Graphite Purity - A Critical Factor in the Manufacturing of Batteries and Fuel Cells
graphite purity is a critical factor in the manufacturing of batteries, fuel cells and nuclear power. With the growth of clean and green technologies, graphite has become a strategic mineral in many countries. Currently, the global graphite supply chain is heavily reliant on China and Brazil.
Unlike diamond, which is a single crystalline form of carbon, graphite is a loosely stacked one-atom thick layer of carbon with the ability to slide around due to its delocalized electrons. This makes it an excellent electrical conductor and lubricant as well as being highly resistant to thermal shock.
Purity is measured by the fixed carbon content of graphite, which can be categorized into high-purity (o(C)>=99.9%), medium-purity (o(C)
As a result, the production of graphite for nuclear applications must be carried out with strict impurity controls. Ash content and boron equivalence are regulated to ensure that the finished product has the lowest possible level of these impurities.
Nuclear graphite is produced from needle coke that has been subjected to a long series of calcining treatments. The process reduces the ash content and boron equivalence of the raw material, making it more isotropic, while keeping its strength and density intact. Afterwards, the material is graphitized to remove impurities and produce high-purity, amorphous, or crystalline, natural flake graphite. This is the graphite that is most often used in the manufacture of lithium-ion batteries and fuel cells.
