https://www.fastmarkets.com/insights/rising-synthetic-graphite-co...

https://www.fastmarkets.com/insights/rising-synthetic-graphite-costs-may-push-battery-makers-to-rely-on-natural-material

"The battery industry has tended to favor synthetic graphite in anodes, due to its higher purity and controlled specifications. It offers a longer lifespan and a faster charge turnaround. On the other hand, synthetic production costs are higher than those for natural graphite-based spherical material. Natural graphite has a lower cost profile (Fastmarkets’ research team estimates about half the cost of synthetic) and can offer a higher capacity."

Synthetic has a dirty base and is expensive, but it has longer lifespan so the battery will last longer before it needs replacement. Natural is cheaper but does not last as long as Synthetic.

So the reason you blend the two is that you get long-life of Synthetic and cost advantage of Natural.
Synthetic is forecasted to be $8,000 per tonne by 2030. Why because manufacturers improving design and manufacturing methods.
Synthetic currently 53% of the graphite sales, expected to be greater than 60% in 2030.

Demand for Synthetic is increasing due to EV demand for long life batteries and the need for high purity and high consistency anode which is difficult to achieve in natural graphite.

The reason natural have a place is because of cost advantage.
When you want to charge more than Synthetic. There is no price incentive to use Natural.

So the forecasted price by Talga for $11,250 per tonne is not realistic.