another stannous chloride qiestion

[au-artifax]

Sorry to start yet another sncl topic, but after searching and finding hundreds of threads containing discussions about sncl, and only finding one person ask this question and not getting an answer, I need to ask it again.

Is pewter an acceptable material to use in making sncl for PM testing?

Again, sorry to tie up the forum with such a minor item, but I don't have any personal contacts to pm my questions to. Thanks for your patience everyone.
Matt

 

[bmgold2]

Might work. Probably would but the copper might color the solution. The tin might just reduce the copper and drop it out of solution. Would be worth a shot if you already have the scrap pewter.

Don't forget to let everyone here know if you try it. Then we'll all have the answer.

 

[jimdoc]

No, it has been discussed before.

Jim

 

[au-artifax]

Thanks bmgold2 for your openess and information. I can see that copper might pose a problem and I didn't think of that.
And no disrespect Jim, but IMHO just because someone somewhere talks about something doesn't mean the information automatically downloads into everyone's mind, especially if they are relatively new on the forum. I've read your posts, you always provide brilliant information, so I am surprised at your short almost snippy reply. IMHO.

 

[jimdoc]

It was less than a month ago;
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=16792&start=20

Jim

 

[Geo]

All test solutions and especially standards, should either be bought premixed (if you are unable to make them yourself for whatever reason) or made with the purest chemicals you can obtain. Testing is one of, if not the, most important process you will learn. With proper testing, you will know what is in your solutions and when you get better, how much of what is in your solutions. Without proper testing supplies, it will be like processing in the dark. Without even the meager light of of your testing solutions, you cant see a thing.

 

[au-artifax]

Thank you Jim for the link and geo for the great advice.

 

[jason_recliner]

My stannous seems a strange colour when I read about all yours being perfectly clear.


I took a 50ml hot sauce bottle, washed it thoroughly - I thought.
I eventually found my material: a small section (about 5g) of no-flux bar of "lead free solder" at 99.3 Sn / 0.7 Cu, and half filled with 32% HCl. I hope that should stay fresh for ages!
It went purple within minutes but 24 hours later is roughly the same colour. So it might be contaminated. I would have expected copper to make it 0.7% green.
However, it seems to be able to detect gold, though even my strongest Au solutions are probably extremely weak. Beginner issues to deal with!

 

[joubjonn]

I just buy mine on eBay. It's cheap and it comes in a dropper bottle and works perfect.

 

[g_axelsson]

Probably some minor contaminant in the metal that made the color shift. It can even be a colloidal solution. The only reason you see it is because the solution is so deep compared to what you would have in a spot plate or on a cotton swab. If you have a standard solution to test it with and it gives correct and consistent results I would not worry.
Anyone who claims that a small contamination of the tin chloride is a problem could try to explain how we then could use it to detect gold in even heavily contaminated solutions.

Just as a test I once put a small circuit board (complete with components) in hydrochloric acid and when the tin was dissolved (60/40 Sn/Pb) I had no problem to detect gold with it.
... okay, I confess, my main reason was to depopulate the board, but it was a nice test anyhow. :mrgreen:

Göran

 

[jason_recliner]

Probably some minor contaminant in the metal that made the color shift.
...
Anyone who claims that a small contamination of the tin chloride is a problem could try to explain how we then could use it to detect gold in even heavily contaminated solutions.

A good point. I'm sure it would have been perfectly fine, as you say. But I've done it again from scratch anyway. I'm resolving to be chemo-pedantic.
It also gave me the opportunity to groove the additional pieces of soft tin with sidecutters for better dissolving.
Ten minutes in and zero colour this time. So I'm pretty sure I didn't get something out of the bottle. Nothing cleans glass like HCl.

 

[MrMylar]

I just buy mine on eBay. It's cheap and it comes in a dropper bottle and works perfect.

