FORFARANDE FOR FRAMSTELLNING AV EN JERNFRI KROM(III)FORENING UR EN SUR VATTENLOSNING INNEHALLANDE JERN OCH KROM

摘要

An iron-free chromium(III) compound is precipitated at an elevated temperature and pressure from an acidic aqueous solution which contains iron and chromium. In order to prevent coprecipitation of iron, an additive is added to the precipitation stage in an amount sufficient to provide in the precipitation conditions at least 2 g/l of bivalent chromium in the solution.