Overview of flotation studies on low grade limestone for sustainable industrial potentiality: A case study

In the present investigation, we used low-grade limestone from the Joldhal region of the Shimoga schist belt in Karnataka to upgrade the CaO and minimize the gangue components for its effective industrial utilization. These samples, having SiO2-10.40%, 42.50% CaO, and 5.20% Al2O3. We used D-12 Denver laboratory flotation equipment for this study. In optimization studies, we used variables 0.8, 1.0, and 1.2 kg/t collector [sodium oleate] dosage and 0.5, 0.6 and 0.7 kg/t depressants [sodium silicate]. In the detailed experimental studies, we used an optimum dosage of 1.2 kg/t collector and 0.7 kg/t depressants. Froth concentrate was collected in cumulative flotation time frames of 15, 30, and 60 seconds, remaining considered as tailings. The collected product and tailings were filtered, dried, and weighed, and the obtained assays were analyzed. It was observed that the optimum result was achieved in a -200# size class with a CaO percentage increase from 42.50% to 52.83% and silica reduction from 10.50% to 2.01% in 15-second products. For the obtained test results, product performance computations such as weight percentage recovery, CaO grade recovery, grade ratio concentration, and weight distribution ratio were performed. When processing this sample, direct flotation proved to be a more effective treatment. The obtained concentrate can be directly utilized in the cement, iron, and steel industries. The results of this study will probably extend the life of raw material resources for future requirements, which will have vital implications for rapidly expanding industries.