Beneficiation of Limestone from Toli Village, Garhwal Dist. U.P.

A low grade limestone sample from Toli village, Garhwal District, U.P., received for beneficiation tests assayed 35.4% CaO, 31.8% SiO2, 1.1% MgO, 2.05% Fe2O3 and 1.16% Al2O3. Quartz which was the principal gangue in the sample was liberated at -150 mesh. Optimum conditions for flotation of limestone were determined for production of a concentrate suitable for cement manufacture. Flotation employing 1.0lb/ton of sodium silicate, 1.5lb/ton of Oleic acid and 0.1 lb/ton of pine oil produced a concentrate assaying 47.15% CaO with a recovery of 96.5% Cleaning of the primary floats improved the grades to 49.2% and 51.4% CaO with recoveries of 92.5% and 80.5% respectively.