Metallica completes SCONI pilot testwork

THE BOURSE WHISPERER: Metallica Minerals (ASX:MLM) has successfully completed the second phase of the company’s pilot metallurgical test program on representative SCONI (scandium-cobalt-nickel) oretypes.

Metallica completed the first phase of the metallurgical testwork earlier this year in two separate steps.

The first step involved the leaching of metals into a pregnant leach solution (PLS) through a High Pressure Acid Leach (HPAL) pilot plant at SGS Lakefield Oretest (SGSLO) in Perth, Western Australia.

The second step used a purpose built, solvent extraction plant at HRL Testing in Brisbane, Queensland to recover scandium from the PLS and subsequently refine the scandium into high-purity (greater than 99.9 per cent) scandium oxide.

The company announced the success of this phase in July.

The recent phase of testwork required Metallica to transport the solvent extraction pilot plant to Perth to be integrated with the HPAL pilot plant.

The fully integrated closed circuit pilot plant operated continuously for eight days, during which time Metallica said it was successful in demonstrating the efficacy of the process.

The company identified this as being crucial in proving the flowsheet it had selected for the SCONI project and for obtaining detailed data it will used in the design of the processing plant in a Definitive Feasibility Study.

A blended bulk sample of representative moderate grade nickel/cobalt/scandium oretypes from the SCONI Greenvale, Lucknow and Kokomo nickel-copper and scandium deposits was processed through the pressure leach autoclave at 265ºC for a continuous eight-day period.

Approximately 2,800 kilograms of typical SCONI ore blend at an average feed grade of 1.2 per cent nickel, 0.08 per cent cobalt, and 103 grams per tonne scandia was leached during the campaign and high average metal extractions were achieved: of greater than 95 per cent nickel and cobalt; and greater than 85 per cent scandium.


Sc-Co-Ni metal extraction (LHS) and acid consumption (RHS). Source: Company announcement


The average iron, magnesium and aluminium content of the samples were 25 per cent, 4.3 per cent, 3.9 per cent respectively and presented no significant issues in the continuous pilot testwork.

The acid consumption was also modest, averaging around 400 kg/tonne.

The high pressure acid leach (HPAL) was integrated with a purpose built solvent extraction circuit to recover scandium from the pregnant leach solution (PLS).

In excess of 96 per cent of the dissolved scandium was recovered into a crude hydroxide intermediate, which will be further refined to pure scandium oxide in Brisbane.

“These results, in conjunction with those previously reported from our earlier pilot program, demonstrate the robustness of the selected process to achieve high scandium, nickel and cobalt extraction and recovery from a range of SCONI oretypes,” Metallica Metals chief executive officer Gavin Becker said in the company’s announcement to the Australian Securities Exchange.

“This testwork has provided the SCONI project process design criteria and is a crucial foundation for the Definitive Feasibility Study of the proposed full scale operation at Greenvale.

“Having the majority of the metallurgical testwork successfully completed with consistently positive results is a major step towards our aim of becoming a significant producer of nickel and the world’s first long-term reliable scandium producer.”