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Author Topic: X-Ray Fluorescence Spectrometry  (Read 5848 times)

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Offline GPEX admin

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X-Ray Fluorescence Spectrometry
« on: April 18, 2009, 10:44:17 PM »
It is my understanding this equipment permits quick, accurate, on-site, nondestructive analysis of materials.

Seeking info on handheld XRF spectrometers - - how well they perform, which brand would be the better to consider, and why?

Might anyone have experience with these, or could offer other helpful feed?
Somebody said that it couldn't be done
But he with a chuckle replied
That maybe it couldn't but he wouldn't be one
Who'd say so until he had tried.

Offline d313373r

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Re: X-Ray Fluorescence Spectrometry
« Reply #1 on: April 19, 2009, 01:10:18 AM »
sounds expensive  :o

Offline PlacerPal

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Re: X-Ray Fluorescence Spectrometry
« Reply #2 on: April 19, 2009, 01:46:40 AM »
Check out the Handheld SPECTRO xSORT Element Analyser at:

RoHS Compliance and Lead Screening, Environmental Testing and Mining Applications Using Handheld XRF

Don't have any experience with the instrument, but I have had dealings with the parent
company AMETEK as an instrument manufacturer and supplier. They were a good company
to deal with and had excellent products.

Only experience I have had with a Spectrophotometer is with a 1.5 M Jarrell Ash using 35 mm B/W Kodak
film to record the spectrum and then read the lines on reader. Results were excellent as we
found a few hardrock mines by analyzing surface samples and plotting the results on a grid.
The Terra Nova mine in N. S. comes to mind - I was the reader. :)

Of course one needs experience in the operation, calibration and use of such an instrument.  ;)

Placerpal

Offline GollyMrScience

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Re: X-Ray Fluorescence Spectrometry
« Reply #3 on: April 19, 2009, 08:11:39 AM »
I have not had experience with them in field work much. More in the lab.
Of the hand held testing I have seen it tested and heard the discussion of the potential and the limitations.
As with many things like this it ain't as easy as it sounds.
My work with the technology has been with microprobe and electron microscopy. Very whizzy and fun as heck to wander over a sample under a scanning electron microscope and "zap" chosen mneral grains for an analysis.

Here are a few things to consider.
The system is essentially a surface test. Coatings of oxide etc will mask chemistry under it.
Mineral grain sizes can goof things up as can varying x-ray absorbing characteristics of a sample.
An experienced operator can make allowances for that.

Thats what sort of turned me off to it at the time - the guy running it started into a long rambling explanation of using standards and the variables etc and I just figured it was gonna be more work than it was worth. Since that time the microprocessor systems and computer support have made huge leaps forward and therefore things are more user friendly. That means I might not have to take a college course to run it.  ;D

I thought at one time that it would be neat to take readings right on rock in situ but the testing I saw was done on powdered sample - supposedly to get around some of the limitations created by surface costing - grain sizes - and absorbtive effects.

There was also testing done on the powdered sample after the first test and the sample was subjected to an acid digest and then the acid was read - was used to track metals like zinc - copper - iron etc. Essentially the same indicator mobile metals we chase in geochem prospecting. The acid could also be evaporated and a read on the material remaining could be done. I have not seen that done but it makes sense - could probably also do the same with water. Test for water soluble materials.

Had potential but still called for a field lab and for my work it would mean duplicate samples would have to be taken as my own results might help guide field work but could not be used for 41-101 level reporting. Independent lab results needed for that. The speed of sample turnaround was attractive but one of the other benefits often put forth is that it is non destructive. I don't care (cold and heartless as that may sound). I give permission to labs to rip samples to their very core to get me what I want and feel no remorse.
If I was doing a test of a potential lost DaVinci painting by checking the mineral makeup of the paint then I would be REAL careful but rocks? Zap em into oblivion for all I care just tell me whats in 'em!  <-laugh->

One place I would try it is in gossan examination. Essentially a gossan - even a thin stain - would be like the acid digest and evaporate method for XRF and you would get a fast read on mobile metals in the system and maybe a surprise or two.

For fast geochem of surface samples in soils you can have some potential and here is a good little article with a pic of the equipment when used for tracking metals contamination. The metals they are tracking are also on our geochem list so there may be some application there for sure.
Forestry Commission - PDF Document - CLAIRE_RB7.pdf

It would be fun to take a unit out for a spin - might add one to the equipment pile for this season and give it a whirl.

What the heck - lets just keep mixin' stuff together till it blows up or smells REALLY bad!

Offline GPEX admin

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Re: X-Ray Fluorescence Spectrometry
« Reply #4 on: April 19, 2009, 01:14:53 PM »
Hmmm…. four college degrees, aye ?  And starting with a Masters in how to properly set the microwave clock. There blows my Grade Three matriculation ! This one certainly sounds more in line with my daughter’s electronic skills, to decipher for daddy.  Suppose I could always go shopping for the book, “XRF Spectrometers for Dummies.” But when it comes to gold and jewels, for some reason man seems to learn quite quickly.

I sincerely appreciate the overviews you chaps have given. I did assume there’d be a big learning curve and to hone one’s skills would likely take a lot of field time. I too would agree the lab assays proves the ultimate, for several reasons, but for field work, I have wondered if such device would be invaluable for targeting and identifying the more prime samples to look closer at. And also in the field, one might then, better trace deposit geology. I also assume these would be optimum for identifying key gemstone geology. And might also find their place with the placer miner.

