Grinding tech may lower Elk Creek costs
Testing shows impressive energy reductions for niobium mine Metal Tech News – August 11, 2021
Last updated 8/17/2021 at 3:02pm
NioCorp Developments Ltd. says testing has confirmed that high-pressure grinding rolls technology is an energy-efficient and low-emission alternative for reducing the size of ore to recover the niobium, scandium, titanium, and potentially rare earths at its Elk Creek project in Nebraska.
Under the mine plan laid out in a feasibility study, Elk Creek would produce 7,220 metric tons of ferroniobium, 95 metric tons of scandium trioxide, and 11,642 metric tons of titanium dioxide annually for 36 years.
This mine plan is based on 36.3 million metric tons of probable reserve averaging 0.81% niobium oxide, 2.86% titanium dioxide, and 65.7 g/t scandium.
Working in partnership with Weir Minerals, the Natural Resources Research Institute at the University of Minnesota-Duluth reduced roughly one metric ton of Elk Creek drill core to the one-millimeter size needed for hydrometallurgical testing.
This initial round of testing found that high-pressure grinding rolls technology could reduce the specific energy per metric ton of Elk Creek ore processed from the previously estimated 4.18 kilowatt-hour to 3.06 kWh. This represents a 32.5% decrease in the amount of installed power needed for processing, when compared to the previous design.
"The results of this testing were very impressive," said NioCorp Developments COO Scott Honan. "This program confirmed that our ore is amenable to HPGR technology, and we are pleased to see the reduction in energy consumption."
In addition to the niobium, scandium, and titanium, the Elk Creek deposit hosts appreciable quantities of rare earths, and NioCorp has recently embarked on testing to evaluate the viability of also recovering this suite of technology elements.
"We think this is logical, given that we are putting a significant quantity of rare earths into solution at zero additional cost to our current mining and processing plans," said NioCorp Developments Executive Chairman Mark Smith.
This work is being carried out alongside the company's investigation into carbonation as a potential alternative metallurgical process for the extraction of niobium from ore at Elk Creek.
Carbonation is a relatively clean, environmentally friendly, and sustainable hydrometallurgical process that can potentially be employed to use and recycle carbon dioxide to extract niobium and other elements in a manner similar to extractions with acids.
Honan said, "The idea is that you can use carbon dioxide to leach things like niobium out of rock."
Initial tests of carbonization showed promise for recovering niobium and Honan said larger-scale testing of this process would include the evaluation of extracting the rare earths that are present alongside the niobium, titanium, and scandium at Elk Creek.
NioCorp says the Natural Resources Research Institute is currently completing a second phase of testing on three metric tons of crushed material suitable for the larger hydrometallurgical testing.
"We look forward to announcing the results of the follow-on work that the material produced at NRRI will facilitate," said Honan.
Recent testing by lithium-ion battery co-inventor Stanley Whittingham shows that niobium added to the cathode could significantly decrease degradation of lithium-ion batteries. More information can be found at Niobium boosts lithium battery potential in the current edition of Metal Tech News.