Your first quote states facts about ionic clays. But does not state or stipulate this is in fact one.
The second comment i assume was taken from this announcement Post #:
61304788
Unfortunately this "recovery" is actually just a comparison test between sampling a drill core with lithium borate fusion and comparing it to a sample result with weak aqua regia.
View attachment 4759438Note the PPM levels. They are the same or lower. You don't sample gold at 10g/t. sample it again with weak aqua regia and get 9g/t and call it a 90% recovery. Well you do, but is that a viable way to process gold? No. Does it tell you if you have weakly bound ionic material. No.
I posted my views on this topic in detail on another aspiring REO in clay in Post #:
63207805In clay systems you can expect colloidal bonds to be the predominant phase. Its when exchangable phase is present in large quantities that you have an ionic material. ion exchange.
1. Colloid phase: REE deposited as insoluble oxides or hydroxides or as part of colloidal polymeric organometallic compounds. These species have low occurrence in ores at the slightly acidic natural conditions and can be recovered only by acid leach.2. Exchangeable phase: REE occur as soluble free cations/hydrated cations or part of positively‐charged complexes in solution adsorbed species on clays. These species account for 60‐90% of total content of rare earths in ores and can be recovered by ion‐exchange leaching with monovalent salts.3. Mineral phase: REE part of solid fine particles with same mineral matrix as the host rocks (REE part of the crystal lattice). This phase usually accounts for the balance from the ion‐exchangeable phase towards the TREE content and can be recovered only by aggressive conditions (alkaline bake and acid leach).here's a list of recent posts which are explaining some of the basics in the space.
Post #:
63185173 Post #:
63174292 explain why weak aqua regia is pretty well useless without a ph3-5
Post #:
63004813 on another project i don't hold explaining what good looks like.
Not to undo the results thus far they are better than most.
But i cannot stress that the met work is the key. And that doesn't mean hitting it with weak aqua regia and considering it a met extraction.
Needs to be leached with ammonium sulphate or sodium chloride. These are monovalent salts. Meaning it's near a neutral PH. That tells you how much of the REO is in exchangeable phase and thus how ionic (if at all it is). PH1-2 is generally as far down the PH scale you want to go as the acid dosing (and therefore cost becomes inherently cost intensive.) "weak aqua regia" is in most circumstances close to PH0. Strip your face type stuff.
Like most companies they don't actually specific what the PH is of the weak aqua regia but for those playing at home some companies did and weak is not actually all that weak.
Like most companies they don't actually specific what the PH is of the weak aqua regia
i'll cite post from another post as well which shows objectivity in the response. Post #:
60986888 Post #:
61559365"Keep in mind pH is a log scale, so each single number change is 10 times the acidity. pH=3 is 10 time more acidic than 4... pH=1 is thus 1000 times more acidic than pH=4 (natural kaolinite clay pH is between 4-5 generally). This is why I shake my head when some companies proudly show off recoveries with 10% HCl (ie MEK) with a pH of -0.44 = 44,000 times more acidic than pH=4 ... shareholder ignorance really is an explorer's greatest advantage."
"MRD used ALS Laboratory’s ME-MS41W with MS41W-REE weak aqua regia digest, which they disclosed in fine print front page, Note 2," AR means Weak aqua regia acid, a mix of 1 molar hydrochloric acid (HCl) and 1 molar nitric acid (HNO3)." (pH=0 as per previous post...140 times more acidic than pH=2.4).
6A1057235_MRD.pdf (hotcopper.com.au)"To re-iterate the grade, thickness and depth to which the results for REO have been found means TAR has a potential to be economic. Don't let what i'm saying come across as negative - that better than 95% of others in the space - i'm just keeping the perspective. The existential next step is a composite sample needs to be sent off for a leach test. 'Sighter' test work. Met extraction. All means the same thing.
Need to be done at PH3-4 to show IF ionic.
Then you can slide down the scale to Ph1-2 to understand if you can extract more with some acid dosing.
Sampling with weak aqua regia honestly tells you very little - only that its a mildly less accurate sampling method for REO in clay when compared to lithium borate fusion.
The table above showing what extraction methodology is being used to process true ionic clays should be proof in the pudding that if "weak aqua regia" was a feasible, low cost method to extract REO in clays everyone would be doing it.
Hope that clarifies.
SF2TH
(20min delay)