Tin as a Collector

[nickvc]

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.

Perhaps add an air bubbler under the cathode..

 

[Yggdrasil]

Perhaps add an air bubbler under the cathode..

Hmm, interesting if it can be done.
It will knock down whiskers and create circulation at the same time.

 

[kurtak]

Perhaps add an air bubbler under the cathode..

Agitation like that in a cell (any cell) WILL cause the slims (ultra fine particles) in the anode bag to come through the pores in the anode bag (kind of like washing dirt out of cloth in a washing machine) those particles in the electrolyte will then end up settling/depositing with the metal at the cathode

So the metals you are trying to collect in the anode bag (which would include the gold) is being washed out of the anode bag resulting in contamination of the metal at the cathode --- you just defeated the purpose of the "parting" cell

Also - just like the slims in a silver cell are mostly silver - the slimes in a tin cell will be mostly tin so you still need to separate the tin in the slimes from the gold in the slimes --- so you do not really gaining anything by running it in a cell because you still have to deal with the tin in the slimes

Kurt

 

[kurtak]

You need some type of mechanical solution to knock of the tin crystalls that have a tendency to grow fast and shortcut the cell

Per the bold print - these are called tin whiskers (like the whiskers on a cat) & they grow VERY LONG & VERY FAST so unlike a silver cell where you can walk away for several hours before needing to knock down crystal growth - in a tin cell you will need to keep a constant eye on the cell to keep the whiskers knocked down

When you first start to run the cell the whiskers will grow between cathode & anode in "about" 5 -7 minutes - as metal (tin) builds up on the cathode the time needed to knock down the whiskers gets shorter & shorter

That is because in the beginning the whiskers are just growing directly from the cathode to the anode - but as those wiskers build up on the cathode whiskers start growing from whiskers so whisker growth speeds up

So you can not just walk away from a tin cell - unless you have a rotating cathode with a bar between the anode & cathode to keep the whiskers knocked down - or other motor operated mechanism on a timer that runs a rod over the cathode to knock down the whiskers

Kurt

 

[kurtak]

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.

Per the bold print - The problem with that is in getting all the dissolved tin solution washed out of the gold sponge

Most dissolved base metals stay dissolved as they get diluted with the water washing

Tin is an exception to that - as tin dissolved in HCl becomes diluted it starts to precipitate meta stannic acid which will result in meta stannic acid tied up in your gold sponge

I suppose you could do the washing with HCl - but - the problem there is that tin dissolved in HCl is a perfectly clear solution - so how do you know if/when all the tin is actually washed out of the gold sponge ?

There is a reason why tin is considered a "refiners nightmare" !!!

If using tin was a method that worked - then don't you think refiners would be using tin as a method ?

Kurt

 

[kurtak]

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.

Per the bold print - yes - So that is another problem with using tin as a collector

Tin in the cupeling process tends to drag PMs into the cupel.

And there you go - another problem with tin

The problem(S) with tin are MANY !!!

There is a reason that refiners do everything they can to eliminate tin BEFORE refining !!!

There is a reason why refiners NEVER use/add tin as a path/method TO refining !!!

The problem(S) with using tin (as a collector metal) have been discussed on this form !!! --- just nor recently

Bottom line - unless you actually WANT to create problems for yourself --- DON'T DO IT !!!

One more time - tin = a refiners nightmare !!!

Kurt

 

[goldshark]

Per the bold print - yes - So that is another problem with using tin as a collector

And there you go - another problem with tin

The problem(S) with tin are MANY !!!

There is a reason that refiners do everything they can to eliminate tin BEFORE refining !!!

There is a reason why refiners NEVER use/add tin as a path/method TO refining !!!

The problem(S) with using tin (as a collector metal) have been discussed on this form !!! --- just nor recently

Bottom line - unless you actually WANT to create problems for yourself --- DON'T DO IT !!!

One more time - tin = a refiners nightmare !!!

