ABSTRACT
The
characterization of clay raw materials of three clay deposits from Northern
Cameroon was investigated. The three deposits, located in Gaschiga, Sekandé and
Boulgou, are locally used as building materials, but no data are available on
these materials and they are relatively unknown. Mineralogical, geochemical and
physico-chemical characteristics were studied, using X-ray diffraction, X-ray
fluorescence and physico-chemical analyses. Mineralogically, quartz was the
most abundant mineral in the studied raw materials. It is associated to
abundant quantity of smectite, kaolinite and K-feldspars, and slightly abundant
to traces of hematite and amphibole. Geochemically, those clayey soils are more
siliceous (SiO2, 51% - 59%) with significant amount of aluminum (Al2O3,
15% - 19%) followed by iron oxides (Fe2O3, 3% - 10%).
Other oxides (K2O, MgO, TiO2, Na2O, MnO, CaO
and P2O5) are in relatively lower proportion. High level
of silica content explains the sandy nature of these clays. The results of
granulometric analysis show that the studied raw material contain sand (39% - 68%)
as major grain size followed by clay particles (17% - 38%), silt (1% - 36%) and
gravels (0% - 16%). The studied clayey soils were moderately plastic, with
plasticity index values ranging from 13% to 30%, and are also characterized by
very high liquidity limits of 34% - 63%.