XRF outcome reliable?

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Slochteren

Well-known member
Joined
Apr 3, 2015
Messages
156
Location
Netherlands
I just sold 2,2 Kilo silver crystal from my cell, the XRF stated 98,87 Ag, 0,897 Au, 0,2 Cu.
This means there was +/ 20 gr gold left if this xrf was good. I cannot believe this...

Feed stock gold plated 800 Silver cutlery. Process in short:

Cut it up in pieces.
Dissolve in 53% nitric.
Decant the silver nitrate.
Filter nitrate thru Coffee filter.
to Ag chloride with salt
Convert chloride with lye sugar method to Ag,
washed with tap water to ph 7
Poored shots from it with a crucible only used for this porpose
Run thru cell
Washed with water till PH 7.

could there be so must gold left after this procedure?

They took a sample of 30 gr crystals, melted it and made an xrf. I did not eye whitness this melting, maybe they used a dirty crucible.

I should have taken it home again and dissolved again to see if there was 20 gr mud left... but i didn't

Thanks Paul
 
Well, nitric can dissolve gold. In very small quantities, very very small. And, silver is an excellent carrier of gold and pgms. But

I think when you did the conversion of nitrate to chloride, the other pm's would have been left in solution.

I also think you left out a number from the xrf reading number.

Its been said here many times, that xrf guns are not completely 100% accurate, and multiple shots should be made, from different angles. On clean metal.

Did you melt the crystal, or shoot the crystals with the xrf?
I believe I have read that gold in silver can be about 1ozt for every 1,000ozt of silver. I will have to check my books again when I get home from getting coffee :shock:

20 grams out of 2200 seems pretty high, doesn't it? I'd bet it was an xrf err.
 
Crystals were melted before XRF,

here is the total xrf:
xrf2.jpg
 
Platdigger said:
Did they pay you for the gold?
No, but i dont think there was that much gold, if it was there this would mean that there is +/- 23 gram gold on 1,2 kilo gold plated 800 silver cutlery. Its heavy plated but not that much.

Verstuurd vanaf mijn Che2-L11 met Tapatalk
 
An XRF needs to be set up for fine silver to get close to a good result.

Your process should produce very nice silver .995 or better. What color is your electrolyte?

The buyer probably just saw an opportunity to get another 1.15% out of you by swearing the XRF is always correct. You could bring in a Canadian Silver Maple Leaf coin or any other recognized quality coin from a mint which is .999+ fine. Let them read the coin and compare what you know is high quality to what you are selling. I think it was your buyer. Many act like that.
 
I wouldn't have argued their reading a bit either, as long as they were willing to pay for the gold it said was there. 8)
Actually I understand your point. There was probably what? Maybe a couple of grams of gold total?
You know, if you just melted the whole lot together. Without any acid or cell.
 
Paul your gold should be in the filter paper or in the remaining nitric sludge, it's easy to find out, put the sludge into a filter and rinse well with distilled water, add the original filter paper and dissolve in reactants of your choice, precipitate the gold and weigh.
 
I'm not searching for my gold, processed that after dissolving the base metals in nitric, with this specific cutlery i have +/- 13 gr gold for 1 kilo cutlery.
Just wondering about the XRF outcome.

Paul
 
The gold wasn't in the silver to begin with, your method was good so your silver should have been good as well.

XRF is not made for reading pure metals it takes calibration which most take advantage of and use to their gain.
 
4metals said:
An XRF needs to be set up for fine silver to get close to a good result.

Your process should produce very nice silver .995 or better. What color is your electrolyte?

Here is a picture off the electrolyte after proccesing 2,7 kilo Ag. And a picture off the last 500 Gr Ag.

sn.jpg


sc.jpg
 
Did you add copper when starting your cell?

Likely you did, which is good for the crystal structure.

The silver you put into the cell should not carry over much silver, hence my question.
 
Originally, the main purpose of the cell was to separate (part) gold from silver. If your cell is set up properly, all the gold should be in the anode slimes. I can't see how you could possibly have gold in your silver crystal unless you had a hole in the filter cloth. Also, any gold in the cell would be in the form of a black powder which would be visible. The gold will not dissolve in the cell. Any inclusion of the gold with the silver would have to be a mechanical one - not an electrolytic or chemical one.
 
Since the silver was digested in nitric and filtered before dropping as a chloride, I would assume most if not all of the gold was collected in that step. If not, I would be working on my filtration skills and choices of filter media.
 
Since it was thin plating most times it's blown to dust and can travel through something like a coffee filter like he is using pretty easy. Then you chloride it and the gold gets trapped with the gold to travel on to the cell. This use to happen when i used bounty filter papers and did gold filled. Gold filled karat can get blowed to dust on a long hard boil and some of it will travel through the paper. After filtering the spent solution is salted and the gold is trapped with the chlorides. But once it passes to the cell it should be in the basket. Like Chris said if it does get through the filter cloth in the cell it's usually pretty easy to spot. It's not going to be co-deposited by chemical means so it should be right under the basket and easy to see. It may also make your solution cloudy. I ran a two step silver cell for awhile and the #2 cell reminded me of looking at a clean and clear mountain spring where you can see 10 FT with crystal clarity! I once had some gold tested at NTR in Atlanta with an XRF that tested like 101% gold. Never got paid for it though! :mrgreen:
 
Nearly 500 oz and your ending solution concentration seems to be about 100-125 grams a liter. You still had room to run more. I probably wouldn't have broken the cell down yet unless you had your reasons to. Put a lid on it and set it aside for the next run. Even then you don't have to break the cell down. With those low concentrations of contaminates i would just replace the evaporated water with nitric ever now and then. The silver crystals will redissolve and boost your concentration back up. Change out the filter cloth as needed which shouldn't be often considering your process and feed stock. Then throw silver at it and run it till the wheels fall off! When you run bigger cells stopping to break down a cell cost time and money! What was you starting solution concentration in grams of silver per liter?
 
I think the outcome off the XRf is wrong/unreliable in this case, and there was no or very litle gold in the crystals. Will search for another buyer next time i think, any suggestion in Netherlands/Germany/Belgium?

The gold plate is actual thick, after dissolving the Ag the gold remains in foils, just ran another job and will make a foto of the foils this evening.

I used +/- 100 gr Ag per liter.

How do i know/see when i have to change to electrolyte, i would have changed it now but if i can use it longer its bettercheaper like Palladium says.


Thanks Paul
 
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