Grindability characterization and work index determination of alluvial ferro-columbite deposits for efficient mineral processing

Abstract

This study emphasizes on the physicochemical and grindability characteristics and work index of an alluvial formed silica dominated ferro-columbite mineral from Rayfield-Jos minefields in Plateau state, Nigeria. Investigations were also carried out in order to determine the mineralogy of the mineral deposits and most essentially the actual energy consumed during comminution and milling of the mineral so as to achieve the liberation size prior to high efficient mineral processing or beneficiation and the extraction of value metals. The distribution of the mineral particles as well as their sizes was determined, with a mineral liberation size fraction range essentially established as -150+90 µm particle sizes. Mass percentage of each size fraction obtained from PSD analysis conducted before and after comminution was also determined, obtaining 80% passing for both the mineral feeds and comminuted products. Berry and Bruce modified Bond’s work index was therefore obtained, and was determined to be within the range of 2.0414 to 2.5667 kWh/ton. Hence, the energy consumed or required to comminute or grind the Fe-columbite mineral to 80% passing is expected to fall within the range of 0.3613 to 0.4543 kWh. Thus, it could be said that a low milling work index as well as moderately low energy is required for comminution and this can be attributed to the mineralogy, mineral source and alluvial formation of the mineral reserve. Therefore, the grindability/PSD result of the mineral sample indicates that its mineralogy is considered a class of moderately soft mineral type in terms of texture with easy grindability.