Verfahren zur Reinigung von auf nassem Wege hergestellter Phosphorsaeure und zur Herstellung von Kaliumphosphat

摘要

1323743 Purification of phosphoric acid and monopotassium phosphate PRODUITS CHIMIQUES ET METALLURGIQUES DU RUPEL 24 August 1970 [22 Aug 1969] 40704/70 Heading C1A Wet process phosphoric acid is purified by (a) reacting with KC1 where the molar ratio of KCl to H 3 PO 4 is less than one to give HCl + KH 2 PO 4 . H 3 PO 4 at an absolute pressure below 260 mm. at below 120‹ C. and (b) decomposing the complex into H 3 PO 4 and KH 2 PO 4 in the presence of a solvent (e.g. methanol) with which H 3 PO 4 is miscible but with which KH 2 PO 4 is insoluble and separating the H 3 PO 4 solution from the mixture. The solvent can then be removed to give purified H 3 PO 4 or the solution can be passed through a cationic exchange resin to give after removal of the solvent a more highly purified phosphoric acid. Different reactors at different temperatures and pressures may be used in series in a continuous process.