Graphite beneficiation processing technology

 Graphite products are divided into two categories: flake graphite and microcrystalline graphite: flake graphite refers to natural crystalline graphite, which is shaped like fish scales and is a product obtained by processing, beneficiation, and purification of crystalline graphite ore; microcrystalline graphite was once called earthy graphite or amorphous graphite, which refers to a dense aggregate composed of tiny natural graphite crystals, and is a product obtained by processing, beneficiation, and purification of cryptocrystalline graphite ore.

01  Ore dressing and processing method of crystalline graphite

Crystalline graphite has good natural floatability, and flotation is basically used for beneficiation in China. Since the size of graphite flakes is one of its most important quality indicators, multi-stage grinding and multiple beneficiation processes are used in the beneficiation method to select large flake graphite as soon as possible. Commonly used collectors for flotation are kerosene, diesel, etc., foaming agents are No. 2 oil, No. 4 oil, etc., adjusters are lime and sodium carbonate, and inhibitors are water glass.

Crystalline graphite beneficiation process

Since the hardness of graphite ore is generally medium-hard or medium-hard and soft, and the grade is generally between 2% and 10%, the crushing process is relatively simple, and three-stage open circuit, two-stage open circuit or one-stage crushing process is often used. The flotation process is generally a closed-circuit process with multi-stage grinding, multi-stage sorting, and sequential (or concentrated) return of intermediate ore. There are three forms of multi-stage processes, namely, concentrate regrinding, intermediate regrinding and tailings regrinding. Crystalline graphite mostly adopts the concentrate regrinding process. Under normal circumstances, the recovery rate of the beneficiation operation can reach about 80%.

02  Cryptocrystalline graphite beneficiation processing method

Crystalline graphite crystals are extremely small, so it is also called microcrystalline graphite. Graphite particles are often embedded in clay and are difficult to separate. Due to the high grade of the original ore (generally containing 60% to 80% carbon), many graphite mines directly crush the mined ore and sell graphite powder products.

03  Graphite Grade

Graphite is divided into high-purity graphite, high-carbon graphite, medium-carbon graphite and low-carbon graphite according to its fixed carbon content. Among them:

High-purity graphite: fixed carbon ≥99.9%;

High-carbon graphite: 94.0%≤fixed carbon<99.9%;

Medium-carbon graphite: 80.0%≤fixed carbon<94.0%;

Low-carbon graphite: 50.0%≤fixed carbon<80.0%.

At present, high-grade high-carbon graphite can be obtained through flotation process. Compared with microcrystalline graphite, flake graphite products are easier to reach high-carbon graphite grade. Taking the African graphite ore shipped by our company as an example, through systematic and comprehensive experimental research, the fixed carbon grade of graphite concentrate is higher than 95%, and the recovery rate reaches more than 92%, achieving better experimental indicators.