Timestone beneficiation by Column and Conventional Floatation Touse A5 Raw material for Cement

Abstract

Limestone, as a raw material for cement manufacturing, has to be beneficiated to produce uniform raw material for the kiln. Investigations were carried out on a low grade limestone sample sourced from southern India. Petrological microscope studies on this sample indicated the presence of gneiss consisting of ferromagnesian silicates and quartz as associated gangue with calcite as valuable mineral. Froth flotation is the most efficient and versatile mineral processing technique for fine particle processing and upgrading the total carbonates content by simultaneously reducing the acid insolubles mainly consisting of silica/silicate bearing mineral phases. The liberation study indicated that 198 µm (d80) as the optimum mesh-of-grind. The run-of-mine limestone assaying 78.5% total carbonates and 20.9% acid insolubles was beneficiated using laboratory scale conventional and column flotation process for improving the grade and recovery by direct flotation technique. A limestone concentrate of 94.3% total carbonates and 4.7% acid insolubles with 79% weight recovery was obtained by column flotation process using a single flotation collector reagent which is also environmental friendly. Thus, a process based on column flotation was developed for the beneficiation of limestone so as to utilize it as raw material in cement manufacturing. The developed beneficiation process has several advantages such as flexibility in controlling the acid insolubles and total carbonates in the concentrate to suite the end user requirements. The rejects of this process could be utilized for value added products like paver blocks, tiles and bricks.