Authors: Mohamed TAHIRI, Marouane JAAFARI
The waste pickle liquor coming from the pickle line in galvanization process of steel is collected in the waste acid storage tanks. The size of the storage capacity determines, for how long the pickling line and the acid regeneration plant can be operated independently from one another.
The combustion gases which build up a certain flow pattern inside of the reactor dry up the droplets of the pre-concentrated acid coming down from the spray nozzles and in the hot part of the reactor the FeCl2 is decomposed according to the following formula:
2 FeCl2 + 2 H2O + 1/2 O2 Fe2O3 + 4 HCl
The solid particles (Fe2O3) will fall down to the lower cone of the reactor in the form of powder and are discharged through a rotary valve which keeps gases inside of the reactor separated from the outside atmosphere.
In order to reuse Iron Oxide obtained during the process of cleaning hydrochloric acid, our team focuses on the conditions of valorization of the oxide Fe2O3. We tried the doping of this product with metal ions such as: Mn2+, Al3+, Zn2+. We succeed to isolate, by dry way, a series of compounds with interesting shades of colors. The heat treatment of these pigments in the molten medium at lower temperature (900.°C) has improved their morphology.
The powders obtained were characterized by X-ray diffraction (XRD), scanning electron microscopy and EDX.
The pigments obtained have sufficient thermal stability to be used in various applications.
Keywords: component: Pigments, Iron Oxide, zinc oxide, solid waste recycling, Steel pickling line; Steel Galvanization