Method for producing nickel powder

A method for producing nickel powder, the method comprising:

• supplying a nickel sulfate ammine complex solution and nickel powder having a particle size of 0.1 μm to 300 μm as seed crystals to a reaction container, continuously supplying hydrogen gas to set a pressure of a gas phase part inside the reaction container to 2.5 MPa to 3.5 MPa while the inside of the reaction container is maintained at a temperature in a range of 150° C. to 250° C. so that nickel ions in the nickel sulfate ammine complex solution are reduced to nickel and the reduced nickel is precipitated on a surface of the nickel powder as seed crystals supplied to the reaction container so as to obtain reduced nickel powder;
• subsequently transferring a reacted slurry containing the nickel sulfate ammine complex solution and the reduced nickel powder to a pressurized storage container which is connected to the reaction container and is maintained at the same as an internal pressure of the reaction container or lower than the internal pressure of the reaction container by a range of 0.2 MPa to 1.0 MPa;
• and
• subsequently reducing the pressure of the pressurized storage container to which the reacted slurry is transferred, and then extracting the reacted slurry from the pressurized storage container to recover the reduced nickel powder.