A Ru catalyst was prepd. by impregnation of active C (extrudates of 2 mm in diam.) with RuCl3 soln., followed by drying, reduction with H and impregnation with an aq. soln. of Ba and Cs nitrates. The grain-shaped catalyst was slightly more active in NH3 synthesis at 350-400 degrees C, 9.0 MPa and H/N ratio 3:1 (differential measurement at 8.5% NH3) than the fine particles (0.2-0.6 mm). A continuous stirred-tank reactor was used for detg. the kinetic characteristics of the catalyst. The reaction kinetics was described by a power equation.