Extraction of group 2 metals

Of the group 2 metals, only Mg is manufactured on a large scale.  Dolomite is thermally decomposed to a mixture of MgO and CaO, and MgO is reduced by ferrosilicon in Ni vessels  Mg is removed by distillation in vacuo.

Extraction of Mg by electrolysis of fused MgCl₂ is also important and is applied to the extraction of the metal from seawater. The first step is precipitation of Mg(OH)₂ by addition of Ca(OH)₂ (slaked lime), produced from CaCO₃ (available as various calcareous deposits).

Neutralization with hydrochloric  acid and evaporation of water gives MgCl₂.xH₂O, which, after heating at 990 K, yields the anhydrous chloride. Electrolysis of molten MgCl₂ and solidification of Mg completes the process.

   Beryllium is obtained from beryl by first heating with Na₂SiF₆, extracting the water-soluble BeF₂ formed, and precipitating Be(OH)₂. Beryllium is then produced either by reduction of BeF₂ or by electrolysis of BeCl₂ fused with NaCl.

The production of Ca is by electrolysis of fused CaCl₂ and CaF₂; Sr and Ba are extracted by reduction of the corresponding oxides by Al, or by electrolysis of MCl₂ (M=Sr, Ba).

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