Old Blister Copper as PM source

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stella polaris

Well-known member
Joined
Sep 11, 2018
Messages
390
Hi!

New on the forum i have a question i can not find an answer to.

In older copper types, before electrolysis became standard, it migth be a content of PM. This since it were more difficult to collect them. ( I am not talking about home made blister. Rather smelted and not processed by electrolysis as in the old days)

Do anyone have any experience with this type of blister copper?
Any easy and smart way to field test this type of copper for PM?
In what range can PM be expected?

My basic idea is to run a copper cell with old copper scrap as anode. This to yield Cu + PM sediment.
 
From the little I understand about PGM recovery most seems to come from nickel mining rather than copper or gold, I could well be wrong and open to correction.
 
I have some information that tells about a guy buying up old copper wire.
I forget the dating of the wire, but it was said to have gold in it because of their ability to refine it like they do now was lacking back then. I think it may have been in a certain area, like San Francisco maybe? And maybe was imported from South America?
I will try to find it, and share it here. I am pretty sure it was in the "Uncommon Sense" newsletters from E, Earl Webb.
 
nickvc said:
From the little I understand about PGM recovery most seems to come from nickel mining rather than copper or gold, I could well be wrong and open to correction.

I am talking about Copper. It can carry PM. Mainly AG and AU
 
The Au and Ag content surely must vary depending on where then Cu was mined. I once spent a few days at the Anaconda Copper tankhouse, in Butte, MT, and I think I can recall some details. If I remember right, they had 2500, 400 gallon copper cells producing about 1,000,000 pounds of pure copper per day from blister copper. From the anode slimes, they recovered about 30,000 tr oz of silver and 3,000 tr oz of gold each month. That would figure about 2 tr oz/ton Ag and 0.2 tr oz/ton Au in the blister copper. This is all from memory about 35 years ago. We were there as a refiner interested in processing their slimes.

https://www.google.com/search?q=anaconda+copper+tankhouse&client=firefox-b-1&tbm=isch&tbo=u&source=univ&sa=X&ved=2ahUKEwib8cbX2c7dAhUJEawKHYFLBVgQsAR6BAgFEAE&biw=1366&bih=614

Here's an article about Raritan Copper in NJ, and the numbers seem to be in the same ballpark. For example, the Au there ran about .25 oz/ton of blister, as compared with .20 oz/ton. However, the Ag at Raritan ran about 35 times higher.

You can download the whole book of 1300 pages - Click on the gear at top right. The 5 page attachment is the Raritan article alone.

https://books.google.com/books?id=FoggAQAAMAAJ&pg=PA692&lpg=PA692&dq=anaconda+copper+tankhouse+amps&source=bl&ots=FxAvfYoIal&sig=EJHlLIe8DQrZx7BVBYXpMtxT3Kg&hl=en&sa=X&ved=2ahUKEwiPv-mv3M7dAhUDc60KHcBPA58Q6AEwAXoECAkQAQ#v=onepage&q=anaconda%20copper%20tankhouse%20amps&f=false
 

Attachments

  • Raritan Copper.pdf
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The amount of PM is defently depending on the ore used. In fact the amount of gold in the ore sometime defines if its a goldmine or copper mine. The old Boliden mine in Sweden is called goldmine. in the 1930 the production was
5000t copper, 20t silver and 7,5 t gold. Recovered by elektrolysis. The very same type of ore but with less gold content may be called copper ore in other places.

In Aitik copper mine in Northern Sweden is the ore considered to be low on PM. 1 ton ore gives 2,9kg copper, 2 gram silver and 0,2 gram gold. You need 15 kg of blister to get 1 gram of gold and 10 gram of silver. Not to forget the almost 15 kg elektorlyte copper u get.

The PM rate in blister copper should thereby be strongly depending of origen. The problem is to locate where the production of copper with high PM rates went in older days. What types of products and usages? What kind of products did the elektrolyte copper go to first?

