Improvements to a new more energy-efficient vanadium process will enable an Australian resource company to diversify and market three products instead of one, while significantly reducing costs at a proposed new mining development. LOUIS WHITE reports
Vanadium, a malleable transition metal predominantly used for steel alloys, is gaining traction for its potential use in the battery market.
Australia is home to world-class vanadium deposits, and TNG, a local strategic metals developer, is gearing itself up to lead the charge globally.
Over the past few years, TNG has been developing its Mount Peake vanadium asset – a titano-magnetite deposit – in the Northern Territory, with the aim of turning it into a productive new mine with a 17-year lifespan.
Having developed a new, patented vanadium recovery process, TNG approached CSIRO to test the process at pilot scale and explore further improvements that could be made.
The TIVAN process promised to be less energy and capital-intensive than conventional processes for titano-magnetite deposits.
Diversifying to reduce financial risks
"The market price for vanadium is relatively volatile and the financial risks of a titano-magnetite deposit are higher when based solely on this commodity," CSIRO hydrometallurgical expert, Ron Pleysier, says.
"Because titano-magnetite deposits are also rich in titanium and iron, we looked at ways to capture these additional minerals using the new TIVAN process, in a way that made economic sense."
Working with TNG and Mineral Engineering Technical Services (METS), CSIRO developed an additional treatment stage to remove the bulk of the iron as a by-product prior to leaching.
Adding a step to remove iron significantly reduces reagent consumption, resulting in substantial savings on capital and operating expenditure.
Reducing the iron content means that vanadium can be recovered directly from the leach solution, and expensive solvent extraction – which is used to separate vanadium from the iron – is no longer required.
"We built and operated a pilot plant at CSIRO's Perth-based facilities, incorporating the additional iron removal stage, to prove the concept and identify further potential refinements," Mr Pleysier says.
Capturing titanium and iron as additional products
The CSIRO team then turned their attention to the TIVAN leach residue.
"We showed that once the vanadium has been extracted, it was possible to produce a titanium dioxide concentrate at 65 per cent purity," Mr Pleysier says.
"Conventional pigment technology could then be used on the concentrate to recover titanium dioxide at greater than 90 per cent (TiO2) purity."
TNG is now looking to enter the titanium pigment market to increase revenue from the mine. Titanium pigment currently sells for approximately US$3000 per tonne.
Overall, the potential to capture two additional saleable products – titanium and iron – has helped to minimise the associated financial risks of the mine plan and increase its net present value.
In-principal approval for a new mining development
Recently, TNG received in-principal approval for a Native Title Mining Agreement that brings the company a promising step closer to developing the Mount Peake mine.
The proposed plan is to establish a three-million-tonne concentrator onsite at the Mount Peake mine and link it by rail to an advanced TIVAN hydrometallurgical metal refinery in Darwin.
Mr Pleysier says that collaboration with TNG, METS, SMS Siemag and other industry experts from the vanadium and titanium pigment industries was key to the successful development and refinement of the TIVAN process.
But CSIRO's work hasn't stopped there, with the organisation already expanding its horizons across the industry.
"CSIRO already works with the broader vanadium industry to evaluate titano-magnetite deposits by hydrometallurgical routes and the more traditional salt roasting techniques," Mr Pleysier says.
Many companies, and ultimately end users, will benefit from this work into the future.