow rate, alloy size, and melt temperature effects were investigated by induction melting forty-five kilogram heats, which were poured into an unfired vessel fitted with a bottom porous plug. Nickel was added and timed samples taken to evaluate dissolution rate. In this study, it was found that for alloying to a nominal 0.35% nickel, alloy particle size was more important to dissolution kinetics than gas flow rate, for the conditions examined. Increasing tap temperature 43°C produced an initial gain in dissolution rate, but the time to approach equilibrium appears to be nearly independent of temperature. Experimental limitations precluded the determination of activation energy and mixing time, independent of melting time.