Patent ID: 7566369

Claim:
A method of de-coating metallic coated scrap pieces consisting essentially of aluminum brazing sheet pieces, the metallic coated scrap pieces comprising a metallic core layer and a metallic coating layer of which the liquidus temperature of the metallic coating layer is lower than the solidus temperature of the metallic core layer, comprising: at least partially removing the metallic coating layer from the metallic core layer of said scrap pieces by agitating the scrap pieces at an elevated temperature T above the solidus temperature of the metallic coating layer and below the liquidus temperature of the metallic core layer, together with abrading particles, wherein the abrading particles are brought into fluidization during the agitating of the metallic coated scrap pieces, thereby forming a fluidized bed, wherein the scrap pieces are submerged in the fluidized bed, wherein the scrap pieces are agitated by bringing them into fluidization together with the abrading particles, wherein the abrading particles have a density in the range of 3 to 7 g/cm 3 and a sieve fraction size in the range of 3 to 10 mm, and wherein the scrap pieces have a thickness in the range of 0.1 to 2 mm and an area of about 4 to 40 cm 2 ; wherein the fluidized bed is within a fluidization bed chamber provided with a perforated drum, the perforated drum having opposed first and second ends and having sidewalls, the first end having a drum inlet, the second end having a drum outlet, the sidewalls having perforations, wherein fluidizing gas passes upwardly through the fluidized bed, wherein the abrading particles and the fluidizing gas pass into and out of the drum through the drum perforations, wherein the scrap pieces pass through the drum inlet into the perforated drum while the perforated drum is rotating about a perforated drum longitudinal axis, the scrap pieces are abraded in the drum by the abrading particles, and the scrap pieces discharge from the drum through the drum outlet and do not discharge through the drum perforations.