pure aluminum, a silvery-white metal, possesses many strengths. It is light, it is nonmagnetic and explosions, is the second largest metals in the scale of malleability, ductility, and sixth. It is widely used for kitchen utensils, decoration of the building outside, and in many industrial applications where a solid, lightweight, easy to construct is required. These
alloys are of vital importance in the construction of modern aircraft and rockets. Aluminum, evaporated in a vacuum, forms a highly reflective coating for visible light and radiant heat. These coatings soon form a thin protective oxide layer and does not deteriorate as do silver coatings. They are used to coat telescope mirrors and manufacture of decorative paper, packaging and toys.
Two important developments in the 1880s greatly increased the availability of aluminum. The first was the invention of a new process for obtaining aluminum from aluminum oxide. Charles Martin Hall, an American chemist, and Paul Héroult LT, a French chemist, invented the process each independently in 1886. The second was the invention of a new process that could cheaply obtain alumina from bauxite. Bauxite is an ore that contains a large amount of hydroxide aluminum oxide (Al2O3 • 3H2O) and other compounds. Karl Joseph Bayer, Austrian chemist, developed this process in 1888. The Hall-Heroult process and Bayer are still used today to produce nearly all of the world's aluminum.
The most important compounds are aluminum oxide, sulfate and potassium sulfate soluble (alum). The oxide, alumina, is naturally the ruby (Al2O3), sapphire, corundum, and Emery, and is used in glassmaking and refractories. Synthetic ruby and sapphire are used in lasers to produce coherent light.
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