| 摘要 |
<p>Method for the removal of colouring materials as iron and halogens from hydrochloric acid. Among the halogens it is especially chlorine and bromine that contribute to the colour. Iron is first removed from the hydrochloric acid preferably by filtration and ion exchange and thereafter a nitrogen containing reducing agent is added to the acid. It is preferred to use compounds containing hydroxyl amine, preferably hydroxylamine hydrochloride (hydroxyl ammoniumchloride). The reducing agent is added in a stoichiometric excess.</p> |
