NioCorp eyes new niobium extraction tech
Testing the use of CO2 to leach superalloy metal from ore Metal Tech News – September 30, 2020
Last updated 9/29/2020 at 9:25pm
NioCorp Developments Ltd. Sept. 9 announced progress on a new and more environmentally friendly process for extracting niobium from its Elk Creek superalloys material project in Nebraska.
A series of metallurgical tests carried out by Utah-based L3 Process Development has established carbonation as a potential alternative metallurgical process for the extraction of niobium from ore that NioCorp expects to mine 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 from ore in a manner similar to extractions with acids such as hydrochloric or sulfuric acid.
"The idea is that you can use carbon dioxide to leach things like niobium out of rock," said NioCorp Developments COO Scott Honan.
During initial small-scale testing conducted by L3 on mineralized samples from Elk Creek, it was established that a single pass of carbonation leaching could extract 11 to 26% niobium present in the ore. Multiple passes of carbonation leaching could potentially achieve a cumulatively higher extraction of niobium.
"We are very pleased with the research and development work that L3 has completed in employing a different type of process to extract niobium from Elk Creek ore," said Honan. "Not only was L3 able to complete this work timely and in a very cost-effective manner, but the results point to the potential of this process to extract niobium without also extracting titanium. Achieving a separation between these two elements at the extraction stage has the potential to save capital and operating costs in downstream operations."
The material used for carbonization testing are the same samples that were used for metallurgical testing to support a 2019 feasibility study for developing a mine at Elk Creek.
Under the mine plan laid out in the 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 per year over a 36-year mine life.
All three of the superalloy metals are considered critical to the economic wellbeing and national security of the United States.
• Niobium is an important ingredient in high strength, low-alloy steel that is increasingly used in bridges and other large infrastructure projects, as well as in high pressure oil and gas pipelines, steel-chassis vehicles, aerospace, and defense systems. Niobium also is a component of superalloys used in nearly all jet engines and power generation turbines. Superconducting magnets made from niobium-germanium, niobium-tin and niobium-titanium alloys are used in a range of important devices, from imaging equipment to particle accelerators.
• Scandium has important uses in environmentally preferred solid oxide fuel cells, as well as in ultra-high-performance aluminum alloys. Scandium greatly strengthens aluminum alloys and allows them to be reliably welded, which presents revolutionary potential for the commercial airline industry.
• Titanium has the highest strength-to-density ratio of any metallic element, and it is used in a wide variety of sectors, including aerospace, national defense, chemical processing, desalination, automotive, health care, communications, sporting goods, and many others. Most titanium, however, is used in its oxide form as a pigment that imparts stark whiteness to a wide range of product such as paints, paper, plastic, sunscreen, toothpaste, and wallboard.
NioCorp said the carbonization leaching process for niobium has the potential to lower up-front capital and operating costs for the proposed mine at Elk Creek and intends to conduct additional carbonation testing at a larger scale to optimize carbonation operating conditions and evaluate total potential extraction for niobium and other elements.
"We look forward to continuing our collaboration with L3 to fully investigate carbonation's potential and evaluate its possible integration into the Elk Creek production flowsheet," said Honan.