Graphite Ore Processing: A Guide to Beneficiation and Purification

 Graphite, a vital non-metallic material used in lubricants, batteries, casting, and more, often contains impurities like quartz, sericite, and pyrite in raw ore. Beneficiation and purification are thus necessary for its application. Below is a concise overview of core processing technologies.

Beneficiation Technologies for Graphite Ore

Beneficiation enriches graphite from raw ore, preparing it for further refinement.

Flotation Method

Leveraging graphite’s natural floatability and hydrophobicity, reagents (coal tar as collector, pine oil/butyl ether oil as frother) concentrate graphite at the gas-liquid interface. For flaky graphite, multi-stage grinding and reprocessing protect its structure. It boosts grade with low costs but struggles with ultra-fine impurities, requiring post-treatment.

Gravity Separation Method

Relies on density differences between graphite and gangue. By removing heavy minerals (e.g., pyrite), it obtains graphite-dominated rough concentrates.

Electrostatic Separation Method

Uses conductivity contrasts—graphite conducts well, while gangue (feldspar, quartz) does not—for separation. Wet high-gradient equipment handles micron-sized particles.

Selective Flocculation Method

Adds polymeric flocculants (e.g., sodium silicate) to multi-component suspensions, forming targeted flocs to separate impurities. It has simple equipment and low costs but low fixed carbon recovery.

Purification Technologies for Graphite Concentrates

Purification enhances concentrate purity for high-end use.

Alkali-Acid Method

Combines alkali fusion (high-temperature molten alkali reacts with acidic impurities to form removable soluble salts) and acid leaching (acids dissolve metal oxides). It raises grade with simple equipment but causes equipment corrosion, wastewater pollution, and graphite loss.

Acid Leaching Method

Used with other processes, strong acids dissolve metal oxide impurities to improve purity.

Chlorination Roasting Method

In a controlled atmosphere, reducing agents and high-temperature roasting make metals combine with chlorine into volatile chlorides for separation. It is efficient and low-cost but uses toxic, corrosive chlorine.

High-Temperature Roasting Method

Uses graphite’s high melting point—heating ore to high temperatures vaporizes impurities, yielding ultra-high-purity graphite. It produces high-grade graphite but has high energy consumption and strict equipment/raw ore requirements.