# Stannous Chloride Test



## aga (Jan 17, 2017)

Prompted by Göran to do the 'acquaintance tests' i thought it best to do a bit of maths first, instead of leaping straight in and botching it again.

Hoke's recipe in chapter IX, page 93 translates to :-
1.56g tin chloride crystals
23 ml water
2 ml HCl (30 drops were measured to find out)

SnCl2, Tin(II)chloride normally comes as the dihydrate (SnCl2.2H2O) giving 1.31g of actual SnCl2 in 23ml water + 2ml HCl.
That works out at 0.28[M], or 53,000 ppm concentration.

Lazersteve's recipe :-
http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=41&t=5271#p45030
2g tin Powder
30ml HCl
This works out as 0.56[M], or 106,000 ppm concentration, about 2x the strength of Hoke's.
His photos show how excellent the colours come out.

Hoke's 'Two Grains in 2 oz Standard Gold Solution' recipe on the same page translates from grains/oz to :-
0.13g gold
57ml acids/water
= 0.012[M] , or 2400 ppm concentration of chloroauric acid.

Making that from clippings off a 1g .999 ingot took about 2 hours before all the 0.13g of gold had dissolved (no heating).

Using the Stannous Chloride i made earlier, 2ml of the solution was put in a plastic cup and diluted first with 2ml distilled water then 4,8,16,32 and so on, in order to halve the concentration each time. 
Each concentration of solution was tested with the SC.

Even the _use_ of the SC test needs some practice, as i got different results depending on which solution the test paper was dipped in, then had a drop of the other applied, or if both were applied as drops. 
Also the amount of solution seems important - too much and not much happens.

So, here are the results at 2400ppm, 1200, ppm etc down to 37ppm gold concentration :-


The 75ppm photo doesn't show much, but a hint of brown was seen with the naked eye.

The most Amazing part is that the SC test easily shows up 150 parts-per-million, which would be a mere 0.09g of gold in 1 litre of solution !

This SC test shows Negative to a concentration below about 70 ppm, so it cannot be used as a 'there is No gold' kind of test, meaning that those very dilute values need be accounted for, if not eventually rescued.

Now, i cannot trust that i've made the stannous chloride solution correctly, nor that i'm using it right by putting it on cheap filter paper, mostly because the colours are not clear.

Chances are that something went wrong when i made the SC solution, so some tin(II)chloride crystals have been ordered so that a testing solution can be made as per the book.

P.S. i _think_ i got the maths right, and checked them twice. There could still be errors though.

Edit: hopefully edited some errors without multi-posting


----------



## g_axelsson (Jan 17, 2017)

Nice post! I like it! 8) 

I make my stannous by dissolving as much tin as I can in a bit of HCl, then I test it against a standard solution I have. It works for me. The make up and concentration isn't critical.

To test I dip the top of a q-tip in the solution, drawing up a bit of liquid but not saturate it. Then I use a pipette to put some stannous solution on the other side so the solutions meet in the middle and often shows a clear purple line where the liquids meet.

Göran


----------



## anachronism (Jan 17, 2017)

Most use Stannous as a qualitative test rather than a quantitative test Aga. 

i.e. Is there gold in there or not? Simplest way to make it is some tin solder in HCl or pewter in HCl. A jar lasts for yonks provided it's not left open.


----------



## aga (Jan 17, 2017)

g_axelsson said:


> Just edit the original post and I'll remove the two next ones.


Editing done.

Yes. Please delete the second and third posts.

To have even Botched an Edit ... Gah ! It'll be a Miracle if i ever refine any Gold into a button !

I like the idea of the reagents converging to form a line.


----------



## aga (Jan 17, 2017)

anachronism said:


> Most use Stannous as a qualitative test rather than a quantitative test Aga


Some say they can get a ballpark idea by the SC result, which is why i tried to put some numbers on it.



anachronism said:


> i.e. Is there gold in there or not?


That's my point about to 70ppm thing really - it cannot be used as a gold-present/gold-absent test.

Certainly an 'is-it-worth bothering' test, but not a 100% 'there is No gold' test.


----------



## UncleBenBen (Jan 17, 2017)

aga said:


> To have even Botched an Edit ... Gah ! It'll be a Miracle if i ever refine any Gold into a button !



