# Metals from picture fixer solutions?



## kurt (Dec 23, 2011)

Ok – I tried a forum search using “picture fixer solutions” & got a no match

I picked up 2 containers of this stuff today from a guy that used to have a 1 hour photo shop & his photo developing machine would recover the metals from the fixer solutions.

One container is 7 lb of the black lump on the left that looks like charcoal & crumbles real easy & melts to the metal in the center

I put this piece of metal in a shot glass with nitric diluted 50/50 & no visible reaction after 5 minutes – so took it out, washed it off & tried HCL – again no visible reaction after 5 minutes – took it out & washed it off & tried AR & again no visible reaction after 5 minutes. This was all done at room temp

The fixer solutions this stuff was recovered from was primarily color pic solutions “some” black & white. I believe chrome was used in color fixers & he mentioned nickel. Also on page 87 of Hokes, she says – “several other metals (besides Ag) including Au, Pt, Fe, Pd, U, & Se find employment in photography, printing paper, & toner solutions. She talks about several ways of recovering the metals from solutions – but I already have the recovered metals – If I had the solutions I could test with stannous & figure out how to approach recovery – so my problem is how to get it back into solution for testing & recovery.

I have 7 lb of the black charcoal like stuff (on the left) & 7 ½ lb of the metal chunk on the right (I haven’t run any test on the chunk to the right yet)

At this point I am thinking I need to inquart with ether copper or silver – then go with nitric – then AR – but thought I would throw it out here to see what the rest of you could suggest.

Kurt


----------



## Harold_V (Dec 23, 2011)

kurt said:


> One container is 7 lb of the black lump on the left that looks like charcoal & crumbles real easy & melts to the metal in the center


You most likely should be melting that material with soda ash and borax, including some scrap steel. Otherwise you may be losing some of the values as sulfides. 



> I put this piece of metal in a shot glass with nitric diluted 50/50 & no visible reaction after 5 minutes – so took it out, washed it off & tried HCL – again no visible reaction after 5 minutes – took it out & washed it off & tried AR & again no visible reaction after 5 minutes. This was all done at room temp


It should be silver. Conducting tests without using heat can be a mistake, so don't take the results as being of value. 

HCl and AR are the wrong test. Remember, you're supposed to be looking for silver, which doesn't dissolve in either of them. 

Can you say Schwerter's solution? There's nothing like it for a fast test for silver. 

Go back to the sample you produced, and place it in a beaker with a few drops of nitric, along with a few drops of water. Heat the material. Silver should dissolve readily. If it does not, I have no clue what you have.



> At this point I am thinking I need to inquart with ether copper or silver – then go with nitric – then AR – but thought I would throw it out here to see what the rest of you could suggest.


Do you understand why one inquarts? If not, review what Hoke says about the process. Mean time, unless you have reason to suspect there's gold in the metal (color is clearly wrong, plus it makes no sense that you'd recover gold from the source mentioned), inquartation isn't even remotely called for. You simply have to quit diddling around doing things poorly and follow prescribed methods that are known to work. That would include heating solutions. 

Harold


----------



## goldsilverpro (Dec 23, 2011)

The black material is probably silver sulfide. If so, the simplest method is to melt it with about 1/2 its weight of borax and a little soda ash, with several lengths of rebar in the crucible. The rebar should be long enough to stick out of the top of the crucible so it can be easily removed before pouring. The sulfur in the silver sulfide combines with the iron and reports in the slag. When poured in a mold, the silver sinks to the bottom and should be quite pure.

The material on the right looks like the brittle silver that is plated from fixer on a rotating cathode drum or plate. It is brittle because it contains silver sulfide and it appears to be from 90 to 95% pure silver. It is purified using the same rebar method as above.


----------



## Dr. Poe (Dec 23, 2011)

The black, crumbly stuff originally was steel wool pads. The "Hypo" (Sodium thio-sulfate. AKA sodium thionate) which contained silver, gold, palladium, and platinum, but mostly silver is scavenged by the adsorption of the Pm's on the steel wool is refreshed and ready to "fix" more photos. My method was to mix soda ash, borax, silica (or fine sand to flux the iron)
with litharge and smelt the mass to a hard lead. Then to remelt the bar to white/yellow heat and impinge hot air upon the molten mass to burn lead and left over iron. What's left is silver containing gold. If nitric acid dissolves it (from this source, it almost always does dissolve it.) remelt it again and pour into shot; dissolve the shot into dilute nitric acid. If it refuses to dissolve, remelt with more silver (inquartation), pour into shot again and dissolve in 50/50 nitric/distilled water . Heat no hotter than 154F. When it's finished, catch the solids from the bottom by decantation and filtering. The rusty left overs will mostly be gold. The liquid will be silver nitrate, a trace of lead nitric, and silver nitro-platinate and palladium nitrate.
Add Salt (NaCl) water to the nitric, and precipitate silver chloride (white cottage cheese-like), the opalescent white that doesn't settle immediately is silver chloro-platinite, which must be treated with aqua regia to dissolve the platinum and drop the rest of the silver as silver chloride. Using the search box above here at the forum search for "shotting" and "quartation" .
8) Dr. Poe


----------



## goldsilverpro (Dec 23, 2011)

Dr. Poe said:


> The black, crumbly stuff originally was steel wool pads. The "Hypo" (Sodium thio-sulfate. AKA sodium thionate) which contained silver, gold, palladium, and platinum, but mostly silver is scavenged by the adsorption of the Pm's on the steel wool is refreshed and ready to "fix" more photos. My method was to mix soda ash, borax, silica (or fine sand to flux the iron)
> with litharge and smelt the mass to a hard lead. Then to remelt the bar to white/yellow heat and impinge hot air upon the molten mass to burn lead and left over iron. What's left is silver containing gold. If nitric acid dissolves it (from this source, it almost always does dissolve it.) remelt it again and pour into shot; dissolve the shot into dilute nitric acid. If it refuses to dissolve, remelt with more silver (inquartation), pour into shot again and dissolve in 50/50 nitric/distilled water . Heat no hotter than 154F. When it's finished, catch the solids from the bottom by decantation and filtering. The rusty left overs will mostly be gold. The liquid will be silver nitrate, a trace of lead nitric, and silver nitro-platinate and palladium nitrate.
> Add Salt (NaCl) water to the nitric, and precipitate silver chloride (white cottage cheese-like), the opalescent white that doesn't settle immediately is silver chloro-platinite, which must be treated with aqua regia to dissolve the platinum and drop the rest of the silver as silver chloride. Using the search box above here at the forum search for "shotting" and "quartation" .
> 8) Dr. Poe



If this is from a 1 hour photo shop, there are no metals involved except silver - none - zilch - no Pt, Pd, or Au. In the literature, there are some emulsions containing Pt, Au, etc., but these are for very obscure applications involving industrial x-rays. Also, Pt or Au solutions are (rarely) used to tone developed black and white photos and make them appear metallic, but I doubt if they ever have been used in a 1 hour photo shop. Even if they were, these metals wouldn't end up in the fixer.

