Development of process flow scheme on a low-grade calcareous graphite ore by split flotation technique

Abstract

ABSTRACT The low-grade calcareous graphite ore contains 14.5% Fixed Carbon (FC), 71.82% ash, and 13.68% volatile matter plus moisture content. The primary liberation size, 210 µm was determined by the mesh of grind. In order to upgrade the ore, the sample was ground wet in a rod mill to obtain a coarse product of 210 µm size. It is further subjected to rougher flotation followed by one-stage cleaning of rougher float to reject the maximum amount of gangue minerals with a minimum amount of graphite losses at this size range. The first stage cleaner float was sieved over 150 µm size to separate +150 and −150 µm size fractions. These size fractions were subjected to grinding for further liberation of graphite values and thereby subjected to multistage cleaning separately to produce high-grade graphite concentrates. Three-stage grinding, and multistage cleanings were involved in the split flotation process to produce a high-grade flake and fine graphite concentrate. The combined graphite concentrate produced using the split flotation technique was 85.56% FC with a weight yield of 13.0% & recovery of 76.6%, comparatively more than 80.68% FC with a weight yield of 12.4% & recovery of 68.8% in the direct flotation technique results.