Non-Chemical Newbie here.. can you take advantage of "phase changing

[AuMINIMayhem]

Hey everyone, I'm new to the gold recovery thing. Hell "the fever" bit me like a rabid dog! I stumbled on it quite by accident and have been playing around with the scrap I have, just trying out very basic techniques. It's been really hard to find any kind of info that is worth it's weight in..ahem, you know what I mean. Kudos for the awesome sight! I've read just about every post!

After reading, I feel comfortable enough to ask if a theory I have would be possible. Although I know in actual application this may not be the most feasible method, I wonder why I have yet to be able to find any accounts of someone trying it. Let me back up a bit and give you my "eureka moment" of a back story..LOL!

I found a good stash of cheap (or so I thought) plated jewelry. About ten pounds of it. I wasn't quite sure what to do with it, so I started looking into gold recovery, then, WHAM!.. gold fever! I wound up purchasing a few things on Ebay (crucibles, graphite ingot molds, a kiln). While I've been waiting for the kiln to arrive I started playing with different torches (propane, then MAPP, then MAPP with an Oxy can attached), just to kind of get the feel of how to handle stuff, how to heat things evenly, how to NOT injure myself as I'm so prone to doing, etc. Basically, just to practice (ok, alright.. you got me... I'm playing with my toys! LOL!)

The other day I had a very interesting thing happen and then I started thinking (if only you knew how dangerous it is when the words "I was thinking" come out.. friends, family, neighbors and pets all shudder).

I noticed that the metal seemed to seperate. (don't jump ahead of me, you've probably already figure out where I'm going with this) It appears as though the torch I most recently used (MAPP+Oxy) got the jewelry scrap I have, just hot enough to melt out a lot of the "base" metals but left a very "nuggety" looking yellowish metallic substance vaguely in the shape of the original jewelry. Without any kind of testing and just looking at various pictures, I believe it to be gold, but of course I'm not entirely sure of it. Eureka!.. (or is it?) :lol: :lol:

Here's my thought/question:

Is it possible by using the simple laws of physics, ie: the laws pertaining specifically to "phase change", to remove a good portion of the base "crap" out of your gold prior to refining. All of the typical metals have differing melting points, right? *reference chart* http://www.lenntech.com/Periodic-chart-elements/melting-point.htm

I guess what I'm saying is, if you know you have a gold and silver alloy, could you not heat it up to, or a little over, silver's melting point (962c), pour it off and be left with gold which although is "hot" maybe even really soft, has not yet reached it's melting point of 1064c? I realize this kind of precision in temperature control is rather difficult without the proper equipment and that alloys are typically far more complex than just two metals, but in theory could this help "prep" your gold to make it easier to refine?..

If I can get my friggin camera to work, I'll take some pictures of the before and after materials so you can see what I'm seeing and either confirm or deny..

Well, thanks for your time, I'll keep an eye out for responses.. be gentle.. I'm still a virgin :wink: :lol:

 

[Harold_V]

I'll be gentle, but I'm going to toss a ton of water on your "Eureka moment". It won't take you long to understand why all of us use chemicals to refine.

I won't work, nor can you melt most metals and separate them by stratification.

I'm not educated, so I can't talk about it the way those that have made a study of it can, but it gets down to how metals share electrons and other interesting things that are beyond my feeble mind. Once you combine most metals, they can be separated only with considerable effort. Simply melting one away form the other doesn't work, for each affects the other in lower the melting temperature, so they all melt at the same time. That's called a eutectic point.

There are metals that don't readily alloy, and will separate by combing them with other metals. Gold in iron is an example. You can pull the gold out of iron with silver, but now you have silver and gold mixed, you still don't have pure metal. In this case, you've really made a good change, for they're very simple to separate, but that's not always the case.

Too bad we can't encourage sue to talk about things like this. He has a serious education, but is reluctant to say much.

Welcome aboard!