(I have access to an old dump site of mainly burned waist from a smaller city. The waist contains metals of witch a good amount is old copper. The dumpsite was closed 70 years ago and its older parts are close to 100 years. This make me think i have a god chance to find at least some good blister. But i must hurry. When 100 year in the ground its no longer scrap and waste but Archaeological artifacts. :shock: )
 
Assuming 95% efficiency in the copper electrolysis (1.126 g/amp-hr) and that there is 7.5 tr oz of gold per metric ton, it would require about 900,000 amp-hrs (900 kw-hrs) to recover $9000 worth of gold, $6000 worth of copper, and $250 in silver . Since there are nearly 9000 hours in a year, it would take a steady 24/7 input of 100 amps to do a ton in a year. For 100 A, I would want about a 20-25 gallon tank, in order to keep the solution from getting too hot. All this is true, if my math is correct.

The cost of electricity isn't that much, but the equipment and labor could add up considerably. You could, of course, add more tanks and/or use bigger tanks.

The $9000 in gold would be on the high side, if you are lucky enough to find that particular blister. As explained in the pdf I gave, there would be downtime and expenses for solution maintenance, especially if you want the copper purity to remain high, so you can get the best price. You'll need a gas crucible furnace plus molds and other associated equipment. You would have to setup (and learn how) to refine the slimes and deal with the Se and Te.

If I were doing it, I would certainly have a fire assay setup to analyze the Cu for Au content - even at 7.5 oz per metric ton, that is only .023% gold. A good thing about fire assay is that you end up with actual gold that you can hold in your hand and weigh. With fireassay, you always know that you have, at least, THAT much gold. Also, I would guess that the PM impurities in the copper are spread fairly uniformly, so sampling might not be that difficult. I would run the samples, all taken from different areas. in triplicate.

If the process is done intelligently, it might work out. The #1 problem, of course, is finding the right material, which might be a lot more difficult than you think it is.
 
Gold is usually present in copper ores and it hangs along in the copper refining until electrolysis. For example Storliden mine that was mined for copper and zinc also produced 0.8g Au/ton ore and gave a nice little bonus, with 300.000+ tons per year it gave a ton of gold in the end after five years mining.

The only way to separate gold from copper before electrolysis became popular was to dissolve the copper in acid and that was expensive so old copper contains a certain amount of gold. The exact amount depends on where the copper was mined.

Electrolysis of copper became common around or even before 1900 so you need to find really old copper. The only source I've heard about is old roofs, mainly on churches. When a really old roof is replaced it was sold based on the gold content and it could pay for the new roof. This has been known for at least a couple of decades now so not only is it becoming harder to find the copper, the value is known so it's not easy to make a good deal.

The problem with digging through an old dump site is that you will be disturbing the waste, exposing it to weathering. This leads to increased leaching of toxins and the responsible person would probably be you.

Göran
 
First of all: I realised I made a mistake not to tell that I am a happy amature, not a hardcore scrap dealer/refiner.
I will not digg in the waste and are not allowed to. I have to stay with whats on the ground and thats is enough for me. I will not sell any gold/silver and have no hurry to refine it. I intend to go slow with this. if it takes me 10 year to refine it, fine with me.

I was thinking of apply for a recovery operation permission due to the amount of copper it must be on the site. Based on what can be seen on the surface an operation that would give a good positive outcome, if considering machine costs to clean the site. On the other hand as fast u put the bucket i a old ash/waste deposit u risk to find some old rusty barrels containing some weird stuff. If so u are in deep shit instantly. Based on that fact i quicly got that idea out of my head.

It was actually the copper roofs Göran talk about that gave me the idea to check for Blister Copper. ( I am Swedish too) And since I rather have a walk outdoor, collecting scrap, than sitting indoors and pulling pinns, I decided to give it a try. Its waste from 1920-1950 laying there. The lifespan of the products were longer at that time compared with today. Chance of Blister should be good.

Now back to my question. How can i do a simple field check if the copper contains PM or not? ( if its no blister there its no idea to start look in to electrolysis now and i have no wish to collect normal copper)
 
Only quick field test I know of for small amounts of gold in alloys is using an XRF-gun. An expensive tool unless you handle lots of scrap metal.

Göran
 
g_axelsson said:
Only quick field test I know of for small amounts of gold in alloys is using an XRF-gun. An expensive tool unless you handle lots of scrap metal.

Göran
I wouldn't trust a gun on gold filled scrap in a well prepared sample. A gun on a few ppm on dirty field sample wouldn't even begin to be reliable.

Fire assay only.




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snoman701 said:
g_axelsson said:
Only quick field test I know of for small amounts of gold in alloys is using an XRF-gun. An expensive tool unless you handle lots of scrap metal.

