Battery graphite depends on one of industry's most dangerous acids. A plant in Australia has just done without it

Renascor reached 99.97% carbon in spherical graphite at its Adelaide demonstration plant without using hydrofluoric acid. The lesson goes beyond chemistry: it shows how a process route can become a competitive advantage outside China.

Renascor Resources, owner of the Siviour graphite deposit on the Eyre Peninsula in South Australia, announced on 7 October 2026 that its demonstration plant in Adelaide had produced purified spherical graphite at 99.97% carbon — battery-grade purity. The tests were run in batches of about five days, using graphite bought from third parties, with samples collected at every stage of the circuit. The route does not use hydrofluoric acid: it combines sulphuric acid leaching with a low-temperature caustic roast. According to managing director David Christensen, the process has moved beyond laboratory validation and has been confirmed at demonstration scale. In July, a company cost study had estimated the operating cost of purification at approximately US$459 per tonne (2026 dollars): US$121 for reagents, US$115 for energy, US$79 for labour, US$74 for maintenance and US$70 for other items. The next steps are batches using graphite from the Siviour project itself later this quarter and then continuous multi-tonne runs, with recycled reagents and water, to validate the design of the commercial plant. The project has Australian federal support, including a 5 million grant and a loan conditionally approved by the Critical Minerals Facility.

The graphite that leaves the mine does not go straight into the battery. Flake concentrate is milled and rounded into small spheres — a shape that improves packing in the anode — and must then be purified to almost pure carbon. That last step is where the problem lies. The most widespread route uses hydrofluoric acid, one of the few reagents able to efficiently dissolve the silicate impurities trapped in graphite. It works, but it charges a high price in another currency: HF is extremely toxic, corrodes glass and metal, demands strict safety protocols and produces fluorine-bearing effluents that need dedicated treatment. The thermal alternative, which vaporises impurities in very high-temperature furnaces, swaps chemical risk for heavy energy consumption. Renascor bet on a third path, closer to classical hydrometallurgy: attack the impurities with alkali and sulphuric acid, common and manageable reagents, and close the loop by recycling reagents and water. The cost data helps read the bet. Reagents and energy add up to just over half of the US$459 per tonne — precisely the lines that recycling and low temperature try to shrink. And there is a cost that does not appear in the conventional route's spreadsheet but weighs on the investment decision: environmental permitting, insurance and compliance for a plant that stores HF. In a country with demanding environmental rules, eliminating that reagent may be worth more than a few dollars per tonne. The second lesson is about method. The company did not jump from the laboratory to the commercial plant. It first validated with third-party graphite, a feed with known characteristics, and only afterwards will it test its own ore — separating process risk from deposit risk. That is how engineering uncertainty is reduced before asking financiers for hundreds of millions. For those working in mineral processing, the case is a reminder that choosing the process route is a strategic decision, not just a technical one: it defines cost, permitting risk and even who agrees to buy the product.

Global battery demand exceeded 1.5 TWh in 2025, and the International Energy Agency notes that virtually all recent growth in refined graphite supply has come from China. Anode manufacturers outside China are looking for qualified suppliers, and qualification takes time — samples, cell tests, audits. A safer, cost-competitive purification route can shorten the path for graphite projects in countries with high environmental standards, including Brazil, which holds significant reserves of the mineral. For process engineers and metallurgists, graphite purification is an emerging specialty, still with few experienced professionals outside Asia.