Harold

 

[AuMINIMayhem]

LOL!.. damn, I knew I should have paid more attention in Chemistry rather than chasing girls! :lol: :lol: Had to ask though, you never know when an "outside of the box" thought could bring about a new methodology. It was worth a shot. anybody got a loaf of bread so's I can enjoy any egg I may have on my face? :lol: )

I am still curious though, to find out what effect it is that I'm seeing.. I'll have to post pics tomorrow, if possible, maybe what I have isn't "scrap" but just plain "crap" and someone might be able to save me a lot of headahces..

Well, I'll be piecing together my electrolytic cell tomorrow.. the hardest part I'm finding (or rather, not finding) is the chemicals... any Walmart/Home Depot/Lowes, etc solutions to this problem or do I need to go to a chemical supply warehouse?.. (if the answer is in another thread could someone post the link for me? that'd be of immense help. )

 

[Harold_V]

I am still curious though, to find out what effect it is that I'm seeing.. I'll have to post pics tomorrow, if possible, maybe what I have isn't "scrap" but just plain "crap" and someone might be able to save me a lot of headahces..

Without seeing the things you've mentioned, it's hard to say what's happening, but what comes to mind is that you have some costume jewelry, made of lead alloy or some such, that melts at a very low temp. If metals are not combined, you can melt one away from the other to some degree, but that wouldn't be an acceptable way to recover values, assuming that's what's going on. For one, unless you have the capability to cupel, it's a good idea to keep lead out of the refining process. Tin, too, presents its share of problems, if for no other reason, filtration.

Sorry I'm no help on the chemicals you seek. I refined for years, but only with nitric and AR------and never ran a sulfuric stripping cell. What little stripping I did was done with cyanide, but there are some good people on this list that can guide you. I've been away from refining for more than 12 years now, so my memory is growing dim----and old age isn't helping!

Harold

 

[toadiesop]

Regarding your cell chemicals...

At Wal-Mart I found 94% sufuric acid in the form of "Liquid Lightning" drain cleaner. It works great in my cell.

It's not by the regular "draino" type products. It over in the hardware section. It should be easy to spot seeing it is a heavy-duty protective plastic bag. :lol:

 

[AuMINIMayhem]

you guys are awesome, thanks!

Harold, not sure if this helps, but when I was hitting the jewelry with the oxy torch, as it reached melt temp. the flame changed to a bluish/green (I'm assuming copper content?) and there was a helluva a lot of smoke coming off of it out of nowhere. Literlly went from just hot to smoking like crazy and then would melt... Pics are coming soon..

Thanks again, guys.. (off to WalMart) 8)

 

[AuMINIMayhem]

Ok here we go:

The piece of scrap on the left is what I started with. After hitting it with the Oxy/Acetyl torch some metal melted off and left a glob (button?) of what appears to be copper, while the gold-toned metal retained it's shape (relatively, you can sort of still see the pattern)..
Sorry about the picture quality, had to use my scanner, the dig camera died

For reference, the colors aren't quite what they look like in person, the upper right blob is the "copper" toned piece that dropped out while I was hitting it with the torch.

Any ideas?..

 

[lazersteve]

Mayhem,

First off the smoke you experienced my have been vaporized silver (

). Silver will boil off rapidly above it's melting point as Chris (GSP) pointed out to me not long ago. As for the coppery metal, I don't think it's pure copper but maybe an alloy of it like brass, because it melted before the gold plating did (copper melts at 1083C). The brass would melt around 920C, the silver would start vaporizing above 960C (the white smoke), and gold melts at 1063C. The smoke is deadly so be very careful (good ventilation, scba gear, etc.).

You would be doing yourself a favor if you go ahead and build the cell and strip these items using reverse plating. You'll be safer and end up with a more workable product (gold powder).

Take Care,

Steve

 

[goldsilverpro]

The yellow material, gold presumably, separating by heat, is very strange. I've never seen anything like it and I've been trying to think of reasons why.

