Tin as a Collector

[Bucknails]

Hi, I want to find out if anyone has a technique for separating out tin when using it as a collector in the refining process. I've been told tin has a high affinity for PMs but refiners don't like working with it too much. I have my own refining lab set up but not familiar with how to separate the goodies from the tin. Thank you for any directions!

 

[goldshark]

I posted this question a while back, but didn't get much response. I think my question was more along the lines of wether or not you could cupel the Tin, into a Magnesia cupel. I don't know, as I never got a response back. I would think the route to go would be to put it in hydrochloric, dissolving the Tin out, as in inquarting with Silver. I fear this would leave a very fine powder, which would be hard to collect. This is due to the relatively high dilution rate of the Tin/Gold alloy. A typical Au/Ag inquart, would have considerably more Au, leaving a very thin Au foil, and not a bunch of very fine powder. This is for small beads encountered in assaying, not for bulk refining quantities. If done in a higher quantity, I don't see why it wouldn't work. Filter, dry, melt dish with Borax, pour, electro win back Tin. Anybody else want to add something?

 

[Golddigger76]

Very interesting topic !!!
I have never tried it but with aqua regia or nitric acid dissolving your tin inquarted gold, you will end up with metastanic acid., this would have to be roasted to form tin oxide which is soluble in hydrochloric acid. IF and I probably will never go that route but that's the only way how I have it pictured happening.
Maybe someone else that has tried can tell you how well it did or didn't work.
As a collector I would think that you would roast it into tin oxide in the cupel.

 

[Golddigger76]

1,800–1,900 °C or 3,270–3,450 °F is the temperature that tin oxide sublimes.

 

[goldshark]

I am thinking more along the lines of using Tin as a collector, but only in fairly high assaying smelts. Parting would be with HCl only, leaving fine powder. After thorough washings, then give a Nitric bath.

 

[Shark]

If this leaves a very fine powder would that allow for better removal of the contaminates from the gold. In other words, leave a cleaner gold powder?

 

[Golddigger76]

Lino1406 will know, I bet if you wait for him to see this he will give you a answer.

 

[goldshark]

The Au particle sizes would more than likely be in the nm range, after the HCl dissolution.. Much finer then melting to shot. I would think this gives a fairly high purity of Au, but would be dependent on what other metals are included in the original alloy, which could be resistant to Nitric only.

 

[andu]

I do like the idea of using tin as collector metal and i cannot understand why people find it so undesirable. I'm still novice but i would try. Feels safer and better than lead.

 

[Shark]

The Au particle sizes would more than likely be in the nm range, after the HCl dissolution.. Much finer then melting to shot. I would think this gives a fairly high purity of Au, but would be dependent on what other metals are included in the original alloy, which could be resistant to Nitric only.

This could also help those in countries where nitric is harder to come by as the finer powders would be easier to redissolve in bleach or maybe peroxide with hydrochloric. If they need higher quality at all. Interesting idea here.

 

[stella polaris]

I had the idea to use the solder tin as collector and asked about it here before. In my question i probably used the wrong terminology since i wrote that i wanted to "boil" the components in tin. To cook is a better expression. Since tin have a high boiling point it seems to be a good collector. Yes tin is a problem if sneaking in into your process. But if you know there is tin you can take care of it.

HCL is quite easy to get hold of and solve tin. Yes it will require some volume of HCL but can you not electro win the tin out of the solution? Or will the copper,in the components, make bronze of it thereby make it more difficult to separate??

 

[Yggdrasil]

I had the idea to use the solder tin as collector and asked about it here before. In my question i probably used the wrong terminology since i wrote that i wanted to "boil" the components in tin. To cook is a better expression. Since tin have a high boiling point it seems to be a good collector. Yes tin is a problem if sneaking in into your process. But if you know there is tin you can take care of it.

HCL is quite easy to get hold of and solve tin. Yes it will require some volume of HCL but can you not electro win the tin out of the solution? Or will the copper,in the components, make bronze of it thereby make it more difficult to separate??

Well, it certainly seems kind of viable, but as many have pointed at the PMs will be very fine.
Maybe even in the colloidal size. I have seen in more than one occasion this nice purplish color when dissolving Tin.
One of the beauties of Lead, is the fact you can cupel it after, leaving a button/slab that can be refined in ordinary ways.
Maybe one can find a third material to alloy with the Tin dore after to achieve better separation, maybe Zinc?

