Method for producing iron hydroxide, hydrated iron oxide and iron oxide from filter salts obtained by the recovery of waste acids

摘要

Recovery of iron hydroxide (IA), hydrated oxide (IB) or oxide (IC) from filter salts (II) from dilute acid recovery comprises dissolving (II) in water, adjusting the solution to pH below 1 and then to pH 2-4 by adding a strong base, with stirring; separating the precipitate as usual; adjusting the solution to pH 6-8 by adding a strong base and/or oxidant, separating precipitated (IA) or (IB), washing and drying and optionally drying and/or calcining to (IC).