| Conditions for determination of weight loss ignition in sponge platinum and palladium production by hydrogen reduction gravimetry were systemic investigated. Effect of contents coming from oxygen, nitrogen, carbon and otherwise nonmetal coexist impurities on analytical result was investigated, and the determined results of the method were compared with that of thermo gravimetry. Results indicate that the weights loss ignition are of 0.0018%~0.0769% and 0.0018%~0.0694%, respectively, in sponge platinum and palladium under the conditions of 2 g sample, hydrogen reduction, subsection heating temperature to 800℃. Relative permissible deviation (RPD), relative standard deviation (RSD, n=11) and repeatability limit (r) are 2.1%~50%, 0.7%~16.0%, 0.0006%~0.0026%, for Pt, and 3.0%~15.8%, 1.0%~5.3%, 0.0003%~0.0020%, for Pd, respectively. The weights loss ignition was composed of oxygen and nitrogen contents, and it is not affected from charcoal content. The proposed method is easy to operated, reliable of analysis results, good accord with those of thermo gravimetry, and to satisfy the analytical requirement for 99.90%~99.99% sponge platinum and palladium production. |
