Metal Refining & Recovery, 18: Lead Free Solder

Metal Refining & Recovery, 18: Lead Free Solder


Hi everyone welcome back to my lab, so many of you will be excited to know that I am bringing back the precious metals Refining and recovery series so one thing that has been requested many times by people is to refine some of this Silver Solder here This is the stuff used in plumbing to replace leaded solder the silver is added to it in about one to five percent by weight to help the mechanical- properties of the Solder.This is actually a sample that a fan sent me and not just one- Or even two, but three separate people have sent me rolls of solder to refine that’s- So obviously you guys want to see this done. So anyway since this is a new season. I guess of this series, I would like to mention again that I am not doing this to make money like- There’s no way I’m gonna make back any sort of money- refining these rolls of silver- At best, I’ll probably recovers the few grams of silver worth just a few dollars And that’s not going to recoup my processing even if I got this stuff for free- I’m mostly doing this series to explore the chemistry that- said my first idea for extracting the silver from this was just to dissolve the whole thing in some ‘Muriatic acid’ or hydrochloric acid Hydrochloric and Muriatic are the same thing by the way, this is mostly tin Probably like 95% tin and tin is soluble in the hydrochloric acid, but silver is not- So it’d be fairly simple to do that But I did the math and it looks like to do a quarter pound of this stuff it would take almost a half a gallon of acid if I account for evaporation losses and stuff because The tin dissolves rather slowly, so I think what I’m actually going to do is I’m going to set up an electrolytic cell here I’m going to set this up and I’m going to use primarily electricity to oxidize the tin and Perhaps recovered over here and actually be left with a purified tin sample Which is something that I might be using in another video as well. Let’s weigh this over here That looks like a hundred and nine and a half grams which Is supposed to be a hundred and thirteen grams on the roll so yeah, that’s probably about right? Let’s take this back over here. I’m gonna wind this into a coil, and we’ll make our electrolyte solution So this is what I’ve come up with here I’ve just wrapped this into a coil around a piece of half-inch dowel and I’ve bent the ends so I can hang it on the edge of this glass dish a little bit of space underneath, so Materials can fall off of this and not short things out so now for the electrolyte Which is primarily going to be water. Which is generally the case. And add enough water to completely cover the coil here. I’m just gonna add a splash of muriatic acid now this is mostly just because it conducts electricity really well and Has lots of chlorine. if there’s chlorine in the solution the silver will not be soluble, I suppose you could use salt but If you’ve got muriatic acid, you may as well cause it’ll actually react with the tin a little bit so now I’m going to hook these up I’ve got 16 volts direct current between these two terminals here Let’s put the negative electrode over there on that stainless steel spoon And the positive over here on the coil of metal that I want to destroy There we go. We got some hydrogen gas bubbling off Soon, we should see some tin being precipitated out over here now if you look at the reactivity series of metals you’ll find that tin is much lower on the activity series, so That’ll be the first thing to be oxidized and pulled off of this the first thing to go into solution copper, bismuth, silver, all that stuff’s gonna fall out of the solution and settle onto the bottom of the Jar here. Look at those crystals forming, isn’t that pretty? Unfortunately those are very likely to short things out. That’s what I got so far I Didn’t get to it in time Must have shorted out fortunately it acts as its own fuse, so… It wasn’t really that big of a deal So this has been working rather well, you can see this coil is crumbled into pieces and I have processed quite a bit of the tin over In fact this has only taken about an hour and a half to do that. There’s a lot of tin left here, but easily three-quarters of it has been transferred, so I’ve actually just unrolled this Spool of wire here, and I’m gonna do another one of these So we can do a whole half a pound of tin, so another one hundred and fifteen point six nine grams, so apparently there is some variation on the weights of these spools… Anyway, I’m gonna set this up, and were gonna process another one. Now would you look at that? I have electroplated some bubbles… Okay, looks like that’s about as done as we’re gonna get for this step as you can see it’s eating my wire right off there… Let’s pull the spoon out of that Get the last of that tin off of it… So as you can see over here I’ve got quite a pile of tin In fact I’d say I’ve transferred over most of it And what we’ve got left in the dish… There’s a couple of chunks of it in there still you can kind of see But primarily it looks like I’ve just got like copper and silver powder So tell you what I’m gonna do is, I’m gonna pull out the bigger chunks of tin After I break off all the little bits of silver and copper from them And I’m just gonna let this sit in the acid overnight. I may even dump off some of this and strengthen the acid a bit to dissolve away these stray pieces of tin crystals and then… once we got that, then we can process it to extract the silver from the copper. And I think what I’m just gonna do here is, I’m just gonna take this tin solder that didn’t convert and I’ll just weigh it, and subtract it from the total I’m sure I could melt it back into a piece of wire and process it again, but at some point, I’m just wasting my time. So it’s the next morning and presumably the acid has destroyed most of the tin There’s probably some tin still left in here, but is definitely Reduced in quantity and so the majority of what we have left here is probably copper and silver And I think what I’m gonna do with this is I’m going to decant off all of the acid I got a little jar here I’ve been pouring it into and I’ll be saving the Tin chloride for later use… Now, I need to get