A myth of tin separating lead.

[45-70 Chevroner]

This has been going on ever sence I started casting my own boolits well over 35 years ago. This is not to prove that I am wright and someone else is wrong. It's just a matter of getting it stright, ie educating ones self. Tin and lead will not and can not separate with the equipment that is avialable to the home caster, and before you get all up set please look up on google this process. Just type in "the process for separating tin from lead". Click on Continus Method of separating tin from lead. The artical is a real good read and the process is quite involved, which includes injecting oxygen and chlorine into the melt and having the melt at a very high degree, stiring the melt quite fast. The equipment that is used probably cost in the thousands of dollars. My guess would be that it is not profitable. Although almost all tin comes from foreign countrys and the price of tin "new supply" is running around $12.00 to $15 dollars a pound. Thats not too far off from the price of silver.
This should ease our minds of worrying about our expensive tin leaving the pot by evaporation or oxydation into drouse.
I certenly hope I have not stepped on anyones feet.

THE HEADING SHOULD HAVE READ:
A MYTH OF TIN SEPARATING FROM LEAD.

[Bass Ackward]

Well, if one does want to educate one's self, they can buy a batch of tin based Babbitt.

They can heat it and flux it and let it cool and then repeat this.

What will be found is that that Babbitt will be getting softer and softer and softer each time.

Now if you remelt this dross into a batch of pure lead, what you will find is that you can make something close to lino in hardness and that pure lead will be shinier than silver.

98% of dross is stuff other than lead. Only about 2% is dirt / contaminant.

I guess the separation is just plain ol FM cause Google can't be wrong.

[blaster]

Silver is not far off per ounce not per pound.

[Leadmelter]

Has anybody done a chemical analysis of dross? I am a little rusty on my chemistry but a simple analytical could be set up for contaminants.
There is an idea for someone for 2011 to make a simple kit.

Gerry

[45-70 Chevroner]

Your right blaster my mistake. A big one at that.

[felix]

Gerry, it would be mucho more fun to see what is in the boolit metal rather than in the crust.
Why? Because.......

Chevroner, now if we had lab grade stuff your statement(s) would be much more true. Things we use for boolits, like strange babbits, mixed or not mixed, in with other junk like WW, range lead, roofing lead, pipe lead plus welds, etc., don't follow text book rules. Bass Ackwards is entirely correct in what he is saying. Any kosher "factory" made babbit will provide instructions for melting and pouring and into what the apparatus is. Metals which are perfectly mated will only stay that way under very specific application approaches. One of the best examples without too much trouble would be to take any babbit well fluxed, for example, that has any amount of copper and pour it back and forth between a pair of pots. You will see a sheeting over the lead during the pouring. That is the frozen copper surrounded by whatever looks silvery, tin, lead, antimony, etc.

... felix

[HangFireW8]

Well, if one does want to educate one's self, they can buy a batch of tin based Babbitt

....

I guess the separation is just plain ol FM cause Google can't be wrong.

I'm not taking sides on this, but isn't Babbitt usually a bunch of stuff besides lead and tin, like copper, silver, etc.?

In other words, I'm not sure the experiment proposed matches the question asked.

-HF

[lwknight]

It don't matter if you have been casting for 100 years in a industrial foundry , you cannot change physics by your opinion.

Ever hear of depleted linotype? Ask an old printer about it.
When the dross ( not drouse ) contains a high tin content that only means that the alloy has a lower tin content. Riddle me how can it be that its impossible for tin to separate if that is the case. Or maybe we are actually doing some alchemy and creating tin out of nothing ?

BTW : Wright is a proper name and the synonym for " correct" is spelled " right " .

Chevroner , your assessment is not entirely without merit. It is difficult to refine lead and tin in commercial volumes but losing tin is cheap and easy.

I would be interested to see what geargnasher has to say as well. I've read his posts and he actually did controlled experiments that shoe the " can't separate tin theory " to be nothing but drivel.

[geargnasher]

Backyard chemistry, not controlled experiments, but conclusive none the less... The results of simple specific gravity determinations performed on lead/tin binary alloy oxides skimmed from an intentionally overheated pot showed upwards of 90% tin content by weight from an alloy containing less than 5% tin. I reduced the skimmed oxides back into elements before doing the SG tests.

Tin melts at much lower temps than does lead. Tin oxidation begins to accelerate at a much lower temperature than lead oxidation does, and even though the two have a strong bond in solution, the oxidation reaction will evidently pull elementary tin away from the lead because of a stronger electron bond. Tin is depleted from binary or ternary boolit alloys due to oxidation reactions and the fact that the oxide floats on the melt. Based upon SG and volume, the primary content of oxide from ternary alloy is still tin, followed by lead, and then trace antimony. Using hardness testing and specific gravity testing I estimated that the oxides skimmed from wheel weight metal with 1% tin added and running at 800 degrees was about 50/50 tin lead. Hardness tests on both lime-cooled and oil-quenched specimens of this same reduced oxide confirmed virtually no antimony was present in the samples I tested, as there was no significant difference in hardness even after aging. It's a fact, and though my tests were primitive, I felt that they were very conclusive. I also feel that my hydrocarbon reduction/oxidation experiments were very conclusive, too, because I can make shiny, pure metals again from a bunch of dull, grey, fluffy oxidized crud.

