Hydration products of calcium aluminoferrite
1983; Elsevier BV; Volume: 13; Issue: 5 Linguagem: Inglês
10.1016/0008-8846(83)90060-1
ISSN1873-3948
Autores Tópico(s)Layered Double Hydroxides Synthesis and Applications
ResumoHydration products of Ca2AlFeO5, steam cured at 72 C, have been identified using X-ray diffraction and Mössbauer spectroscopy. Iron-bearing phases are hydrogarnet Ca3FeyAl2−y(OH)12 with y = 0.22, and non-crystalline ferrihydrite Fe(OH)3.nH2O. These two are readily distinguished in Mössbauer spectra at 4.2 K where they give, respectively, a single unsplit absorption line and a magnetically split hyperfine pattern with Hhf = 501 kOe. Addition of 5 wt% lime to the calcium aluminoferrite increases the proportion of iron in the hydrogarnet to y = 0.32 while leaving the ferrihydrite unchanged, whereas 5 wt% gypsum eliminates iron from the hydrogarnet entirely and produces an even more disordered non-crystalline ferric hydrate.
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