Whether the black material is from treating fixer in a steel wool canister or in an electrolytic unit, it is still likely to be silver sulfide and can be easily melted with rebar as in the method I gave. This method is fairly standard in the industry. A place I worked processed canisters by the semi truck load. They washed the silver sulfide and silver metal out of any remaining steel wool and then dewatered it and melted it with rebar. Very simple.

Why contaminate the silver with lead or any other metal when it's pure to start with? We consistently produced 99.98% silver by simply melting the black sludge with rebar.

Dr. Poe. I realize that you are just trying to help but, in this case, I think you've stepped out of your realm of expertise. You've taken a simple thing, made some faulty assumptions, and made a long convoluted process that is complex, unnecessary, and dangerous (burning off the lead!). I would highly recommend that no one should follow your lead in this case.


----------



## Juan Manuel Arcos Frank (Dec 23, 2011)

Kurt:

You can also use the potassium nitrate process for silver sulphide,the step by step process has been posted by me right here in the Forum.

Hope it helps.

Kindest regards.

Manuel


----------



## kurt (Dec 23, 2011)

Thanks guys – after Harold said –“You most likely should be melting that material with soda ash and borax, including some scrap steel. Otherwise you may be losing some of the values as sulfides.” --- it jogged my memory to a thread I read awhile back concerning this. – So I did a search using “rebar” as I remembered that being mentioned in the thread. Rebar took me to the thread titled “silver fixer” which is what I was looking for when I used “photographic fixer solutions” & got a “no match” result.

Harold – the reason I was thinking inquarting was because of what I read in Hokes about other metals being associated with photographic waste. The Au & Pt in particular. I have never worked with this kind of material so didn’t know if they where maybe significant enough (or not) to block the reaction with the acids. Another words high enough in maybe Au & Pt to block the reaction of the nitric on the Ag while at the same time the Ag blocking the reaction of the AR on the Au &/or Pt. (which is something I remember from the very first time I read Hokes – don’t need to re-read that one to understand it)

Also – the reason I did a very small melt test on the charcoal like stuff was to see if it was actually primarily a metal precipitate from the fixer or if it was primarily dried chemicals from the fixer – it was just a test of a “small” amount.

Also – I always run my acid tests (on unknowns) first at room temp then if I don’t get the expected results based on what I think it might be I put heat to the acid test – as we know, some metals require heat to cause a reaction with the acid – some don’t --- Silver & nitric shouldn’t need heat to get a reaction going – which is what caused me to stop & question what I had.

Heating the acids would not have got me on the right path anyway – being as how I am dealing with a sulphide. Also I did both a search on the forum & referred to Hokes before posting to the forum – So I guess what I am trying to say is –I think I am following procedure when dealing with an unknown. Run some tests, do some research, if your not finding the answer, ask a question.

And as always Harold – thank you for getting me on the right path with the sulphide, flux, scrap steel answer. It gave me the info I needed for a forum search that alluded me other wise.

Kurt


----------



## kurt (Dec 23, 2011)

Juan Manuel Arcos Frank said:


> Kurt:
> 
> You can also use the potassium nitrate process for silver sulphide,the step by step process has been posted by me right here in the Forum.
> 
> ...



Manual - could you point me to this thread so I can read it & ad it to my tool box

Thanks Kurt


----------



## jimdoc (Dec 23, 2011)

I think it is this one;
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=11061&p=108932&hilit=potassium+nitrate+process#p108932

Jim


----------



## Dr. Poe (Dec 23, 2011)

GOLDSILVERPRO You happen to be addressing an issue of which I am way more experienced than you.
OK, use bismuth instead of lead. There is most certainly gold in color photography. Apparently you know nothing about color photography, recycling hypo or the refreshing tank. The silver is a hundred times more plentiful because the base of color photography is the silver bromide emulsion. I think that maybe you have processed a bucket before and left the gold, platinum and palladium in the silver. If you don't agree, let's move this discussion to debates and discussions where I will be glad to educate you further. Also, where you worked, I doubt if you were in on all of their secrets. Dr. Poe


----------



## 4metals (Dec 23, 2011)

Dr. Poe

Please read my feelings about your post in Debates and Discussions.


----------



## butcher (Dec 23, 2011)

:shock:

This winter may be a long one, all of us cooped up in the house too long? I think we need a few breaths of fresh air and to cool off some. it is too early in the winter to be getting cabin fever already.

I would like to hear a friendly discussion about this we all can learn from it, but do not care to hear an ego pissin contest.


----------



## nickvc (Dec 24, 2011)

butcher said:


> :shock:
> 
> This winter may be a long one, all of us cooped up in the house too long? I think we need a few breaths of fresh air and to cool off some. it is too early in the winter to be getting cabin fever already.
> 
> I would like to hear a friendly discussion about this we all can learn from it, but do not care to hear an ego pissin contest.



I am in complete agreement with that sentiment.


----------



## kurt (Dec 24, 2011)

jimdoc said:


> I think it is this one;
> http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=11061&p=108932&hilit=potassium+nitrate+process#p108932
> 
> Jim



Jim - thanks for the link - I had already read that thread after Harold pointed out to me that I was working with a sulphide & needed to use some scrap iron when melting with soda ash & borax flux. Once Harold gave me that answer here it jogged my memory to having read that thread & his mention of using rebar so rebar is what I used as a serch to find it.

Anyway - in that thread (silver fixer) Manual only mentions using potassium nitrate & then to follow his step by step instuctions posted on the forum.

So I used "potassium nitrate + silver sulphide" as a search & found his actual step by step instructions. It's a pdf down load (complete with pictures) under "Silver" with the thread title "Process to convert silver sulphide into metalic silver"

Awesome job Manual & thanks for taking the time to produce that pdf & posting it here on the forum.

I will now try both of these methods with about an oz or 2 per method to decide which method is going to work best for me to process the 14 lb of meterial i have.

But first I need to melt & cast into bars the 35 - 40 oz of silver cement I just dried from my last batch of contact points

Again thank to all of you for your help & in put here - your an awesome bunch!

Kurt


----------



## Harold_V (Dec 24, 2011)

kurt said:


> Harold – the reason I was thinking inquarting was because of what I read in Hokes about other metals being associated with photographic waste. The Au & Pt in particular. I have never worked with this kind of material so didn’t know if they where maybe significant enough (or not) to block the reaction with the acids. Another words high enough in maybe Au & Pt to block the reaction of the nitric on the Ag while at the same time the Ag blocking the reaction of the AR on the Au &/or Pt. (which is something I remember from the very first time I read Hokes – don’t need to re-read that one to understand it)


Fair enough---although the likelihood that you'd encounter photographic wastes from a source that had even a small amount of either platinum or gold within is not good. While I never processed a great deal of this type of material, I never, once, found even traces of anything but silver. I expect your experience will be much the same. 