rid of the copper..And to do that I’ve got several things I can do first is nitric acid of course but unfortunately nitric acid and tin do not really get along. Makes an insoluble white gunk that is very hard to deal with. I could use sulfuric acid, but then tin doesn’t dissolve in that very well either I could take this and roast it in fact commercially if I was doing very large quantities I think that would be the way to go you know just basically smelt the silver out But I think today what I’m going to do is just simply add in some more muriatic acid and then I’m going to add in some hydrogen peroxide to oxidize the copper… And that should dissolve most of it, little bit of hydrogen peroxide here… Okay. Looks like that’s working. I was afraid that maybe this silver would cause it to decompose too rapidly, but really all I need to do is get a little bit of the copper chloride to form and then just oxygen diffusing in from the air will take care of the rest. As the copper chloride kind of acts as like a catalyst to help the copper further decompose. This will take a while though, so Guess I’ll come back in… I don’t know… Six or eight hours? In case you’re wondering I do have a fan, and it is currently going. Normally though I turn it off when I’m filming because of reasons which I hope are obvious. So anyway, we’ve got… this which appears to be done. And… I guess that is silver in the bottom there. It seems like not very much though, so I suspect the pH of this must have been too high… And I’ve run into an issue of the silver chloride actually dissolving even though it’s not supposed to. So let me actually pour most of this liquid off into this other container here… and let’s uh… see if this contains silver chloride Simply by diluting, the acid, should also turn from green to blue… Yes, very nice. Okay, any silver precipitating? Okay, there’s a little bit of white clouds in there. There’s not very much… I guess this solder didn’t have all that much silver in it Let me uh… let’s wash this off So that’s really all of our silver… After letting it settle out, washing it, settling out again, I’m left with this… Now this is primarily silver chloride… but there’s not very much here. Now It might look like a bunch, but, having refined silver before I know that there’s, you know, it really expands when it’s in water like this, so this is probably much less than a gram here… But we’ll put it into a crucible and furnace it down anyway… I don’t know what’s wrong with this furnace… It just refuses to get hot, and it got hot for a while, and then it started cooling back down… So there’s the problem… Looks like a wire burned off. Look at that right there, the wire goes down and comes back up… What’d it do, break off? And then just arc out and until it stopped functioning? I ought to have this sent in and have it warrantied. This is a brand new furnace, it shouldn’t do this… It’s still giving an error… Guess I’m gonna have to see if I can send it in to have it warrantied… In the meantime, it did melt the silver… How about we just break it out of this little crucible instead of pouring it out. [Hammer hitting crucible] Oh hello bug! Go away! So you can probably see right here that there are some beads of silver… Not very much is it? So let’s set this over here on my weighing paper… There we go… Looks like around a tenth of a gram… Now, of course my recovery is not going to be a hundred percent… I lost some because the furnace wasn’t hot for long enough, and the you know microscopic beads didn’t come together But I don’t think I lost 90 percent.. All right, I would imagine ten to thirty percent is what my losses are here… so… either I’m a terrible chemist… or… the companies that make the solder, only put enough silver in them to say that they did… [Chuckles] [Breathes in] I mean… If the silver didn’t make all that much difference and the price of silver was extremely high then, wouldn’t you? Anyway, let’s weigh these pieces of solder that didn’t get destroyed in the electrolysis… Just to see how much we need to subtract from our totals here, so then get some numbers. Okay about 29 grams… While I’m at it I may as well melt down my ball of tin here… Looks like I broke my dish… [Whispers] Pour this out… Let’s weigh this tin that I recovered. Looks like a hundred and ten grams, so I started with around with 200 grams of solder that was destroyed with the electrolysis… So I recovered, you know, around 50 percent of the tin… Now, that kind of recovery I would expect, because, well a lot of the tin oxidizes while you.. are melting it because is so thin and I have all the tin oxide still I can still recover that some acid and stuff But it may not be worth my time. I can tell you right now, that this tin is worth way more than the silver was… [Laughs] See, it’s around… you know ten dollars a pound? That’s around a quarter pound right here, so, two, three dollars in tin… few cents in silver… Anyway, let’s put my gloves back on… Let’s do some math… Definitely wouldn’t want to get any of this math on my hands. Some nasty stuff isn’t it? So… the silver… recovered is point 106 Grams… Point. Oh dear. That’s really zoomed out. Zoom this in a little bit here. So the solder that I started with 225 Grams Solder that was left over… Was 29 grams… so that means the solder that we actually processed… was 196 Grams so point one, zero six divided by 196 Both of those are three sig figs that’s kind of cool… that equals point zero zero zero five four… And then converting that to percent that’s point zero five four percent silver… now of course that means it had at least that much silver in it, right? They on their website, I think it said that it contained one to five percent silver So I am seeing you know roughly… that really Wow, that’s like a hundredth of what they said they’ve got in there, something’s up. I may return to this project at some point. I would love to get one of those xrf handheld devices that we were using back up in the university, because then I could just check my waste materials and just see hurt hurt just the solder itself for instance and see how much silver is got in it At least I was able to recover it and show you guys the chemistry Hope you enjoyed I’ll see you next time. [Uplifting Music]

