Dephosphorization of the oolitic iron ore from Gara Djebilet using combined methods

Purpose. The aim of this study is to evaluate the effect of microwave pre-treatment on the mineralogical and microstructural changes in oolitic iron ore from Gara Djebilet, as well as its influence on the performance of low-intensity dry magnetic separation, with a view to improving iron enrichment and reducing phosphorus content. Methodology. Representative samples of oolitic iron ore from Gara Djebilet were subjected to mineralogical and physico-chemical characterisation. The ore was then pre-treated using microwaves, varying the power (400, 700 and 1,000) W, the exposure time (60 and 90 s) and the particle size distribution (-3 + 2, -2 + 1 and -1 + 0.5 mm). After crushing and sieving to determine particle size, the fraction between 0.075 and 0.5 mm was processed by low-intensity dry magnetic separation. Findings. Microwave pre-treatment significantly improved the recovery of iron ore from the oolitic deposit at Gara Djebilet. Under optimal conditions (1,000 W, 90 s, particle size −1 + 0.5 mm), a concentrate containing 64.14 % Fe and 0.27 % P2O5 was obtained, representing a reduction of approximately 86 % in phosphorus content compared with the raw ore. Originality. The originality of this work lies in establishing a correlation between the mineralogical and microstructural transformations induced by microwave pre-treatment and the improved metallurgical performance achieved through low-intensity dry magnetic separation, thereby opening up a new avenue for the sustainable processing of oolitic iron ores. Practical value. This study represents a sustainable alternative to conventional processes, particularly in arid regions where water use is limited. It thus offers concrete prospects for the industrial processing of oolitic ores and their integration into the steel production chain, whilst reducing operating costs and environmental impact.