Investigation ellipsométrique de la cristallisation de la goethite en milieu basique
Written by sctunisie no commentsThe geothite precipitation from amorphous ferrihydrite in alkaline medium at 70°C has been studied by single wave length ellipsometric data. Optical parameters such as ψ, Δ, n and k of the precipitates obtained at different reaction times have been determined. Goethite content of the precipitates have been determined by XR diffraction and 1R spectroscopy. Variations of n and ψ are particularly significant, the former decreases from 2.65 to 2.198 and the later increases from 1.09 to 7.40 degrees. Both of parameters are suitable to be used as goethite crystallization indicators. At the same time, the colors of precipitates have been determined in the L*a*b* color space. b* has been verified as simple indicator of goethite crystallization and a positive relationship has been established between n , ψ and b*.
A. Hamzaoui, M. Soua, M. El Maaoui
Goethite, Ferrihydrite, color, refractive index, crystallisation
Pages 1371-1381
