Evolution of Mercury from Iron Ores in Temperature-Programmed Heat Treatments

The behavior of Hg released from iron ores during temperature-programmed heat treatments (TPHTs) in air has been mainly studied using an online monitoring method. The Hg release behavior in TPHT significantly depends on the type of ore being processed, which includes forms evolved as Hg0 and Hg2+, and forms that remain thermally stable up to 950°C. In addition, the TPHT experiments for model Hg compounds suggested the presence of several types of Hg forms (HgCl2, Hg2Cl2, HgS, HgO, HgSO4, and associated mineral-Hg) in the iron ores used. The amounts and proportions of suggested forms of Hg species substantially depend on the type and composition of the iron ore used. These observations may be important in designing an efficient method for the removal of Hg from iron ore and gaseous Hg.