Breakthrough in rare earths processing technology

Australian rare earths company Arafura Resources has successfully completed the hydrochloric acid regeneration program, a key part of its wider, previously reported technology program. The process involves taking calcium chloride residues from the phosphate circuit and re-acting them with sulphuric acid to produce re-useable hydrochloric acid, a key raw material in Arafura’s pre-leach circuit, and calcium sulphate (gypsum), a potential saleable product into various end applications. This reduces Arafura’s dependence on external hydrochloric acid sources.AMMTEC successfully operated the demonstration plant on a continuous basis at its facility in Perth, Western Australia, with involvement from experts from the University of Montreal, Canada, and Arafura’s Technology team.

The demonstration facility has successfully achieved:

  • Production of 32% hydrochloric acid from a simulated recycle stream similar to the phosphate circuit waste liquors, with a recycle efficiency of at least 97.5%
  • Production of crystalline gypsum with filtration characteristics suitable for processing via commercially available filters
  • Production of Dihydrate gypsum. Feedback from one major gypsum user indicates that this material has potential for future commercial use
  • Provision of detailed design and operating data for the Bankable Feasibility Study.

Arafura’s Managing Director and CEO, Dr Steve Ward: “The successful completion of this demonstration program highlights Arafura’s commitment to the Nolans project and its efforts to de-risk key technological aspects. This is important for potential financiers and provides valuable technical and operating experience for Arafura. The logistical and economic benefits of hydrochloric acid regeneration and gypsum production will now be incorporated into the BFS. Engineering design is now underway for the overall flowsheet, and customers are being further engaged for evaluation of the gypsum product for potential offtake.”

The Nolans project comprises operations at two sites within Australia: the Nolans Bore mine in the Northern Territory; and the Whyalla Rare Earths complex in South Australia. The project is underpinned by a world-class rare earths deposit which has sufficient resources to support mining and chemical processing operations for at least 20 years. Annual production of 20,000 t of rare earth oxides from Whyalla, equivalent to about 10% of the world’s supply, is on schedule to commence in 2013.