> Also – the reason I did a very small melt test on the charcoal like stuff was to see if it was actually primarily a metal precipitate from the fixer or if it was primarily dried chemicals from the fixer – it was just a test of a “small” amount.


Not a problem---and the residue can be processed further for extraction of any values. Just a "heads up" that you should have used a different procedure. The point being if it is a sulfide, you most likely wouldn't realize there is any metal present. The addition of scrap steel yields results that would have, otherwise, been totally missed. With such material, if you add silver (to serve as a collector) and process without the scrap steel, you actually lose silver to the melt in that it readily combines with any sulfur that is present. It can be recovered, of course, by re-melting, adding the rebar that has been mentioned time and again. I know this to be true because I've had that very experience, albeit not from photographic wastes. 



> Also – I always run my acid tests (on unknowns) first at room temp then if I don’t get the expected results based on what I think it might be I put heat to the acid test – as we know, some metals require heat to cause a reaction with the acid – some don’t --- Silver & nitric shouldn’t need heat to get a reaction going – which is what caused me to stop & question what I had.


You made a decision not based on good logic. On more than one occasion, making electrolyte with pure silver and nitric, dissolution didn't proceed immediately, and was accelerated by dilution. To say that heat helped would be an understatement. Sorry, but I still say you should have heated the solution. We most likely wouldn't be having this conversation now had you, because I truly believe that what you have is silver, and nothing more. My money says you should revisit the dilute nitric dissolution, but not until you have melted the piece once again. With all the screwing around you've done, it's entirely possible there's a thin crust of silver chloride that may prevent immediate penetration of the nitric. I've seen that on many occasions, although generally with a gold alloy, where the silver chloride turns a gray/green color. 

So then, melt the glob, cool, then place in dilute nitric and dissolve until it is gone. if there's any Pt or Pd present, you'll know by the color of the solution. If it's nothing but silver, as I suspect, it will dissolve completely, leaving no solids behind. Solution will be, at best, a hint of yellow, or maybe even slightly green, depending on if there's any nitric gasses present after dissolution. Pretty simple, at least in my mind.



> Heating the acids would not have got me on the right path anyway – being as how I am dealing with a sulphide.


Wrong. You are NOT dealing with a sulfide---at least not the piece you showed. If you've seen silver in a sulfide, you'd know that wasn't the case with your piece. The piece you attempted to dissolve is metallic in nature--it is not a sulfide, It should have reacted with nitric, assuming it's silver, and I expect that it is, and that it will. Follow the tip I provided (re-melt) and do the test, only this time heat the solution. 



> Also I did both a search on the forum & referred to Hokes before posting to the forum – So I guess what I am trying to say is –I think I am following procedure when dealing with an unknown. Run some tests, do some research, if your not finding the answer, ask a question.


I made an issue about heating for good reason. All too many here do not use heat. It's critical that it be used if you hope to achieve acceptable results. What may take a day to accomplish at ambient temperature may demand only a few minutes when heat is applied. Beyond that, you generally achieve better results from the volume of acid used. While there are some tests that can be accomplished at room temperature (stannous chloride and Schwerter's solution being amongst them, along with a drop of nitric on an unknown non-ferrous alloy to determine the presence of copper or nickel), heat is almost always beneficial. Next time you try a test similar to this one and you don't achieve the results you expect, make sure you apply heat before drawing any conclusions. 



> And as always Harold – thank you for getting me on the right path with the sulphide, flux, scrap steel answer. It gave me the info I needed for a forum search that alluded me other wise.


I hope it helped, and I have hopes that my somewhat misguided attempt at humor in making the comments I did in my previous post are helpful as well. There's some very good information in my comments, information that will spell the difference between success and failure. 

Love to hear more when you get back to the project. I'm curious if flux and scrap will increase the yield. 

If, by chance, there's any traces of either gold or platinum in the material, you'll know almost immediately. Unlike the good Doc's comments, if you dissolve the resulting material, there's no way in hell it can escape you unless you're a complete fool. I expect that is not the case, but I also expect that neither of those elements will be present. 

Harold


----------



## kurt (Dec 24, 2011)

As always Harold - thanks for your feed back - your advice (as always) is well recieved. It is the kind of advice that helps to clear the stumbling stones from the path of learning.

Kurt


----------



## goldsilverpro (Dec 24, 2011)

Dr. Poe said:


> GOLDSILVERPRO You happen to be addressing an issue of which I am way more experienced than you.
> OK, use bismuth instead of lead. There is most certainly gold in color photography. Apparently you know nothing about color photography, recycling hypo or the refreshing tank. The silver is a hundred times more plentiful because the base of color photography is the silver bromide emulsion. I think that maybe you have processed a bucket before and left the gold, platinum and palladium in the silver. If you don't agree, let's move this discussion to debates and discussions where I will be glad to educate you further. Also, where you worked, I doubt if you were in on all of their secrets. Dr. Poe



Since Noxx locked the other thread, I'll continue with this one. I was wrong and Dr.Poe is right about there being gold, etc., being used as a sensitizer in at least some of the color film. However, info concerning how much is very sparse on the internet. I did find an early 70s Kodak patent that used 5 mg/Mole of silver. However, that was as a gold compound, so it would be a little less. I found one other reference that said 3mg/M of Ag. So, if the figure is, say, 3mg/M Ag, that would mean that there is $.15 in gold per $101 worth of silver or, dollar-wise, 1 part of Au per 673 parts of silver, if my math is right. Weight-wise, this is .00003 parts of Au per part of silver.

If you can provide links that more closely define these quantities (also of Pt and/or Pd), please post them.

To me, that small amount of gold isn't worth going after, especially with that long involved process that you propose. If one wanted the gold and/or Pt, the simplest method would be to melt the silver and then run it through a silver cell.

Since I was the chemist at that place, I knew everything technical that went on. We probably ran at least 100,000# of steel wool canisters during the time I was there. However, most all of this was from x-ray processing. We also ran maybe 20,000# of undeveloped "film ends" from photo processors, but, thinking back, I seem to remember Au being present in the final silver in trace amounts - too little to worry about.

In the canisters, when we melted the black sludge that had been separated from any undissolved steel wool, we didn't get all of the silver without the use of rebar. This indicates to me that at least some of the silver was in the form of silver sulfide.

In the photo, the chunk of silver on the right is most definitely from an electrolysis unit. This silver is never pure and always includes some silver sulfide. After running 1000s of pounds of this "silver chip" or "silver flake", the highest purity I've seen is about 97%. In most cases, however, the Ag from the electrolytic unit doesn't look like that. Unless the operator runs the unit perfectly, much of the silver can be in the form of a black sludge, which is mainly silver sulfide and the silver content of the dried sludge can run as low as 80%. I would bet that the black material in the photo is from an electrolytic unit and not from a steel wool canister. If a company is using an electrolytic unit, they often use a steel wool canister to "polish" or remove that last bit of silver from the solution. These canisters are generally exchanged periodically by the seller of the canisters. They take the used canisters and then pay for whatever silver they contain (uh-huh). For this reason, there would be no reason for the 1-hour photo shop to ever open a sealed canister. The stuff in the photo is from an electrolytic unit.


