Reduction of Silica content in a Limestone sample from Rajpipla, Narmada Project

Abstract

A sample of low grade limestone from Rajpipla, Narmada Project assaying CaO 36.14%, CO2 31.52%, MgO 3.20%, SiO2 17.12%, Al2O3 7.31% and Fe2O3 2.99% was received for beneficiation studies. The main object of the status was to produce a concentrate suitable for cement manufacture. The gangue minerals in the sample consisted mainly of quartz, feldspar and micas and were very finely disseminated in the crypto-crystalline fine grained compact carbonates; this necessitated extremely fin grinding for getting a good grade of concentrate by froth flotation. Flotation studies indicated that the low grade limestone could be upgrade after fine grinding and flotation employing Oleic acid (0.9 Kg/ton) as collector for carbonates. The weight percent of the concentrate was 59.5% for a grade assaying 12.33% insolubles. If higher insolubles can be tolerated in the concentrate for use in cement manufacture, the yield figures could be much higher as indicated by the flotation experiments.