Platina Resources Ltd (ASX:PGM) (OTCMKTS:PTNUF) (FRA:P4R) will advance its trial of vat leaching for scandium extraction at its namesake project in NSW after initial tests highlighted its potential as a cheaper alternative to high-pressure acid leaching (HPAL).
A second phase of test work for the Platina Scandium Project (PSP) is planned to confirm these preliminary results and to obtain leach solutions for further processing.
These tests will determine whether scandium can be recovered using a solvent extraction process similar to that in use at titanium dioxide pigment plants to recover scandium from spent acid.
This will provide data to enable an initial economic evaluation of the process to determine its viability.
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Traditionally used for oxide gold and copper ores and sometimes nickel laterite ores, vat leaching of PSP ore produced encouraging results towards a proof of concept and delivering a smaller, lower-cost project better aligned to the low volumes of scandium in the current market.
While conventional HPAL may recover more metal, the technology is more complex, larger scale and requires considerably more capital than vat leaching.
Assessing process plant
Platina has also been assessing the technical and economic viability of developing a battery materials processing plant that would produce nickel, cobalt, high purity alumina (HPA) and scandium from ores sourced throughout the Australia/Pacific region and blended with PSP ore.
Platina managing director Corey Nolan said the establishment of a cheaper, western world supply source of scandium would support the company’s international campaign to secure production offtake agreements and enable project financing.
“We have been targeting potential customers in the US, Europe, Asia and Australia but the key to unlocking a deal is lower prices for scandium oxide that can compete with other aluminium alloys in the market.
“As such, Platina has been assessing a number of smaller-scale development options to the HPAL process that formed the basis of our 2018 definitive feasibility study whilst assessing different processing options for the ability to scale-up production should demand increase."
Vat leaching trial
Initial agglomeration tests of PSP ore were carried out in bottle rolls to establish the right measure of acid, chemical binder and water relative to the dry ore sample to create suitable characteristics for vat leaching.
Scandium extraction was 22% after 31 days, with acid consumption of just over 100 kilograms acid per tonne of ore. Based on the linear leaching rate, 50% scandium extraction could be achieved in about 24 weeks.
Similarly, acid consumption is linear after the initial few days of leaching and the calculated acid consumption for 50% scandium extraction is 477 kilograms per tonne of ore. A counter-current vat leaching arrangement would lower the acid consumption.
This concept involved designing the plant size to minimise capital expenditure and generate an attractive economic return for investors.
The smaller plant size would also reduce technical and financial risks compared to large scale HPAL projects.
Initial modelling of the process option based on published information and historical test work showed that a processing operation based on a blend of 90% imported limonite rich nickel/cobalt laterite ore and 10% scandium-rich PSP ore at around 250 t/d could be feasible.
This operation is based on using novel leach and recovery technologies from Australian suppliers. The potential products that could be produced include nickel/cobalt mixed hydroxide, scandium oxide and HPA.
Sources of the imported high-grade nickel/cobalt laterite ores have been identified. State Development Areas on the eastern seaboard with suitable shipping logistics and access to power and natural gas are being reviewed.
Platina has started a process of seeking potential development partners for the concept, including working with Traxys.