----------



## Dr. Poe (Dec 24, 2011)

17 months ago I tested a silver bar made from a photo shop canister. It was sold to us as pure silver, but it contained 1% gold.
Normally, not a big deal except we were using silver salts in lieu of lead or bismuth for our cupel assays. We did this because a lot of the ore being tested had electrum which needed inquartation to process. The amount of gold contaminate from the silver that would be in the final bead (from using that bar), would be unacceptable. So I rejected that bar of silver.
It would have given a false assay. Often in some literature, a mistake is made concerning percents. 1% is erroneously printed as 0.01% (one part per ten thousand). When the writer can't make up his mind to print 0.01 or 1% . I can't tell how much chromium has replaced gold in the emulsions since I first started in 1966. I do know that cheaper film and cheaper print paper would have more chromium and less gold. At the time that one ounce troy silver bar sold for $9 and gold for around 1400.
That made the true value of that silver bar $22.91. Yet as an assay metal, it was worthless.
Wether or not it's worthwhile to further refine a silver bar to 5 9"s depends on the refiner's needs.
I do know that some companies (like Kodak) pay a premium for 999.99 silver and will reject 99% silver as unsuitable.
This will be my last reply on this subject. 8) If someone wants to discuss it further with me, they should e-mail me.
Dr. Poe


----------



## Anonymous (Dec 24, 2011)

Dr. Poe said:


> This will be my last reply on this subject.


You obviously have a lot to offer to others,that want to learn about this subject.Do not make this your last public post,just do not make it "personal" when someone says you are wrong about something.
This forum is a place for others to come and learn,why not help those out? Our son taught us a good phrase that he learned in the military,I am sure you have heard it...."All gave some,some gave all".GoldSilverPro is one of the few that has given his all to this forum,and showed his humility by apologizing.The least you can do is help the new members,that come here in the future.Share your knowledge,for once it is written here,it will remain long after all of us are gone.
I apologize for what I said also,I take that sort of thing very persoanally.With a lot of help from several members,I am much better than I was 4 years ago.So please accept my apology,and keep this going.
Johnny


----------



## jimdoc (Dec 24, 2011)

Dr. Poe,
I also apologize. We are all here to learn, some are here to teach or share their knowledge.
I just don't think there should be a contest of who is the smartest one here. That is what it was starting to appear to me. 

Jim


----------



## goldsilverpro (Dec 24, 2011)

Dr.Poe,

In the only 2 references I found giving the amount of Au in color film, the gold concentrations were given in mg of gold per Mole of silver, and not in percent. Here again, they were 3 and 5 mg/M of Ag.


----------



## kurt (Dec 24, 2011)

I agree - after all its only human nature to get a little loud when we feel we have been put on the defence. Sometimes we say things that don't quite sound the way we ment it or we hear something different then how it was ment. 

Such things should be nothing more then a small bump in the road for grown men.

Kurt

(edit) that Is I agree with mic & jim - I personaly have enjoyed the debate on this


----------



## Juan Manuel Arcos Frank (Dec 26, 2011)

I agree 100% with GSP...there is not gold in B&W or colour comercial emulsions,probably there is gold in other kind of films or processes.

If my mind is right there are some gold baths for B&W negatives or pictures,but I read it in an old book(1890)of photography that I am trying to find in my disorderly library.

In the other hand,the presence of gold in a silver bar from a photo lab it does not mean that photo lab wastes(or photo emulsions) contain gold....all my silver bars contain gold(in very small amount)!!!!!!,but it comes from contamination in the´convection´s oven vessel of the company I sell my silver.I promess to post the analysis report.

Finally,I want to express my gratitude,respect and admiration to Mr. Chris Owen(worldwide known as GSP),who is a man with a vast knowledge,he has a great willingness to share with us his great hands on experiences in PM recovery/refining.

Manuel


----------



## glondor (Dec 26, 2011)

I second that Juan. 2 thumbs up for GSP. Thanks for all your help this year.


----------



## kurt (Dec 27, 2011)

Ok – here is where I am at on this one. I am simply not set up to deal with this yet (don’t have my fume hood set up yet in the lab I am building nor do I have a furnace yet) so I am going to take it to a friend that is better set up & is also a member of the form. I will be going to see him a week from today as he is gone till then. (I have some other stuff I was going to take to him anyway so not making the trip just for this)

Anyway – between now & then I would like to run a couple of experiments on each of the types of material I have for a couple of reasons (1) to get a grasp/feel for the process & (2) to get an idea of what kind of yield to expect.

The picture shows the set up I have for running my experiments. The propane camp stove is used to preheat the crucible & the acetylene torch to effect the actual melt (& yes I move the set up outside to do the work as well as wear the respirator)

Now for my questions to run my experiments (1) using the rebar flux method – what does my borax to soda ash flux ratio need to be & do I mix it v/v or w/w (2) then what does my flux to Ag sulfide ratio need to be (3) & being as how I am doing this with a torch instead of with a furnace should I bring the flux Ag sulfide to a melt – then put the rebar in & continue heat till I see no more reduction in the rebar – or start melt with the rebar already inserted in the mix.

Experiments using the potassium nitrate method I will follow Manuals step by step instructions.

One more note – I talked to the guy I got this stuff from (concerning the container of black charcoal like stuff) & he said to the best of his knowledge it is just the sludge from the bottom of the tank, no steel wool used (he actually owns a pharmacy & had a couple girls that ran the photo lab & as far as he knew they didn’t use any steel wool when cleaning/maintaining the equipment)

Kurt 

P.S. I am hoping the recovery from this & the Ag from my last set of contact points is going to provide the funds I need to finish building my fume hood & build or buy a furnace. Getting tired of doing everything outside & with a torch.


----------



## kurt (Dec 27, 2011)

Oooops forgot to post pic of melting set up


----------



## kurt (Dec 27, 2011)

One more comment – I do realize that I would have to have the rebar at least red/orange hot (or hotter) if I was to melt the flux Ag sulfide before adding the rebar.

Kurt


----------



## goldsilverpro (Dec 27, 2011)

kurt,

I always did this in a crucible furnace. I first blended about half (by weight) as much anhydrous borax as I had silver sulfide. I then put it in the crucible. When it started to melt, I added several lengths of rebar that were long enough to protrude about 6-8" out of the top of the crucible. The reason I used rebar, instead of chunks of iron, is because it was easier to remove them before pouring. Also, I could use them to stir the melt. There is a dwell time involved. I don't know the exact time, but I probably left the rebar in there for about 30 minutes. That may be overkill, but it always worked.

I can't see how this process would lend itself well to torch melting. Maybe Harold has tried this with a torch and could give some pointers. With a torch, you may be better off trying Manuel's niter method.


