Have I struck gold?

[bemate]

Well, I'll admit I was under the impression that I needed pure tin to get the best results, but pure tin is difficult to find in reasonable amounts for a test solution. But 99,3% Tin solder is a lot easier to find, so that goes on my shopping list for my next trip to the hardware store.

 

[bemate]

A quick follow-up question if anyone takes the time to read and answer: I realize my pins are best suited for a sulphuric cell since they are entirely covered, however, that is not an option for the time being as I have no way of setting up a cell and running it in a safe way. Cyanide is also not an option, both because of the inherent danger, but also due to the legal issues of using it. That leaves me with AP, which is looking to be my most viable option for most of my material. I don't particularly care if it takes a long time, I am not in a hurry, but will the AP be able to get to the base metal of my pins at all? From my small-scale tests, it looks like my pins are copper all the way through, but the gold covers them entirely. From my understanding, that means the CuCl2 will have problems getting to the base metals underneath.

Is it an option to start off the process with an overdose of peroxide to intentionally dissolve some gold to expose copper, and then count on the gold to cement out as the process continues?

 

[patnor1011]

Use only small bit of peroxide. Get yourself fish tank bubblier that is all you need and patience. Pins will look coppery or dark first but just wait till they completely dissolve. If you want to speed things up little bit search forum for crock pot method.

 

[bemate]

Use only small bit of peroxide. Get yourself fish tank bubblier that is all you need and patience. Pins will look coppery or dark first but just wait till they completely dissolve. If you want to speed things up little bit search forum for crock pot method.

That was my original plan, I'll just stick with that then. I'll add some premixed CuCl2 -solution as well, I have some pure salt.

Thanks!

 

[FrugalRefiner]

That was my original plan, I'll just stick with that then. I'll add some premixed CuCl2 -solution as well, I have some pure salt.

If you're going to add some CuCl₂, you don't need any peroxide. The purpose of adding peroxide at the beginning is to oxidize a bit of the copper to get the process started. HCl won't dissolve copper, but it will dissolve copper oxide, so the peroxide oxidizes a bit of the copper, the HCl dissolves the copper oxide and creates CuCl₂. The CuCl₂ then oxidizes more copper and the process continues.

Dave

 

[johnny309]

Old pins like that?
Deep colour..... no sign of Ni......layer barier is often Pd/Ag......95/5....or 90/10.....
Be aware of Be..... is added to ensure the "elasticity" of those pins .
I use a flat screw driver ....just in the middle of the connector....is fast for me.
P.S.:the windup wire in the connection is copper plated with Ag.

 

[jason_recliner]

...will the AP be able to get to the base metal of my pins at all?

Yes.

Is it an option to start off the process with an overdose of peroxide to intentionally dissolve some gold to expose copper, and then count on the gold to cement out as the process continues?

I can see what you're thinking. And while it would occur as you say, it's not necessary.
CuCl2 will penetrate and undermine the gold layer. If you have plenty of time, don't let apparent inactivity undermine your patience. And for obvious reasons, once it eventually starts visibly, it will accelerate.

 

[bemate]

Old pins like that?
Deep colour..... no sign of Ni......layer barier is often Pd/Ag......95/5....or 90/10.....
Be aware of Be..... is added to ensure the "elasticity" of those pins .
I use a flat screw driver ....just in the middle of the connector....is fast for me.
P.S.:the windup wire in the connection is copper plated with Ag.

I'll keep that in mind, not done reading yet, so I'll make sure to look up the hazards of beryllium (which I would do anyway as I work my way through the safety section...). As for using a screwdriver, I assume you mean to score the surface to expose the copper? With 1800 pins that is not a very appealing prospect... ;P

Judging from outside temperatures and so on, I will probably not start this up until late April anyway.

 

[nickton]

wouldn't reverse electroplating be the best method for these? Oops I just noticed you posted you can't do a sulfuric cell for some reason. Sorry.
:mrgreen:
:?:

 

[jason_recliner]

Judging from outside temperatures and so on, I will probably not start this up until late April anyway.

Do yourself a favour. Throw them in a bucket now, covered with with 2 parts HCl to 1 part water. Regardless of the Norwegian weather of which a Melburnian like myself has utterly no comprehension, they'll likely be ready (or close to ready) by April. Even if they're not entirely decomposed, the outer layer of base metal will be so rotten that the gold plating will flake off when you rattle it around.