100 thoughts on “Metal Refining & Recovery, 18: Lead Free Solder

  1. Cody are you right handed ?
    Because when i saw you writting down your calculus i spot that u write like me with my left hand but i'm right handed ahah

  2. another way to get the solder to electrolyzing better is to cast it into an ingot first. Coils are notorious for not fully electrolyzing!

  3. A thought perhaps, but why not combine all the solder into an ingot of some sort before refining electrochemically? The amount of tin would remain the same but there'd be less bits left over, using a wider/deeper container would likely reduce the chances of shorting out as well.

  4. Hydrochloric is the scientific term. The other term is its name like water is h20… but its actually hydrogen and oxygen. 2-1

  5. Nitpick, when rounding floating numbers to fixed count, you should +1 to next digit if it's greater or equal to 5. For example, 5.45 ~= 5.5, 4.55555 ~= 4.5556 ~= 4.6 ~= 5.

  6. What sort of concentrations of hydrogen peroxide do you use? In England, we're terribly limited as to what concentrations amateurs are allowed to have.

  7. I have the same furnace and the aluminum contact blocks they use melt when you use them. I replaced them with steel bolts and its working fine so far.

  8. CODDDYYY its way late but I always binge watch your videos at work, (it’s a pretty lenient workplace) and I was curious, you said the crystals would short it out, how does that happen?

  9. Cody always tell people to not put molten tin in water to cool it It will explode and send hot metal everywhere

  10. 14:40 They say that highly intelligent people have terribly legible writing. You back up that theory my friend. Love all your videos and love you man, you're an inspiration! Thank you 🙂

  11. I guess your silver is mostly in the knob of "tin" you made… By uncontrolled electrolysis you force the formation of silver chloride. And although it does not dissolve well in water some goes into solution. Then during electrode the most noble metal in solution plates at the cathode first. This is where the silver went! ;(

  12. Cody! Record that reaction from start to end and post it as a separate video. Watching at 2x speed on YouTube and it was awesome. Looked like magma solidifying

  13. not followed up on this (since it has been nearly 2 years since this was put out) but I am guessing if you had used hydrogen peroxide, and a chloro-alky cell (spelling?) ie a tank with water, and peroxide, and one with salt water, putting the system together so that the chlorine would be drawn from the saltwater via a tube of water and capped on the ends with a filter to avoid the salt spreading out through the both tanks of water, you should have been able to use the chlorine from the table salt to break down your tin, till it was gone, and probably the silver as well as everything else for a buck or two of table salt, with plenty to spare, and been left with sodium hydroxide mostly in the tank that the sodium is attracted toward, then it would just be a matter of making supersaturated solution of water and tin/copper/silver chloride, and then let it cool off letting the silver precipatate out first as a chloride salt, filter, heat again till it is super saturated, and repeat to do crystal fractionalization. to sort the various salts, and finish from there to get a much purer reaction and capture much more of your substances. also the stannous chloride would be nice to see you do a video on how to make that and glass into conductive transparent glass. 🙂 (yes I know with out the iridium it wont be as tough, I just like the idea of transparent conductors since this might improve energy collection from photovoltaic cells 🙂

  14. Why do Americans call it "Sodder"? There's an "L" in there, you know, it's written on the packet. From the Latin solidaturam .

