Method for producing nickel powder

A method for producing nickel powder from a nickel ammine sulfate complex solution, the method comprising treatment steps of:

• (1) a seed crystal production step of mixing a nickel sulfate solution and hydrazine to produce nickel powder having an average particle size of 0.1 to 5 μm serving as seed crystals;
• (2) a seed crystal addition step of adding the nickel powder having an average particle size of 0.1 to 5 μm obtained in the step (1) as seed crystals to the nickel ammine sulfate complex solution to form a mixed slurry;
• (3) a reduction step of blowing hydrogen gas into the mixed slurry obtained in the seed crystal addition step (2) to form a reduced slurry by precipitation of a nickel component in the mixed slurry on the seed crystals;
• and
• (4) a growth step of subjecting the reduced slurry formed in the reduction step (3) to solid-liquid separation to separate the nickel component in the reduced slurry to form a recovered nickel powder as a solid phase component and then blowing hydrogen gas into a solution prepared by adding the nickel ammine sulfate complex solution to the recovered nickel powder and thereby causing the recovered nickel powder to grow and form high purity nickel powder.