Ensure that you have a loose fitting lid, to impede dirt ingress and to prevent pressure build-up. I use a tight fitting lid that I pierced in three places (I like redundancy).

Which brings me to my tip to the frugal: My local Dairy Bell (ice-cream shop) sells empty 11 litre buckets with tight (but soft and stabbable) lids for around 40c each. Actually I paid $1.70 for four. Last time was $1.10 for three. How they calculate it I cannot fathom and I have I little confidence that the 16 year old kids running the shop know what they're doing. But in any case, it's a good deal.

 

[bemate]

Judging from outside temperatures and so on, I will probably not start this up until late April anyway.

Do yourself a favour. Throw them in a bucket now, covered with with 2 parts HCl to 1 part water. Regardless of the Norwegian weather of which a Melburnian like myself has utterly no comprehension, they'll likely be ready (or close to ready) by April. Even if they're not entirely decomposed, the outer layer of base metal will be so rotten that the gold plating will flake off when you rattle it around.

Ensure that you have a loose fitting lid, to impede dirt ingress and to prevent pressure build-up. I use a tight fitting lid that I pierced in three places (I like redundancy).

Which brings me to my tip to the frugal: My local Dairy Bell (ice-cream shop) sells empty 11 litre buckets with tight (but soft and stabbable) lids for around 40c each. Actually I paid $1.70 for four. Last time was $1.10 for three. How they calculate it I cannot fathom and I have I little confidence that the 16 year old kids running the shop know what they're doing. But in any case, it's a good deal.

I see your point, but the idea of digging the container out of the snow every few days to check that it has not frozen solid and cracked does not appeal very much to me... Typically, we will have somewhere from 30cm to 1,5 meters of snow building up through the winter, and having a can of strong acids somewhere inside a pile of snow is not within my idea of safe handling, especially with my kids playing in the snow.

But I will start it earlier than April if we have a spring thaw, so even early March might be viable, but we'll see.

 

[jason_recliner]

Well my friend, you know your area and I do not. So advice is only that.
I thought HDPE could withstand -40°C (or -40°F, if you prefer) continuously. Just how cold does it get where you are?!
(I ask this from a zone that sometimes reaches the despairing depths of -2°C in July)

 

[bemate]

Well my friend, you know your area and I do not. So advice is only that.
I thought HDPE could withstand -40°C (or -40°F, if you prefer) continuously. Just how cold does it get where you are?!
(I ask this from a zone that sometimes reaches the despairing depths of -2°C in July)

Usually we have nighttime temperatures ranging from -5 to -15 from mid-December through to mid-March, with occasional warm weather around 0 and cold spells down to maybe -25 in the extreme. I have no doubt the plastic will hold up, I was referring to the risk of ice expanding and cracking the container, not to mention the risk of puncturing it with my snow shovel... But just as much it comes down to me not wanting to spend more time outside to check my air bubbler or anything more than I need to. I plan to use the cold months to collect gold-bearing scrap and educate myself, building the equipment and planning, and then starting up the chemical processing once it's getting warmer and more pleasant outside, at least for my first few runs.

I only do this for fun, and frotbitten fingers are not on my list of fun things.

 

[macfixer01]

I would use known, clean ingredients for a test solution like that. I would not go with 'I think it's mostly tin chloride'. Get yourself some lead free sinkers or something like that, and use those.

Sent from my SAMSUNG-SM-G891A using Tapatalk

Lead free sinkers are likely mostly bismuth, and very little tin if any?

 

[upcyclist]

I would use known, clean ingredients for a test solution like that. I would not go with 'I think it's mostly tin chloride'. Get yourself some lead free sinkers or something like that, and use those.

Sent from my SAMSUNG-SM-G891A using Tapatalk

Lead free sinkers are likely mostly bismuth, and very little tin if any?

Around here (US), they're tin. I bought some lead-free sinkers from Walmart and they work like a charm.