The yellow material didn't discolor and, therefore, is most likely gold. The metal underneath could be pot metal or, by another name, zinc based die casting. This has a low melting point of somewhere around 400 deg C. I couldn't find the exact figures. I have seen a few pieces of gold plated pot metal costume jewelry, although it is rare. If that's what it is, the white smoke was probably zinc and lead, both of which are quite toxic. I don't know why the glob is copper colored but, it may be tarnish. To test it, scrap or file away some of the surface and check to see if the color underneath is whitish or gray. Also, try and cut it with a knife and see how hard it is. If it's softer than copper, it is most likely pot metal. By your description, it seems that the separation happened fairly quickly. If so, this would be another indication of pot metal. I think it is probably pot metal.

This metal is called "pot metal" because casters used whatever happened to be in the pot. This would most always be zinc plus things like lead or tin. Zinc based die castings are about the same but are made using an exact formula.

How heavy is the yellow foil? Maybe it held together because it has a heavy nickel and/or copper plated backing.

All in all, for safety reasons, don't do it any more.

 

[AuMINIMayhem]

Hey, thanks guys.. I had no idea of the toxicity, I figured it wasn't good and took precaution, but deadly?.. that's whole different playing field :shock:

The gold "foil" you asked about is quite solid and the color runs completely through (I looked under a 10x microscope at work after cutting and scraping it).

The copper looking material is the same throughout as well.. I talked to someone (the guy I got this scrap off of actually) and he said it was quite possibly "gold filled" as opposed to plated... I'm still trying to wrap my head around what exactly the difference is.. I know it's probably not "karat" gold because there are no markings on it..

Thoughts?..

Thanks again!
Derek

 

[goldsilverpro]

So far, I'm batting zero.

Is the glob soft?

It sounds like the guy is probably right. It very well could be gold filled. I still can't see how copper, which has a higher melting point than the karat gold used in gold filled, would melt first. Maybe Steve is right and it is brass. This would explain the white smoke. Common brass is 30% - 40% zinc but, most brasses are yellow, not copper colored. I'm now thinking it could be bronze. Many bronzes are copper colored and are alloyed with things like zinc, tin, or aluminum which can give them much lower melting points. I read that some bronzes melt as low as 500 deg C.

Any time you heat almost any metal to the point that it's giving off smoke (vaporizing), you're in a very dangerous situation. Acetylene torches can reach a temp. of 3000 deg C and it's very easy to get metals too hot.

 

[lazersteve]

Chris and All,

Here are some common metal compositions and melting points:

Check the aforementioned metals:

http://www.muggyweld.com/melting.html

Chris you hit the zinc right on the head. I could be wrong about the silver, but with the posters description of events and the close mp of the brass and silver it is possible silver and zinc are the mystery smoke...still bad for our poster.

The melting point of the copper is depressed by the zinc with which it is alloyed and the melting point of the zinc is raised by the copper, that's how I figured it's brass.

Steve

 

[AuMINIMayhem]

you guys amaze me.

it's jewelry scrap from India and a guy I work with is moving and got rid of a lot of his refining stuff.. he just happened to find a couple boxes (about 10-15lbs worth) of jewelry scrap and heard me talking at work about wanting to get into this, so he just gave it to me.. that's why I don't have to much of an issue "playing" with it until I figure out what the best way to recover the stuff is.. I'm thinking the cell is going to be my best bet, but I'm wondering how I avoid getting the other mystery metals in solution. Do I just watch it and pull the plug once the gold hue has gone?

Steve, I just tried a little in a solution of "Zap" and water (about 50-50) just to see that it's set up properly and no shorting out, etc. There was a black substance that dropped to the bottom as described in your tutorial and the water turned a shade of bluish-green (I'm assuming copper present). but the voltage never dropped.. the metal changed from the yellow gold color during this process and turned a reddish color, very much like this color. At this point, should I just take it out even though the voltage never dropped?

