I have a decent understanding of process flowsheets, and an ok understanding of metallurgy as it relates to constructing process flowsheets, as a lot happens before recovery btw. But obviously as I stipulated in the past I don't know much about rare earths itself. I personally think linking hard rock process flowsheets for other minerals to REEs and clay process flowsheets themselves are misleading, and I also think talking DMS processes for REEs is misleading in itself given the actual process for REE extraction and getting to a concentrate is far more complex.
Anyway, in a HMS process, and talking spodumene here and tin, they can be separated adequately because the specific gravity of each is quite different, assuming they can be easily separated from the lattice of the ore before that DMS stage btw. But there are other things in the ore that have specific gravity close to spodumene hence liberation before this stage is a key to reduce the trashgoing into DMS itself btw. If can't liberate spodumene from the ore lattice then you go to a ball milling circuit - i.e. whole of floatation process flowsheet as a agnst a DMS/floatation design, that crushes the ore basically to a pulp of say P80 of 106 microns and then floatation does its magic in the ion exchange process, which is a completely different MET test btw as well - 43129938 In DMS/HMS crush sizes are larger (3.35 mm or 5.6mm from recollection). Note: In terms of REEs particle size is far less than this DMS crush size in spodumene btw btw. Anyway, my problem is a lot of Anns of companies use DMS/HMS/HLS interchangeably, btw despite the fact they are different, but I don't think that is an end all for investors becase the key becomes how reliable is the plus or minus aspects of say a DFS. Anyway, suspect will get a better guide in the Scoping Studies etc etc, then PFS then DFS.
Anyway, here is the PLS process flowsheet to understand complexities around process flowsheets per se albeit spodumene itself is not a good example when looking at REE extraction LOL - note the HMS and floatation stage, noting IXR is not producing HMS type product here anyway, and it's product is more akin conceptually to 'floatation' product btw, so not sure whey DMS was raised anyway here: Point of this post, is the METs themselves are around process itself and just not using terminology - you have other circuits before that stage. Anyway, the long of the short is that throw enough money at METs you will get a solution, but the answer is how commercially viable is that solution itself - that is the key with METs been how it translates to capex and opex for justifying an investment.
And that is why for complex projects you often have pilot plants to establish the facts, and how it translates to opex and capex costs, but the key point is when you get to SS the thing to look for is the plus or minus, and these plus or minus's firm up in a PFS (to plus or minus 25%) and a DFS (+ or minus 10%) in achieving stated NPV itself. And in those documents you have to be sure that the METs work, as well as all your other capex and process spends btw. Your METs do aid process flowsheet design. The other day I posted on what a SS can look like in a plus or minus concept - Post #: 48563445
Now, the question itself is loaded because each REE process flowsheet has some unique differences especially because of ore type, but as a first call I will simply say a REE clay deposit is very different to a hard rock REE deposit, and even REE hard rock deposits are very different depending on what is the host ore, because processes also differ depending on the ore type. There is little/limited bonding of the REE to clay as against REEs in hard rock, meaning separation is a lot easier as well at the benficiation stage, which allows improved ability to separate minerals, say through using their specific gravities for example from the gangue, to then move to the other aspects of the process flowsheet. This pic from BioLantanidos explains that best too me - http://www.hochschildmining.com/en/exploration/greenfield_exploration/biolantanidos
The other pic is this one: From the below, the beneficiation stage is a lot more straight forward for clays when compared to hard rock for REEs is the point, which then aids costs further downstream as well, but is still relatively complex. Anyone wanting to get into the nitty gritty probably should read and seek to understand this paper below - unfortunately opens up more as a word doc so you need to find it yourselves - basically even REE clays have to go through the chemical treatment/separation/purification stages, but mining and beneficiation is where the real competitiveness exists for such clay deposits over hard rock ones is the point :
Now looking at even established plays your process flowsheet can differ at the beneficiation stage , and that is where the METs come in because the METs is what designs the process flowsheet as well, because each host ore or clay is also different because the composition of REEs is also different from one deposit to another - the beauty and need for testing - below some hard rock differences in extraction and they relate predominantly to the host rock been different btw from https://www.researchgate.net/publication/309662296_Review_of_Flotation_and_Physical_Separation_of_Rare_Earth_Element_Minerals:
Point of all the above - if posters are generally interested in the METs, they need to go back a few Anns to understand the process itself. The key one too me which explains what they are doing is the one on 18 February 2020. Process is a lot more complicated than the statements alluded to, in comparison to say, AV'Z's spodumene in its essentially DMS process etc etc
In terms of the current IXR Ann the table at the back, signed off by a Competent Person also holds good info. But back to the 18 Feb Ann - they are working with clay, and what they are doing in the METs is interesting in itself - whilst extracting REEs from clays may be easier than hard rock, the process itself is still relatively complex IMO - people should read this Ann (Post #: 42988999) From this Ann is the below, which is akin moreso to a 'floatation' concept in producing product:
From this link - http://www.eurare.eu/docs/eres2014/fifthSession/VladimirosPapangelakis.pdf: So in effect saying easy release from the clay and then use leaching methods to get the REO grades required etc. The above is an interesting paper especially Tables 1 - 3 which have some African deposits, but also interesting in the sense of 'methods' they are looking at to increase recovery.
