THE EFFECT OF COBALT ON THE REACTANTS ADSORPTION AND ACTIVITY OF FUSED IRON CATALYST FOR AMMONIA-SYNTHESIS

Modern adsorption study facilities as well as scanning electron micros copy, X-ray diffraction, Mossbauer spectroscopy and X-ray fluorescence spectroscopy were used to investigate the effect of cobalt on the ads orption of nitrogen, hydrogen and ammonia on the surface of cobalt mod ified iron fused catalysts. Adsorption studies were carried out at the temperature range specific for ammonia synthesis (385 degrees C). Act ivity tests were carried out under 10 MPa in the 350-450 degrees C tem perature range. Investigations were performed on the traditional multi promoted iron catalyst and on the series of catalysts prepared with ad dition of cobalt. Introduction of cobalt changed considerably the samp le behaviour during activation and ammonia synthesis. Addition of coba lt promoted the iron catalyst for ammonia synthesis. The most active s ample was that containing approximately 5.5 wt% Co. Cobalt changed the adsorption behaviour of the catalyst. Chemisorption of nitrogen is mu ch higher for ''cobalt'' catalysts. Growth of nitrogen chemisorption a nd decrease of ammonia adsorption resulted in the growth of catalytic activity of ''cobalt'' catalysts in ammonia synthesis.