Bah! I got the feeling you will be holding your first button before too long.

Nice post aga!


----------



## anachronism (Jan 17, 2017)

Oh it's certainly a good thread Aga don't mistake me.


----------



## aga (Jan 17, 2017)

UncleBenBen said:


> Nice post aga!


Thanks ! 

The Devil speaks and once again Gold Fever strikes to the very core ! :G :roll:


----------



## aga (Jan 17, 2017)

anachronism said:


> Oh it's certainly a good thread Aga don't mistake me.


No mistake, no problems at all.

Honest replies are Good.


----------



## Topher_osAUrus (Jan 17, 2017)

How long after the initial drop of stannous were the pictures taken?

Was the nitric killed off of the auric chloride firstly?

I believe I have read that stannous can be as sensitive as 4ppm. But, I don't know if that is something you can "take to the bank" as far as accuracy goes. But, it does make one wonder. Since hoke says the excess acid needs to be killed off. I wonder if it is all neutralized (the nitric anyways) if the test would be more sensitive and get down to the lower ppm range.


----------



## UncleBenBen (Jan 17, 2017)

aga said:


> UncleBenBen said:
> 
> 
> > Nice post aga!
> ...



You've got to keep an eye on the ol' Sly Fox. Always looking to drag unsuspecting souls down into the abyss of gold and silver! :twisted: 
:lol: :lol: 

Take a look at your test strips tomorrow after they have time to dry and see if there is a difference.


----------



## aga (Jan 18, 2017)

Topher_osAUrus said:


> How long after the initial drop of stannous were the pictures taken?
> 
> Was the nitric killed off of the auric chloride firstly?


No. The test was done immediately - i missed the bit about getting rid of the nitric first, again  

When the 'proper' stannous chloride crystals arrive i will re-do the whole thing, properly (with luck) and report the findings/images of the colours versus ppm concentration.


----------



## Topher_osAUrus (Jan 18, 2017)

I believe Hoke goes into great detail about "testing solution A" (stannous) in her "Testing precious metals" book.
In it, she says you can simply use a flame (lighter) to heat up the drop of pregnant solution. I cannot recall exactly, but she says either add a drop of water or HCl if it dries up all the way. Then go about your testing with stannous.

That testing book of hers is great, it really really is. It is significantly shorter than "Refining precious metals", but the information contained within is remarkable. Granted, she uses a $35 ozt gold price, and pennyweight as her scale...but, still, minor details. She goes over how to discern regular nickel-white golds from platinum group ones, and the flame test, etc... If you have yet to read it, it should really be one of the next things you do. You will not be disappointed.


----------



## Lou (Jan 18, 2017)

Topher_osAUrus said:


> How long after the initial drop of stannous were the pictures taken?
> 
> Was the nitric killed off of the auric chloride firstly?
> 
> I believe I have read that stannous can be as sensitive as 4ppm. But, I don't know if that is something you can "take to the bank" as far as accuracy goes. But, it does make one wonder. Since hoke says the excess acid needs to be killed off. I wonder if it is all neutralized (the nitric anyways) if the test would be more sensitive and get down to the lower ppm range.




4 ppm sounds right to me


----------



## aga (Jan 18, 2017)

Still reading the first, but already have the second book downloaded.

It will take about a week for the SC crystals to arrive, so should have read them both by then.

After that, another attempt at emprical testing to see if 4ppm is achiveable by a noob.


----------



## Topher_osAUrus (Jan 18, 2017)

aga said:


> Still reading the first, but already have the second book downloaded.
> 
> It will take about a week for the SC crystals to arrive, so should have read them both by then.
> 
> After that, another attempt at emprical testing to see if 4ppm is achiveable by a noob.



Did you happen to check the tests at all after the pic op? Maybe the test would reveal more of its "true colors" after awhile. I believe Ben suggested to look the next day. What did they look like? Did you happen to check 30 minutes after you initially tested? An hour or two? the next day?

I've also seen posted on here, it can be done on good grade filter paper, a drop on a drop (or beside one another, letting them run into one another). Then you can see the individual lines of gold, platinum, palladium if they are there... I know palladium can be a bit of a chameleon when it comes to stannous testing. DMG is by far the definitive test for Pd.

