cooled reclaimed lead- gold/purple sheen on top- what is this?

[superchikn]

A few weeks ago I finally got a propane burner and could melt the 25 lbs of pellets gathered from my traps.
I melted it all together and fluxed with saw dust. I poured all into ingots and noticed a gold sheen with a touch of purple when the ingots cooled.  i cleaned my Lee 10 lb pot and melted some of those ingots to clean and flux again figuring it might be added metals that could be fluxed off. WhentThat pot cooled the surface color was still there.


The pellets in the trap are a mix of JSB/AA, H&N and Crosman. Roughly an even mix of the three.
I know H&N and Crosman are harder pellets and if this is tin, antimony, bismuth or whatever that is where it would have come from.


The other possibility was that when I melted the lead over the propane burner it was too hot and burned the lead.  I don't know if that even happens or not.


So, is this hardening alloys, can i remove some of it if it is?
Should i not worry about it?
Should I dillute the lead with more pure lead?




Thanks In advance!

[Motorhead]

Impurities will rise to the top ... skim them off and your good to pour

[K.O.]

honestly in my opinion they are so close to pure sb that I do not think it matters...

Crosman pellets have been analyzed and have been found to be 1% sb but at 1/3 of the mix it takes it down to trace levels...

also smelting at high temps will tend to oxidize tin and antimony causing it to join the dross at the top of the melt... if you want the tin and antimony in the mix you will need a reductant like wax... not a flux like sawdust/carbon...

the colors are just an indication of being smelted at high temps... least that is what I was told gowin up...

[K.O.]

https://castboolits.gunloads.com/showthread.php?63550-Gold-and-purple-and-blue-Oh-My!

[triggertreat]

Ideally you would want to render the metals back together in the pot using paraffin or bees wax before you begin fluxing to remove any dross with sawdust or borax, etc.  This way you don't toss out good metals which may be misconstrued as dross.  Once the metals are mixed together, they tend to stay together unless improperly rendered or too high of a heat is used that would change or separate the metals.  I would imagine what you may be seeing are some separations of metals from overheating or lack of rendering the metals.

[superchikn]

Thanks for the replys, this is interesting.
To clarify, This gold color only shows up on fully solidified melt.  When it is liquid the color is normal. Dross looks normal before skimming as well.  does this make any difference?

[bear air]

Following

[superchikn]

OK so tonight I fired up the furnace again, despite what i said in my previout post the gold and purple is now showing up in the melt. I skim it off but it just comes back and the longer I wait to skim it the thicker it gets.


so if this is overheated lead does it do this forever or should it go back to normal after solidifying and cooing down, then melting again?
I do not believe I am continuing to over heat the lead in the electric furnace, I have already cast 8 lbs or so of pure lead before this reclaimed lead, in this furnace and there is never any color but silver.


If seperated metals i can render back together.  It is not casting properly in my 22 mold.  dull areas on the pellet heads.


I will try in a 357 slug mold tomorrow and see how that goes.