Sent from my SAMSUNG-SM-G891A using Tapatalk

 

[bemate]

Brief update:

I have processed the small batch of pins with solder in HCl/H2O2, partly because I got impatient, and partly to look at some related issues, see: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=39&t=22918

The process worked quicker than expected, and it took only a few days for the acid to eat through the pins, leaving the expected mix of Gold foils, solid AgCl and whatever else came out of the solution and stuck in the filter.

Testing with Stannous showed me I have not dissolved any Gold, so that is the first hurdle safely navigated, now my filters are sitting in a beaker waiting for AR tomorrow.

This should give me a rough idea of the gold content in my pins, though I forgot to count the pins beforehand, so I don't know the exact amount of pins to calculate yield from, and the solder throws my figures off if just going by weight, but it will give me some ballpark numbers.

Will be back tomorrow with some pictures.

 

[bemate]

Well, my gold is now safely in a filter, though not quite the purity I'd hoped for, it's a rather dark brown. Not that it matters terribly much, I think I'll group my various filters with dropped gold at some point and do a re-refining to make sure my first button is nice and shiny...

So, the numbers. My first batch of pins consisted of the 67 or so grams of pins with solder and wire. While I have no accurate number of pins, I would estimate about 25% of that weight to be solder and wire, so about 50 grams of pure pins. That comes down to about 150 pins, that gave me around 250mg of gold in the filter. Rounding down to err on the side of caution, that means in the region of 3 grams of pure gold in my total batch of 1800 pins, slightly below my estimate of 5 grams calculated from surface area and an assumption of 30 microinches plating thickness, but not too bad.

Of course, there are numerous (non)educated guesses in these numbers, but the proof will be in the pudding/button/filter when I get to scale up and do my large batch of pins come spring.

My Auric Chloride after filtering:


And after adding SMB:

 

[jason_recliner]

Good job. The clarity of the solution and the in-progress precipitation look appropriate for a first refine off pins.

If it appears too brown to you, it's to your credit. I say that because some have melted their dark brown powders only to achieve a dark brown splat... and wonder why. You will be amazed the colour that will wash off your powder with HCl rinses, and then a second refine should return you an encouragingly paler result.

Finally, and this is not intended to be condescending, but as you gain experience strive to do this using less and less solution. Remember how much acid Ms Hoke wrote is required to dissolve an ounce.

Hooked yet?

 

[Tzoax]

Brief update:
The process worked quicker than expected, and it took only a few days for the acid to eat through the pins, leaving the expected mix of Gold foils, solid AgCl and whatever else came out of the solution and stuck in the filter.

I would suggest incineration of remaining solids in filter paper/HCl simmer boil for removing tin because of possible gold particles trapped with tin oxide.

 

[bemate]

Good job. The clarity of the solution and the in-progress precipitation look appropriate for a first refine off pins.

If it appears too brown to you, it's to your credit. I say that because some have melted their dark brown powders only to achieve a dark brown splat... and wonder why. You will be amazed the colour that will wash off your powder with HCl rinses, and then a second refine should return you an encouragingly paler result.

Finally, and this is not intended to be condescending, but as you gain experience strive to do this using less and less solution. Remember how much acid Ms Hoke wrote is required to dissolve an ounce.

Hooked yet?

Thank you, and no, I don't find any of this condescending, while I'm pretty confident in my lab chemistry skills, I realize I'm still a more or less complete novice in this game.

As for the powder, I have a reference sample of dropped gold from some chemically pure gold salts (see my profile pic), and they are a very light brown, and I assume that is gold in the order 4-5 nines since it originally was sold to be used for making gold nanoparticles used in electron microscopy of cell organelles. That serves as my reference as to how the gold 'should' look before attempting a melt. And in any case, I only have about one gram of precipitated gold in total so far, so I'll store them and collect them to a bigger button first.

The volume is very large, I'm aware of that. This is mostly due to two facts: when I started off with my filters from the first drop, I just poured in enough HCl to cover them, I didn't think about them dissolving and making more room in the beaker, and then, when I was filtering, I washed with a lot of water to get all the yellow colour out of the filter with the pulped filters from the AR, effectively tripling my volume after adding ice to cool the solution to precipitate out any AgCl or PbSO4. The filters are safely tucked away in a box with some other filters containing the precipitated AgCl and any gold remains. I will build up that stockpile a bit before I burn and process them, I don't see the point in doing a recovery from just one or two filter papers.