 

[Lino1406]

Lino1406 will know, I bet if you wait for him to see this he will give you a answer.

Our ancestors found 2 facts making lead work for cupellation, 1st forming lead oxide which combines with other oxides and readily absorbed in bone ash, 2nd favourable gold/lead ratio (not "high dilution"). Now days some kind of cement or magnesia replace bone ash, so if non lead metal is wanted, trying of another fusible metal, not necessarily tin, can not be rejected from the beginning. Some examples: zinc, aluminium, indium, bismuth...

 

[slsmp40]

I wrote a whole long explanation and hit post and it disappeared into the ether. So I guess I will just go with tin is a pest when it comes to parting it from precious metals. Bismuth is leads only competition but it is still 10x the cost. Tin makes a great test solution. Leave it at that or leave your gold go to the sea where you must want it to be or you would not have used tin as a collector metal.

 

[Yggdrasil]

I wrote a whole long explanation and hit post and it disappeared into the ether. So I guess I will just go with tin is a pest when it comes to parting it from precious metals. Bismuth is leads only competition but it is still 10x the cost. Tin makes a great test solution. Leave it at that or leave your gold go to the sea where you must want it to be or you would not have used tin as a collector metal.

I would not exclude Tin yet.
There may be techniques we overlook.
In the old days I guess Tin was way more valueble as Bronze so it became the bad stepsister to Lead in the refining industry?

 

[andu]

The thing is that lead is toxic and tin is not, it's the only reason i'm personaly reluctant to use lead in any case. I also find it funny to work with tin, atleast in a molten state while tin becomes unhealthy at the very least. I will , perhaps with a bit of luck in a future try fairly madly with tin see what's up and how bad it can be.

 

[slsmp40]

The thing is that lead is toxic and tin is not, it's the only reason i'm personaly reluctant to use lead in any case. I also find it funny to work with tin, atleast in a molten state while tin becomes unhealthy at the very least. I will , perhaps with a bit of luck in a future try fairly madly with tin see what's up and how bad it can be.

Bismuth is your best bet. Don’t believe tin is nontoxic. Its just not as toxic. Bismuth is even safer and has great collection properties. Tin is a wonderful metal, its just not so wonderful to separate from other metals. Its also very expensive in comparison.

 

[goldshark]

Hi, I want to find out if anyone has a technique for separating out tin when using it as a collector in the refining process. I've been told tin has a high affinity for PMs but refiners don't like working with it too much. I have my own refining lab set up but not familiar with how to separate the goodies from the tin. Thank you for any directions!

I called an assayer at a major lab, to get the skinny on Tin and cupeling. Apparently, Tin in the cupeling process tends to drag PMs into the cupel. The assayer said to use sodium carbonate to put the metal into the slag. It was early in the A.M., so forgot to ask about the use of an oxidizer to convert the Tin to an oxide, in addition to the Soda Ash. Tin will cupel, but at the cost of heavy PM losses.

 

[goldshark]

I called an assayer at a major lab, to get the skinny on Tin and cupeling. Apparently, Tin in the cupeling process tends to drag PMs into the cupel. The assayer said to use sodium carbonate to put the metal into the slag. It was early in the A.M., so forgot to ask about the use of an oxidizer to convert the Tin to an oxide, in addition to the Soda Ash. Tin will cupel, but at the cost of heavy PM losses.

It seems like the best way to remove a lot of Tin, with PMs, is to use an electrolysis cell, to remove the Tin. You will need to put the material into a fine filter bag, to catch the slimes, which will hold the PMs. A cell, as demonstrated by Sreetips on Youtube, for his Silver cell, would work perfectly. Ramp up the size for bigger production.

 

[stella polaris]

It seems like the best way to remove a lot of Tin, with PMs, is to use an electrolysis cell, to remove the Tin. You will need to put the material into a fine filter bag, to catch the slimes, which will hold the PMs. A cell, as demonstrated by Sreetips on Youtube, for his Silver cell, would work perfectly. Ramp up the size for bigger production.

You need some type of mechanical solution to knock of the tin crystalls that have a tendency to grow fast and shortcut the cell. That as well as some way to recover the tin so in not going back in solution. A bottom top cell seems better than side by side due to this.