Method for producing nickel powder

Abstract

Provided is a method for controlling generation of scaling in a reaction vessel to reduce time and cost required for removal of the scaling in the process of producing nickel powder from a solution containing a nickel ammine sulfate complex. This is a method for producing nickel powder, including: adding, to the solution containing the nickel ammine sulfate complex, seed crystals in an amount of 0.3 times or more and 3 times or less the weight of nickel in the solution to form a slurry; and blowing hydrogen gas into the slurry to reduce a nickel complex ion and to thereby form a nickel precipitate.

1 . A method of producing nickel powder, comprising:
 adding, to a solution containing a nickel ammine sulfate complex, seed crystals having a particle size of 1 to 20 μm in an amount of 0.3 to 3 times a weight of nickel in the solution to form a slurry;   charging the slurry into a reaction vessel, maintaining a liquid phase portion occupied by the slurry and a gaseous phase portion other than the liquid phase portion within the reaction vessel;   blowing hydrogen gas into the slurry to reduce a nickel complex ion and to thereby produce and recover nickel powder in which a nickel precipitate is formed on a surface of the seed crystals; and   performing hydrogen reduction by adding the solution containing the nickel ammine sulfate complex to the recovered nickel powder in which the nickel precipitate is formed on the surface of the seed crystals and blowing hydrogen gas into the nickel powder to precipitate nickel on the nickel precipitate and to thereby produce grown nickel powder.   
     
     
         2 . The method of producing nickel powder according to  claim 1 , wherein a polyacrylate salt dispersant is added to the slurry in an amount of 0.5 to 5% based on the weight of the seed crystals added to the slurry. 
     
     
         3 . The method of producing nickel powder according to  claim 1 , wherein the hydrogen reduction is repeated to precipitate on the nickel precipitate and to thereby obtain further grown nickel powder. 
     
     
         4 . The method of producing nickel powder according to  claim 1 , wherein a temperature of the slurry is 150 to 200° C. when hydrogen gas is blown into the slurry. 
     
     
         5 . The method of producing nickel powder according to  claim 1 , wherein a pressure of the gaseous phase portion in the reaction vessel is in a range of 1.0 to 4.0 MPa when hydrogen gas is blown into the slurry. 
     
     
         6 . The method of producing nickel powder according to  claim 1 , wherein the seed crystals are nickel powder having the particle size of 1 to 20 μm. 
     
     
         7 . The method of producing nickel powder according to  claim 1 , wherein the hydrogen reduction is repeated to precipitate on the nickel precipitate and to thereby obtain further grown nickel powder. 
     
     
         8 . The method of producing nickel powder according to  claim 1 , wherein a temperature of the slurry is 150 to 200° C. when hydrogen gas is blown into the slurry. 
     
     
         9 . The method of producing nickel powder according to  claim 1 , wherein a pressure of the gaseous phase portion in the reaction vessel is in a range of 1.0 to 4.0 MPa when hydrogen gas is blown into the slurry. 
     
     
         10 . The method of producing nickel powder according to  claim 1 , wherein the seed crystals are nickel powder having the particle size of 1 to 20 μm.