Synthesis and Characterization of High Purity Ruthenium Sponge

Ruthenium is widely used as catalyst, magnetic recording and electrode materials. In this study, high-purity (≥99.995 wt%) ruthenium sponge was synthesized from crude ruthenium (≤99.9 wt%) by chemical refining technique. Initially, crude Ru was transformed into H2RuCl6 by distilling treatment. The H2RuCl6 was, then, added with NH4Cl powder to precipitate (NH4)2RuCl6 powder. Afterward, the (NH4)2RuCl6 powder was ignited in air and transformed into RuO2. Finally, RuO2 was changed to Ru by hydrogen reduction method. Impurities included in the starting Ru powder were eliminated after distillation and precipitation treatments. As-obtained ruthenium particles were spherical-like agglomeration, the average size was about 6 μm and the powder density was 11.83 g/cm3. The details of chemical transforming mechanisms in the refining process were described.