MINERAL PROCESSING
Graphite processing: flotation, purity and flake preservation
Graphite processing upgrades graphitic ore into a saleable concentrate. For natural flake graphite, the challenge is to increase carbon content without destroying crystals that may support higher-value products. The flowsheet must respond to mineralogy, rock texture and target markets.
A typical natural graphite route
After ore preparation, liberation commonly combines crushing or scrubbing, staged grinding and flotation. Graphite’s naturally hydrophobic surface attaches to bubbles and separates from gangue. Controlled regrinding between stages helps release locked particles while limiting unnecessary size reduction.
Saprolitic ores may require less crushing energy than fresh rock, but clay and fines can affect handling and flotation. Representative tests are essential for energy, water, reagent consumption, recovery and final quality.
- Preparation, scrubbing and classification
- Staged grinding to preserve flakes
- Rougher flotation, cleaning and controlled regrinding
- Thickening, filtration, drying and concentrate sizing
Value-defining indicators
Feed grade alone does not determine economics. Recovery measures how much carbon reaches concentrate; purity and impurities determine addressable markets; size distribution shapes the product basket; and mass yield affects costs and tailings. Bench and pilot testing must balance these indicators.
Higher-specification applications require further assessment of ash, sulphur, trace elements, morphology and purification response. A consistent concentrate can then move to customers or downstream routes such as purified spherical graphite.
Itabela’s future metallurgical programme
Metallurgy remains a future step at Itabela. MNS must first confirm grades and continuity through assays and drilling. Representative samples can then test liberation, recovery, purity and flake preservation, allowing a project-specific flowsheet and product basket to be defined.
FAQ
Frequently asked questions
What is graphite flotation?
A physical-chemical separation process that uses graphite’s natural hydrophobicity to recover it with bubbles from a mineral slurry.
Why preserve flake size?
Larger fractions can serve premium applications if purity, recovery and other specifications are also achieved.
Has Itabela completed metallurgical tests?
The programme schedules characterisation and testing after targets and grades are confirmed by assays and drilling.