A freaking nightmare on 4th Street

So I inquart with copper 545 grams dental alloy, its 38% Au and 22% pd by the XRF. I go straight to AR instead of just nitric parting (I have my reasons aka 5.97% Cr) and I test with stannous and after about 1 hour it shows mostly green and a small rim of black around the drop of stannous........that was yesterday. I left the solution sit over night and then check again this morning to see if its all digested, and its not, so I add more nitric and give it some heat, then when its all dissolved I check it again with stannous and NOTHING, no black, no green and in fact it turns the cotton swab colorless :-( my heart skips a beat, and I panic a little thinking "Oh no, did I boil my values away? I didnt use THAT MUCH heat"

I then test some of my other solutions and again NO color change on the swab..........soooooooooo I make a new batch of stannous and the nightmare is over

the stannous was good yesterday and today completely defunct, has that happened to anyone else that overnight it goes bad? (There was only maybe 5-10 ml left in the bottle)

Mlgdave

Yea I have had similar action happen. Good catch.

The key to good stannous:

1 gram SnCl2 dihydrate
5 mL c. HCl
20 mL DI water
put pure tin powder on the bottom.
Keep it closed, lasts for up to a year.

Heptane or mineral spirits on top is another thing to keep the air out.

Mlgdave,
So are there any future tv shows on scrapping and refining in the works? I liked the segments you did on the Meltdown show.

Thanks,
Macfixer01

macfixer01 said:

Mlgdave,
So are there any future tv shows on scrapping and refining in the works? I liked the segments you did on the Meltdown show.

Thanks,
Macfixer01

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Naaaa, they didnt like that I wouldnt be a drama queen. 1 season only, was kinda fun!

I do have an idea for a different type of show and I talk to my producer often (we became good friends)

mlgdave

Can I make stannous solution without the elemental tin?
I have SnCl2 dihydrate so if I use the same prep will the solution still work?

Thanks.

Chase54 said:

Can I make stannous solution without the elemental tin?
I have SnCl2 dihydrate so if I use the same prep will the solution still work?

Thanks.

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Yes, directly dissolved SnCl2 will work. But it have low stability and oxidize quickly over time by oxygen in the air and slow hydrolysis to tin oxides. SnCl2 is often badly hydrolyzed already in the containers of older age, but somewhat still works. Just as said by Lou, dissolve it to dilute HCl - this slow down the hydrolysis.Tin is added to prevent overoxidation to Sn(IV) stuff, which is no use in detecting gold or PM in solution
I think if you don´t have tin, solder wire will also do the job.

Use a straw to breath carbon dioxide from your lungs into the container to displace oxygen.

I recommend keeping a small amount of gold standard test solution. Make a solution of of gold chloride 1g/L and keep a small dripper bottle on hand in your work area. When you are testing and for whatever reason, your test is negative, test your stannous chloride against your gold standard test solution. That way you will know for sure if your stannous chloride test solution has oxidized. Never place your container of stannous chloride near a heated reaction as infrared heat destroys the solution and causes it to oxidize.

I use 95/5 tin/antimony solder to make my stannous chloride with and have never had problems. The antimony does not dissolve in HCl and will stay in the reaction vessel and the stannous chloride can be decanted into your test bottle.

Geo said:

I use 95/5 tin/antimony solder to make my stannous chloride with and have never had problems. The antimony does not dissolve in HCl and will stay in the reaction vessel and the stannous chloride can be decanted into your test bottle.

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My local stores only have a few options for solder my best options are 50/50 tin/lead or 60/40 tin/silver, will either of these work to make stannous chloride?

It should work.
I'd go for the one with Silver.
The silver would then be left with some tin in the bottom. And clean Stannous in solution.
Lead will dissolve with the tin, I'm not sure if it will cause some problems or not.

Yggdrasil said:

It should work.
I'd go for the one with Silver.
The silver would then be left with some tin in the bottom. And clean Stannous in solution.
Lead will dissolve with the tin, I'm not sure if it will cause some problems or not.

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Thank you so much, I will give it a try on my next day off and will share my results

I found a 99% tin flux core solder, I melt with a low torch to burn off the flux in a crucible. Amazon sells this.

Flamemagus said:

My local stores only have a few options for solder my best options are 50/50 tin/lead or 60/40 tin/silver, will either of these work to make stannous chloride?

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Go to any fishing supply store, including Walmart, and buy "lead free" fishing weights. They are pure tin unless they are marked differently. There are steel weights so read the package or ask someone that would know.

There is also lead-free wheel weights in most auto parts stores. The stuff is out there. You just need to know where to look.

Pewter is a high tin alloy, a cheap piece from a thrift store will last a long time. It is soft it will cut into strips with sheet metal snips
Heard it here, tried it it works

+1 on the pewter. I got a teapot from the thrift store that weighs like 5lbs for 1$. Solder is expensive.

Thanks to everyone on this amazing forum for the incredible advice. This will help me very much and save me some cash. You are all wonderful people and I am so glad to be a part of this group, I’ve been searching for something like this for a long time and it is so hard to find such knowledge or experienced people elsewhere, ive been reading as many threads I can in my spare time and feel I’ve doubled what I already know about recovering and refining precious metals and there’s so much more to read!!
Once again thank you everyone