Separation of aluminum from articles composed of aluminum bonded to ferrous metal

摘要

The method is effective for separating substantially all of the aluminum from an article composed of an aluminum part bonded to a ferrous metal part. The article, such as a die cast aluminum engine cylinder block including one or more cast iron cylinder sleeves, is immersed in a molten salt bath maintained at a temperature above the melting point of the aluminum and retained in the bath a sufficient time for all the aluminum to melt and flow away from the cylinder sleeve, while maintaining the cylinder sleeve out of contact with molten aluminum accumulating in the bath. The resulting substantially aluminum-free sleeve is removed from the bath and residual salt on the exposed surfaces is removed, such as by washing with a hot detergent solution and rinsing with hot water. If the cylinder sleeve is acceptable for reuse, the salt bath is maintained at a temperature below about 1340 DEG F. in order to prevent deterioration of the metallurgical properties of the sleeve.