Also, I'm not sure who the moderator is, but if you want to move this over to the proper thread (I'm assuming tutorials Q and A), as this is heading in that direction, it's cool.

Thanks again!
Derek

 

[lazersteve]

Assuming ZAP is sulfuric acid I would not dilute it if it were me. I use my acid at full strength. The exposed metal is likely copper. The voltage won't drop, the amperage will. Does your charger have a built in ammeter? The black powder is your gold plating that was on the jewelry.

You should pull the item out when the gold layer is gone. Be sure to rinse the item of all black powder before discarding.

Steve

 

[goldsilverpro]

Like Steve said, don't dilute the sulfuric. Sulfuric, when very strong, will dissolve only traces of copper and other base metals. As you dilute it with water, more and more base metals will dissolve. Thus, the blue green color of your solution. The amps aren't going to zero because you're dissolving copper and nickel. Were I you, I would start over.

It does, however, improve the stripping to have a little water in the solution. If I were using the 94% "liquid lightning" product, I would add 5% water, by volume. Always add the acid to the water. However, toadiesop has been using this product at full strength with great success. Steve is using a sulfuric drain cleaner product that is slightly weaker and would never need additional water. I think he has also mentioned a greenish solution.

AuMINIMayhem. Please don't take offense. You seem to be a very experimental type person, which is great but, you often seem to not look before you leap. I don't want you to get hurt. There's tons of info on this forum to keep you safe and, yet, get maximum capabilities out of these chemicals. If you want to experiment, I would suggest asking us what we think about your idea, before you do it. When you gain experience, you'll know better about what you can or cannot do.

 

[AuMINIMayhem]

yep, someone mentioned the liquid lightning earlier and that's what I got. Steve, I have the same battery charger as the one that was in your tutorial (quite by accident). The amperage (sorry I think I said voltage) hasn't been an issue since I switched to the liquid lightning. goldsilverpro, thank you, no offense taken, it's nice to have someone looking out for me I appreciate it. At this point I'm going with the tried and true and going by the tutorial. 8) I'll let you know how it goes.

Thanks again guys!
Derek

 

[AuMINIMayhem]

Houston, we have black precipitates! So far I've managed to run a few batches of this scrap through their paces and I'm getting quite a bit of yield. It's taking upwards of 2-3 minutes before the voltage drops on some of the pieces I have. Very promising indeed. I'm going to run the rest tomorrow and then go through the rinsing procedures. I'll update again to let you know what I wind up with. I think I'm going to discard the sulfuric when I'm done. Heck it was only 8 bucks at Walmart plus 2 or 3 for the glycerin, so no real big loss there.. *shrug*

On a side note, I have a few questions.

a) I'm having a helluva time seeing what going on due to the amount of suds created. perhaps I added too much glycerin?

b) any way to "neutralize" this stuff so it's safe to dispose of ?

c) anyone know of any reputable refiners I could ship this stuff off to? (or would anyone on here be willing to smelt it for me at a decent price?) I've read alot of articles saying refiners can be a bit of a gamble when it comes to the ethical side of things. I simply don't have the setup I need to do it. I had bought a kiln on ebay, but I haven't heard from the guy who sold it to me and it's been about a month. He did say that they're drop shipped, so I don't believe I've been hosed, I'm just worried about being too "green" to try it on my own as of yet.

Thanks again guys, you've been a great help!
Derek

 

[lazersteve]

Mayhem,

Sorry but I typed for an hour this morning on a detailed reply to this one and somehow lost the post. Boy was I ticked off!

I'll retype a new one later when I cool down.

Steve

 

[goldsilverpro]

AhHa, it happened to you, too. That is very frustrating. I finally learned to copy and save to a Word doc, every so often.

 

[AuMINIMayhem]

Awww, Steve.. it's the thought that counts..

Did a bunch more today, now I think I'm ready to go do a bit of rinsing.. I'll check back later to see if you remembered what all it was you typed. If not, understandable..