Method of production of tantalum powder with low impurity level

Abstract

The production of tantalum powder having a low impurity level is provided by a method in which potassium heptafluotantalate is added to a mixture of alkali metal halides in reactor vessel in which the internal surface and auxiliary input accessories of the reactor are covered with a tantalum coating. In one embodiment, the production of tantalum powder with low impurity level includes depositing a protective tantalum coating onto an internal surface of the reactor vessel and auxiliary accessories of a reactor by electrolysis of a mixture of alkali metals halides and potassium heptafluotantalate.

1 . A method for production of a tantalum powder in a reactor vessel, comprising: 
 depositing a tantalum coating onto an internal surface of a reactor vessel and onto at least one auxiliary accessory thereof;    adding a quantity of potassium heptafluotantalate to the reactor vessel having the tantalum coating;    adding a quantity of a mixture of alkali metal halides into the reactor vessel; and    reducing the potassium heptafluotantalate using sodium in the reactor vessel.    
     
     
         2 . The method of  claim 1 , wherein depositing comprises depositing the tantalum coating by electrolysis of a molten salts mixture.  
     
     
         3 . The method of  claim 1 , wherein reducing comprises using as a cathode said at least one auxiliary accessory in which the mixture of alkali metal halides and potassium heptafluotantalate is electrolyzed with the tantalum coating.  
     
     
         4 . The method of  claim 1 , wherein said at least one auxiliary accessory comprises one or more of a stirrer, a shell of a thermocouple and a head of the reactor vessel.  
     
     
         5 . The method of  claim 1 , wherein said mixture of alkali metal halides comprises a waste products of a tantalum powder production by sodium-metallothermic process.  
     
     
         6 . The method of  claim 1 , wherein said reactor vessel is comprised of one of a mild steel, stainless steel, nickel and nickel-containing material.  
     
     
         7 . The method of  claim 1 , wherein the tantalum coating has a thickness of not less than 30 micron.  
     
     
         8 . The method of  claim 1 , wherein said mixture of alkali metal halides comprises a mixture of sodium chloride, sodium and potassium fluorides.  
     
     
         9 . A method for production of a tantalum powder in a reactor vessel, comprising: 
 adding a quantity of potassium heptafluotantalate to the reactor vessel, wherein the reactor vessel and at least one auxiliary accessory thereof have a tantalum coating;    adding a quantity of a mixture of alkali metal halides into the reactor vessel; and    reducing the potassium heptafluotantalate using sodium in the reactor vessel.    
     
     
         10 . The method of  claim 9 , wherein the tantalum coating is formed by electrolysis of a molten salts mixture.  
     
     
         11 . The method of  claim 9 , wherein reducing comprises using as a cathode said at least one auxiliary accessory in which the mixture of alkali metal halides and potassium heptafluotantalate is electrolyzed with the tantalum coating.  
     
     
         12 . The method of  claim 9 , wherein said at least one auxiliary accessory comprises one or more of a stirrer, a shell of a thermocouple and a head of the reactor vessel.  
     
     
         13 . The method of  claim 9 , wherein said mixture of alkali metal halides comprises a waste products of a tantalum powder production by sodium-metallothermic process.  
     
     
         14 . The method of  claim 9 , wherein said reactor vessel is comprised of one of a mild steel, stainless steel, nickel and nickel-containing material.  
     
     
         15 . The method of  claim 9 , wherein the tantalum coating has a thickness of not less than 30 micron.  
     
     
         16 . The method of  claim 9 , wherein said mixture of alkali metal halides comprises a mixture of sodium chloride, sodium and potassium fluorides.