If you've recovered gold from any materials before, then I'm sure you've used HCL a few times. Why buy the stannous already made up when you have no idea as to how long it has been sitting? Unless you have a piece of tin in the solution, it will go stale within a few weeks. I make my own stannous because it saves me money and I've read it before that if you're going to refine gold, you had better know how to make your own stannous and have some gold solution to test against. If not, a person shouldn't be refining because they're missing out on an important aspect in the refining.

I started making mine last year and it has saved me more money than buying the stannous already made up and in a white plastic bottle. I use a glass vial and after adding the HCL + stannous chloride + distilled water + a piece of pure tin, I let it sit loosely for a few hours with the top on it and then I close it up. After months of it sitting idle, my stannous test shows positive on my gold standard solution.

The most expensive item you would need to buy would be the stannous chloride. Other than that, you'll save yourself all that money and not even knowing if your solution is fresh or not. And if you don't have any tin metal in the solution, it won't last long.

Do yourself a favor and start making your own stannous. It's worth it and it'll show that you know more of the basic aspects of refining gold when you test it against your own gold standard solution. Sacrifice a little bit of your AR solution that is positive for gold and keep it in a glass vial. If you know for a fact there is gold in the solution, then you'll always know if your stannous solution is stale or not without any guessing.

One more thing, if your stannous solution gets cold, it will cloud up white like milk. The solution is still good, but you must let it warm up to room temp or at least 70 degrees and after a few days it'll be as clear as water. On the other hand, if you have your solution in a white squeeze bottle, you'll never know if your solution is cloudy or not and you may get a negative result on your test.


Hope that helps!

 

[bswartzwelder]

I bought stannous chloride (I believe it said anhydrous, but not sure about that) on eBay. Mixed a few granules in a bottle with a little HCl and distilled water. Then I added a few very small pieces of tin (also bought on eBay). It has worked for several years now without problems. I keep it in a brown glass bottle in the refrigerator at a place where no kids could reach it. Only my wife and me living at home now since the kids are grown and families of their own. My wife knows what it is and respects it. The bottle is plainly marked.

Stannous chloride solution can go bad after a period of time. Adding a little tin will help keep it fresh. Also, keeping it chilled and away from light is beneficial. I also purchased a small bottle of 1% gold chloride solution. Every time I get the stannous out, I also get out the gold chloride. First thing I do is dip a Q-Tip into the gold chloride solution and then drop a drop of the stannous chloride onto it. If it doesn't turn dark (mine usually turns dark black) then there is a problem, most likely with the stannous.

It is of no value to use stannous chloride solution without testing it first to see if it is good. If it isn't good, you will get false negatives all day long and never know how much gold you really may have lost. I am amazed at the number of people who say "I did this or I did that" and don't know what's wrong but have not tested with stannous. It's always one of the first things I take outside when I'm about ready to work with any recovery or refining process.

 

[rickbb]

With the wide spread availability of lead free solder making almost pure SNCL is really easy.

Buy a small tube of 96/4 tin/silver solder from Radio Shack or a similar local store. The tin will dissolve in the HCL and the silver will drop out to be either removed by filtering or you can leave it. It won't hurt your testing.

 

[kadriver]

I bought these chemicals almost five years ago off eBay and still have enough to make enough stannous chloride test solutions for the next five years.

This video shows exactly how to make and use the stannous chloride test solution (Hoke refers to it as "test solution A"). It lasts for about three months. Hope this helps.

https://youtu.be/Hz8odRIqtuQ

kadriver

 

[solar_plasma]

With the wide spread availability of lead free solder making almost pure SNCL is really easy.

Buy a small tube of 96/4 tin/silver solder from Radio Shack or a similar local store. The tin will dissolve in the HCL and the silver will drop out to be either removed by filtering or you can leave it. It won't hurt your testing.

I use 96Sn4Cu solder that works great. The copper does not dissolve and lies as heavy black powder at the bottom. Even after shaking the solution is completely clear after 2 seconds.