Synthesis‐identification of hematite and kaolinite ‐hematite (k‐h) system

In pedogenetic environments where oxidative prevail, structural iron released from silicates is precipitated in the form of one or more ferric oxide minerals. Therefore, in highly weathering soils, kaolinite and iron oxides occur as father stable products of weathering. Such soils frequently posses excellent aggregate stability, but the role played by kaolinite and hematite in aggregate formation is not yet fully established. This study proposes to determined if hematite does in fact associate with kaolinite and if so, what is the type of association. For this reason, the formation of hematite from amorphous Fe hydroxide in aqueous system at pH 6.0 and 70°C with oxalate and the formation of hematite‐kaolinite (h‐k) system from hematite and hydrogen‐kaolinite saturated in aqueous system at pH 6.0 and room temperature were followed by X‐ray, NMR, FT‐IR spectroscopy , specific surface area and magnesium exchange capacity (Mg.E.C).