How to remove zinc from a lead ingot?

[Big_Blue]

How can I remove zinc from a lead ingot? Can I bring the temperature up to the temperature lead melts at and scoop off the remaining solid zinc? Seems to me it should work.

I've been controlling my own smelting temperatures so I'm not worried about zinc in my ingots. But I've picked up a few lead ingots of unknown origin and wonder how to remove any zinc that may be included.

[detox]

How can I remove zinc from a lead ingot? Can I bring the temperature up to the temperature lead melts at and scoop off the remaining solid zinc? Seems to me it should work.


Some say that will work. I would flux the melt first, then skim off zinc. 600-650 degrees should work since zinc melts at a higher temperature of over 700 degrees. I forget exactly at what temp zinc melts.

[Wal']

Zinc melts at 786F°, I keep any sus' lead below 750F just to be sure.

[bobthenailer]

What i do is melt the pot of contamated alloy to 600 degrees flux & lightly stir , remove as much as i can of the lumpy stuff on top including some tin & antomony, cast a few bullets & check hardness & quality and set aside for blending with another alloy , delution of the alloy is the easyest way to dispurse zinc in the mix. I just did 100 lbs of coww zinc contamated alloy and skimmed off 10 lbs off the top and it still checked @8 bhn and showed good fill out and normal apperance, i will possibly delute alloy or use as is at a later date.

[gareth96]

Flux with sawdust... a few times..

From the Fryxell book.. http://www.lasc.us/Fryxell_Book_textonly2.pdf

"The benefits of sawdust are that it‘s a sacrificial reductant that can reduce any oxidized tin back to the metallic state, and it‘s cheap enough that the caster can use enough to form an effective barrier layer to protect the alloy from subsequent oxidation. What’s more, as the sawdust chars on top of the melt, it forms activated carbon, which is a high surface area, porous sorbent material that has a large number of binding sites capable of binding Lewis acid cations like Ca, Zn and Al. So it not only keeps the tin reduced and in solution, but it effectively scavenges those impurities that raise the surface tension and viscosity of the alloy (Al, Zn and Ca), keeping the alloy in top shape for making good bullets. Vigorously stirring in a heaping tablespoon of sawdust into a pot full of bullet metal does a fine job of conditioning and protecting that alloy. Sawdust doesn’t really qualify under the formal definition of “flux” as it doesn’t produce a fusible slag, but it does very cheaply and very effectively accomplish the three primary goals that we set out for cleaning up bullet metal. Reduce, remove and protect, sawdust does it all!"

[44man]

Don't flux before skimming! It will mix in the zinc and make crummy boolits.

[cbrick]

By skimming off the top you may be able to reduce the percentage of zinc but you will only remove what was at the surface, what is below the surface is still there. If you were to repeat that process enough times (lot's and lot's of times) you could get it down. Best is as was mentioned, dilute it with good alloy until it casts well.

Rick

[boltaction308]

There's a thread on using sulfur to remove zinc. I picked some up at a recent gun show to have just in case.

http://castboolits.gunloads.com/showthread.php?63082-Zinc-Removal-with-Sulfur-Report&highlight=sulfer

[BubbaJon]

I found that getting the alloy at about 600F then using a ladle and pouring from a height will cause the "oatmeal" to form and also get any precipitate **** like sand to come to the top. I skimmed until it looked clear then fluxed with sawdust. It worked! 44man provided the methods - I only added the pouring from a height which I discovered by accident.

[turtlezx]

do the sulfur to get it out as 308 posted ++++++1