Require method of purifying Tin from 3% Impurity of Silver

[yatendrao]

Dear All

 

we have source of Tin alloy. in that 97% of Tin and in 3% of silver impurity which we would like to remove kindly advice the proceduer for the same

 

Regards

 

Yatendra Joshi

[John Cuthber]

Does this help?

http://www.google.com/patents/US1157830

[StringJunky]

Does this help?

http://www.google.com/patents/US1157830

What addiitive could you use that is specific to making a silver compound that is insoluble in the electrolyte?

[John Cuthber]

What addiitive could you use that is specific to making a silver compound that is insoluble in the electrolyte?

Why bother?

[fiveworlds]

If we heat the alloy to liquid form will the silver float to the top to be skimmed off? As far as melting the tin is concerned it doesn't look too difficult

 

Edited June 28, 2015 by fiveworlds

[John Cuthber]

If we heat the alloy to liquid form will the silver float to the top to be skimmed off? As far as melting the tin is concerned it doesn't look too difficult

 

How do you think they made the alloy in the first place?

It doesn't matter because the silver will dissolve but silver is denser than tin.

 

Also, soda cans are not made of tin.

And, if it was that easy, do you think I would have suggested electrolytic refining?

[fiveworlds]

Also, soda cans are not made of tin.

 

Yes they are made of aluminium

 

It doesn't matter because the silver will dissolve but silver is denser than tin.

 

Then skim the tin off the top.

 

And, if it was that easy, do you think I would have suggested electrolytic refining?

 

Probably not but sure I thought I'd ask anyway

[John Cuthber]

 

 

Then skim the tin off the top.

 

 

Did you not understand the bit where I said "It doesn't matter because the silver will dissolve"?

[Enthalpy]

They won't separate by melting, but you can separate them by distillation.

At 1bar, Ag boils at 2160°C and tin at 2620°C.

For 10mbar vapour pressure, Ag needs 1509°C and tin 1834°C.

[John Cuthber]

They won't separate by melting, but you can separate them by distillation.

At 1bar, Ag boils at 2160°C and tin at 2620°C.

For 10mbar vapour pressure, Ag needs 1509°C and tin 1834°C.

Both of which exceed the melting point of steel.

What were you planning to make the equipment from?

How were you planning to heat them?

[Enthalpy]

And? Many processes exceed the melting point of steel, beginning with the production of pig iron and of steel. Several metals are produced in vapour phase, which advantageously separates them.

 

Yatendrao didn't write: "we have three grams and operate in a kitchen".

[Sensei]

The thing is it's not smart way. It's pretty brute force way. Just a single step from making plasma and then separating them using electric/magnetic external fields. Obviously it would work. But at what cost!

 

Smart way is to use chemical reaction, utilization of some property of their compounds, to separate these two metals from each other using as less energy as possible, at the lowest cost as possible, as fast as possible. Without having to build expensive factory/device..

 

Take for example solublity of two compounds:

Tin sulfate has 33 g/100 mL @ 25 C

Silver sulfate has 0.83 g/100 mL @ 25 C, 0.57 g/100 mL (0 °C)

So after adding right amount of sulfuric acid, one should be still dissolved, while other will be gathering at the bottom as solid.. Filter it, repeat cycle..

Then find smart way to turn sulfate back to metal state..

SnSO₄ + heat -> SnO₂ + SO₂

SnO₂ + 2 CO -> Sn + 2 CO₂

perhaps

SnO₂ + C -> Sn + CO₂

 

Other example:

Tin chloride has 83.9 g/100 ml (0 °C)

Silver chloride has 520 μg/100 g at 50 °C

Even larger difference in solublities..

[John Cuthber]

And? Many processes exceed the melting point of steel, beginning with the production of pig iron and of steel. Several metals are produced in vapour phase, which advantageously separates them.

 

Yatendrao didn't write: "we have three grams and operate in a kitchen".

Sure, you could distil them (it's not obvious how but never mind).

it's true that steel and other metals are commonly melted during processing at temperatures much higher than those mentioned.

And it's true that some metals are vacuum distilled.

 

but I don't think many people do both.

Also, why go to the trouble of some hugely difficult system?

 

If you are going to be outrightly silly about it, why not suggests separating them one atom at a time under an STM?

It's true that he didn't say he was planning to do this in a kitchen but where exactly would vacuum distillation be a good choice?

Where, for example, would it be a better bet than electrolytic refining?

[Enthalpy]

Nobody talks about plasma and electric fields. Sensei, if you have such bizarre ideas, please don't suggest anybody else brought them.

 

I propose distillation because evaporating a metal takes less energy than most chemical reactions do, which separate atoms too and often ionize them, and involve more reactants. In addition, much of this heat can be recycled (in the preheating of the input material), and heat is a cheap form of energy.

