Globe Metals & Mining (ASX: GBE) has received positive metallurgical testwork results on the concentrate material from the Kanyika Niobium Project in Malawi, with extraction of both Niobium and Tantalum above 99%.
TCM Research Ltd (TCM) is currently conducting a metallurgical testwork programme for the application of its proprietary vapour metallurgical processes on a concentrate sample sourced from the project.
The initial base-line test (OR1) showed 98% Niobium and 90% Tantalum extraction. Based on this encouraging result, a series of kinetics and optimisation tests were conducted. This culminated in tests (OR12 & OR13) showing above 99% extraction for both Niobium and Tantalum.
The tests further demonstrate high extraction yields for other potentially marketable products, namely Titanium and Zirconium, with extraction yields of above 99% and 96% respectively.
With an extraction of 99.9% achieved on OR13, the expectation of the engineering team is that the overall recovery across the refinery will be 99% comparing favourably to Globe’s August 2021 feasibility study of 95% based on the HF process.
The test results validate the decision to move from using a hydrofluoric acid and sulphuric acid-based process with fluoride and sulphate rich wastes that need to be neutralised and disposed of to a chlorination-based process with no such toxic waste and where chlorine is regenerated and recycled.
Globe expects that partners, off-takers and future buyers will demand a sustainable Niobium oxide supply and the chlorination process meets that requirement. The metallurgical testwork programme has now advanced to the next stage with separation and refining tests well underway.
“An extraction of >99% is a marvellous result as we continue to maximise the efficiencies of our various processes, and will have a direct, positive and project-long effect on our profitability. Combined with its superior ESG profile these outcomes continue to validate our decision to switch to chlorination technology in our refinery and I look forward to positive results from the next stage of test-work,” Globe’s CEO Grant Hudson said.
The process employs a selective reductive chlorination technique, where the target metals are volatilized and thereby removed from the host matrix. These metals can be further separated and purified to produce individual metals or compounds. The basis of the process is the formation metal chlorides, with differing melting and boiling point temperatures, allowing for downstream processing.
The second stage of the process involves the refining and production of saleable products. Metal Chlorides can be separated and refined via vapour metallurgical (dry) techniques, fractional condensation, de-sublimation, fractional distillation, chemical vapour transport and halide substitution.
The final stage of the process is where product differentiation options can be explored, with the ability to produce a range of saleable forms: mixtures or individual; chlorides, fluorides, oxides, carbonates, hydroxides, metals, or metal alloys and powders.
Specifically for Niobium/Tantalum concentrates where Niobium and Tantalum are usually the only metals extracted, TCM presents the opportunity to produce commercial co-products from other constituents in the concentrate like Titanium, Zircon, and Iron, and potentially the recovery of any rare earth elements present.
The process has numerous intrinsic benefits, including: