Method of manufacturing precious metal pellets with reduced contamination

Abstract

Disclosed herein is a method of manufacturing a wire. The method comprises skiving a metal rod to produce a wire that is substantially devoid of carbonaceous contamination. A circumferential surface layer of the wire that contains embedded carbon contamination is removed during the skiving. The metal rod and the wire comprise a precious metal.

What is claimed is: 
     
         1 . A method of manufacturing a wire, the method comprising:
 skiving a metal rod to produce a wire that is substantially devoid of carbonaceous contamination; where a circumferential surface layer of the wire that contains embedded carbon contamination is removed during the skiving; and where the metal rod and the wire comprise a precious metal.   
     
     
         2 . The method of  claim 1 , where an outer circumference of the wire is substantially removed by the skiving of the metal rod. 
     
     
         3 . The method of  claim 1 , further comprising casting a molten metal into a mold to produce the metal rod; where the mold has a length to diameter ratio of 3:1 to 150:1. 
     
     
         4 . The method of  claim 3 , where the casting comprises a continuous vertical casting of the molten metal. 
     
     
         5 . The method of  claim 4 , where the continuous vertical casting is conducted in a vacuum. 
     
     
         6 . The method of  claim 3 , further comprising rolling the metal rod in a lubricant free process to produce a rolled rod. 
     
     
         7 . The method of  claim 6 , where the rolling of the metal rod results in a diameter reduction of 50 to 90% of an original rod diameter. 
     
     
         8 . The method of  claim 6 , further comprising drawing the rolled rod to produce a drawn rod in a single pass. 
     
     
         9 . The method of  claim 8 , where the drawing results in a diameter reduction of 0.4 to 10%, based on a final diameter of the rolled rod. 
     
     
         10 . The method of  claim 9 , where the drawing results in a diameter reduction of 1 to 4%, based on a final diameter of the rolled rod. 
     
     
         11 . The method of  claim 8 , where the skiving comprises mounting the drawn rod on a draw board and pulling the drawn rod through a skiving die that shaves off a complete outer circumferential surface of the rod to produce the wire. 
     
     
         12 . The method of  claim 11 , where the skiving die has a knife edge that contacts the entire outer circumferential surface of the rod to remove the complete outer circumferential surface and any embedded contamination with it. 
     
     
         13 . The method of  claim 11 , where the wire and its outer circumference is substantially devoid of carbonaceous or oxidative contamination. 
     
     
         14 . The method of  claim 1 , where the precious metal comprises a precious metal alloy. 
     
     
         15 . The method of  claim 1 , where the precious metal includes gold, silver, platinum, palladium, rhodium, iridium, ruthenium, osmium, or a combination thereof. 
     
     
         16 . The method of  claim 1 , where the metal rod and the wire further comprise a non-ferrous metal, an alkali metal, an alkaline earth metal, a transition metal, a metalloid, or a combination thereof. 
     
     
         17 . The method of  claim 1 , where the metal rod and wire further comprise iron, nickel, cobalt, scandium, titanium, vanadium, chromium, manganese, zinc, yttrium, zirconium, niobium, cadmium, hafnium, tantalum, tungsten, rhenium, boron, silicon, germanium, tin, arsenic, antimony, tellurium, aluminum, or a combination thereof. 
     
     
         18 . The method of  claim 1 , where the wire has a purity of greater than 99%, based on a total weight of the wire. 
     
     
         19 . The method of  claim 1 , where the wire has a purity of greater than 99.99%, based on a total weight of the wire. 
     
     
         20 . The method of  claim 1 , further comprising chopping the wire to form a pellet.