The overall vanadium recovery forecast for the entire process is regarded as exceptional due to a combination of favourable ore characteristics and significant technical development by AVL.
Australian Vanadium Ltd (ASX:AVL) (OTCMKTS:ATVVF) (FRA:JT71) has completed pilot-scale pyrometallurgical test-work at the Metso testing facilities in the US, confirming world-leading vanadium extraction with high combined vanadium roast/leach extractions of up to 94.9%.
The work comprised detailed testing and optimisation work on pelletised concentrates and has reconfirmed pilot test results from July 2020.
This represents a major step towards AVL’s goal to design, build and operate the world’s lowest-cost primary vanadium operation in Western Australia’s Mid-West region.
Vanadium recovery ‘exceptional’
Concentrates used as feed for the pyrometallurgical test program were generated during AVL’s CMB pilot test work in 2019.
An early years blend typical of the average of the first five years of forecast production and a later scheduled average blend (LOM) were campaigned separately.
AVL describes the vanadium recovery from the CMB circuit as ‘exceptional’ – 69% for Y0-5 and 76% for LOM, reflecting the unique characteristics of the AVL Gabanintha orebody.
The concentrate grades achieved at the target particle grind size P80 of 75 µm were similar.
Robust process
This program was completed in February 2021 after some delays due to COVID-19 and repairs to the kiln.
The key process parameter for vanadium extraction from either the hematite or magnetite rich blend was the kiln operating temperature.
By testing a range of potential commercial roasting durations no appreciable difference in vanadium leach extraction resulted, indicating a robust process and rapid completion of the salt-vanadium reaction.
LOM magnetite-rich pellets showed a marginally lower, but more consistent and repeatable vanadium roast-leach extraction, averaging 92% at the selected roast temperature.
The LOM blend material provided more than 9% higher vanadium recovery from the CMB circuit compared to the Y0-5 blend, more than offsetting its slightly lower roast performance.
Work underway to support BFS
With completion and reporting of the pyrometallurgical test-work program, AVL’s engineers are updating the design of the grate kiln area to support the bankable feasibility study (BFS).
Ongoing work related to the company’s CRC-P Research Program for production of high purity vanadium products is aimed at further increasing efficiency and improving certainty in the vanadium purification flowsheet design, which will be part of the Australian Vanadium Project Processing Plant near Geraldton.
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