Method of recycling mixed alloy scrap parts

Abstract

A method of processing mixed-material vehicle scrap includes conditioning the mixed-material vehicle scrap and heating the mixed-material vehicle scrap. The mixed-material vehicle scrap comprises a first group of parts and a second group of parts. The first group of parts includes a first alloy and the second group of parts has a substrate of a second alloy and a coating disposed over the substrate. The mixed-material vehicle scrap is conditioned such that an element of the second alloy is diffused into the coating to form a diffused coating. The diffused coating has a melting temperature greater than a melting temperature of the first alloy. The mixed-material vehicle scrap is heated to a temperature above the melting temperature of the first alloy and below the melting temperature of the diffused coating, thereby allowing the second group of parts to separate from the first group of parts.

What is claimed is: 
     
         1 . A method of processing mixed-material vehicle scrap, the mixed-material vehicle scrap comprising a first group of parts and a second group of parts, the first group of parts comprising a first alloy and the second group of parts comprising a second alloy, each of the second plurality of parts having a substrate comprising the second alloy and a coating disposed over the substrate, the method comprising:
 conditioning the mixed-material vehicle scrap such that an element of the second alloy is diffused into the coating to form a diffused coating, the diffused coating having a melting temperature greater than a melting temperature of the first alloy; and   heating the mixed-material vehicle scrap to a temperature above the melting temperature of the first alloy and below the melting temperature of the diffused coating, thereby allowing the second group of parts to separate from the first group of parts.   
     
     
         2 . The method of  claim 1 , wherein the first alloy comprises an aluminum alloy. 
     
     
         3 . The method of  claim 1 , wherein the first alloy comprises a magnesium alloy. 
     
     
         4 . The method of  claim 1 , wherein the coating is applied with an electrocoating process. 
     
     
         5 . The method of  claim 1 , wherein the coating comprises a zinc alloy. 
     
     
         6 . The method of  claim 1 , wherein the coating has a thickness between about 2 microns and 10 microns. 
     
     
         7 . The method of  claim 1 , wherein the diffused coating comprises gamma phase constituents. 
     
     
         8 . The method of  claim 1 , wherein conditioning the mixed-material vehicle scrap comprises heating the mixed-material vehicle scrap to a temperature between about 450° C. and about 600° C. for up to about 60 minutes. 
     
     
         9 . A method of processing mixed-material vehicle scrap, the mixed-material vehicle scrap comprising aluminum parts and steel parts, each of the steel parts comprising a steel substrate and a coating disposed over the steel substrate, the method comprising:
 conditioning the mixed-material vehicle scrap such that iron from each of the steel parts is diffused into each of the coatings to form a diffusion layer, the diffusion layer having a melting temperature greater than a melting temperature of the aluminum alloy; and   heating the mixed-material vehicle scrap to a temperature above the melting temperature of the aluminum alloy and below the melting temperature of the diffusion layer, thereby allowing the steel parts to separate from the aluminum parts.   
     
     
         10 . The method of  claim 9 , wherein the coating is applied with an electrocoating process. 
     
     
         11 . The method of  claim 9 , wherein the coating comprises a zinc alloy. 
     
     
         12 . The method of  claim 9 , wherein the coating has a thickness between about 2 microns and 10 microns. 
     
     
         13 . The method of  claim 9 , wherein the diffusion layer comprises gamma phase constituents. 
     
     
         14 . The method of  claim 9 , wherein conditioning the mixed-material vehicle scrap comprises heating the mixed-material vehicle scrap to a temperature between about 450° C. and about 600° C. for up to about 60 minutes. 
     
     
         15 . The method of  claim 9 , wherein the mixed-material vehicle scrap is heated to above 700° C. and the aluminum alloy becomes molten. 
     
     
         16 . A method of processing mixed-material vehicle scrap, the mixed-material vehicle scrap comprising aluminum parts and steel parts, the aluminum parts comprising an aluminum alloy and each of the steel parts comprising a steel substrate and a coating, the method comprising:
 conditioning the mixed-material vehicle scrap by heating the mixed-material vehicle scrap to a temperature between about 450° C. and about 600° C. for up to about 60 minutes such that iron from each of the steel parts is diffused into each of the coatings to form a gamma phase diffusion layer, the gamma phase diffusion layer comprising intermetallic constituents and having a melting temperature greater than a melting temperature of the aluminum alloy;   heating the mixed-material vehicle scrap to a temperature above the melting temperature of the aluminum alloy and below the melting temperature of the diffusion layer, thereby allowing the steel parts to separate from the aluminum parts.   
     
     
         17 . The method of  claim 16 , wherein the coating is applied with an electrocoating process. 
     
     
         18 . The method of  claim 16 , wherein the coating comprises a zinc alloy. 
     
     
         19 . The method of  claim 16 , wherein the coating has a thickness between about 2 microns and 10 microns. 
     
     
         20 . The method of  claim 16 , wherein the diffusion layer has a thickness between about 2 microns and 10 microns.