Abstract: Both aluminum scrap covered with a volatile coating and a heated airstream having a low oxygen content pass through a kiln where the airstream causes the coating to volatilize. The temperature of the airstream, where it enters the kiln, is maintained essentially constant, slightly below the melting temperature of the aluminum, and likewise the temperature of the airstream is maintained essentially constant where the airstream leaves the kiln, this being achieved by varying the mass flow of the airstream to compensate for variances in the nature and mass of the aluminum scrap within the kiln. Beyond the kiln the airstream enters an afterburner where it is heated in the presence of sufficient oxygen to effect combustion of the volatile components of the coating. The airstream then passes through a heat exchanger and back to the kiln. The mass flow within the kiln is controlled by diverting some of the airstream from the heat exchanger or by varying the speed of the fan which creates the airstream.

Abstract: Both aluminum scrap covered with a volatile coating and a heated airstream having a low oxygen content pass through a kiln where the airstream causes the coating to volatilize. The temperature of the airstream, where it enters the kiln, is maintained essentially constant, slightly below the melting temperature of the aluminum, and likewise the temperature of the airstream is maintained essentially constant where the airstream leaves the kiln, this being achieved by varying the mass flow of the airstream to compensate for variances in the nature and mass of the aluminum scrap within the kiln. Beyond the kiln the airstream enters an afterburner where it is heated in the presence of sufficient oxygen to effect combustion of the volatile components of the coating. The airstream then passes through a heat exchanger and back to the kiln. The mass flow within the kiln is controlled by diverting some of the airstream upstream from the heat exchanger or by varying the speed of the fan which creates the airstream.