Making Stannous Chloride (SnCl2) from "scratch"

[Chumbawamba]

Ok, so I finally got some time to continue to prepare for my first foray into refining. I decided that something quick and simple to do in the time that I had was to make Stannous Chloride. I went around to various hardware stores last night and was able to find some tin based solder that was mostly tin. First I went to Radio Shack (for you non-US folks this is a national electronics store chain) and found a 96/4 tin/silver solder; $4 for 1/2oz (see photo below). Catalog number is 64-026. This is nice because if you render it down to SnCl2 you can recover the silver and get some of your money back

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But I went to Orchard (for you non-US folks this is one of our larger national chain hardware stores) and found a much bigger roll of 95/5 tin/antimony solder; $12 for 8oz (see photo below). This is what I ended up using for my first batch of SnCl2.

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I didn't know any exact formula other than dissolving it in HCl. So I weighed 10g (in two sections) of the Sn/Sb solder on my scale and poured 100mL of 31.45% HCl into my beaker. I then dropped the two solder pieces into the beaker and stood back to watch.

The only other time I've worked with HCl was the 14.5% solution you get from the pool section of the local hardware store, which is fairly weak, but it was enough to clean up some old metal gas cans I had laying about. This 31.45% stuff I got from the local pool supply place in town. I got 4gal for ~$30 (including a $5 deposit for the bottles and crate).

This being the first time I worked with this concentration of HCl I didn't realize it would fume so much. The night air was cool and slightly damp, so I could see the fume cloud. Of course it was smart that I was outside on my patio in the open air so it could waft away. I just had to stay out of the fume cloud to avoid choking. I'll definitely need to eventually rig up a fume hood and scrubber. I don't like the idea of this stuff just venting out into the world.

The solution became cloudy after a short period of time. I didn't have a glass stirring rod handy so I stuck a plastic knife into the solution to stir it around and noticed the tin was still mostly intact. After waiting a while I decided to pull out the tin strips. They were definitely dissolving away, as the diameter of the wire was diminished from the original, but I thought it would go faster if I chopped them down into little 1mm bits back into the solution. This definitely helped the dissolution.

Meanwhile, I was whiling away the time waiting for the tin to completely dissolve by reading the forum. I came across this thread where LazerSteve shared his formula for making SnCl2:

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=41&t=5271#p45030

Doing some quick math I figured I probably didn't have enough HCl, so I topped it up to 200mL to get closer to Steve's ratio and that seemed to help. After a while (and a nap...I was doing this after midnight in the wee morning hours) the solder was completely dissolved. There was a grayish precipitate at the bottom of my beaker, which I assume was the antimony. The solution was clear, just as it was supposed to be.

I filtered out the solution through a coffee filter, separating the antimony muck from the Stannous solution and ended up with about 200mL of what I hope is Stannous Chloride (see photos below).

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I currently have it stored in a PETE #1 juice bottle. Is there a problem with this? I didn't have a glass bottle handy and will transfer it ASAP. I also plan to store it in a dark place to preserve it. If I'd known that this stuff doesn't have a shelf life I wouldn't have made so much.

So I guess I should add about a gram of the solder to help preserve it?

By the way, I did employ adequate safety gear at all times, including goggles and shoulder-length rubber gloves. A facemask or respirator might've also been a good idea to avoid the many times I found myself in the path of the fume cloud :shock:

This was fun, if extremely simple. I still have lots of prepping to do before I delve into the really fun stuff (actually recovering PM from the various forms of scrap I have). In the meantime I've been a busy little hunter/gatherer and have lots of tools, materials and sources to share as far as what I got and where I got it from. I'll post about that stuff as I find more time.

 

[Anonymous]

add more tin, so that a little piece is left in the bottom, it will stay fresh longer.

JIm

 

[Chumbawamba]

So per suggestion, last night I added 5g of my Sn/Sb 95/5 solder to my SnCl2 solution . I left the cap loose to prevent a build up of any evolved gasses. This afternoon when I inspected the bottle I found that the solder has completely dissolved and there was the 5% of stibium particles settled at the bottom of the bottle.