Something else I noticed, under certain conditions antimony can "oatmeal" on the melt, usually after most of the tin has been burned out and the melt cooled to near the melting point of lead. Antimony alloys with tin much more easily than lead, and the intermetallic bond of tin and antimony keeps the antimony in suspension until the tin is gone. Lead and antimony have an affinity for each other, but it is not as strong and the antimony can "freeze out" of the melt sometimes. Just try adding a cold Linotype ingot to a 700* pot of soft lead, see how much of a time you have getting the oatmeal to go back in. Add a hunk of silver solder and voila! smooth alloy again. Interesting stuff.
Gear

[Bass Ackward]

I'm not taking sides on this, but isn't Babbitt usually a bunch of stuff besides lead and tin, like copper, silver, etc.?

In other words, I'm not sure the experiment proposed matches the question asked.

-HF

OK, then do Linotype if that qualifies for you. It just takes longer and in the end, the part about putting the dross into pure lead WON'T show as dramatic results, but it will still show you. The higher the percentage of lead, the harder it is to make happen. SO if you are using a batch of 40-1, then you can get kinda tired before you produce it.

Newspaper companies used to have to throw in pills (tin and antimony) to refresh the lino once it got down far enough that they couldn't use it.

That's what makes this so strange is that after hundreds of years of real world history of it happening, that we still get people today that say it's impossible.

[runfiverun]

those pills were called foundry type.
it's job and only purpose was to replenish lino-type.[it's in my notes somewheres]
airc it was made up of like 12%-20%tin and 20% antimony.
anyways the paper guy would either sample the lino and send in a sample or guess at it himself and add the foundry type.
many posts on here regarding "is this zinc?" is the classic antimony grey bubbles.
at the foundrys that i have researched they inject zinc into the scrap lead stream to strip the tin from the alloy.
how they get the antimony out i don't recall. but the zinc may scavenge that out also.
something we are not set up to do at home for sure.
but we can surely deplete a pot of tin easy enough.

[2Tite]

Just a quick note for lwknight...........I think you meant to spell "show" in your post. A "shoe" is something that goes on your foot. People who live in glass houses.............

[watkibe]

Just a quick note for lwknight...........I think you meant to spell "show" in your post. A "shoe" is something that goes on your foot. People who live in glass houses.............

Thanks for saving me the time I would have spent writing exactly what you wrote!

Geargnasher - I detect a little bit of proffesional metallurgical background, or at least molten metals experience beyond hobby casting boolit at home, in your post. Thanks for your contribution to the thread.

[lwknight]

Just a quick note for lwknight...........I think you meant to spell "show" in your post. A "shoe" is something that goes on your foot. People who live in glass houses.............

The " W " key is right next to the " E " key.
A typo is a bit different that someone going against the grain with their lecture and not even bothering to use proper language. It sorta detracts from the credibility.

[dualsport]

Be nice fellas. We can debate without personal stuff. This is a hot topic because we covet our tin! I know I do anyway, bothers me to chuck that dross, what if it contains all the good stuff? And I like to cast hot and fast too, dangit. I guess there's no free lunch. I have, however, found a little trick that seems to help reduce dross, I put a empty can, like a dog food can or whatever fits good, upside down on top of my bottom pour Lee pot. Seems to hold heat better too.

[2Tite]

lwknight, Well then if you must.......proper language would be: It doesn't matter if you have been casting for 100 years........not "It don't matter". That's improper english. The point is that we all understood what he was writing. It did not need your attempt at correction. Especially when we consider that you made mistakes in your correction. Finger pointing at such small things isn't necessary. Just giving you a dose of your own medicine. It seems you don't like the taste of it. That will end it for me.........

[leftiye]

Tin oxide floats on any lead alloy. This (tin oxide) is a major part of dross. Flux(FLUX!!!) before you dross!

[prs]

Dang! If type-o's are illegal, I will be locked away for a long time! Even my grammer, poor ole gal that she is, would be in jeopardy.

I have often said, wasting tin is a SiN. Flux very thoroughly before removing "dross'. The "stuff" we want to keep should them "mostly" be retained. We are gonna lose some oxides of good as well as bad, but such is the fee to the troll.

prs

[John 242]

I've seen the questions asked before, but I might as well be the guy to ask anyway...
Can dross be returned back into the melt or is it simply waste?

If dross is a combination of lead oxide, tin oxide and other 'stuff', can anything useful be accomplished by saving the dross and then returning it to a melt latter?
I've got a coffee can that's about half full of dross. Is it worth mixing that dross into a pot of lead and fluxing the heck out of it, or is it a wast of time?

[Dannix]

Isn't the practical conclusion to just have a layer of sawdust on top of the melt (bottom pour)?