Australian Vanadium has announced the selection of Metso for the next phase of definitive feasibility study pilot testing at its Australian Vanadium project.

Metso was chosen because of its world-renowned expertise in Grate Kiln (GK) processing solutions, the ASX-listed company said.

“AVL and Metso are committed to working together to develop an improved thermal processing solution involving pelletising of the vanadium rich iron concentrate produced at the Australian Vanadium project,” Australian Vanadium said.

The solution will involve pelletising the concentrate and processing it through a GK system. Pelletising has been used previously in Europe and China for the processing of primary vanadium-titanium-iron ores, with the benefits including:
• Improved roasting reaction;
• Minimal dusting, and;
• Reduced build-up of residues within the kiln.

Bench-scale tests have already been completed by the company on its pelletised vanadium-rich iron concentrate and have confirmed that pelletised concentrate roasting offers a substantial advantage to the traditional rotary kiln technology currently employed by all primary vanadium producers, AVL said.

AVL’s pelletised roasting tests have shown vanadium extraction results averaging 95.4%, versus a rotary kiln extraction of 85-88%, which is typical of standard vanadium roasting technologies, according to the company.

The next phase calls for pilot scale testing to simulate and optimise the GK process.

“The GK system is a combination of a travelling grate furnace for pre-processing with a rotary kiln for final roasting,” AVL said. “The feed concentrate is formed into pellets of a particular size that are well-suited for the process. The pellets are then loaded onto the traveling grate and pass through multiple furnace heating zones where progressively hotter and hotter gases from the kiln are forced through the bed of pellets.”

This process accomplishes gradual and controlled drying and preheating of the pellets while recouping much of the energy from the hot kiln exhaust gases, according to the company.

The rotary kiln is then dedicated to the final roasting of the pellets after they’ve been dried and preheated and can be controlled independently to achieve thermal profiles which result in higher levels of vanadium extraction.

AVL said: “Although the GK technology is more commonly used for indurating iron ore pellets, it has also been successfully applied to similar roasting applications because of its unique ability to improve upon conventional rotary kiln processing.”

The pilot scale testing will be conducted at Metso’s Pyro Technology laboratory located in Danville, Pennsylvania, USA, where over 120 GK testing programs have previously been performed, according to the company.

Todd Richardson, AVL’s Chief Operating Officer, said: “Vanadium roasting technology has not changed much since the 1930s, when cement kiln technology was adapted for salt roasting vanadium bearing ores. Since that time, the technology has gone largely unchanged.

“By partnering with Metso, a world leader in pyrometallurgical processing, AVL is confident that the roasting process can be greatly improved.”

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