Method for producing fine, low bulk density, metallic nickel powder

Abstract

A method of producing a fine, low bulk density nickel powder, comprising a) charging particles of at least one reducible nickel salt within a furnace so as to form a moving bed of furnace charge, and b) reducing the furnace charge with a H 2 containing gas at a temperature ranging from about 300° C. to about 500° C., the bed of furnace charge being moved gently so as to minimise formation of hard agglomerates and obtaining a fine, low bulk density nickel powder. A similar method, wherein the furnace charge is static and contained within a shallow bed.

1 . A method of producing a fine, low bulk density nickel powder, said method comprising: 
 a) charging particles of at least one reducible nickel salt within a furnace so as to form a moving bed of furnace charge; and    b) reducing said furnace charge with a H 2  containing gas at a temperature ranging from about 300° C. to about 500° C., said bed of furnace charge being moved gently so as to minimise formation of hard agglomerates and thereby obtaining a fine, low bulk density nickel powder.    
   
   
       2 . The method according to  claim 1 , further comprising: 
 c) collecting said fine, low bulk density nickel powder; and    d) screening said fine, low bulk density nickel powder, thereby producing an essentially unagglomerated, low bulk density nickel powder.    
   
   
       3 . The method according to  claim 1 , wherein said furnace is a rotating kiln operating with a peripheral velocity of less than about 25 cm per minute.  
   
   
       4 . The method according to  claim 1 , employing a continuous production of said fine, low bulk density nickel powder.  
   
   
       5 . The method according to  claim 1 , employing a batchwise production of said fine, low bulk density nickel powder.  
   
   
       6 . The method according to  claim 1 , wherein said hydrogen containing gas contains at least 20 volume percent hydrogen.  
   
   
       7 . The method according to  claim 1 , wherein said hydrogen containing gas is in excess during the reduction step.  
   
   
       8 . The method according to  claim 1 , wherein said reducible nickel salts are in form of a dry powder.  
   
   
       9 . The method according to  claim 1 , wherein said reducible nickel salts are calcinated in nitrogen or another inert gas in either a first compartment of the furnace or in a separate furnace.  
   
   
       10 . The method according to  claim 1 , wherein said hydrogen containing gas is preheated before the reduction step.  
   
   
       11 . The method according to  claim 9 , wherein said calcination is made at a temperature ranging from about 300 to about 350° C.  
   
   
       12 . The method according to  claim 10 , wherein said preheating is made at a temperature ranging from about 300 to about 350° C.  
   
   
       13 . The method according to  claim 8 , wherein said reducible nickel salts are calcinated in nitrogen or another inert gas in either a first compartment of the furnace or in a separate furnace.  
   
   
       14 . The method according to  claim 8 , wherein said hydrogen containing gas is preheated before the reduction step.  
   
   
       15 . The method according to  claim 9 , wherein said hydrogen containing gas is preheated before the reduction step.  
   
   
       16 . The method according to  claim 13 , wherein said calcination is made at a temperature ranging from about 300 to about 350° C.  
   
   
       17 . The method according to  claim 14 , wherein said preheating is made at a temperature ranging from about 300 to about 350° C.  
   
   
       18 . The method according to  claim 1 , wherein said reducible nickel salts include nickel carbonate.  
   
   
       19 . The method according to  claim 1 , wherein said reducible nickel salt includes salts selected from the group consisting of nickel oxide, nickel hydroxide and nickel oxalate.  
   
   
       20 . The method according to  claim 1 , wherein said reduction temperature ranges from about 350 to about 450° C.  
   
   
       21 . The method according to  claim 2 , wherein said screening is performed onto a 100-mesh screen.  
   
   
       22 . A method of producing a fine, low bulk density nickel powder, comprising: 
 a) charging particles of at least one reducible nickel salt within a furnace so as to form a static, shallow bed of furnace charge;    b) reducing said furnace charge with a H 2  containing gas at a temperature ranging from about 300° C. to about 500° C., said static bed of furnace charge being shallow so as to allow penetration of reducing gas into the bed and minimise formation of hard agglomerates, thereby obtaining a fine, low bulk density nickel powder.    
   
   
       23 . The method according to  claim 22 , further comprising: 
 c) collecting said fine, low bulk density nickel powder; and    d) screening said fine, low bulk density nickel powder, thereby producing an essentially unagglomerated, low bulk density nickel powder.    
   
   
       24 . The method according to  claim 23 , wherein said screening is performed onto a 100-mesh screen.  
   
   
       25 . The method according to  claim 22 , wherein said hydrogen containing gas is in excess during the reduction step.