Effect of grinding on beneficiation of a low grade limestone sample

Abstract

Beneficiation studies were conducted on a low grade limestone sample from Gola area. Hazaribagh District, Bihar. The sample assayed 42'()'1;. CaO. 4,()% MgO, 2.66 % AIP" 3.20% FeO and 21.38% insoluble. Mineralogical studies indicate that the sample was fine grained variety of limestone containing calcite as the chief mineral with quartz as the principal gangue. The calcite being intimately associated with quartz. it is necessary to have fine grinding of the sample in order to have fine liberation for high concentration. The object of the studies was to optimise the grind condition and to develop a process to produce a concentrate with 54% CaO and <2.0% insoluble. Detailed flotation studies were conducted on the sample using anionic collector. Grind variation studies were conducted to fix the optimum grind of the sample for notation. The optimum grind was found to be 60%-74. Flotation studies were conducted with the sample ground to different fineness. The results indicated that at optimum grind, a rougher concentrate weighing 67% and assaying 51.5% CaO and 5.7% insoluble with a recovery of 82.3% CaO could be obtained. The grade of cleaner concentrate varied from 53.8% CaO and 2.4% insoluble to 54.0% CaO and 1.8% insoluble with the variation of number of cleaning from one to three.