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Why are carbonates important sources of metals such as calcium and magnesium?

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A labeled diagram of the periodic table entry for carbon, showing its atomic number 6, symbol C, electron configuration, atomic weight range, solid physical state, hexagonal crystal structure, and weakly acidic oxide properties. Color coding and icons indicate it is a nonmetal, solid at room temperature, with hexagonal structure and weak acidity. — carbon Carbon and its properties.

Carbonate minerals are important sources of metals like calcium and magnesium because they are widely distributed in the Earth's crust and form stable, concentrated mineral deposits that can be economically extracted.1

Calcium

Calcium is primarily sourced from calcium carbonate ( $C a C O_{3}$ ), which is the major constituent of limestone, marble, and chalk. Limestone is frequently processed to produce lime (calcium oxide), a vital industrial material used in steel manufacturing, glass production, and water treatment.23

Magnesium

Magnesium is commonly sourced from the mineral magnesite ( $M g C O_{3}$ ) and dolomite ( $C a M g (C O_{3})_{2}$ ). In industrial magnesium processing, dolomite is often calcined to produce magnesium oxide and lime, which are then reduced to extract magnesium metal. While magnesium can also be extracted from seawater, carbonate minerals remain significant terrestrial sources due to their high concentration in specific rock formations.4567