| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing high-purity platinum powder, in which the high-purity platinum powder, that hardly contains impurities such as sodium and chlorine, can be produced at a high platinum recovery rate of 99% or more.SOLUTION: The method for producing high-purity platinum powder comprises: a first step of adding a part of a stoichiometric amount of a hydrazine compound, which is required to reduce ammonium chloroplatinate to the Magnus' salt thereof, to a solution of the ammonium chloroplatinate being a raw material; a second step of adding an ammonia compound of suitably 4-12 times of the molar quantity of the platinum contained in the raw material to the liquid obtained at the first step so that generation of the Magnus' salt is started at 60°C or lower temperature; a third step of adding the hydrazine compound of the remainder or more of the stoichiometric amount to the liquid obtained at the second step so that the generation of the Magnus' salt is completed at 60°C or lower temperature; a fourth step of adding the hydrazine compound to the Magnus' salt obtained at the second and third steps so that the Magnus' salt is reduced to platinum powder at 60°C or lower temperature; and a fifth step of decrepitating the platinum powder obtained by reduction suitably at 700-950°C. |
