So, it's a nice day and I decide to smelt the soft lead sheet, pipe and ingots from the scrap yard.
I almost fill the large cast iron dutch oven with melt. There is not a lot
of dross, but what is there is a very fine, dark, heavy powder, difficult to
remove, even after fluxing with Borax and then beeswax. Clearly, there is
lead intertwined with this stuff. I manage to remove it all.
I cast six muffin tins of ingots, they look good, and decide to add more lead to the melt. After the pot is about half full, one leg of the burner begins to rapidly sink into the dirt. I guess the dirt under the burner had melted and that leg was sitting on ash or something. I manage to remove the kettle from the burner, but, in doing so spill a good bit of melt on the dirt. I wasn't hurt, I had on thick boots
and pants and gaiters. I get the kettle on blocks and continue with the melt.
After I get the melt back to around 650ºf, I peel the lead off of the dirt and add it back to the melt. There is a lot of crap stuck to it, since I melt next the
burn pile. I continue adding sheet lead, removing the fine, heavy powder as
I go. One extra thick sheet, marked "low level radiation shielding" takes a particularly long time to dissolve, and some of the thin sheet seems to float a little, but does melt. I assume that the really thin stuff has a heavy coating of oxidation.
I flux again and begin seeing a pretty weird thing: Brown/red/green dross "bloom" starts rising out of the melt. I remove it. It is very heavy, with a consistency of dirt. Molten lead can be seen trapped in it. the melt temp is now at 780ºf, and I turn off the burner.
As I remove it, more rises to the surface. It's looks like that this is an oxide, forming as the surface of the melt is exposed. I realize that I could sit there and remove it all day. It looks like rusty dirt, but is not magnetic. If I scoop some
up with a strainer, as the molten lead drips out of it, it leaves a
stalactite of slag, which begins to glow and burn off, giving off a thick
yellow smoke. I do have a respirator on.
What the &^%$# is happening here?
I cover the pot and turned off the heat. I wash all my clothes and throw out the gloves that had on.
Any ideas?
Thanks!