XRF analysis results? Reading them?

[pacog]

Hey guys I recently had a XRF analysis done on some Black sands and I am wondering about some of the readings I got back.

It list's the several minerals that were in the samples and what they would yield per ton. That's the easy part to understand.

My question comes because there is a long list of elements that are listed as NON DETECTED. The person who ran the test told me, these elements were detected but in very small qtys, that were just barely readable by the XRF machine. The problem is these elements have Higher Numbers( I assume they are PPM results) listed next to them than some of the Elements that were listed in OZ per Ton section So I am confused because the person who conducted the test said that these tested very low, but the numbers listed are very high. I would assume 1-40ppm would be very low

I am still waiting to hear back from the Testing Facility to see if those numbers that are listed for the NON Detected are the PPM of each element.

 

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[jewelerdave]

xrf is not perfect but can be useful.

Concentration Conversion Calculator a nice calculator for conversion

 

[pacog]

xrf is not perfect but can be useful.

Concentration Conversion Calculator a nice calculator for conversion

Thanks for the response Dave. Got a few things cleared up, but I mostly learned, if you want to know if you have PM's in your sands get a Fire Assay done first.

XRF is still very confusing if you don't fully understand how to read the outcomes. Plus it's not very exact for certain elements. I want to know Exactly how many PPM of an Element I have and not just that it tested lower than a certain level, that the machine can detect.

Talked to Ken at TCB refining and he was very helpful.

 

[Clay Diggins]

if you want to know if you have PM's in your sands get a Fire Assay done first.

Bingo!

 

[jewelerdave]

My XRF is mainly for metal analysis. Not so accurate on minerals as mine is specialized for gold and silver and refining.

It is helpful to determine that there is gold in some items.

Black sands can be a pain to work with. With the correct separating equipment you dont really need to do much else with them.
Or you have to just be ok with letting that last little bit go away.

XRF is kind of like throwing a fire cracker off in a barn. it counts each moo and nay and oink and cluck, and then tries to figure out how many and what kind of animals are in the barn.

but its not perfect, depending on the setting and type of machine there can be artifact and false reads, its all interpretation of data.

I trust it on homogenous metals. but on rock. The penetration is only so deep.
It can tell you what is there but not in a satisfactory way to determine quantity. its just a tool to show you what is seen. A quick and dirty.

 

[911Met]

Here is a comparison table for XRF models Compare XRF Analyzer Brands | Metallurgy Testing & Research
XRFs are great on rocks/soil samples if you have the correct machine Compare X-Ray (XRF) to Laboratory -Measurement Reliability ICP Comparison | Metallurgy Testing & Research
and the correct sample preparation XRF Sample Preparation Methods/Procedure | Metallurgy Testing & Research

Elements like Zinc will boost your Au/gold readings.

On gold, XRF are great estimator, but Fire Assay rules.

 

[rustbucketguy]

XRF Readings, explanation and important relationships for the layman
An x-ray source excites various electrons and displaces them from their normal position. When the displaced electrons regain their normal positions, secondary x-rays are generated by the sample. The energy level of these secondary x-rays can be used to determine the elements responsible and the quantity of the specific x-ray can be used to calculate the abundance of the element. Note that some elements will have more than one secondary x-ray energy: that characteristic is used to allow the software to further identify the elements present.
The XRF machine has no idea how many grams are in the sample. Results are reported based on the number of atoms of each detectable element present, compared to the total number of detectable atoms in the sample. The tricky part is that the detectable elements varies significantly from mfr to mfr and especially between detection modes (primarily "mining" or "alloy"). If the machine cannot detect a particular metal (or even a particular element, it CANNOT report it). Typically, NONE of the machines can report Li, Be, Na, Mg, Al, Si, or P unless they are specially equipped to detect them. ALL machines typically require special features if metals such as Au, or platinum group metals are to be reported. ALL machines and their software must be capable of detecting, measuring, and reporting the various results: most have very limited reporting capabilities based on screen displays; software-based reporting can be very extensive, but you still have to know from the mfr what those capabilities are. Alloy machines typically are the most limited when it comes to detecting and reporting metals, especially if there is a limit to the number of elements in the reporting capabilities.
In case you missed it, you must read the results as: the number of molecules of (element) is present in the sample as ___ percent of the total number of molecules detected. Tip: check the screen display and you will find that the components reported will ALWAYS total up to 100 percent.