And if Lou says that it is accurate to 4ppm, THAT is something you can take to the bank. (after bookmark searching, it was 4metals who I initially read that posted it... and both of those men, Lou and 4metals {and numerous others} you should creep their old posts... you will be amazed at what you learn)


----------



## Lou (Jan 18, 2017)

Please see link:

https://books.google.com/books?id=i_JMAAAAMAAJ&lpg=PA70&ots=fKwrbf9pph&dq=detection%20sensitivity%20stannous%20chloride%20gold%20purple%20of%20cassius&pg=PA69#v=onepage&q=detection%20sensitivity%20stannous%20chloride%20gold%20purple%20of%20cassius&f=false


----------



## Topher_osAUrus (Jan 18, 2017)

Very nice, thank you Lou

That is a downloadable pdf too, (clicking the cog in the upper right hand corner, and download pdf)
Cool. 8)


----------



## FrugalRefiner (Jan 18, 2017)

You can also put your pointer over the red EBOOK FREE icon at the left of the page and click on Download PDF from the pop up window.

Dave


----------



## aga (Jan 18, 2017)

Thank you for the replies. 

I actually binned each one after the photo :!: 

Noob error, granted. Far too concerned about having a photo to post than thinking clearly.

Lou says it works to 4ppm so i will try and get as close to that as possible.

I will plan it better and try to Do it better when the SC crystals arrive.

Hopefully the gold solution was made right as that will be the basis for the tests.

0.13g of .999 gold was snipped/weighed and put in a 100ml plastic bottle with a screw-on lid.
About 8ml of 20% HCl was added, then about 2ml 56% HNO3, both from plastic pipettes.
The bottle had the screw lid put on, and then i put it on top of the air pump for the stock pot, in a way that meant it got vibrated but could not fall off. Took roughly 2 hours before the gold dissolved despite an occasional shaking by hand.

If anyone can see that was all wrong, please chime in and say how it should be done.

If i did it wrong, the tests/photos are/will be worthless.


----------



## aga (Jan 18, 2017)

Topher_osAUrus said:


> That is a downloadable pdf too, (clicking the cog in the upper right hand corner, and download pdf)


It does not give me that option.

Would you mind uploading it here or somewhere we can all get it from ?


----------



## aga (Jan 18, 2017)

FrugalRefiner said:


> You can also put your pointer over the red EBOOK FREE icon at the left of the page and click on Download PDF from the pop up window.


I get a red 'GET PRINT BOOK' button with 'No eBook available' underneath it.

I'm in Spain, Europe, so there's probably some Google $ to hand over somewhere.


----------



## g_axelsson (Jan 18, 2017)

Google only gives the download alternative in USA (and probably Canada). For the rest of the world it only shows snippets of pages. :evil: 

Here are a world readable copy.
https://archive.org/details/samplingandassa00smitgoog

Göran


----------



## g_axelsson (Jan 18, 2017)

aga said:


> I actually binned each one after the photo :!:
> 
> Noob error, granted. Far too concerned about having a photo to post than thinking clearly.


You binned gold!  

You have a long way to go before you can call yourself a refiner.

Never!!! Trow!!! Away!!! GOLD!!!

One part of refining is to save any filters and test papers in a burn pile, then incinerate and recover the gold in it.

Göran


----------



## Topher_osAUrus (Jan 18, 2017)

As you wish, aga:
View attachment The_Sampling_and_Assay_of_the_Precious_M.pdf


It's a pretty big book, I'm excited to read it.


----------



## aga (Jan 18, 2017)

Thanks Lou and Topher for the PDF, which is now in the reading-queue after Hoke's books are read (for the first time at least).

Göran, c'mon man. I've thrown Gold away for years - i'm married with kids.

It's a hard habit to quit !

If anyone has started a Goldseekers Anonymous self-help organisation, i'm in, but just for the gold.

Edit:



g_axelsson said:


> You have a long way to go before you can call yourself a refiner.


Looks like i have Long way to go before i get anything metallic out of anything, including metal !

