| Summary: | Bibliography: leaves 103-108. === Chromium can exist in a number of oxidation states but the environmentally stable forms are trivalent (Cr(III)) and hexavalent (Cr(VI)) chromium. These two forms are noted for their different degrees of toxicity and mobility. Hexavalent chromium is more toxic and mobile and has been responsible for a number of illnesses in humans (Sheehan et. al., 1991). Elemental chromium and its compounds have a variety of uses in the industrial sector. The ferrometallurgical industry in particular makes use of chromium since this element imparts properties such as hardness and strenght to stainless steel. However, this industry also produces slags that contain residual amounts of chromium oxide (Cr[2]O[3]) along with other constituents such as calcium oxide (CaO). Thermodynamic data from the literature, has shown that Cr[2]O[3] can undergo oxidation at ambient temperature when in contact with CaO and atmospheric oxygen (Kilau and Shah, 1984; Hattori et al., 1978). Furthermore, the oxidation of Cr[2]O[3] in the presence of Ca(OH)[2] has also been observed at ambient temperature (Petersen, 1998).
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