Göran
I wouldn't trust a gun on gold filled scrap in a well prepared sample. A gun on a few ppm on dirty field sample wouldn't even begin to be reliable.

Fire assay only.
We are not discussing gold filled, we are discussing old copper from pre-electrolysis times.

XRF is used by mining companies in the field, both when prospecting and while mining to track gold ore.

Göran
 
g_axelsson said:
snoman701 said:
g_axelsson said:
Only quick field test I know of for small amounts of gold in alloys is using an XRF-gun. An expensive tool unless you handle lots of scrap metal.

Göran
I wouldn't trust a gun on gold filled scrap in a well prepared sample. A gun on a few ppm on dirty field sample wouldn't even begin to be reliable.

Fire assay only.
We are not discussing gold filled, we are discussing old copper from pre-electrolysis times.

XRF is used by mining companies in the field, both when prospecting and while mining to track gold ore.

Göran

My point about gold filled is that it's low grade material.

I have a pretty good understanding of the limitations of XRF technology, and it's use in the field. In the field it's used with correlative data and known associations, not the actual measurement of gold. You track elements that are known to be associated with gold, and compare this to a series of fire assays you have performed.

Have you used an XRF gun much? You can see considerable resolution problems when discussing 10^-2 resolution if you aren't skilled. In order to accurately measure in the 10^-3 range, you need to have stationary sample and long sample times. Even then, the numbers on the screen are only suggestive and you are looking for the pattern of minerals. With Wavelength dispersive technology, you can get 10^-4 with long sample times and a really good analyst comparing results to gravimetric data. But even when discussing 3 oz / ton, very good blister, you are talking about 10^-5. You would now be trying to make use of a number that is smaller than your uncertainty.
 
As Goldsilverpro pointed out. The first problem is to find the material. I have no wish to drag home normal copper. There for i need some type of test. Fire assay is out of the question. Its to work demanding. We are talking copper nails, pices of piping and cooking ware type scrap. It would be to many samples from to small objects. A gun is far to expensive.

So how to classify the copper? The colour is one indicator. The sorting will be cruder and the amount of non blister would be higher. Still a way to go. If a lot of silver in the blister I can se it. The gold and silver goes hand in hand so if silver there is gold could be used as a rule of tumb. But I have no feeling for the colour when low rate of silver. (any photos of copper with known pm rates would be very helpful)

Got one idea when writing this.
What if doing a similar test of the copper as the gold buyers do. Like testing it if its >0,01 karat. U take the copper scrap and make a good thick line on your testing stone. Then u add chemical X on the line. The testing chemical X removes the copper and leave the gold visible on the stone. Might work considering the ability of gold to cover in a very thin layer. But what Chemical X to use for such a test? Any ideas? Cheap and not to dangerous to have in the backpack.
 
@Snoman701

The only need i have is to get an answer to the question; Is this blister. Yes or no.
Exact amount would be fun to know but not needed. Would love to have a gun but the price is a little to expensive. (They are even more expensive in Sweden since an importer should have his share as well)

U mention 3 oz/ton as a very good blister. Its a blister but not a very good one, gold point view. Gold content of 30 oz/ton is a very good blister. The extremes can be higher than that. So the gold amount that should be detected not that small. Moreover there is silver as well that could be detected. Normally in higher concentration than the gold. Perhaps i should testing for silver instead of gold. They go hand in hand.


Just for fun.
Go out and take a look on your roof. What would it cost to replace it with a copper roof? Check it up and get a chock. Now calculate how much gold your present roof must contain in order to cover the cost of the new roof,
The roof story is true. There was even some scandals. Roofs older than USA were replaced and sold as scrap, just for profit, due to its gold, Thats old blister copper.
 
snoman701 said:
g_axelsson said:
snoman701 said:
g_axelsson said:
Only quick field test I know of for small amounts of gold in alloys is using an XRF-gun. An expensive tool unless you handle lots of scrap metal.

Göran
I wouldn't trust a gun on gold filled scrap in a well prepared sample. A gun on a few ppm on dirty field sample wouldn't even begin to be reliable.

Fire assay only.
We are not discussing gold filled, we are discussing old copper from pre-electrolysis times.

XRF is used by mining companies in the field, both when prospecting and while mining to track gold ore.

