A new method of extracting nickel from Australia’s low-grade laterite reserves could make millions of tonnes of untapped nickel laterites economically viable.

Around 70% of the world’s nickel reserves are found in the form of laterites, which are soils rich in mineral ores. Many of these reserves remain untapped due to the complexities of extraction from laterites. Australia has abundant nickel laterite reserves, but until now extraction of nickel from these laterites has been challenging and expensive, resulting in the generation of large amounts of waste chemicals. Traditional techniques for the processing of nickel laterite use large quantities of sulphuric acid at high temperatures and pressures, resulting in expensive waste treatment and disposal of the chemicals used in the extraction process.

Nickel laterites are becoming a priority for mining companies as traditional nickel sulphide reserves are depleted. In 2010, global nickel production from laterites exceeded nickel sulphide-based production for the first time.

In collaboration with Direct Nickel, a Sydney-based SME, CSIRO is testing a new extraction process that could make millions of tonnes of untapped nickel laterite reserves economically viable. Direct Nickel has developed a more cost-effective and efficient way to extract nickel from laterites using small amounts of nitric acid. About 95% of the nitric acid can be recycled and reused as a processing reagent, which vastly reduces the amount of waste produced and avoids the costly neutralisation and disposal of used acid.

With only a few kilograms of nitric acid used per ton of laterite, compared with at least half a ton of sulphuric acid per ton of laterite, this new method offers a more environmentally sustainable and cost-effective processing option. To facilitate the transition from laboratory-scale to industrial-scale mineral processing CSIRO invested in a pilot plant at its Waterford site in Perth, for large-scale testing of the new method. The new process has been successfully demonstrated at pilot scale.

Direct Nickel has signed an agreement with Indonesian mining company, PT ANTAM, to co-operate in the development of nickel laterite deposits and processing plants in Indonesia. The agreement promises to significantly improve the efficiency and economics of nickel laterite processing and unlock the world’s nickel laterite supply.