Determination of percentage zinc loss during melting of zinc scrap in a crucible furnace

During the melting process of zinc scraps, not all the zinc metals in the scrap are recovered. This article evaluates the extent of zinc loss during melting of zinc scraps. Zinc scraps were melted in a charcoal-fired crucible furnace, and the percentage zinc loss was determined. Two modes of zinc loss were observed – zinc loss through evaporation and zinc loss through the dross. It was determined that 2.2 percentage of the total zinc was lost through evaporation while 10.8 percentage of the total weight was lost in the dross when zinc scrap was melted without fluxing. The total zinc loss when zinc scrap was melted without fluxing was found to be 13 percent. With fluxing, using  chloride-salt based flux (17% KCl, 20% NaCl, 63% ZnCl2 salt system), 0.79weight percent and 1.74weight percent was lost through evaporation and dross respectively. The total zinc loss was reduced to 2.53weight percent with fluxing. This work will help foundrymen in method and economic decision making when working on zinc scraps.