Göran

My point about gold filled is that it's low grade material.

I have a pretty good understanding of the limitations of XRF technology, and it's use in the field. In the field it's used with correlative data and known associations, not the actual measurement of gold. You track elements that are known to be associated with gold, and compare this to a series of fire assays you have performed.

Have you used an XRF gun much? You can see considerable resolution problems when discussing 10^-2 resolution if you aren't skilled. In order to accurately measure in the 10^-3 range, you need to have stationary sample and long sample times. Even then, the numbers on the screen are only suggestive and you are looking for the pattern of minerals. With Wavelength dispersive technology, you can get 10^-4 with long sample times and a really good analyst comparing results to gravimetric data. But even when discussing 3 oz / ton, very good blister, you are talking about 10^-5. You would now be trying to make use of a number that is smaller than your uncertainty.
You are correct, I have no personal experience of using XRF, the equipment I have is part of an electron microscope and not brought back to a running state yet. I got the detector (a SiLi diffused detector that needs liquid nitrogen to run) and the electronics associated to it, but after the last move the SEM ended up in a corner of my storage and hasn't been set up yet.

My experience of XRF in the field is only discussions with the geologists on a nearby gold mine and I never asked them if they were looking for tellurium or gold when they analyzed the samples or the walls in the mine. At the last visit I found an interesting specimen, they didn't have the XRF at the mine at that time, but they kept a sample and I got the result from the test after a week. The minerals we found showed high number of lead and tellurium with traces of gold. How high numbers I don't know.

Going online and doing a quick googling there are for example claims of detection limits of 20 ppm Au and 10 ppm Ag ( https://www.911metallurgist.com/equipment/handheld-xrf-analyzer/ ), that would put the gold in GSP's example at undetectable levels while the silver would be detectable. There are other contaminants like zinc, lead, iron... that would also show up. Blister copper contains between 98.5-99.5% copper so there are 0.5-1.5% contamination that can be detected with an XRF to show if you are dealing with blister, a copper alloy or electrolytic copper.

I found this article about refining blister copper, http://eprints.nmlindia.org/3800/1/54-58.PDF
In it they give numbers of gold and silver up to 100 (0.01%) respectively 1000 (0.1%) grams per ton.
These numbers would be detectable if he above XRF data is true.

Every method have it's limitations but I would still prefer XRF for sorting copper in the field over fire assay.

stella polaris, there are no streak test for copper that I know of and I suspect that just as for gold when you get close to 95% or more the streak test doesn't work any longer.

I was trying to come up with a simple sorting method but as there are copper alloys with similar amounts of other metal or silicon I can't see any easy test.
The most I could come up with would be to dissolve the copper in nitric acid, filter off the solids and then add a drop of aqua regia (just add a drop of HCl) and test with stannous.

Another test would be to check for presence of silver. Clean a piece down to pure copper surface to avoid false positives from silver plated scrap. Dissolve a piece in nitric acid, filter off any solids so you have a totally clear solution. Then add salt or HCl and look for the white precipitate (check for turbidity with a light source).

First test would be to use a file, pure copper is soft. But you would need a number of samples to test that method to see if it is a working method.

Göran
 
What electron microscope do you have? I just bought a defunct one for the vacuum chamber....if you need any parts you are welcome to them.

I've still got that bag of dips I need to send you as well.


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Electron microscope? Now we talking!

Nice with guys that taken a closer look at things.
What u think about this?
1.I put nitric acid on a spot and let it work for a moment.
2. i clean with water and let it dry

Would i be able too see any structural diffrence in the point. Does blister leave a diffrent surface compared to electrolyted? If so, can this be observed with help of a simpler optical magnifier?
 
Dissolve some filings with drop nitric, add small drop of hcl, then test with stannous. Even then, you are hoping the gold is uniformly distributed and gold qty is above the threshold for stannous. From memory, that's 5 ppm, but that's for a solution that is prepared without excess oxidizer which will be difficult in your timeframe.

It's a losing venture unless you are collecting for definitive cu content and using possible au as a bonus.


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I start to realise I have to go stone age in field on this one.

I will try sorting on visual, hardness and type of product. Then try the scrap pieces at home. Learn by doing so to say. Anyhow I thank you all for your input. If I come up with something I let you know.
 
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