----------



## Smack (Dec 27, 2011)

sorry


----------



## Juan Manuel Arcos Frank (Dec 27, 2011)

Ok,here I am exactly as I have promised.These are the latest reports from my silver bars,take a look.As you can see there are gold and platinum but in very low amount.


----------



## Juan Manuel Arcos Frank (Dec 27, 2011)

Besides,I have found the old book of photography and it says that gold(and platinum) are used in photographic print tonning.I am posting a page of this old book.Sorry guys,it is in spanish.

If you want to learn more about photographic toning go to the following link:

http://en.wikipedia.org/wiki/Photographic_print_toning

Uppsss!!!!..I almost forget to post some patents that say something about using gold as sensitizer.

Is there any gold in photographic emulsions?,that is the question.

Kindest regards

Manuel


----------



## Juan Manuel Arcos Frank (Dec 27, 2011)

Hey Kurt...that propane torch will not reach 1100 C so you will never see your silver in a metalic form.You need an oxygen/propane torch.

All silver compounds could be transformed to silver sulphide,if there is any sulphur present.This is exactly what happens with old photographic solutions and this is the way that Mother Nature produces silver,by transforming all silver compounds into silver sulphide using sulphur and heat from volcanoes,lovely,is not it?

Kindest regards.

Manuel


----------



## qst42know (Dec 27, 2011)

You should be ok using your propane torch if you stack a fire brick enclosure. 

Do you have some of the light weight fire bricks?


----------



## Juan Manuel Arcos Frank (Dec 27, 2011)

Kurt..is that plated tank acetylene?.....If it is then BE CAREFUL!!!!!!...NEVER ever use acetylene to melt a silver compound because a very big explosion could ocurr.

Come on,Kurt go to these links and work safe using oxygen instead of acetylene.

http://www.powerlabs.org/chemlabs/acetylide.htm
http://www.c-f-c.com/specgas_products/acetylene.htm

Manuel


----------



## Harold_V (Dec 28, 2011)

goldsilverpro said:


> I can't see how this process would lend itself well to torch melting. Maybe Harold has tried this with a torch and could give some pointers. With a torch, you may be better off trying Manuel's niter method.


No, I agree, Chris, it's not really a torch proposition because the material benefits by a soak period, so the sulfides have a chance to convert. Like you, I used to use lengths of rebar, and for the same reasons. If you pay attention, you can tell when the conversion is complete, for the rebar ceases being dissolved. 

I'm not suggesting that it can't be done by torch, but I'd hate trying. You can't really heat the entire mass as is required, nor can you maintain the required heat due to losses. That might not be true if a few oxy/acet rosebud torches were played on the crucible. This is most definitely a furnace proposition. 

Harold


----------



## Dr. Poe (Dec 28, 2011)

Your posts are very convincing. Yet I know what I remember. Could it be the 30 year difference represents the different results due to innovation in photo film? The canisters that I refined were before Kodachrome. The silver bar from 2010 that I found 1% gold in it could have sat on a shelf for 30 years. Who knows? Maybe it's about grades of film, ASA speeds or just that Kodak chemists have been working on formulations that needed less gold for the last 30 years. I don't care. One should take special attention to Juan"s warning. Acetylene introduced to a precious metal in the presence of hypo (sodium thiosulfate AKA sodium thionate) will cause a deadly explosion! And that's no theory---it's a grim fact.  Dr. Poe


----------



## Harold_V (Dec 28, 2011)

I'm not familiar with the reaction you speak of, acetylene and silver compounds, but in my suggestion of using an oxy/acet torch, I question if that would be troublesome. It would be restricted to playing on the crucible, not on the charge. A torch is never a good fit with a crucible, as I've mentioned before (that's why one uses melting dishes). Beyond that, my thoughts are that so long as the flame is oxidizing, there's no free acetylene present to cause a problem. Not looking for an argument, but an explanation, for a better understanding. Is there one forthcoming? Anyone willing to enlighten me (us)?

In regards to photo solutions containing greater values than silver, sure, it's possible, but in practice, in particular in modern photography, were they used? For starters, the price of these metals escalated to unrealistic heights, to such a point where even silver was reduced in quantity in many situations. If memory serves, color film had precious little, if any. That was my point in making mention that in all my years, I never encountered anything but silver, keeping in mind that I processed, at most, a few hundred ounces of recovered silver, primarily from an electrolytic recovery unit. Still, were it reasonably common, I'd expect I would have seen at least traces. It's virtually impossible to miss either platinum or palladium when alloyed with silver due to the shift in color when it is dissolved. I have always been in tune with the colors of solutions, and tested virtually everything, routinely. 

Harold


----------



## butcher (Dec 28, 2011)

From what little I understand the acetylene gas would need to be bubbled through solutions or metal powders to form alkynes or acetyl ides.

I have used an acetylene torch many times on (flames) metal powders, and never seen any adverse reactions, note these are flames although sometimes in (oxidizing flames) or reduced flames that may be richer in fuel, which would surely burn.

I too would like to hear how this could be dangerous, and many fuels are carbon based, would other fuels create this hazard.


----------



## Dr. Poe (Dec 28, 2011)

The danger is from acetylene making acetyanalides. Which would only happen if the acetylene was not burned. A reducing flame, a pop off (losing the flame while adjusting) there's probably a hundred ways that acetylene could accidentally be introduced to the thiosulfate. Acetyanalides explode by touch. Is it wise to take such a chance? 
While I'm posting here let me take this opportunity to apologize to goldsilverpro: Just because I was processing film and hypo tanks long before you doesn't make me still an expert on the subject. It's obvious that innovations have changed the nature of scrapping. I think that I'll stick to references to natural ore refining, something that which I still rule. Even the computer parts that I refined were from computers prior to 1981 where much more gold was found than today's computers. My field is geochemical research and refining. I specialize in telluride and other refractory ores. Back then, we could get 3/4 ounce from a single computer. Goldsilverpro, you were wrong that there was no gold in color film, but I was wrong that the gold amounted to anything of value. Dr. Poe


----------



## butcher (Dec 28, 2011)

Granted I know almost nothing of organic chemistry, and would not want to inadvertently make a compound that may disfigure or kill me, so any advice on this subject I would gladly like to be corrected on, and any information on these compound or dangers will be received with interest.

From what I see many very dangerous compounds are formed with salts of metals, some of these we either form or come close to forming when we recover or refine these metals, many of the powders, or salts of these metals too can become catalyst for other reactions when heated, but I also believe many times the conditions we are using (with a few exceptions) are far enough away from forming a dangerous substance in quantity may keep us safe.

(I really do not know how to say this, but we may actually form minute amounts of an very dangerous compound in our mixture of recovered powders (organics or traces of other chemicals involved), but the compound as a whole keeps the dangerous compound from forming or reacting in an unwanted fashion, the chemical reaction as a whole is unfavorable for the chemistry of the reaction of these dangers to occur and thus not becoming a danger as the whole of the compound removes the danger of the minute component from reacting negatively (or giving us the unfavorable reaction non of us wish to see when holding a glass jar up to our face to see what it looks like).