As a final point and using mineral sands as an example, the key is assemblage. The extent and level of each mineral sand in a minerals sands deposits means the concentrate varies in itself because process itself is about providing the optimal recovery at the maximum profit, and that process is worked on in part by the optimal configuration of extraction noting in mineral sands deposits the extent and makeup of payable minerals varies per deposit. Similarly, REEs are the same, hence why I used a Heavy Minerals Sands deposit example. Each REE is worth x, so the mix, with the 17 REE differing in each deposit varying, is based on what extracts maximum value as there are so many REEs that recovery of each is actually quite different (hence the MET tests per se and more tests required and even the latest Ann says more tests - why, they are looking at optimal configuration, and how to deal with differences in teh deposit as the deposit makeup I doubt will be homogeneous, or another way to put it determine a blending strategy so that the feedstock can be as uniform as possible - which is just a hunch).
Using spodumene and tin is not a good example in any event given the difference in specific gravity to start with, when compared against up to 17 rare earths where depending on recovery method the recovery rate for each can differ itself given the 'solutions' used to aid recovery, and noting whilst specific gravities can be used to separate from gangue, the REEs themselves at times have very similar gravity specs and are difficult to separate from other REE at times etc. But would appear too me recovery is simpler for REEs in ionic clays than hard rock as per the 20Feb Ann.
Maybe posters should provide a specific example of concern for the METs, and reasons for that concern might aid discussion here, and why the reason for raising the topic itself for a clay REE deposit, which would have less issues than a REE ore deposit btw - it is why the capex costs for hard rock REE deposits can be quite large. This paper below clearly shows recovery of REEs from hardrock can be difficult but not insummountable. Ionic clays provide easier recovery, but still difficult recovery btw given the process for getting a concentrate, so at the end of the day the METs as they relate to a pilot plant will aid bedding down the + or - in SS, PFS and DFS. https://www.uvm.edu/giee/pubpdfs/Golev_2014_Resources_Policy.pdf
Whilst the above paper is also interesting, it is more on hard rock REE, I will simply say it shows that solutions are based on the complexity around extraction of the REEs from the host source. As I said, clay, extraction of REEs is easier.
Maybe SF2TH, when next you speak to management, ask them: 1. Why are they conducting the METs and the extent of METs. 2. What are they expecting to learn say from a pilot plant. 3. How do the seek to ensure consistency in feedstock into the process flowsheet. 4. And ask them to provide an explanation of how the METs flow through to the process flowsheet itself - here I presume they will be explaining this aspect in the SS when released etc etc
If the question is more around inputs/discard and recycling of inputs that is a different question. But from an environmental perspective things can be managed adequately provided the right environmental framework is put in place. Use of chemicals is not a new thing in mining. Anyway, METs, processes are quite complex per se, so ultimately how all this comes together is really the ambit of pilot plant or confidence levels that the process flowsheet is scoped well enough that you get your say plus or minus outcome in a DFS around costs of production and capex costs (noting the main driver of NPV been price is often outside your control but as long as you do your METs/design correctly you do have initial control over capex and opex costs outcomes). What I like about what IXR is doing around METs is trialling different approaches and tweaking approaches - if people want to understand the reason why PLS didn't achieve initial recovery rates in the spodumene area it was because of lack of testing throughout the deposit itself hence the plant was scoped appropriately and hence retrospective capex spend in the floatation circuits. IXR is seeking to test the deposit itself, and I wouldn't be surprised it works out a blending strategy to ensure consistent feedstock etc into a plant - not rocket science if doing lots of testing.
At the end of the day a forum provides high level guidance but if want specifics need to yabber to the company as each deposit is different and different combinations of chemicals are used in recovery itself because not all deposits are identical, and especially in terms of REE depsoit there makeup is often quite different in each deposit around the PPM of each mineral in that deposit.
Hopefully all the above is as clear as mud. Won't add further to this topic until the process flowsheet is revealed in the SS etc etc and/or specs of pilot plants are provided etc etc
All IMO
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