I guess this means there's still a good deal of unreacted Hcl in the solution. Should I keep adding tin until it no longer reacts so readily? Is there a hard and fast rule for how much tin will react with so much HCl? Some quick stoichiometric calculations will provide the answer I'm sure.

 

[Anonymous]

not sure of an amount, I have some small test tubes I usually just put a little acid in and add a piece of solder and apply a little heat to get it going.

Jim

 

[markqf1]

Just add another piece and another piece and so on, until it stops dissolving.
Then, it's best to start over and mix up more.
Always check it with a known solution.

Of course you could add a little more hcl and dissolve more, but I've found it's best to start from scratch at this point.
Just my two cents.

Mark

 

[tlcarrig]

To help the process go faster, use a metal file to "powder" your solder. This type of solder is a lot harder that Sn/Pb solder so it will take you a while to powder up the amount you want.

 

[Chumbawamba]

Terry, I've found that simply dropping in a piece and giving chemistry the time it needs to work will suffice nicely. It doesn't have to be heated, and in fact still works quite well in colder environments. Just drop in your solder and leave it overnight. In the morning you'll have your SnCl2 along with the Sb droppings at the bottom of your container.

 

[roddenberry]

I was wondering about the "limited shelf life" of SnCl2... I guess the solution breaks down over time, or it oxidizes? Would Stannous Chloride be more stable if it was dehydrated into crystals?

What if I were to boil-off the water and save the dried crystals in a bottle? Would this make the SnCl2 more stable? I was thinking crystals could just be dissolved in water as needed...

Robert

 

[eeTHr]

roddenberry;

Yup.

http://store.hvchemical.com/browse.cfm/4,330.html

It's white, like a coarse powder, and will harden and clump. (I've also made it with tin, but didn't try crystalizing it.)

Some people just dissolve the crystals in HCl, while Hoke says a little HCl to dissolve it, then add some water, but that it should end up milky (I guess that some being undissolved at first, makes it last longer). She says to put a small piece of tin in it to make it last longer, too.

I tried dissolving it with just water and it seemed to work OK.

 

[roddenberry]

Cool. I'll try to prepare a little batch and crystallize it. Thanks!
- Robert

 

[LittleJohnnyH2SO4]

Take it out of that bottle and store it in glass. PETE is attacked by acids and if you stick it somewhere for a while you will come back to an acid spill everywhere and crusty insoluble tin oxychloride caked on things.

If you keep air out, it will technically be stable indefinitely, but that doesn't happen. It's quite cheap and easy to prepare. Making crystals out of it would seem to be making work for yourself. The crystals aren't entirely air stable either.

 

[lala14]

Take it out of that bottle and store it in glass. PETE is attacked by acids and if you stick it somewhere for a while you will come back to an acid spill everywhere and crusty insoluble tin oxychloride caked on things.

If you keep air out, it will technically be stable indefinitely, but that doesn't happen. It's quite cheap and easy to prepare. Making crystals out of it would seem to be making work for yourself. The crystals aren't entirely air stable either.

her is something you guys should try an yes try doing this to crystalis your solution dont boil it i tryd an dint work for me but this did http://www.youtube.com/watch?v=XJFfS_YbbYI :lol: also here is another way to make cristals faster http://www.youtube.com/watch?v=D26gaY6jAto

 

[Irons]

I bought a quarter pound of anhydrous SNCl2 on Ebay for $9 US. It's enough to last me a lifetime if I store it properly. When I need some, I'll mix up a couple of cc's or just drop a tiny crystal in the spot plate.

Making your own is good to know. I like making chemicals from dirt.

If you don't understand chemistry, go buy it on Ebay. How much is your time worth?

 

[t.c.moffat]

I have been reading on this forum since I joined and have not been able to find an answer to to the following question.

I have a roll of solder(generic no-name) from Wally-World that is labeled as being 99.3% Tin and 0.7% Copper.
Will this work or will the Copper render the solution unusable?

