source：proactive
American Rare Earths Ltd (ASX:ARR) (FRA:1BHA) has received positive interim metallurgical test-work results on rock chip samples from the original resource area at La Paz Rare Earths Project in Arizona USA, providing support for a new test program.
The current round of test-work, which was conducted by the Saskatchewan Research Council (SRC) in Canada, produced concentrate grades similar to what was achieved in historical work but using wet high-intensity magnetic separation (WHIMS) only.
Rock chip material returned more than 50% silica, with minor magnetite and hematite.
Rare earths are predominantly hosted in the mineral allanite, with minor monazite also being present.
WHIMS technology：Initial work centred on a staged grind-WHIMS beneficiation approach.
Concentrate is currently being produced from an additional composite of rock chips at the SRC using the WHIMS beneficiation flowsheet adopted for the initial work.
The concentrate will be subjected to acid baking and water leaching to produce leachate that will be sent to Lawrence Livermore National Laboratories for patented biosorption technology that uses a biological ligand metal extraction of total rare earth elements (TREEs) and scandium.
Work planned on a bulk composite of diamond drill core from the deposit will address optimisation of grind size to enhance TREE and scandium recoveries and grades in the separation from gangue minerals.
Introduction of flotation to reject barren silica is expected to further enrich the TREE and scandium concentrate grades which will have a positive impact on project economics.
The intent is to apply flotation first and use WHIMS technology to provide further upgrading by rejecting barren silica after most iron oxide gangue minerals have been rejected in flotation.
The next round of work will focus on new generation flotation collectors
Given that allanite beneficiation is not commonly practised, with most global rare earth operations processing monazite and bastnaesite bearing ores, testing of new generation flotation collectors and gangue depressants will be a large focus in the next round of test-work, working closely with specialist reagent suppliers.
This work will be undertaken by Nagrom Laboratories in Perth, Western Australia, and co-ordinated by Wood PLC.
Future work：A bulk run will be undertaken with rougher WHIMS only to produce concentrate for flotation testing.
A portion of this concentrate will also be used for acid bake test-work to generate leachate for enzyme absorption test-work at the Lawrence Livermore National Laboratory in California to assess potential REE extraction from magnetic concentrate.
Future work will be undertaken on enriched concentrates as the concentrator flowsheet is progressed and optimised.
The current round of test-work has produced concentrate grades similar to what was achieved in historical work but using magnetic separation only.
Introducing flotation to reject barren silica is expected to further enrich the concentrate grades which will have a positive impact on project economics.
A larger concentrator program will be undertaken when diamond drill core becomes available in May, exploring the use of new generation flotation collectors and promoters to specifically target rare earth bearing allanite.