How is potassium metal commercially produced from potassium chloride?

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A periodic table element box for potassium shows atomic number 19, symbol K, atomic weight 39.0983, electron configuration [Ar]4s1, and name potassium. Icons indicate it is an alkali metal, solid at room temperature, body-centered cubic crystal structure, and has strongly basic higher-valence oxides. A key explains the symbols for alkali metals, solid state, body-centered cubic structure, and strong basicity. — potassium Properties of potassium.

Potassium metal is not produced through electrolysis because there are few salt additives capable of lowering the melting point of potassium chloride to a range where electrolytic processes are efficient.1

Instead, commercial production is achieved through the sodium reduction of molten potassium chloride at 870 °C (1,600 °F). In this process, molten potassium chloride is continuously fed into a packed distillation column while sodium vapour is passed upward through it. The reaction is represented by the following equation:1

$Na + KCl \to K + NaCl$

By condensing the more volatile potassium at the top of the distillation tower, the reaction is effectively forced to the right, allowing for the recovery of the metal.1