Sample of catalyst, granules of ammonia synthesis converter, ICI 35-4, stored in glass flask (displayed inverted) for animated process flow display, part of model of 'Ammonia Four', an ammonia synthesis plant at ICI Agricultural Division, Billingham works, by Cleveland Process Designs and ICI Ltd, Stockton on Tees, England, 1976. Sample of catalyst, granules of ammonia synthesis converter, ICI 35-4, for ICI Billingham 'Ammonia Four' model 1976