A process for the preparation of phosphoric acid free from arsenic

摘要

Phosphoric acid is treated with phosphoretted hydrogen in order to separate arsenic present as impurity. In an example, 80 per cent phosphoric acid is treated with phosphoretted hydrogen, excess of the latter is removed by passing carbon dioxide and the elementary arsenic which separates in the form of flakes is removed by filtration after the acid has been diluted with distilled water.