Process for producing nickel powder

Abstract

The purpose of the present invention is to provide a process for producing nickel powder capable of obtaining fine nickel powder in wet process, and also, capable of decreasing content of impurities by medicament (additive) used in crystallization of nickel powder which is reduction reaction. 1. A process for producing nickel powder, comprising a crystallization step for obtaining nickel crystal powder by reduction reaction in reaction solution in which at least water-soluble nickel salt, reducing agent, alkali hydroxide, if necessary metal salt of metal more noble than nickel, and water are mixed, and which is blended with sulfur-containing compound in advance, wherein the reducing agent is hydrazine (N2H4), the sulfur-containing compound is a compound having any of sulfur-containing functional group structure represented by —SH, sulfur-containing functional group structure represented by —S—S—, sulfur-containing functional group structure represented by —O—S(═S)(═O)—O— at least in molecule, and a ratio (A) of substance quantity of the sulfur-containing compound and nickel in the reaction solution ((molar number of the sulfur-containing compound/molar number of nickel)*10) [molar ppm], an effective multiplication factor (B) of the sulfur-containing functional group of the sulfur-containing compound [magnification] (—SH: 1, —S—S—: 2, —O—S(═S)(═O)—O—: 1), and a ratio (C) of substance quantity of the metal salt of metal more noble than nickel and nickel ((molar number of metal salt of metal more noble than nickel/molar number of nickel)*10) [molar ppm] is in a range of 0.1≤A*B≤0.75C+30 (0≤C≤100).