Beneficiation studies on low-grade, limestone of Shahabad area, Shahabad, Gulbarga district, Karnataka

Abstract

In India more than 60% of lime stone is used in the manufacture of cement. Other than this, it is widely used in calcium carbide, sugar industries, textile, glass and paper industries, it is also used in blast furnace and steel melting process. Lime stone does not occur in pure form and it is always admixed with the silica, magnesia and iron oxide. The specification of lime stone in the cement and steel industries are rather stringent. Both industries require CaO of more than 40% with MgO, silica and alumina as low as possible. Lime stone used for chemical industry requires more than 50% of CaO. As the high grade lime stone is depleted due to its utilization for different industries, it is inevitable to use low-grade lime stone without beneficiating to meet the present specification and demand. Keeping this in view in the present investigation low-grade lime stone of Shahabad area Gulbarga district is subjected to beneficiation studies by flotation process to reduce silica and other gangue minerals to make it suitable raw material for different industries. The samples collected were subjected to sieve analysis. Since liberation of particles (lime from silica) were at its maximum in the size range of 200 microns, hence froth flotation process was adopted and experiments were carriedout accordingly. The low-grade lime stone ore assaying 34% lime, and it was subjected to beneficiation studies by froth flotation process to obtain lime concentration by removing silica and other gangue minerals. By using different concentration of reagents as depressant, collector and frother a considerable amount of silica and other gangue minerals were reduced and lime was upgraded, to an extent of 43.2%.