You people have a wonderful forum here(so much information, so little time).
Please be gentle as this is my first post.

Thomas

 

[Cody Reeder]

I have been reading on this forum since I joined and have not been able to find an answer to to the following question.

I have a roll of solder(generic no-name) from Wally-World that is labeled as being 99.3% Tin and 0.7% Copper.
Will this work or will the Copper render the solution unusable?

You people have a wonderful forum here(so much information, so little time).
Please be gentle as this is my first post.

Thomas

the copper probably wont even disolve and if it did it wouldent be enugh to hurt things.

I usualy get my tin from roto metals:
http://www.rotometals.com/Tin-Ingot-s/27.htm
its 99% + pure, fairly cheap, and ships fast. (although the price has gone up to almost 20$ a pound, its still beter by weight than soder)

 

[Militoy]

I have been reading on this forum since I joined and have not been able to find an answer to to the following question.

I have a roll of solder(generic no-name) from Wally-World that is labeled as being 99.3% Tin and 0.7% Copper.
Will this work or will the Copper render the solution unusable?

You people have a wonderful forum here(so much information, so little time).
Please be gentle as this is my first post.

Thomas

I can't answer your question on the copper - but I picked up pure tin for my stannous from our local Wal-Mart. They sell no-lead split shot sinkers in their sporting goods area that are pure tin - or at least pure enough that they leave no residue when they dissolve. I did make one small mistake the first time I mixed up a batch; I mixed in a 1 ounce Boston bottle with an eyedropper top. I added a few extra pieces of tin after the reaction stopped, tested the solution, and sealed the bottle after letting it sit for about an extra half hour. The next afternoon, I noticed the bulb of the eyedropper had inflated like a balloon - almost to the point of bursting. The temperature change seemed to have encouraged a little more activity out of the HCl. Luckily, I had extra bottles - but I've made my later batches in a separate container, with a little heat from a hot plate. I haven't had the same problem again.

 

[aflacglobal]

If all you have is two metals like tin and copper that are dissolved in the hcl solution and you heat it to saturate the solution, then the lesser of the two should cause any higher metals on the reactivity series to drop out upon cooling. So if you heat it and push extra tin into the solution upon cooling any extra copper should precipitate out. Something like copper does with dissolved gold in a saturated solution of AP.

 

[Militoy]

...the lesser of the two should cause any higher metals on the reactivity series to drop out upon cooling. So if you heat it and push extra tin into the solution upon cooling any extra copper should precipitate out....

I was kind of surprised to notice this same kind of reaction when first testing saturated copper chloride solution for possible gold. When a drop of stannous chloride was added to a few drops of the green solution on a filter paper, the green color instantly cleared. Inspection with a 600X microscope later showed metallic copper that had been forced to precipitate by the tin in the stannous.

 

[t.c.moffat]

Thank you all for your quick answers. Still gathering supplies and wanted to make sure that solder(that I have had for a few months longer than I have been a member of this forum) would be alright to use. Again, thanks to all.

Great forum!!

Thomas

 

[capt_dugout]

Ok I successfully made some stannis chloride using the walmart tin sinkers and 20% HCL. To test the SnCl2 I disolved 3 pentium4 processors in 250Ml of poor mans AR (having overlooked the nitric acid bath to remove base metals) resulting in a color change from almost clear to a dark yellow almost brown solution with little to no sediment that does show a positive for Au. I will keep several Ml of this to check the SnCl2 before use in the future, precipitate and evaporate the rest down and incenerate to process it properly. After I get some clean Au I will remake my pregnant AR so I can reprocess the contaminated SnCl2.
The resulting test showed just a medium purple color. Would this indicate a weak SnCl2 solution, low Au content, or a combination of the 2 ?

P.S. After heating my SnCl2 for an aditional 2-3 hrs now on a hot plate, I get a dark almost black purple stain indicating to me that the HCL/tin reaction was not complete on my first test