Combined roasting and leaching treatment for reducing phosphorus, aluminum and silicon in oolitic iron ore

Abstract

Purpose. To enhance the quality of oolitic iron ore extracted from the Gara Djebillet mine in southern Algeria by reducing the levels of silicon, aluminum, and phosphorus, thus making it more suitable for use in the steel industry. Methodology. The study involves pre-treating the Gara Djebillet iron ore through roasting, followed by two stages of leaching with separate acid and base leaching steps. Additionally, the impact of introducing an additional roasting step at 800 °C between the two leaching stages is examined. Findings. Chemical leaching of the raw ore without roasting pre-treatment results in a reduction in silicon, aluminum, and phosphorus contents from 4.45, 5.11 and 0.61 % to 2.68, 3.36 and 0.3 %, respectively. However, the iron content decreases from 52.42 to 45 %. Pre-treating the ore with roasting combined with the two leaching stages reduces the phosphorus content to 0.15 % and increases the iron content to 55.25 %. The silicon and aluminum contents decrease to 4.2 and 5 %, respectively. Introducing a second roasting step between the two leaching stages further decreases the phosphorus content to 0.15 %, but the iron content only increases to 54.25 % after the second acid leaching step. The aluminum and silicon contents increase to 4.5 and 5.3 %, respectively. Originality. This study introduces a novel approach to improving the quality of oolitic iron ore by investigating the efficacy of pre-treatment with roasting followed by two stages of leaching. The research contributes valuable insights into the effectiveness of these methods for reducing undesirable elements in iron ore. Practical value. The findings offer practical implications for the steel industry, suggesting potential methods for enhancing the quality of iron ore from the Gara Djebillet mine. Implementing these methods could lead to increased efficiency and cost-effectiveness in iron ore processing, ultimately benefiting steel production processes.