LAUSR

Abstract In this study, to clarify the evolution of Hg during the heating process of iron ore, a combination of sequential leaching and temperature-programmed heat treatment (TPHT) was utilized to investigate the form of Hg in iron ore and volatile Hg species during heating. The TPHT of fractions obtained from the sequential leaching of Indonesian hematite revealed that the water-soluble Hg was composed of Hg species that evolved at both low and high temperatures and at least seven species were identified. One of these species may be HgCl2, which was inferred from comparisons to the TPHT results of model compounds. The Hg species leached in AcOH/HCl and KOH exhibited two evolution peaks in the temperature ranges of 300–600 °C and 500–850 °C, respectively. HNO3-soluble Hg species were mainly Hg volatilized in the range of 750–850 °C. HCl/HNO3-soluble Hg evolved in the range of 600–900 °C and consisted of at least three Hg species. Based on the information obtained through the TPHT of each the fractions mentioned above, the Hg evolution behaviors of five iron ores were curve-fitted and it was determined that the Hg species that volatilized up to 950 °C in all samples were mainly water-soluble Hg species. Synopsis: Elucidation of Hg morphology in iron ore and the evolution behavior is useful for controlling Hg release from ironmaking industry.