SYNTHESIS OF RED IRON OXIDE PIGMENT ON THE BASIS OF CONVERTER STEELMAKING SLAG FOR CONSTRUCTION INDUSTRY

Abstract

The article presents a method for producing a red iron oxide pigment with the use of converter steelmaking slag as the main iron-containing component without magnetic separation stage. To fulfill the task, the slag was subjected to preliminary processing operations in order to obtain a powdery material and remove impurities, by dissolving iron and its compounds with sulfuric acid to form a solution of iron (II) sulfate and by further thermal decomposition at a temperature of 650 ºС (copperas red process). It has been found thatthe iron oxide pigment obtained by the proposed method consists of α-Fe2O3 hema-tite (93–95 %), has high quality and coloring characteristics, and an extremely low content of undesirable substances that worsen its properties. Phosphoric anhydride (Р2О5), being a constituting element of the slag, had a favorable effect on the process of pigment synthesis as a mineralizing additive. The degree of extraction of iron, calcium and magnesium is extremely high (97, 99.3 and 97 respectively), what indi-cates at the high efficiency of this method. This research work is of great importance for the construction industry, especially in the field of decorative concrete and mortars.