I guess what I am trying to say is if there is a real danger in doing a process I want to either stay away from that process, or to know enough of the chemistry to now how to keep the process safe and keep myself from danger.

But then again I do not want to fear a reaction that may occur in a reaction that would really not form any dangerous situation because the conditions for forming such a reaction are so remote that it would almost be impossible to form the reaction even if that was the goal.

If this melting of metal salts including copper salts was so dangerous with an acetylene torch, I wish to know, but if there is more of a possibility the dust in my shop would react with oxygen in the air in the room and blow my shed roof off, than any reaction to occur melting a metal powder with this torch I would also like to be aware of that.

Yes there are scary things out in the woods in the dark, but I have no fear of the dark woods, because I know the same things are there in daylight, and I do not fear the woods in daylight, and realized long ago that is just as safe at night as day, yes maybe some critters like to roam at night but they fear me the same in light or dark, and I should not fear my own imagination of what could possibly be (but be so much remote as almost impossible).

Can anybody understand what the heck I am trying to say?
Or should I be fearing the dark?


----------



## steyr223 (Dec 28, 2011)

Avoid copper, silver and mercury. Explosive acetylides can be formed on copper and aluminum bronze.


----------



## Dr. Poe (Dec 28, 2011)

I refuse to reveal how to make these explosives purposely. We all know that it would lead to someone's disaster. I'm sure that the moderators would not like it either. Neither the Homeland Security. 
AVOID!!! : Ammonium ions with precious metals except for ammonium thiosulfate with ores only.
acetylene, map gas with sodium thiosulfate (sodium thionate), or ammonium thiosulfate in the presence of precious metal ions.
Oxalic acid with silver.
Any heavy metal with fumaric acid.
Heating lead di-chloride made from lead electrodes in an AC current. (It's bright yellow!)
Nitric acid and sulfuric acid with any organic or carbon but especially oils and fats and cotton.
Linoleic acid with cotton (auto-ignition).
Modern anti-bacterial dish soap and bleach.

LEGAL TROUBLE: Avoid assisting someone living in a sanctioned country (example: if you live in Canada, avoid jail time by assisting the Syrians) My favorite chess player, Bobby Fischer, became a fugitive for playing chess in a sanctioned country.
The penalties are sevier and the label of 'Traitor' difficult to remove.
This is something the moderators should watch out, as we could lose our forum.
I'm sure none of us want that!
:| Dr. Poe


----------



## Anonymous (Dec 28, 2011)

Dr. Poe said:


> This is something the moderators should watch out, as we could lose our forum.


Jesus! Just when I thought we were getting back to normal rational discussions!


----------



## rusty (Dec 29, 2011)

mic said:


> Dr. Poe said:
> 
> 
> > This is something the moderators should watch out, as we could lose our forum.
> ...



IMHO mic your comment is unwarranted, your leaving out the most important part of that conversation were Dr. Poe stated that his favorite chess player had become a fugitive from American justice.

Since we do not talk about politics and religion I will not elaborate further on the world chess champ, other than to suggest you google the fellows name, who won that tournament pocketing 3.3 million. But become a fugitive and labeled a traitor in doing so.

Then again the mans name wasn't sue.


----------



## jimdoc (Dec 29, 2011)

rusty said:


> Then again the mans name wasn't sue.



The man named Sue left a few years ago, if that really was his name.

Jim


----------



## rusty (Dec 29, 2011)

jimdoc said:


> rusty said:
> 
> 
> > Then again the mans name wasn't sue.
> ...



Well Jim some seem to think this man sue is alive and well and may have joined the forum using a new nic.


----------



## Harold_V (Dec 29, 2011)

Dr. Poe said:


> AVOID!!! :
> Nitric acid and sulfuric acid with any organic or carbon but especially oils and fats and cotton.


This is but one of the reasons that I have promoted incineration before refining. It has, chiefly, fallen on deaf ears. 
Want a good example of reactions of cotton that have been wetted with nitric? Try burning an anode bag from a silver cell. No need to wait until it's dry.

Harold


----------



## kurt (Dec 29, 2011)

Wow – This has turned into quite the discussion – both informative & thought provoking 8) 

Anyway – I didn’t post anything yesterday because I spent about 4 or 5 hours researching primarily the acetylides thing - but also the PMs from photo fixer/toner solutions thing.

Photo toning (wiki link provided by Manual) = Metal replacement toners replace the metallic silver, through a series of chemical reactions, with a ferrocyanide salt of a transition metal. Some metals, such as platinum or gold can protect the image. Others, such as iron (blue toner) or copper (red toner) may reduce the lifetime of the image
Metal replacement toning with gold alone results in a blue-black tone. It is often combined with a sepia toner to produce a more attractive orange-red tone. The archival Gold Protective Solution (GP-1) formula uses a 1% gold chloride stock solution with sodium or potassium thiocyanate.[7] It is sometimes used to split tone photographs previously toned in selenium for artistic purposes.[8]

So there is the potential to have as much as a 1% gold content & maybe even some Pt. – I don’t have this expectation – but the potential is there. So the “potential” is 1oz Au per 100 oz Ag :shock: (I have about 200 oz so I can only hope without expectation) 8) maybe

Concerning the thing about acetylides (I spent the better part of 4 or 5 hours researching this one) acetylene gas is a hydrogen carbon H2C2 triple bond gas (meaning the bond is straight line H-C-C-H) 

The acetylide is formed by the pure acetylene gas giving up it’s 2 H element replacing them with the elements that it will react with the acetylene (Ag, Au, Cu, Hg, & Se) It will do this “most readally” with the salts in an aqueous solution with the readyness to form the acetylide desending in order of dry salt, molten metal, solid metal – meaning it takes more time for acetylene gas to form the acetylide with a solid piece of elemental Ag then with silver in an aqueous solution (silver nitrate)

The reason for this is that as a salt in an aqueous solution the Ag is more readaly avalible to brake the bond of the hydrogen in the acetylene & form the acetylide. 

The reason that acetylene can & will form an acetylide with sold elemental Ag is that acetylene it’s self is a “weak” acide (weaker then water) & even here it takes the acetylene being in the form of a liquid to brake the Ag down to a salt so that the bond exchange can take place between the hydrogen & the Ag (the very reason you should always drain your hoses after turning off the valve on your acetylene tank – brass fittings = 70% copper + acetylene = copper acetylide.

The reality here is that if acetylene was of any real concern when working with ether sold or molten Ag, Au, or Cu they would not be using brass fittings in acetylene torch set ups & plumbers & heating & air guys would not be using the same acetylene turbo torch set up I have to solder & silver braze copper pipe & tubing & metal fabricators would not be using oxy/acetylene set ups to cut, braze & weld these metals in there every day work.

