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

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.

KEYWORDS:

• Split flotation
• direct flotation
• multistage grinding
• rod mill
• ball mill

Disclosure statement

No potential conflict of interest was reported by the author(s).

Novelty

Low grade calcareous graphite ore is upgraded to high grade graphite by introduction of split flotation concept after the first cleaner flotation compared to direct flotation.