In the activated oil shale ash sample, the quartz peak has disappeared and those of tobermorite (T), katoite (K) and
gibbsite (G) have appeared, with some amount of calcite remaining in the material.
The available alumina and reactive silica results quoted are based on low temperature bomb analysis (143AC), and the results indicate that the majority of alumina present is as the tri-hydrate mineral
gibbsite.
It consists largely of the minerals
gibbsite Al (OH)3, boehmite g-AlO(OH) and diaspore a-AlO(OH), together with the iron oxides goethite and hematite, the clay mineral kaolinite and small amounts of anatase TiO2.
* [alpha]-[Al.sub.2] [O.sub.3] (Korund Benatky, SRO, Czech Rep.); [lambda]-Al[(OH).sub.3],
gibbsite (Lachema Brno Comp., proven by XRD method); kaolinite (Kaolin Sedlec IA Standard, Sedlecky kaolin AS, Czech Rep.); aluminum phenoxide Al[([H.sub.2]O).sub.3][([C.sub.6][H.sub.5]O).sub.3] (Sigma Aldrich, elemental analysis see Table 1); as polyphenolic complex, Al-catechin complex prepared according to (Chen, Wang and Huang, 2006) was chosen.
Furthermore, the mineralogical composition (~58% quartz, 22% hematite, 7%
gibbsite, 5% goethite, 1% anatase, 1% desilication product (DSP), 1% muscovite, and 0.3% boehmite; Taylor and Pearson 2001), and the presence of amorphous Fe and Al oxides (0.7%) ,suggest BRS contains colloids that can limit plant nutrient availability due to specific adsorption mechanisms (e.g.
Calcium aluminate + Water [right arrow] Katoite +
Gibbsite (2)
Bayer liquor is a highly concentrated caustic solution used to extract primarily
gibbsite [Al(OH)3] from bauxite ore.
Other, less common mineral species that have been reported from the Klein Spitzkoppe occurrences include bixbyite, chabazite, columbite, euxenite-(Y),
gibbsite, nacrite, opal (hyalite), pyrophyllite, talc, ferberite and zircon.