  15. Cody can you try refining silver solder used by HVAC techs? I'm one of those guys and we use solder that's supposedly 15%. The top rated sticks are at least.

  16. ………hate to see waste, that was good solder……..but in reading the comments I saw mention of the claimed silver content is not as claimed…Any reason for not using a carbon electrode instead of a stainless steel spoon?… Always some variation on the weights of spools but never over it's always under. …I remember that our boxes of matches in 1970s claimed average content of 50 per box but when I counted many of them I found hardly ever more than 47 yet I never came across a count of 53, 52,51,50,49. Today these match boxes only claim 46 matches per box.

  17. @Cody's Lab, have you ever done a follow up with the xray detector?

    Have you tried real silver solder (my experience in the plumbing and HVAC trades has taught me that common solder, like you used, is far different then what I was taught is silver solder. "Real" silver solder is used by the HVAC guys who connect AC line sets and such. It has a much higher melting temp then the types used for standard plumbing, and is also supposed to be stronger then the copper it connects!)?

    And lastly, could you help me to understand/make a video on: How I can process my own scrap- As a plumber/HVAC mechanic, I come across a lot of copper, brass, and of course solder joints. The scrap value is down right now, I'm willing to experiment to refine some of the metals I have (Cu, Zn in the brass, Sn, etc.). Thanks again Cody, love your work in educating your fellow man:)

  18. I didn't know, I haven't been wearing proper PPE in Math class… Thanks for the great videos as always. 🙂 I know this is an older one, and you'll never see this, but it's been a heck of a week and I'm binge watching your videos to relax.

  19. When you add water to your demonstrations, do you use filtered, distilled, deionized, or just tap water? Most tap water has a lot of minerals dissolved in it, right?

  20. Remember back in chemistry class where the one kid who never paid attention would start doing the maths without their gloves on and the teacher would scream at them for being dangerous

  21. hi Cody. thanks for the video.
    my name is Alexandre. and I am from Brazil.
    I need to ask for help.
    If I put a motherboards or a power board from computers in hcl the solder will disolve and the tin, lead and some silver goes to the soluction. How can I recover the tin and lead from the soluction.??

  22. You may make a profit if you convert to silver nitrate. 42.5 g of 99.9999 makes 96g of silver nitrate so $40 to $280 haha

  23. This refining scheme is crap! Most of the metals plated through to your "tin". You drove the electrolysis so hard that everything plated through. Either do slow electrolysis (pain because tin shorts cell), or dissolve everything in nitric acid, then precipitate out the silver with HCl. You could also use "poor man's aqua regia" (HCl and a nitrate salt) to dissolve the tin and copper faster. (This is the crude scheme used to make nitric acid). Once you get the silver chloride, add this to NaOH solution until it turns black, then add sugar a little at a time as it heats up. Silver powder results which you can melt with a torch.
    In order for electrolysis to work, you need one metal in the majority, along with a parallel-plate geometry and careful control of the voltage to achieve separation. You would have been better off using the HCl along with some peroxide to push things along, and rolled the solder thin.

  24. I will play you 10 thousand dollars a week be my chemistry teacher.
    Plus I will pay for any of the gold, silver or mercury in the practical lessons.

  25. The silver doesn't add much to it in any case. Badger solder that uses antimony is just as good if not better.

  26. They always lie on the content. I noticed the silver solder you use in HVAC you have to use more heat to solder the copper together than before.

  27. I wish i could do things like this…

    Buttt nooooo, i am a mucisian, chemistry shouldn't be one of my intrests!
    Well i fucking love chemestry, physics, math. Those are the things that can make me understand how the universe works, not mozzart!

  28. I have did electrolysis of lead as both Anode and Cathode in Nacl solutions what was i get a Cloudy Solutions what was that ?

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