Integrated Roasting and Acid Leaching for Phosphorus Removal from High-P Oolitic Hematite Ore: A Case Study from El Bagrawiya, Sudan

Abstract

This study presents a combined approach of roasting and acid leaching for the removal of phosphorus from high-phosphorus oolitic hematite iron ore sourced from the El Bagrawiya region, Sudan. Phosphorus is a detrimental impurity in ironmaking due to its adverse effects on steel properties. The raw ore, containing 60.74% Fe and 0.91% P₂O₅, underwent thermal treatment in a muffle furnace at temperatures ranging from 500 °C to 900 °C. Optimal roasting at 600 °C in the presence of 3 wt% CaO enhanced iron enrichment and reduced gangue minerals. Subsequently, leaching experiments were carried out using sulfuric, nitric, and hydrochloric acids under varied concentrations and agitation times. Sulfuric acid achieved the highest phosphorus removal rate, reaching 66.8% under optimal conditions (1.0 M H₂SO₄, 650 rpm, 60 min). Instrumental analyses, including XRF, XRD, and SEM-EDS, confirmed significant mineralogical and morphological changes, supporting the observed dephosphorization efficiency. This study demonstrates the potential of an integrated thermal–chemical process as an effective method for upgrading high-phosphorus iron ores, particularly in underexplored regions.