The biggest concern here would be not draining your hoses after turning the acetylene tank off & allowing the gas to sit in the regulator, hoses & torch head for long periods of time. Pure acetylene gas (no flame) & salts are another story – one that should be avioded at all cost.

So I gotta go with butcher on this one – I don’t think the sky is falling
Kurt


----------



## kurt (Dec 29, 2011)

OK – I couldn’t wait till next week when I am going to take the bulk of this to a guy that has a furnace to melt it for me. What can I say – I just had to play. :lol: 

So – I mixed a flux 50/50 borax/soda ash – weighed out 1 OzT of the Ag sulfide – mixed it 50/50 Ag sulfide/flux – put in crucible with rebar – stacked fire brick on three sides of crucible – directed flame on outside of crucible with acetylene turbo torch set up from open end of 3 sided fire brick enclosure – directed flame from propane turbo torch set up on Ag sulfide/flux/rebar inside crucible – turned crucible occasionally to get more uniform heat on outside of crucible from acetylene torch.

Took 45 min. to mix – heat/melt – pour – ending with nice 28.4 gram bar --- that’s about 92% of starting sulfide 8) 

I included the rebar in the pic to show the reduction that takes place in the process

Kurt


----------



## Dr. Poe (Dec 29, 2011)

Thank you Kurt for a very informative post. Acetylene doesn't cause problems (make explosives) unless it is used with 'Hypo".
Acetylene precipitates metallic gold from solutions of gold chloride without danger. Thank you also for finding that 1% to which I have been referring.  Doesn't matter though, goldsilverpro won that debate fair and square and I lost. The odds of having a canister with the 1% gold are very low, and shows just how out of date that I am concerning the processing of scrap silver. But to add something of value to this post: The use of re-bar in smelting to counteract the sulfur family is wise.
Do one thing different. Bend the re-bar into a jay shape on the bottom else you will slowly drill a hole in the bottom of the crucible. One can also hang the re-bar (bent into a jay shape) up side down on the lip of the crucible where the point doesn't reach the bottom. Having the re-bar also helps stop boil over from the foaming.
Thank you again for showing every one that even though I was wrong (in today's reality), I was not totally crazy. :mrgreen: 
Dr. Poe


----------



## Anonymous (Dec 29, 2011)

rusty said:


> mic said:
> 
> 
> > Dr. Poe said:
> ...


Mostly likely true.I just see this entire thread going south again,and everyone getting off track again,when it seemed like it was smoothing out.I'll do some looking later and see what I can find.


----------



## butcher (Dec 29, 2011)

Kurt, great information, thanks for your sharing your study and posting your results, sounds from your figures you got a good conversion of silver from the chemistry in your melt, thanks again, we are all learning something.

I have read where acetylene gas sitting inside copper pipes with silver solder will build some crystals of acetyl ides inside of the pipe at the silver soldered joint, and copper lines or silver soldered piping and of course is not recommended when handling acetylene gas, I have always drained unused gases from the line to protect regulators, but never heard of any trouble with acetylene and brass, the valves on tanks as well as regulators are brass, and in my mind would be safe for the purpose, I would worry more about getting oils, or thread dope (with oils) around the fittings on my oxygen tanks, than I would brass fittings in a torch, or gauges.

As far as the chess player the country at the time was at war with communism and were most likely justified keeping out bad apples, even if they could play chess, I think they did not get all of that problem out of the country and now we are infiltrated with that type of thinking, long after the cold war, but what does this have to do with refining?

Lets just get back to helping each other recover and refine gold and forget all of this nonsense.

Nice hunk of silver.


----------



## Harold_V (Dec 30, 2011)

Dr. Poe said:


> Do one thing different. Bend the re-bar into a jay shape on the bottom else you will slowly drill a hole in the bottom of the crucible.


Considering my experience with the use of rebar, I think I'd recommend against the idea of bending. Not that it's of big concern, but the problem then becomes one of the bent piece being eroded at some point above the end. Should it detach, you then have a solid piece of steel that must be fished out of the crucible. Not fatal, but certainly worth avoiding if possible. 

I used more than once piece of rebar at a time, and avoided working the sharp end against the crucible. Didn't notice any particular problem with the tip piercing the crucible, nor did I notice much damage from the sharp point. I also exercised care, secure in the knowledge that there was a potential for problems. 

Harold


----------



## kurt (Dec 30, 2011)

Dr Poe – You posted – “Acetylene precipitates metallic gold from solutions of gold chloride without danger.” --- Can you back that up with some real data??? I ask because in my research Au is listed as one of the metals that will form an acetylide. Wiki says that “some” acetylides are explosive – so evidently not all aceytlides are explosive. Copper acetylide (like siliver acetylide) is VARY explosive – in fact Cu acetylide is more sensitive to explosion then Ag acetylide & Cu acetylide is made by precipitating Cu acetylide from a copper (1) chloride solution. 

In my research – Au is listed as one of the metals that will form an acetylide & it was listed with the other metals that are explosive in nature as an acetylide. 

Here is the info I found in my research --- The hydrogen atoms in acetylene can be replaced by metallic elements to form acetylides--e.g., acetylides of silver, copper, or sodium. The acetylides of silver, copper, mercury, and gold are detonated by heat, friction, or shock.

Please Dr Poe – If you have info suggesting that acetylene can be used to precipitate gold from a solution “without danger” – post the step by step instruction for doing so – or it could result in someone dead &/or very seriously injured. --- We get a lot of people on this forum that are new to all of this & completely unaware of some of the dangers &/or have had their head filled with a bunch of garbage floating around out there on the net.

Kurt


----------



## butcher (Dec 30, 2011)

pH?


----------



## kurt (Dec 30, 2011)

I think a thanks to Manual is in order here for being the one to point out that there is even a danger in employing acetylene in refining metals. --- Without his pointing that out in the first place I certainly would have never guessed such a thing & the journey of researching it has taken me on “very” informative & educational journey to say the least.

Thank You Manual :!: :!: :!: 

Here is a “bit” more of what I found in my research --------

Copper(I) acetylide, or cuprous acetylide, is an inorganic chemical compound with the formula Cu2C2. It is a heat and shock sensitive high explosive, more sensitive than silver acetylide[citation needed]. It is a metal acetylide. It is similar to silver acetylide and calcium carbide, though it is not called carbide in literature. Though not practically useful due to high sensitivity and reactivity towards water[citation needed], it is interesting as a curiosity because it is one of the very few explosives that do not liberate any gaseous products upon detonation.
Copper acetylide can be prepared by passing acetylene gas through copper(I) chloride solution in presence of ammonia:
C2H2 + 2CuCl → Cu2C2 + 2HCl
The reaction product is a reddish precipitate. The reaction is used as a test for acetylene.

