Development of a Roasting–Magnetic Separation Technology for the Beneficiation of Ferruginous Manganese Fines

The aim of this study was to develop a roasting–magnetic separation technology for ferruginous manganese fines generated during the processing of ores from the Tur deposit in order to reduce iron content and increase manganese concentration in products suitable for subsequent metallurgical applications. A process flowsheet involving magnetizing reduction roasting with a carbonaceous reductant (Shubarkol coal) followed by magnetic separation was proposed. The effects of key process parameters, including reductant dosage (20 and 30 wt.%), roasting duration (180 and 300 min), and particle size distribution, were systematically investigated. The separation efficiency of iron and manganese was found to depend strongly on the roasting conditions and the reduction degree of iron-bearing phases. The proposed technology demonstrated high efficiency, with the best results obtained at 30 wt.% coal and 300 min of roasting, achieving manganese recovery of up to 73.40% in the non-magnetic product while reducing iron content to 2.13%. Furthermore, the inclusion of a preliminary magnetic separation stage improved process selectivity, producing a manganese concentrate containing up to 31.9% Mn and 2.0% Fe. X-ray diffraction analysis confirmed the formation of (Fe,Mn)O, hausmannite, and braunite, while quartz remained the dominant gangue phase. The results demonstrate the potential for efficient utilization of ferruginous manganese fines and the expansion of the metallurgical raw material base in Kazakhstan.