Contaminated scrap is the hardest material to melt profitably. It is dirty, mixed, coated, and often wet. A single-chamber reverb furnace will choke on it — losing metal to oxidation, generating excessive dross, and struggling to maintain temperature. A rotary furnace can handle it, but consumes salt at a rate that eats into margins. The twin-chamber furnace is the middle path. It separates the melting of dirty scrap from the holding of clean metal. It uses less salt than a...
