Method for producing nickel powder

Abstract

Provided is a method for producing nickel powder, wherein fine nickel powder serving as seed crystals needed for production of nickel powder is produced from a solution containing a nickel ammine sulfate complex according to the amount needed for the production of the nickel powder. The method for producing nickel powder is characterized in that: the solution containing the nickel ammine sulfate complex, an insoluble solid, and a dispersant are continuously fed into a reaction vessel, followed by stirring to prepare a solution containing a nickel complex ion; hydrogen gas is blown into the prepared solution to reduce the nickel complex ion in the solution containing the nickel complex ion, thereby forming a precipitate of nickel particles on the surface of the insoluble solid; and thereafter the post-reduction solution is extracted from the reaction vessel.

1 . A method of producing nickel powder, wherein: a solution containing a nickel ammine sulfate complex, an insoluble solid, and a dispersant are continuously fed into a reaction vessel, followed by stirring to prepare a solution containing a nickel complex ion; hydrogen gas is blown into the solution containing the nickel complex ion to reduce the nickel complex ion in the solution containing the nickel complex ion, thereby forming a composite including a precipitate of nickel particles on a surface of the insoluble solid, to thereby prepare a reduced slurry containing the composite; and thereafter, when the reduced slurry is extracted from the reaction vessel, a feed amount of the solution containing the nickel ammine sulfate complex, the insoluble solid, and the dispersant and a discharge amount of the reduced slurry are adjusted to keep a constant amount of the solution in the reaction vessel. 
     
     
         2 - 7 . (canceled) 
     
     
         8 . The method of producing nickel powder according to  claim 1 , wherein an amount of the dispersant to be added is controlled to control the number of nickel powder obtained through the formation of the precipitate of nickel in the reduction. 
     
     
         9 . The method of producing nickel powder according to  claim 8 , wherein the dispersant is a polyacrylate and the amount of the dispersant to be added is in an amount of more than 1.0% by weight and 10.0% by weight or less based on a weight of the insoluble solid in the reaction vessel. 
     
     
         10 . The method of producing nickel powder according to  claim 8 , wherein the dispersant is a lignosulfonic acid and the amount of the dispersant to be added is in an amount of more than 2.0% by weight and 20.0% by weight or less based on a weight of the insoluble solid in the reaction vessel. 
     
     
         11 . The method of producing nickel powder according to  claim 1 , wherein the dispersant is a polyacrylate and the amount of the dispersant to be added is in an amount of more than 1.0% by weight and 10.0% by weight or less based on a weight of the insoluble solid in the reaction vessel. 
     
     
         12 . The method of producing nickel powder according to  claim 1 , wherein the dispersant is a lignosulfonic acid and the amount of the dispersant to be added is in an amount of more than 2.0% by weight and 20.0% by weight or less based on a weight of the insoluble solid in the reaction vessel.