Bauxit

Bauxit is the primary ore from which aluminum is extracted on an industrial scale. It is a sedimentary rock composed mainly of the minerals gibbsite (Al(OH)₃), boehmite (γ-AlO(OH)), and diaspore (α-AlO(OH)), along with impurities such as iron oxides, titanium dioxide, and silica. The name "bauxite" derives from the French town of Les Baux, where the ore was first identified in 1821 by Pierre Berthier.

Bauxite forms in tropical and subtropical regions through the weathering of aluminum-rich rocks, such as granite, under conditions of high rainfall and temperature. Over millions of years, the chemical breakdown of these rocks releases aluminum oxides and hydroxides, which accumulate as a residual layer. The ore typically occurs in laterite soils, often mixed with clay, iron oxides, and other minerals.

The global production of bauxite has been steadily increasing since the early 20th century, driven by the growing demand for aluminum, a versatile and lightweight metal used in construction, packaging, transportation, and consumer goods. Major producers include Australia, Guinea, Brazil, China, and India, with Australia alone accounting for approximately one-third of world reserves.

Mining bauxite involves open-pit operations, where large quantities of overburden (soil and rock) are removed to access the ore. The extracted material is then crushed, washed, and subjected to a chemical process called the Bayer process to separate aluminum hydroxide from impurities. The hydroxide is subsequently calcined to produce alumina (Al₂O₃), which is further refined into aluminum metal through electrolysis.

Environmental concerns surrounding bauxite mining include habitat destruction, soil erosion, and water pollution. Efforts to mitigate these impacts include sustainable mining practices, reforestation, and the use of selective mining techniques to minimize ecological disruption.