Copper acetylide can form inside pipes made of copper or an alloy with high copper content, which may result in violent explosion.[1] This was found to be the cause of explosions in acetylene plants, and led to abandonment of copper as a construction material in such plants.[2] Copper catalysts used in petrochemistry can also possess a degree of risk under certain conditions.[3]

The conclusion to all of this is that acetylides ( “some” of which are “very” explosive) can most certainly be formed by employing pure acetylene gas with many of the metals we encounter in refining. However – in order for the acetylides to be formed – the metals need to be in a solvent state (aqueous solution) – They can also be formed if these metals are in a dry state (dry salt or the elemental metal) 


However this only occurs due to the fact that acetylene it’s self is a weak acid (very weak – weaker then water) thereby allowing the acetylene to be it’s own vehicle to make the salt (aqueous) to form the acetylide.

Being such a weak acid it would take a considerable amount of time of exposure of pure acetylene gas to the metals concerned here to form the acetylide in any amount that would pose a problem in using an acetylene torch for melting these metals. Is it possible? Yes – but “very” unlikely. – you would have to have a torch blow out & allow the pure acetylene gas to be exposed to the metal for a very long time to form enough acetylide to pose a danger.

Kurt


----------



## Dr. Poe (Dec 31, 2011)

kurt said:


> Dr Poe – You posted – “Acetylene precipitates metallic gold from solutions of gold chloride without danger.” --- Can you back that up with some real data??? I ask because in my research Au is listed as one of the metals that will form an acetylide. Wiki says that “some” acetylides are explosive – so evidently not all aceytlides are explosive. Copper acetylide (like siliver acetylide) is VARY explosive – in fact Cu acetylide is more sensitive to explosion then Ag acetylide & Cu acetylide is made by precipitating Cu acetylide from a copper (1) chloride solution.
> 
> In my research – Au is listed as one of the metals that will form an acetylide & it was listed with the other metals that are explosive in nature as an acetylide.
> 
> ...


 :shock: 
Oh No, That was just a simple fact. I don't recommend that to anyone! The statement is true with pure HAuCl4 but what if the gold comes from an ore. And what if that ore occurred with natural sodium thiosulfate (which happens a lot!).
No, No! Forgive me for even mentioning it. I think maybe some people even produce sodium thiosulfate in their sweat.
There's no argument here as if someone did use acetylene to reduce gold as a habit, eventually they would probably blow themselves up. :shock:


----------



## Dr. Poe (Dec 31, 2011)

Harold_V said:


> Dr. Poe said:
> 
> 
> > Do one thing different. Bend the re-bar into a jay shape on the bottom else you will slowly drill a hole in the bottom of the crucible.
> ...


I still prefer to hang the bar on the side where the tip misses touching the bottom. Where the problem of drilling has occurred with me was with the very large crucibles where three or four feet of rebar was used. Those crucibles cost over $500 each.
A five inch thick (approximate) bottom was bored by the rebar 1 1/2 inches deep.


----------



## Harold_V (Dec 31, 2011)

I heartily endorse the hanging of the rebar from the lip of the crucible, although it does limit its useful life. 
I used small crucibles (#8), so the overall length of the scrap metal in use was relatively small. I can see where a long piece of #8 or greater could prove to be quite a load. Largest I used was only #6. 

A comment on crucible size. 

While a #8 sounds pretty small, in the scheme of things, it was an excellent match for the size of operation I ran. I could pour 200 oz. anodes with ease, and a full crucible of cement silver yielded a button that was a perfect size to load in the crucible. My recovered silver, both from silver nitrate and from silver chloride, was melted and fluxed, then poured to a cone mold. The resulting buttons were re-melted and poured as ingots after chipping all of the slag. Any sulfide layers that may result were always rerun in the furnace, along with some scrap steel to recover any traces of values that may be entrapped in the sulfide layer. 

Harold


----------



## steyr223 (Dec 31, 2011)

Wow l love it
Dr. Poe did u say 3/4 of an ounce of gold
From a single pc
was this at lab grade or at home grade
I mean ,you know, you weren't pulling 1g of gold
From a 55gal drum of gold chloride in your garage ....

Or were you. :lol: 
Thanks steyr223


----------



## rusty (Dec 31, 2011)

steyr223 said:


> Wow l love it
> Dr. Poe did u say 3/4 of an ounce of gold
> From a single pc
> was this at lab grade or at home grade
> ...



Probably before most forum members were born.

IMB System 360, most machines were scrapped when they could no longer profitably be leased, partly for the gold and other precious metal content of their circuits.

http://en.wikipedia.org/wiki/IBM_System/360


----------



## Dr. Poe (Dec 31, 2011)

steyr223 said:


> Wow l love it
> Dr. Poe did u say 3/4 of an ounce of gold
> From a single pc
> was this at lab grade or at home grade
> ...


No, not a PC, a computer (PC stands for personal computer which were just beginning back then). To help you understand; Donkey Kong and Pack Man were new arcade games. Computers back then were way too expensive for the average person.
Components were bigger and were heavy gold plated on heavy silver plate on nickel plate on solid copper or gold on solid silver pins. Although there were transistors, there were also vacuum tubes.
Televisions: Zenith 'Works in a drawer' had just come out. Dr. Poe


----------



## Juan Manuel Arcos Frank (Jan 2, 2012)

kurt said:


> I think a thanks to Manual is in order here for being the one to point out that there is even a danger in employing acetylene in refining metals. --- Without his pointing that out in the first place I certainly would have never guessed such a thing & the journey of researching it has taken me on “very” informative & educational journey to say the least.
> 
> Thank You Manual :!: :!: :!:
> 
> ...


----------



## Ian_B (Apr 1, 2014)

I can definitely see the advantages of using the re-bar method as it is cost effective compared to purchasing Potassium Nitrate but If one didn't have access to a gas furnace to use the iron re-bar redux method and Potassium Nitrate was unavailable wouldn't Nitric acid work fine to convert the Silver Sulphide to Silver nitrate without any adverse effect? I have done a bit of research and have found a number of equations through google where silver sulphide is reactive with Nitric 
Ag2S + 2 HNO3 → H2S + 2 AgNO3

The off gas being Hydrogen Sulfide you would want to do it under a fume hood or in a well ventilated area. 

I have done a very small test with less than a gram of Silver Sulphide and it does indeed dissolve in nitric on the small sample I tested however was curious if anyone else has used this method on a larger scale and if their is any adverse effects besides cost effectiveness compared to the re-bar method.

The few thoughts I have on the subject is that you would want to be careful with adding the powdered Silver Sulphide to the nitric acid as the small particle size could cause a violent reactive if too much was added to quickly.
Availability of nitric acid and cost could become an issue.
Costs of copper and use of distilled water 
City tap water may cause silver chloride to form causing more steps to be needed to recover the silver.

Of course in a perfect world the iron method or Manual's Potassium Nitrate method would be preferable to use.

I was thinking that this method might be effective if the silver sulphide was from non-fixer sources or photographic sources which may contain unknown amounts of other metals?

Just bouncing idea's off a wall.  thought's and criticisms welcomed and encouraged.


----------

