Magnetite ammonia catalysts Manufacture

A great many patents describe preparation, use, and regeneration of the fluidized catalyst. Fused iron of the synthetic ammonia type is mentioned for catalyst manufacture and such ores as hematite, limonite, magnetite, pyrite, as well as mill scale, bloom scale, and other materials. 

The catalytic activity of an ammonia catalyst may be reduced in the presence of certain chemical compounds, referred to as poisons. These may be gaseous, occurring as minor components of the synthesis gas, or as solids introduced to the catalyst during the manufacturing process, as impurities in the natural magnetite from which the catalyst is made. The latter will not be dealt with here, since they are already covered in Chapter 2. 

As an exception that proves the rule, the KAAP (KBR Advanced Ammonia Process) ruthenium-on-carbon catalyst was introduced to commercial application with a Canadian plant retrofit in 1992. The manufacturer claims that the activity of the catalyst exceeds that of magnetite-based materials by about an order of magnitude. 

The various physical properties characterizing the mechanical strength of catalysts are discussed abrasion resistance, cmsh strength, attrition resistance. The related measurements have been performed mainly using ASTM standard methods with some improvements. It is shown how modifications of the manufacturing technology can improve the abrasion resistance of the traditional ammonia synthesis catalyst (oxide-promoted magnetite) and of the PTA catalyst (Pd on active carbon). 

---