Further questions - - in practical use, would the unit have to be held stationary over the desired area for a predetermined length of time for capturing the reading, or could they simply be used in a sweeping manner for motion scanning across a surface ?

I have heard that one brand runs a cool $32K, surely there must be others at least a little more affordable ?  I assume the XRF Spectrophotometers are primarily intended for use by the small to mid-range prospector (prospecting party/company), whereas the larger companies might employ other more technical and broad-ranging methods. One might think the price range then ought to settle in the teen-thousands, as I’m sure the actual component cost would be so marginal, as compared to the shelf price. I’m also confident more would be sold if they fell into a reasonable price range. For the electronic gurus, I presume, an ideal build.

As a field prospecting tool, do these things host their own analytical database storage ? And are they functional to the effect of also recording the exact coordinate the reading was taken at ?

Would anyone dare to venture which brand might out perform the others ?  If spending that kind of money, it would only be prudent to stick with the one showing the best performance quality.

Tom, something is wrong with your link, possibly you’d be so kind as to re-post it ?

Thanks
Somebody said that it couldn't be done
But he with a chuckle replied
That maybe it couldn't but he wouldn't be one
Who'd say so until he had tried.

Offline PlacerPal

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Re: X-Ray Fluorescence Spectrometry
« Reply #5 on: April 19, 2009, 02:39:52 PM »
I don't want to sound like an instrument sales rep but after reviewing a bit of
the online promotional information and having experience in both assay and
quality control laboratories, I could probably get quite interested in an XRF
Spectrophotometer. And perhaps more so if I was in your business.

There are several different manufacturers and types of the instruments.
I have only looked at the Spectro xSort promotional information.
There is a U-Tube video of the Spectro xSort in operation - probably taken
at a trade show. There are also 30 other similar videos on XRF related instruments shown.
Might be worthwhile watching some of the videos.

The xSORT Handheld XRF Analyzer from Spectro Analytical
YouTube - The xSORT Handheld XRF Analyzer from Spectro Analytical

There is also a Screen Show on the xSort instrument here:
Screenshow SPECTRO xSORT

In the Screen Show typical uses for the xSort are mapping ore bodies and
even linking the sample analysis to GPS. The instrument also seems to do some
statistical error and correlation reporting.

I note that Spectro offers e-Training for most of their instruments.
To get more detailed info, one must sign up at their website.

A thought comes to mind in that once one gets reams of data, one then
needs to know how to use the data. Possibly another degree in Geochemistry
and/or Geological Engineering may be needed to do the work.
Sorry, can't help you there.  <-NO_>

It has been mentioned by GollyMrScience that sample preparation is an issue.
In my experience, sample preparation is critical to meaningful results. Sample
prep could involve bucking and that is another area that requires some expertise.

Another thought is also maybe you can get a Demo Unit or rent/lease an instrument
before committing to a huge expense that does not suit the needs?

Mainly you are on your own to do the DD being mindful that any lab type
instrument has ongoing maintenance costs, and one gets what one pays for.
Ongoing support and consultation from the manufacturer is also essential.

10-4

Offline GollyMrScience

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Re: X-Ray Fluorescence Spectrometry
« Reply #6 on: April 19, 2009, 04:40:05 PM »
The server at the other end seems to be goofed.

Here is a link to the HTML that will get you the text but no photos.
What the heck - lets just keep mixin' stuff together till it blows up or smells REALLY bad!

Offline 911Met

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Re: X-Ray Fluorescence Spectrometry
« Reply #7 on: October 08, 2015, 10:22:47 AM »
For anyone on the market for a handheld XRF, I prepared this XRF Specification Comparisons to help your shopping.

Offline Finn from Ecuador

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Re: X-Ray Fluorescence Spectrometry
« Reply #8 on: October 09, 2015, 12:00:18 AM »
Hi 911

I really appreciate that you do these comparisons, like this one and the one that you made about microscopes.  If you still could add maybe a short comment about features which are most important for prospectors and placer miners in these XRF units, like you did with microscopes. One might make a mistake in purchasing a unit which has unnecessary features or lacking features.  I have been thinking for example that for to make a correct flux for smelting, one should be able to see also light components of the black sand, not just gold and PGM: s.

Maybe i'am wrong.

Your comment would be highly appreciated.

Salud

Finn 

Offline 911Met

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Re: X-Ray Fluorescence Spectrometry
« Reply #9 on: October 09, 2015, 03:23:57 AM »
Yea, I guess I overlooked at.

You want a GeoChem XRG with gold/Au/Ag capability.  A prospector will need to read soils more than alloys.

All machines are fundamentally the same insides.  Most differ in the software/models to read the target.

They are great VS lab assays if you need frequent assays Compare X-Ray (XRF) to Laboratory -Measurement Reliability ICP Comparison | Metallurgy Testing & Research

I own an Olympus DELTA Professional.

I like Olympus as the product line is simple unlike Niton who gives you headaches with a line of too similar machines:
XL3t-950 GOLDD+
XL3t-960 GOLDD+
XL3t-970 GOLDD+
XL3t-980 GOLDD+

XL3t-500
XL3t-600
XL3t-700
XL3t-800

XL2-950 GOLDD
XL2-960 GOLDD
XL2-970 GOLDD
XL2-980 GOLDD

XL2-500
XL2-600
XL2-700
XL2-800
XL2-100

XL3p-800

XLp-818
XLp-300A
XLp-700 Series
XLp-305A
XLp-522REE

 


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