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Major advance for ilmenite production on Iron Range

NRRI announces pilot-scale success in processing ore from Longnose deposit

Marshall Helmberger
Posted 5/25/17

REGIONAL—Minnesota could soon have a new mining and value-added industry on the Iron Range, with a lower risk of significant environmental impact.

Officials with the Natural Resources Research …

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Major advance for ilmenite production on Iron Range

NRRI announces pilot-scale success in processing ore from Longnose deposit

Posted

REGIONAL—Minnesota could soon have a new mining and value-added industry on the Iron Range, with a lower risk of significant environmental impact.

Officials with the Natural Resources Research Institute announced on May 25 that they have successfully produced high quality titanium dioxide from an ilmenite deposit near Hoyt Lakes.

NRRI partnered with Process Research Ortech (PRO), of Ontario, to conduct pilot scale testing on ilmenite ore mined from the “Longnose” deposit near Hoyt Lakes. The company utilized a proprietary hydrometallurgical process, successfully producing nearly pure titanium dioxide concentrate with high market value. Currently, titanium dioxide’s market value is approximately $3,200 per ton. For comparison, the market value of Iron Range taconite pellets is about $70 per ton.

NRRI tested a 10-ton sample from the deposit, which is owned by American Shield Titanium Group LLC. It is the largest and richest known ilmenite deposit in the United States. This particular deposit also has little overburden, a confined mining footprint, and low sulfur content, all of which would suggest far more limited environmental impact than other mining operations in the region.

According to a 2012 technical report on the Longnose site, the ilmenite deposit is close to the surface and measures 700 meters in length, north-to-south, 600 meters east-to-west, and is about 150 meters thick. That would limit the mine pit to not much more than 100 acres, although related infrastructure would likely occupy significantly more nearby property. “The deposit is lying flat and provides a geometry that should be amicable to open pit mining,” states the report, produced by SRK Consulting for Cardero Resource Corp.

It’s long been known that among Northeastern Minnesota’s rich mineral mix are deposits of ilmenite, which is the primary source of titanium dioxide, used in hundreds of daily use products, and eventually for titanium metal. The challenge with commercializing the resource has been the magnesium oxide impurities that could not be removed with conventional processing.

“As a trained geologist, I’ve known about the ilmenite there for 30 years,” said company President Bill Ulland. “This process demonstrated by NRRI and PRO appears to be very cost effective with commercial potential. There’s a very strong market now for titanium dioxide.”

The separation process recovered an estimated 64 percent of ilmenite as concentrate. The following PRO technology targeted removal of iron and titanium oxides. After two scale-up processes, NRRI and PRO were able to achieve titanium purity of 99.8 percent. Pure iron oxides were also separated at 98.5 percent (unoptimized) purity and could add to the market value of the deposit.

“This is especially exciting because we have an opportunity to process the ilmenite to an end product, titanium dioxide, here in Minnesota,” said NRRI Executive Director Rolf Weberg. “NRRI’s role is to define the state’s portfolio of mineral opportunities. That is how we retain wealth, add value to our resources and take care of our environment.”

A preliminary marketing study by UMD’s Center for Economic Development found that there are few U.S. producers of titanium dioxide and many consumers for a wide variety of applications – especially in paints and coatings, plastics and paper. With further processing, titanium dioxide can also be used for titanium metal production and niche products, like electronics and energy storage. NRRI intends to seek further funding to pursue additional geological, metallurgical and environmental studies. One goal is to optimize the hydromet process for iron and titanium, and to understand the feasibility of isolating other high value materials.