[Sensei]

Nobody talks about plasma and electric fields. Sensei, if you have such bizarre ideas, please don't suggest anybody else brought them.

 

What?!

Read posts you're replying to..

I said "Just a single step from making plasma"..

 

BTW, it's not bizzare idea.

It is/was widely used technique for receiving pretty pure isotope.

f.e. Manhattan Project Uranium purification.

https://en.wikipedia.org/wiki/Calutron

Thousands labolatories around the world that have mass spectrometers are using this technique in analyze/detection of chemical compounds they're working with.

Edited August 3, 2015 by Sensei

[John Cuthber]

Nobody talks about plasma and electric fields. Sensei, if you have such bizarre ideas, please don't suggest anybody else brought them.

 

I propose distillation because evaporating a metal takes less energy than most chemical reactions do, which separate atoms too and often ionize them, and involve more reactants. In addition, much of this heat can be recycled (in the preheating of the input material), and heat is a cheap form of energy.

Just for the record, what do you think the minimum voltage drop across an electrolytic refining cell is?

 

What?!

Read posts you're replying to..

I said "Just a single step from making plasma"..

 

BTW, it's not bizzare idea.

It is/was widely used technique for receiving pretty pure isotope.

f.e. Manhattan Project Uranium purification.

https://en.wikipedia.org/wiki/Calutron

Thousands labolatories around the world that have mass spectrometers are using this technique in analyze/detection of chemical compounds they're working with.

Only a project with the sort of budget that the Manhattan project had would consider using a mass spec to separate macroscopic amounts of materials.

to do it for something as cheap as silver (or gold) would be bizarre.

[Enthalpy]

Distillation costs little energy and it separates compounds (here the metals) due to the difference of vapour pressure. Nothing comparable with plasma, especially not the expense.

 

In theory, between electrodes of identical composition, no voltage would be dropped - but chemistry is not theory. You hardly get below half a volt across a cell, and this is already a lot of energy, especially if compared with heat. 300K equals only 26meV. Even better, heat can be recycled in part.

[John Cuthber]

Well, that's that.

All you need to do is tell essentially the entire copper industry that they are doing it wrong and they should be vacuum distilling copper in an unobtanium flask instead of their silly persistence in using electrolytic refining.

 

 

You might also want to tell them why you think this

"300K equals only 26meV. "

is important.

 

I'm still waiting for an answer to my earlier question re. vacuum distilling tin and silver;

"Where, for example, would it be a better bet than electrolytic refining?"

[Enthalpy]

Would you tell us why you believe that no metal has ever been heated to 1000 or 2000°C, and by the way, why this should need inexisting materials, and as we're there, how do you imagine the Pidgeon process makes the magnesium we use?

 

Copper uses electrolysis, fine. The ore contains many metals, some of which possibly evaporate about as easily as copper. Here we have tin and silver, which distillation separates easily.

[John Cuthber]

Would you tell us why you believe that no metal has ever been heated to 1000 or 2000°C, and by the way, why this should need inexisting materials, and as we're there, how do you imagine the Pidgeon process makes the magnesium we use?

 

Copper uses electrolysis, fine. The ore contains many metals, some of which possibly evaporate about as easily as copper. Here we have tin and silver, which distillation separates easily.

OK let's start with the straw man claim.

"Would you tell us why you believe that no metal has ever been heated to 1000 or 2000°C"

it's a straw man since I don't believe that, nor suggested that I did (in fact, i said the opposite). Not worthy of a reply except to point out that it's a breach of the rules.

 

Re. "how do you imagine the Pidgeon process makes the magnesium we use?"

No problem.

From

https://en.wikipedia.org/wiki/Pidgeon_process

"The atmospheric pressure boiling point of magnesium metal is very low,"

 

But this talk of magnesium, copper and so on is a bit beside the point.

Can you show me where someone vacuum distils either silver or tin on a commercial basis?

Also, can you suggest something that the still could be made from?

​Remember it has to have considerable strength at very high temperatures and also not be attacked by the molten metal mixture in it (That's significant- hot metals are often rather good solvents for other metals.

I'm not saying it's impossible- but I suspect that most things that would meet the criteria are more expensive than silver

Edited August 10, 2015 by John Cuthber

[Enthalpy]

All your "arguments" would also apply against humans melting iron. Since we do have steel for quite some time, your arguments are wrong.

[John Cuthber]

On exactly what planet does saying "it's true that steel and other metals are commonly melted during processing at temperatures much higher than those mentioned." would be an argument against being able to smelt iron.

 

 

So that's just another straw man isn't it.