Ann: High Purity Manganese Flowsheet Optimisation Progress Update, page-15

You are correct this is the first step in upgrading to a high purity manganese content, which can either be HPEMM (via sx-ew, electrowinning) or HPMSM (via adding sulphate which extracts the non Manganese in some kinda cool chemistry way).

Basically they now take this high manganese content sludge and extract all the remaining non manganese content as best possible.
99.95% purity means the final product has <50ppm of non manganese in it, which is what we need to get to to have a saleable product.

Recovery refers to amount of pure manganese content that is retained through the process, whereas purity refers to the contents of that final product. Saying 97% recovery is fantastic, there is basically no loss of manganese content through the process.

Recovery is key in making the process economically viable.
Purity is the key in having a saleable product, if we can't get to 99.95% purity - we cannot sell it into the EV market.

Test work has been done before, we know we can get to 99.95%. This was via HPEMM, so now just to show the same for HPMSM. I don't think there's much risk.

I'm not a chemist but yes I believe ambient temperature refers to exogenous forces and the 90 degrees is from the chemical reaction.

They don't name what the leaching agent is - its CSIRO secret i believe. I think i've seen it referred to as a 'pickle solution' in my rummaging through CSIRO docs - might imply peroxide? @PirataCzornomaz ???