Kurt

I searched the forum, and never found any info on Tin, as a collector, how to remove from PMs, basically no info at all. That is why I asked, as well as others, about its use, and how to deal with it. If it is in the forum some where, it needs to be easily found. I typed "cupeling Tin " into the search, not getting a specific thread, but a link to all the threads with the word "cupel" in it. A very lengthy list. There needs to be a more streamlined way to search, or people will keep asking the same questions.

 

[galenrog]

Shortly after joining GRF, I made it a point to read every post on the forum. Every thread, from first post to last. I have done that and continue the practice today.

The problems regarding tin, in both recovery and refining, have been mentioned several times. While I do not recall any thread specific to tin, the discussions are here, and can be found.

Might I suggest the single search word “tin” and read every thread from first post to last. While most of it will not address the issue at hand, a few will.

Time for more coffee.

 

[goldshark]

Shortly after joining GRF, I made it a point to read every post on the forum. Every thread, from first post to last. I have done that and continue the practice today.

The problems regarding tin, in both recovery and refining, have been mentioned several times. While I do not recall any thread specific to tin, the discussions are here, and can be found.

Might I suggest the single search word “tin” and read every thread from first post to last. While most of it will not address the issue at hand, a few will.

Time for more coffee.

I hear you on your answer. The problem, as I see it, is the forum has grown so much in that time, that there is so much new talk, it would take years to read every post in every thread now. Time is precious. Just saying it would be nice to be able to do a search on a certain item, and only have the pertinent info come up. Eliminate all the rebuttals, like what I am typing now.

 

[Yggdrasil]

I hear you on your answer. The problem, as I see it, is the forum has grown so much in that time, that there is so much new talk, it would take years to read every post in every thread now. Time is precious. Just saying it would be nice to be able to do a search on a certain item, and only have the pertinent info come up. Eliminate all the rebuttals, like what I am typing now.

Searching the forum has become a chore at times, but learning search techniques will improve the hit rate.

 

[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.

I have been thinking about this. But what we often refere to as "Tin" is often solder. Older ones contain not only tin but also a good percentage of lead. Newer lead free ones contains not only tin but also other metals. On top of that you have some that also contains silver.

My situation looks like this. I have old office telefone boards . All goldplated and with gold base for the number buttons. Swedish made Ericsson telefones of good spec. + other goldplated bords. Now i do not want to put them in AP with a lot of solder on them. The solder also contains some gold. (If 2% as stated in some cases i do not know.) But i do not want to throw away that solder since 1 kg solder could contain up to 20 gram of gold.

So even if Tin is the hell on earth i want the heaven of the sky within it.

Questions.
How well can i seperate the diffrent solder metals with electrowinning a HCL solution? Diffrent materials, voltages and so on.

Can I elektrowin collodial gold?

 

[Spaceships]

There's another way to get rid of Tin if you make sure you take the relevant precautions and that's Sodium Hydroxide. A hot bath will take it all out but be advised to check for any other metals there that may react with it. You can electrowin the Tin out of the solution Stella. Alkali chemistry is a completely different field of study but done correctly it's remarkably effective for some things.

Edit: Just be careful of the risks because there's very little danger difference between hot Sodium Hydroxide and hot Sulphuric. Face/eyes/skin.

 

[Yggdrasil]

I have been thinking about this. But what we often refere to as "Tin" is often solder. Older ones contain not only tin but also a good percentage of lead. Newer lead free ones contains not only tin but also other metals. On top of that you have some that also contains silver.

My situation looks like this. I have old office telefone boards . All goldplated and with gold base for the number buttons. Swedish made Ericsson telefones of good spec. + other goldplated bords. Now i do not want to put them in AP with a lot of solder on them. The solder also contains some gold. (If 2% as stated in some cases i do not know.) But i do not want to throw away that solder since 1 kg solder could contain up to 20 gram of gold.

So even if Tin is the hell on earth i want the heaven of the sky within it.

Questions.
How well can i seperate the diffrent solder metals with electrowinning a HCL solution? Diffrent materials, voltages and so on.

Can I elektrowin collodial gold?