If one day i end up a Refiner, God will surely have been very drunk indeed on that day (or at least not looking)


----------



## UncleBenBen (Jan 18, 2017)

aga said:


> If one day i end up a Refiner, God will surely have been very drunk indeed on that day (or at least not looking)



Haha! You will get it aga. Try not to over think it at first. Keep it simple, follow the processes as laid out, and soon enough you will be holding your first refined gold. 

Recovering that gold can get a bit more complicated, especially with escrap, but you've already seen that! :lol:


----------



## Grelko (Jan 18, 2017)

Topher_osAUrus said:


> And if Lou says that it is accurate to 4ppm, THAT is something you can take to the bank. (after bookmark searching, it was 4metals who I initially read that posted it... and both of those men, Lou and 4metals {and numerous others} you should creep their old posts... you will be amazed at what you learn)



I absolutely agree with this.

Also, if you use a spot plate "white ceramic/plastic", the purple will leave a stain. If you don't see a positive result in the solution itself, you might be able to see it on the plate after rinsing it off.


----------



## rucito (Jan 23, 2017)

http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?t=9902


----------



## Topher_osAUrus (Jan 23, 2017)

rucito said:


> http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?t=9902



The pictures are dead in that post, as well as in the link now


----------



## aga (Jan 23, 2017)

It is a shame those images are not available anymore, either in the thread or the link provided.


----------



## rucito (Jan 23, 2017)

The text is more important than the pictures.


----------



## Topher_osAUrus (Jan 23, 2017)

Is not a picture worth a thousand words?
Probably worth more when trying to describe and understand the small differences in color hue.

Regardless, that was a good post with lots of good information.
Pictures would simply be a bonus


----------



## aga (Jan 23, 2017)

Without an image, a noob such as me would not what to look for.

Posting the link was Good.
Not checking that it still worked and still contained useful info was just idleness.

When i posted garbage about oxidation, at least i was very drunk.
No excuse i know, but at least i can admit it.

What exactly was your reason for posting a link to an obsolete thread ?


----------



## FrugalRefiner (Jan 23, 2017)

Let's not get confrontational. Let's just move on helping each other.

Dave


----------



## aga (Jan 23, 2017)

Good call.

I'll re-do the images when some shop-bought stannous chloride arrives, including Gören's cotton bud thing - that seems to work really well.

Perhaps any perceived antagonist will post their results sooner, saving me all the effort, although i doubt it.

Tends to work out that way.


----------



## aga (Feb 2, 2017)

Happily a delivery of porcelain spot/reaction plates and stannous chloride crystals arrived today - woohoo !

An SC test solution was made exactly following Hoke's instructions, then compared with the previous batch made by Lazersteve's recipe.

Additionally, the spot-plate, filter paper strip and cotton bud methods were compared.



Both SC recipes seem to work pretty much exactly the same.

Using the 2400ppm gold solution, the new SC was tested all the way down to 8ppm.

The spot-plate method certainly shows the colour better than filter paper, because there is none of that chromatography effect going on, although i guess that is useful when there's a mix of PMs & colours.



(the 150ppm spot-plate test had way too much SC added which diluted the colour a lot)

The filter paper & cotton bud results were ok down to 75ppm, but came out pretty much blank at ~32ppm, whereas the colour was still obvious on the spot-plate.

At ~16ppm i fancied i could still see a faint hint of brown on the plate.
At ~8ppm it looked the same as a drop of distilled water in the spot next to it.

Maybe it was slightly over-diluted each time, or the tiny amount lost at each step due to the tests, but i could not get a result below 16ppm - not even a slight stain on the plate after 5 minutes.

Something like a spectrophotometer (or a younger person) would likely detect the colour better than my eyes can !

An immediate and obvious result at ~32ppm is still pretty awesome.

The accuracy of the measurement would be much improved if a larger volume of standard gold solution was used at the start, so i might give it a go with 10x starting material to see if i can get anywhere near Lou's 4ppm.


----------



## UncleBenBen (Feb 2, 2017)

Awesome post aga!

Be sure to save all the cotton tips, test strips, and paper towels you soak up your spot plate with. That gold can be recovered later. I toss them in an old cottage cheese container and snap the lid back on.


----------



## aga (Feb 2, 2017)

Of course i didn't just throw them in the bin, and am not rummaging through the bin at the moment to collect all the gold-containing bits.

