Windimurra has turd quality ore. It is low grade and oxidised. During the first failed operation it recovered less than 30% of the vanadium to concentrate. Then it lost another 25% to the roasting and lost another 5% to tge hydromet circuit. Overall yeild was terrible. The second failed attempt tried to increase magnetic recovery of concentrate from the same low grades and had a modest improvement. The problem was that the concentrate was still dirty, and that carries over into the kiln and leach circuit requiring greater use of reagents. Also, the cost of energy to Windiumurra is huge. The gas seller and two pipeline tariffs resulted in terrible roasting costs. Other places in the world use coal or have cheaper gas.
Salt roast is the lowest risk way of making pentoxide. You need: high magnetic recovery, low silica in the concentrate, good solubilisation efficiency in the kiln and cheap energy. African operations feed >2% V2O5 to their kilns. Largo has even higher grades again.
Unless the ore can deliver >80% recovery of vanadium to concentrate, it is pointless to even consider a salt roast operation unless the energy and reagents are incredibly cheap.
Soda Ash is the best salt to use in the roasting - it's not cheap and the higher the impurities in the concentrate, the more soda ash is needed. Windimurra the frst time around tried to use waste sodium oxalate from the alumina industry. That stuff is seriously toxic. The second time around they used soda ash and lots of it.
As we all know most of the windimurra concentrate circuit burned to the ground. The kiln has sat idle and would probably need a re-line if it is salvagable. Woe be tied to whoever has to pay the gas bill for a re-light.
Forget about TiVan - it hasn't been done in a commercial operation and only a fool would believe that the costs are lower than conventional salt roast. Acid is not free.
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