Sorry, links font copy paste here, hotcopper fks with them so...

Sorry, links font copy paste here, hotcopper fks with them so they dont work. The article was from Stockhouse.

"What is an ionic deposit?

No clay REE deposit exists purely as ‘ionic’. They are formed as nature and time weather a REE-rich hard rock source, like granite, into three distinct phases.

The adsorbed (ionic) phase is easily, quickly and cheaply desorbed with a salt solution at pH4, for instance.

Then you have a secondary mineral phase. Here, as the minerals release the rare earths as they break down, which then form a secondary mineralisation.These rare earths can be extracted with a modest pH solution, which is more expensive, but doable.

Finally, there is a resistive phase. That’s the mineral containing rare earths which hasn’t been broken down. This stuff is uneconomic to extract at the low grades characteristic of IAC deposits.

Which means not all clay hosted rare earths deposits are created equal.In fact, some ASX IAC projects could be total duds.

To determine whether an IAC project is economic or not – whether it has a large proportion of the first two phases mentioned above — a simple, easy metallurgical test is required.“There’s no point having [a decent proportion] of clays that aren’t ionic,” IXR’s Tim Harrison told *.“It is very easy to determine via test work, how much is ionic and then potentially whether there are other secondary rare earths minerals there which can be mobilised, can be solubilised, by adding a little bit of acid,” he says.The challenge with that is when you add acid you are adding cost and also increasing the amount of impurities which go into the leach liquor.“Those impurities then manifest in potentially higher downstream product purity costs,” Harrison says.“It is a fine line, a balancing act between getting the right leaching conditions to try and maximise the amount of rare earths you can extract from the clay, and the trade-off on the cost of then dealing with the impurity elements.”

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