Air plasma induced low metal loss

Abstract

Even a very small amount of air plasma can reduce the dross during melting. A method and device is shown, whereby substantial saving in the cost of melting aluminum and the energy to melt aluminum is possible by the technique of introducing a small amount of air plasma in the melting environment. In this manner even though the air contains oxygen, and the common practice is presently directed at air being eliminated from the melting environment, an air plasma is able to very effectively be utilized.

1 - 10 . (canceled) 
   
   
       11 . An apparatus for processing a metal comprising:
 a receptacle for containing the metal; and   at least one plasma arrangement configured to provide a combination of a heated gas and an ionized gas over a free surface of the metal,   wherein, when the plasma arrangement provides the combination over the free surface, a dross that is formed when an entire charge of the metal is melted comprises less than about 3% by weight of the entire charge.   
   
   
       12 . The apparatus of  claim 11 , wherein the combination provides at least about five percent of the total heat used for melting of the entire charge. 
   
   
       13 . The apparatus of  claim 11 , wherein the receptacle comprises a heating arrangement configured to provide heat to the entire charge. 
   
   
       14 . The apparatus of  claim 13 , wherein the heating arrangement comprises a plurality of resistance heating elements. 
   
   
       15 . The apparatus of  claim 14 , wherein the resistance heating elements comprise molybdenum disilicide. 
   
   
       16 . The apparatus of  claim 11 , wherein the heated gas is air. 
   
   
       17 . The apparatus of  claim 11 , wherein the heated gas comprises oxygen. 
   
   
       18 . The apparatus of  claim 11 , wherein the combination comprises a small amount of the ionized gases. 
   
   
       19 . The apparatus of  claim 11 , wherein the combination comprises less than about 1% of the ionized gases. 
   
   
       20 . The apparatus of  claim 11 , wherein the combination comprises between about 0.5% and about 1% of the ionized gases. 
   
   
       21 . The apparatus of  claim 11 , wherein the metal comprises aluminum. 
   
   
       22 . The apparatus of  claim 11 , wherein the receptacle comprises at least one of a launder system or a molten metal transportation vessel. 
   
   
       23 . The apparatus of  claim 11 , wherein the at least one plasma arrangement comprises a plurality of plasma arrangements. 
   
   
       24 . The apparatus of  claim 11 , further comprising an enclosure configured to provide an enclosed region above the receptacle, wherein the combination is provided into the enclosed region. 
   
   
       25 . The apparatus of  claim 11 , wherein the receptacle comprises at least one of a furnace, a crucible, a holding furnace, a melting furnace, or a casting furnace.