Honest


----------



## Topher_osAUrus (Feb 2, 2017)

Very nice aga

A couple more questions, for the sake of science :mrgreen: 

Did you denox the gold solution? Or was it an HCl+Bleach dissolution? -I still wonder if that is the reason why it's not as sensitive as it should be (although darn close)

Were the pictures taken immediately? 
Was there any change in the prominence of color after an extended time had passed?

Good work, good sir! Got to love pictures. :twisted:


----------



## aga (Feb 2, 2017)

The gold solution was made as per Hoke, and it had not been de-nox'd before testing.

Edit to add:

The photos were taken immediately.

Left for 5 minutes there was no noticeable change.


----------



## UncleBenBen (Feb 2, 2017)

aga said:


> Of course i didn't just throw them in the bin, and am not rummaging through the bin at the moment to collect all the gold-containing bits.
> 
> Honest



Ha! Save them up! Along with filter papers or anything else that gets gold solution on it. Even gloves, but I'm going to wait until I've got a better incineration set up before I burn those. 

When you get enough saved to justify the time and acids they can be incinerated and leached to get that shiny shiny gold back.

Here is a good one by 4metals on the value of a drop of gold solution...
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=60&t=23003


----------



## aga (Feb 2, 2017)

If you do refining regularly, all those tiny drops will mount up over the years, representing a large amount of $.

In my situation, losing that little bit of gold in order to get a handle on what the SC test can look like is worth the loss. My bin's GPS co-ordinates will be tracked, just in case.


----------



## Mezira (Feb 15, 2018)

I am happy to read this post .. here I also do a test with sncl2 mengahsilkan purple and didiamkam in more than 1 hour about how much ppm when viewed from its color


----------



## g_axelsson (Feb 15, 2018)

You can't tell the concentration of gold in solution just from a spot on a paper towel like that. You need to have a known solution that you know the concentration of to begin with and then do a dilution series as aga did in his post. The color depends on several factors where the quality of your stannous chloride is just one factor. But if everything else is the same then a dilution series can get quite close.

Your test doesn't look like it contains any precious metals much. If I got a test like that I would first test my stannous and if that is good then I would just dump it in my stock pot or maybe even going straight to waste.

Do some research on stock pot with copper scrap in it. Here is a link to get you started.
http://goldrefiningwiki.com/mediawiki/index.php/Stock_pot

Göran


----------



## Mezira (Feb 15, 2018)

g_axelsson said:


> You can't tell the concentration of gold in solution just from a spot on a paper towel like that. You need to have a known solution that you know the concentration of to begin with and then do a dilution series as aga did in his post. The color depends on several factors where the quality of your stannous chloride is just one factor. But if everything else is the same then a dilution series can get quite close.
> 
> Your test doesn't look like it contains any precious metals much. If I got a test like that I would first test my stannous and if that is good then I would just dump it in my stock pot or maybe even going straight to waste.
> 
> ...


in this case i do on the rocks of gold veins ... sncl2 i made based on the hook method


----------



## Mezira (Feb 15, 2018)

aga said:


> If you do refining regularly, all those tiny drops will mount up over the years, representing a large amount of $.
> 
> In my situation, losing that little bit of gold in order to get a handle on what the SC test can look like is worth the loss. My bin's GPS co-ordinates will be tracked, just in case.


the honorable mr aga here I send video link test results of gold veins using sncl2 ... I made based on the instructions in this forum on his advice and his opinion I am very grateful ... my question is whether the gold in the rock is high ppm

https://youtu.be/avil3PioVwY


----------



## saadat68 (Jun 18, 2021)

Hi
How much gold (in ppm) is in this solution approximately? What do you think? 
It is cyanide solution and I tested it with stannous chloride.

https://i.imgur.com/6Yq7TvM.jpg


----------



## Lino1406 (Jun 18, 2021)

You do not use acidic stannous chloride on alkaline cyanide. What I see is tin oxide


----------



## saadat68 (Jun 18, 2021)

Hi lino
As Hoke recommended, I add some HCl to cyanide test solution under my hood and then test with SnCl2
As you can see the purple color indicates gold but I want to know what is gold amount in test solution in ppm


----------

