iTech (ASX:ITM) has commenced second stage metallurgical trials at its Caralue Bluff high purity kaolin and clay hosted REE project on the Eyre Peninsula, South Australia.
The company has received the results from the first stage of diagnostic metallurgical test work at the Caralue Bluff Project on the Eyre Peninsula in South Australia. The aim of the test work was to determine if standardised leach conditions for ionic clay hosted rare earths would readily liberate the rare earth element hosted in the high purity kaolin clays at Caralue Bluff.
Tests were undertaken at pH 4 with 0.5M ammonium sulphate and sulphuric acid to assess the ionic component and at pH 1 with just sulphuric acid to assess the colloidal component. All tests were undertaken at atmospheric pressure and temperature.
Maximum recoveries of the four magnet REEs (Nd, Pr, Dy and Tb) range between 28-65% which suggest the potential to increase extractions with variations to the leaching conditions.
In consultation with experts at ANSTO, iTech has now commenced stage two leaching trials with the aim of increasing recoveries by testing the effects of increasing acid concentration and/or increasing leaching temperature. Another option the company will be investigating is to leach the beneficiated kaolin fraction (-45 micron) which has shown significantly increased REE grades.
“Clay hosted REE projects typically have complex metallurgy, and it normally takes several iterations of test work to ‘crack the code’ for good recoveries. Having a high purity kaolin as the host to REE mineralisation at Caralue Bluff allows iTech to explore a range of metallurgical techniques to recover the REE’s into solution while keeping impurities at low levels,” Managing Director, Mike Schwarz, said.
Next Steps
In consultation with experts at ANSTO, iTech has now commenced stage two leaching trials with the aim of increasing recoveries by testing the effects of increasing acid concentration and/or increasing leaching temperature.
Results are expected in the next four to six weeks.
As has been seen with other clay hosted REE project worldwide, several iterations of metallurgical test work are required to determine the optimum leaching conditions for a particular deposit.
The standardised tests used by iTech initially are intended to act as a guide to determine effective leaching conditions in the next round of test work.
The Caralue Bluff Project also contains a significant high purity kaolin exploration target; the company will be investigating the potential to leach the beneficiated kaolin fraction which has shown significantly increased REE.
Having a high purity kaolin as the host to REE mineralisation at Caralue Bluff allows iTech to explore a range of metallurgical techniques to recover the REE’s into solution while keeping impurities at low levels.
For further information please visit: https://www.itechminerals.com.au/
