TORONTO (miningweekly.com) – Quebec-based project developer Critical Elements on Monday said a metallurgy optimisation programme for its flagship Rose lithium/tantalite deposit, in James Bay, Quebec, had resulted in significant tantalite recoveries that could “dramatically” increase the project’s expected tantalum output.

Tantalum is a critical component in modern capacitors used in consumer electronics and is also widely used as a minor component in alloys. As with a number of minor metals, new technologies, leading to the miniaturisation of electronic devices, had resulted in increased use of tantalum.

The Rose optimisation programme had achieved recoveries of up to 84%, and concentration grades of 11.71 kg/t tantalum in laboratory batch tests, using wet high intensity magnetic separation. The average tantalum recovery rate for the programme stood at 77.6%, with a concentration grade of 10.7 kg/t tantalum in batch magnetic separation tests.

The initial economic numbers from the December 2011 preliminary economic assessment (PEA) were based on a tantalum recovery of 50%. However, the latest results indicated a 27.6% increase in the average recovery, compared with the PEA figures, which could potentially mean an additional 100 000 lb of tantalite produced per year.

The estimated final recovery rate and quantity of tantalite to be produced would be better defined by pilot plant testing, as well as in the upcoming feasibility study.

"To the best of our knowledge, the Rose lithium/tantalum deposit is the only new economic conflict-free tantalum industrial-scale source in the world. The recent robust recoveries and high-purity results from the optimisation testing programme prove the standalone class of the deposit, which has the potential to become a key source of strategic metal supply," Critical Elements president and CEO Jean-Sébastien Lavallée said.

He added that the new forecast level of tantalite concentrate output could make Critical Elements one of the largest tantalum producers in the world. He pointed to recent tantalum mine closures in Canada, Mozambique and Australia as creating a significant shortage of supply, which the company expected to benefit from.

The programme had also resulted in optimising lithium recovery rates and grades. Batch flotation tests yielded an average recovery of 90.88% at 6.20% lithium oxide, and simplified the flow sheet.

The company said the recent results from the optimisation programme would be used to finalise the flow sheet for the pilot plant programme, which was expected to produce enough material to proceed with testing flotation or other suitable beneficiation methods aimed at increasing the grade of the tantalite concentrate.

Critical Elements said laboratory services provider SGS Canada had also determined that spodumene grains and the flotation concentrate contained significantly low levels of iron, making it potentially suitable for use in the ceramics industry.