| 摘要 |
<p>A neutralizing reagent is added to a solution of chloroplatinic acid containing impurities to adjust the pH value of the solution to 5.5-7.0, the insoluble impurity compounds that precipitated in this first neutralization step is filtrated off, a neutralizing reagent is added to the first filtrate of chloroplatinic acid to adjust the pH value of the solution to 9.5-10.5, the insoluble impurity compounds that precipitated out in the second neutralization step is filtrated off, hydrochloric acid is then added to the second filtrate in which the insoluble impurity compounds have been removed, and ammonium chloride is added to the processed solution to convert platinum compound to ammonium chloroplatinate, which is intensely heated to yield platinum sponge. The preferred neutralizing reagent is NaOH or KOH. Filtration is preferably performed with a filter of which opening size is equal or less than 0.3 mu m.</p> |
