Graphite foam flotation process design

Natural graphite is further divided into three main types, crystalline flake graphite (or flake graphite), crystalline vein or block graphite, and amorphous graphite (very fine flake graphite), which have different physical properties, appearance, Chemical composition and impurities. At present, flake graphite is the most common form of graphite, and its market share ranks first in the world. It also has future demand for technologies such as lithium-ion batteries, fuel cells, electronics, graphene and other structural materials

Graphite is the first ore concentrated from crushed bodies through froth flotation. The prerequisite for froth flotation is to crush and grind the graphite rock. The froth flotation process is used to selectively separate hydrophobic and hydrophilic minerals in aqueous suspensions. The surface of graphitic carbon particles is water-resistant, making them ideal for flotation in water with selective conditioning agents. Hydrophobic graphite particles connected to the bubbles in the suspension move to the foam layer on top of the fluid and separate from the hydrophilic particles.

Flotation process design varies in complexity, depending on the degree of freeness and preferred purity of the product. Typically, however, it consists of several rougher/fine flotation steps and intermediate regrinding steps. Usually, flake graphite ore is purified through multi-stage grinding-flotation steps. This process can prevent the graphite flakes from being destroyed during the regrinding process and producing a large amount of medium slag. In a typical graphite beneficiation process, the treatment methods for graphite slag include centralized return, gradual return, and separate process technology. A moderate return that is known to be concentrated can simplify the entire process. However, when the amount of midmine is large or the properties of midmine are greatly different, it will have a negative impact on flotation. Step-by-step return is suitable for improving the recovery rate of graphite ore with poor floatability.

Flotation affects the chemical properties of mineral surface chemistry. However, the purity of discrete graphite particles usually does not change. The symbiotic residual impurities in the graphite are then removed chemically or thermally to obtain a high quality grade. In addition to their natural floatability, the introduction of reagents such as kerosene and pine oil can facilitate the separation of mica, quartz, feldspar and carbonate gangue. Additionally, selectivity can be improved by adding a pH adjuster (caustic soda) in the range 7.7–8.5. Flotation has been labeled as a separate operation for the recovery and purification of sulfide ores. During downstream processing, small changes in the chemical and physical properties of the ore during comminution can have a significant impact on mineral recovery.