Showing papers on "Calcium aluminates published in 1987"

Surface composition of anhydrous tricalcium aluminate and calcium aluminoferrite

Abstract: Electron spectroscopy and optoacoustic spectroscopy (OAS) have been used to study the surfaces of synthetic tricalcium aluminate, Ca3Al2O6 and calcium aluminoferrite, Ca2AIFeO5. The surfaces of these compounds have compositions which differ markedly from those of the bulk. The surface of tricalcium aluminate is depleted in calcium and enriched in aluminium and also carries relatively stable hydroxyl groups, which can be detected by OAS. Calcium aluminoferrite has a surface enriched in aluminium and depleted in calcium and iron. Again, some hydroxyl groups are present on the surface. These differences in surface composition are discussed with particular reference to the early stages of reaction with water.

Binder for a refractory material and refractory product containing this binder

Abstract: A binder for a refractory material and also a refractory product containing this binder and a refractory material are provided. The main component of the binder is a calcium aluminate. This calcium aluminate is selected from the group consisting of the amorphous calcium aluminates of the composition CaO+Al2O3, CaO+2Al2O3, 3CaO+Al2O3, 3CaO+3Al2O3+CaF 2, 11CaO+7Al2O3+CaF2 and 12CaO+7Al2O3, the crystalline calcium aluminates of a composition 3CaO+3Al2O3+CaSO4, the amorphous calcium aluminates of the composition 3CaO+3Al2O3+CaSO4 and mixtures of these materials.

Surface state of calcium monoaluminate in the presence of phosphoric acid solution

Abstract: Observation par microscopie electronique a balayage de surfaces hydratees ou non de CA et analyse par spectrometrie EDS des regions proches de la surface qui resultent de CA en solutions H 3 PO 4 afin d'examiner le comportement de H 3 PO 4 a la surface de CA, dans cette region critique ou l'hydratation a cesse