EFFECT OF PRELIMINARY HEATING ON THE ACTIVATION OF MODEL IRON CATALYST FOR AMMONIA-SYNTHESIS .2. STRUCTURAL-CHANGES LEADING UP TO THE NUCLEATION PROCESS
A. Pattekjanczyk, EFFECT OF PRELIMINARY HEATING ON THE ACTIVATION OF MODEL IRON CATALYST FOR AMMONIA-SYNTHESIS .2. STRUCTURAL-CHANGES LEADING UP TO THE NUCLEATION PROCESS, Applied catalysis. A, General, 124(2), 1995, pp. 267-280
Microscopic and microprobe studies of significantly active, fused mode
l iron catalysts with increased amounts of wustite are reported. The c
atalysts were examined in untreated form and after annealing. Two type
s of magnetite (isometric and lamellar) were found. A definite influen
ce of the annealing on the relative content of both magnetites was obs
erved. In the annealed sample a third kind of magnetite (enriched in i
ron) was found. The creation of iron nuclei in the catalyst precursor
is discussed and an suitable model is proposed.