Abstract: An improved ion exchange process for purifying and/or concentrating hydroxylamine from an aqueous solution comprising hydroxylammonium ion and counter anions wherein ion exchange process conditions including effluent pH, effluent conductivity, and ion exchange bed height can be monitored and used to identify when to switch from an ion exchange step feed to a water wash feed, and to switch from a desorbent step to a water rinse step.

Abstract: HF can be recovered from aqueous streams, particularly those which are dilute and have a concentration of HF lower than the azeotrope between HF and water. Such aqueous streams are contacted with carbon molecular sieves, preferably those having an average pore size of about 3.5 Angstroms, which adsorb both HF and water. When regenerated by heating, more dilute aqueous streams are desorbed at lower temperatures, followed by desorption of HF which is free of water, making possible a separation of HF and water and avoiding formation of the azeotrope.