I can not say how easy it is to separate the metals out of Solder.
It can surely be done since Tin is mined and separated industrially.
How easy and economically is beyond me at the time.
No colloidal metals can't be electrowon. (Not a solution and no physical contact between the individual particles)
The best solution is to re dissolve them and drop/cement as usual.

 

[stella polaris]

FYI
If you want to buy 1 kg, of pure Tin, in Oslo, Norway, you have to pay 100 usd. A veritable chock for those that buy a tin soldier form to the kid. Spot is when you buy 50 tons at a metalmarket. Transport is your cost. VAT. Storage, Handeling....

So tin is more than spot, at the spot. : )

 

[Yggdrasil]

FYI
If you want to buy 1 kg, of pure Tin, in Oslo, Norway, you have to pay 100 usd. A veritable chock for those that buy a tin soldier form to the kid. Spot is when you buy 50 tons at a metalmarket. Transport is your cost. VAT. Storage, Handeling....

So tin is more than spot, at the spot. : )

Makes sense, kind of, it is not a commodity for the general public.

 

[kurtak]

The solder also contains some gold. (If 2% as stated in some cases i do not know.) But i do not want to throw away that solder since 1 kg solder could contain up to 20 gram of gold.

Yes there is gold in the tin solder from CBs - that is because the "solder pads" on the CBs are first gold plated - then when they solder components to the board (such as IC chips) the gold plating on the solder pads "migrates" into the tin solder

However - your numbers for the amount of gold in the solder are wrong

Instead of 2% it is actually more like 0.2% (plus/minus) so a kilo of solder from CBs will be more like 2 grams per kilo (plus/minus)

Kurt

 

[NobleMetalsRecovery]

Tin that has gold alloyed with it can be heated to 250C to 450C and then you would add molten aluminum to the solution of tin/gold. With good mixing the aluminum will completely remove the gold from the tin. At this point you will have gold/aluminum, aluminum, and tin in the molten bath of metals. The gold/aluminum alloy solidifies at about 1000C. So as the molten tin (containing the gold/aluminum alloy) is allowed to cool, the lighter gold/aluminum alloy solidifies and floats to the top as a dross which can be skimmed off.

Separating the gold from the aluminum would be pretty straight forward. Would probably use a hydroxide. This method was developed by the Bureau of Mines almost 50 years ago. If you do a search for "Recovering Gold from Scrap Electronic Solders by Drossing" you should locate the free PDF file to view or download.

 

[kurtak]

Tin that has gold alloyed with it can be heated to 250C to 450C and then you would add molten aluminum to the solution of tin/gold. With good mixing the aluminum will completely remove the gold from the tin. At this point you will have gold/aluminum, aluminum, and tin in the molten bath of metals. The gold/aluminum alloy solidifies at about 1000C. So as the molten tin (containing the gold/aluminum alloy) is allowed to cool, the lighter gold/aluminum alloy solidifies and floats to the top as a dross which can be skimmed off.

Separating the gold from the aluminum would be pretty straight forward. Would probably use a hydroxide. This method was developed by the Bureau of Mines almost 50 years ago. If you do a search for "Recovering Gold from Scrap Electronic Solders by Drossing" you should locate the free PDF file to view or download.

Interesting - here is a link ---------

https://redesign.911metallurgist.com/blog/recovering-gold-scrap-electronic-solders-drossing/

Kurt

 

[andu]

Whatever they say, I love tin. Both tin and lead are horribly slow to dissolve in my experience but that is only problem i encountered, maybe just needed some heat, perhaps selective cementation would be an answer.
I'm still waiting to experiment and see what's all the fuzz about tin.

 

[Tomcat]

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.

I saw a video of a guy who crushed up Pepto Bismal tablets and used it as a collector metal then cupelled with it and it worked. Do you know if Bismuth cupels easier and faster than lead? Lead cupelling does not work. I have thrown tons of heat and air and fans at the process and it does nothing. Maybe it works for those who have an oxygen torch or special cupelling oven, but the other videos are fake. Im also wondering is there any other metal that would collect the gold out from the lead?