%0 Journal Article
%T Influence of Ce3+ on the Formation of ¦Á-Semi-Hydrate Gypsum
%A Nora KYBARTIEN£¿
%A Violeta LE£¿KEVI£¿IEN£¿
%A Zenonas VALAN£¿IUS
%J Materials Science
%D 2012
%I Kaunas University of Technology
%R 10.5755/j01.ms.18.4.3102
%X Influence of Ce3+ on the formation of ¦Á-semi-hydrate gypsum was investigated in this work. ¦Á-semi-hydrate gypsum is normally obtained by heat conversion of the dihydrate gypsum. The model system: CaSO4¡¤2H2O¨CCe2(SO4)3¡Á8H2O was designed. The amount of Ce2(SO4)3¡Á8H2O corresponding to 0.1; 0.5 and 1 % of Ce2O3 from the mass of dry materials (gypsum) was added to solution. Maleic anhydride (C4H2O3) was used as crystal modifier and 0.1 % of C4H2O3 from the mass of dry materials (gypsum) was added to solution. Water/gypsum of the suspension was equal to 2. The system was processed under hydrothermal conditions at 128 ¡ãC ¡À2 ¡ãC and 138 ¡ãC ¡À2 ¡ãC temperature; the duration of isothermal curing was 3 hours. The product obtained was treated at 400 ¡ãC temperature. The X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR) scanning electron microscopy (SEM) was used to characterize the product. The results showed that the larger amount of Ce3+ in the system, the larger the remaining amount of un-dehydrated dihydrate gypsum in the final product, and the resulting crystals of ¦Á-semi-hydrate gypsum are tiny, indefinite and irregular in shape. Therefore, the results obtained lead to a conclusion that Ce3+ has a negative influence on the dehydration of dihydrate gypsum (or on the formation of ¦Á-semi-hydrate gypsum) and the morphology of ¦Á-semi-hydrate gypsum crystals. DOI: http://dx.doi.org/10.5755/j01.ms.18.4.3102
%K gypsum
%K ¦Á-semi-hydrate gypsum
%K cerium sulphate octahydrate
%K dehydration
%K crystal morphology
%U http://www.matsc.ktu.lt/index.php/MatSc/article/view/3102