Aim-listed Sovereign Metals has reported that further testwork completed on graphite from its Kasiya rutile/graphite project, in Malawi, has confirmed that the graphite has the key characteristics required for use in expandable – fire retardant – and expanded – gaskets, seals and brake lining – applications.

The comprehensive testwork programmes were completed by ProGraphite and Dorfner Anzaplan in Germany.

Sovereign says the tests confirm that Kasiya’s medium to coarse flake material achieved high expansion ratios using standard reagents at room temperature and short durations, providing a competitive advantage over other current and potential sources of graphite supply.

"Our continuous graphite downstream application testing has shown that the high-quality Kasiya concentrate is suitable for the three key natural graphite markets: the high-growth anode materials for graphite fines; the stable and large refractory materials market for coarse flake; and the growing expandable and expanded graphite markets for medium to coarse flake.

“These results, along with our industry-low cost position, offer Kasiya the potential to become the world's dominant natural graphite supplier, while remaining a primary rutile project,” says MD and CEO Frank Eagar.

The company explains that a key use for expandable graphite is as a flame retardant. Growth for expandable graphite flame retardants is driven by environmental and health concerns related to the use of halogen-based flame retardants, which include brominated and chlorinated flame retardants.

In this application, the natural graphite is pre-treated with acid and an oxidiser, but not expanded through heat treatment. When exposed to a fire, the expandable graphite swells, forming a protective layer that slows down the fire.

Expandable graphite represents a low-cost, good flame retardancy and low-smoke solution, typically as a filler in polyurethane foams. Flame retardant applications for expandable graphite include the construction, chemicals and textiles industries, Sovereign says.

Expanded graphite, meanwhile, is used in gaskets, seals, brake linings, bi-polar plates for fuel cells and thermal management in electronic devices, where the inherent properties of graphite are combined with the flexibility of expanded graphite.