ELTEE DMCC

DubaiUnited Arab Emirates

In its mineral form Bauxite, Aluminium is the most abundant metal in the earth’s crust. Bauxite contains one of a variety of hydrated aluminium oxides (gibbsite, boehmite or diaspore), which are often expressed as Al₂O₃xH₂O but are more commonly regarded as impure Al₂O₃. Bauxite is claylike and earthy, and ranges in colour from white to deep brown or red according to the nature and quantity of its components. The major impurities in Bauxite are iron oxides (goethite & hematite), silicon dioxide, the clay mineral kaolinite as well as small amounts of anatase (TiO₂). Consequently, its composition varies considerably with alumina constituting from about 50% to about 70%. Aluminium content can be accurately and precisely determined over a broad analytical range simultaneously along with Si, Fe, Mn, Ti, Zr and up to 20+ other elements.

Zinc ore is most commonly found as zinc carbonate (ZnCO3), known as calamine or smithsonite. It generally occurs as rounded, crystalline crusts or granular, honeycombed masses that have a vitreous or pearly luster and are typically dirty brown or grey in colour.

Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic table. In some respects, zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn2+ and Mg2+ ions are of similar size. Zinc is the 24th most abundant element in Earth’s crust and has five stable isotopes. The most common zinc ore is sphalerite (zinc blende), a zinc sulfide mineral. The largest workable lodes are in Australia, Asia, and the United States. Zinc is refined by froth flotation of the ore, roasting, and final extraction using electricity (electrowinning).

The main copper sulphide minerals are chalcopyrite (CuFeS2) chalcocite (Cu2S), covellite (CuS), bornite (Cu5FeS4), tetrahedrite ((Cu, Fe)12Sb4S13) and enargite (Cu3AsS4). The largest source of copper is from porphyry ore deposits in which one or a combination of the minerals occurs. A typical copper sulphide ore contains various levels of iron sulphide types that generally include pyrite (FeS2) and pyrrhotite (Fe1-xS). Often gold and silver are present which may either be associated with the sulphides or are free. The gangue particles can consist of a range of silicate minerals from quartz to talc and clays.