Woe and Intrigue: Thick Brown Dross

[Woodsroad]

How big is that "large" Dutch oven?.

It's a 20 qt, fired by the Bayou Classic SP10 burner I keep the lid on as much as possible, but, yes, I think that you may be right about the lead getting bound up in the slush.

I am going to reheat the pot, skim the remaining dross, flux again, then cast ingots. I will then attempt to remelt dross, in smaller quantities, using charcoal in the mix , keep it covered and see what happens. The lead should drop out!

I'll make pix and post them.

Good thinking about thew slush layer, although the pot did hit 780ºf (ouch), it is a possibility.

[Woodsroad]

i am thinking that bismuth might be your culprit here.
you might want to try adding a bit of tin to your melt and see if that helps.
just a small batch and 50-1 might help.

Bismuth, eh?
I think that I'm going to pass some of this dross on to a friend who cna get it assayed at his work....

[Woodsroad]

The assay results are in.

33% by weight Cadmium.

I am fairly certain that the cadmium came to me in the form of octagonal ingots with "SJ" on them. They must have been pure cadmium. I will make some photos and do a more complete write up as time permits.

We all need to be vigilant about cadmium. It looks and feels like lead. It is deadly when inhaled during smelting. Death can occur within 72 hours, with complete renal shut down and cardiopulmonary edema.

Thank God I donned protective gear once the stuff started to look out of the ordinary. ALWAYS keep a high quality respirator with p100 filters handy. ALWAYS use gloves when handling metals. ALWAYS be vigilant of the slightest deviations from the norm in the appearance of your smelting pot. I did, and it saved my life.

[briang]

Wow, that's scary. Thanks for the heads up.

[odoh]

Death in 72 hrs might have been inviting for the victims of Itai, Itai (Japanese word Ouch, Ouch) disease from drinking cadmium contaminated water downstream from a factory in the 1960's. The cadmium would deteriate their bones allowing them to break easily. Its victims shrunk 10" or more as result a slow agonizing death. The factory prevailed in that court case. I recall the newscast that showed an elderly lady that shranked so much she could almost fit in a suitcase. Thanks for sharing.

ON EDIT: After posting this, I googled and surprisingly Wikipedia Free dictionary did list it and said the victims prevailed. My translator had said otherwise at the time ~ donno, maybe on appeal.

[Woodsroad]

It appears that if you do not show symptoms within 48 hours, then toxicity levels are below threshold. The Japanese victims (and employees of smelting operations) were exposed to moderately excessive levels over a long period of time: chronic exposure.

I can only hope that I escaped this unscathed. My lab training stood me in good stead.

Time will tell.

[runfiverun]

cadmium..wow.
i would like to see the ingots.
might help someone from making a terrible mistake.

[Woodsroad]

The ingots were melted, and I never mad pix of them. They were octagonal, with "SJ" on them. But that doesn't really matter. Cadmium will be encountered in many forms, all of which look like lead.

[Slow Elk 45/70]

WoodRoad, thanks for the heads up, these are some of the best reasons for posting unusual situations encountered while smelting/casting.

Thanks again, It sounds like you saved your own bacon when you used the safety precautions you employed. Good for you. This is a good example for all of us to pay attention to what is going on when we are smelting.

[xsquidgator]

Did these ingots come from a radiation therapy department? (I work in one). Until recently we kept hundreds of pounds of "Lipowitz's metal" on hand for making blocks out of this alloy, it melts at 190F. I'd forgotten about it, I knew not to try to use it for boolit making but I'd forgotten about the Cd in it and didn't know or remember Cadmium being deadly.

If you do have some silvery looking ingots that might be this stuff, an ordinary electronics soldering iron will melt into it pretty easily since it melts at 190F. The good news is that in the U.S. anyway, the hand-made block technology is being phased out for something else. We used the low-melting point alloy to make custom blocks for shaping x-ray beams used to treat cancers. Each patient would normally have a set of 2-6 of these blocks made just for him/her and then we'd melt 'em down again after the treatments were complete. We still make blocks occasionally but we have some computer-controlled devices on the linear accelerator x-ray machines that have replaced 95% of the blocks that we used to make. So, at least it is less likely that you will encounter this Lipowitz's metal if you take waste lead and lead-like material from a radiation therapy or radiology department. Radiation oncology --> make sure it's not this special metal, if you're getting the waste stuff from Radiology you don't need to worry, because radiology doesn't use this stuff.

[SciFiJim]

Wow, what a heads up. Scary stuff. I think I'll stick with wheel weights. Mystery metal is something to be careful of. Is there a way to determine the presence of cadmium with out an assay or spectroanalysis?

[303Guy]

If I may ask, where is the flame being applied? I got the impression that the flame was being directed directly onto the melt?

[Woodsroad]

Did these ingots come from a radiation therapy department?

I do not know what the origin was. I bought them as scrap from a recycler...

[Woodsroad]

Wow, what a heads up. Scary stuff. I think I'll stick with wheel weights. Mystery metal is something to be careful of. Is there a way to determine the presence of cadmium with out an assay or spectroanalysis?

Well, it is less dense. Not a lot, but....so you could check volume vs weight.

[Woodsroad]

If I may ask, where is the flame being applied? I got the impression that the flame was being directed directly onto the melt?

Just like anyone else smelts. The metal in the cast iron kettle, the burner is under the kettle.

[Woodsroad]

FOLLOW-UP:

I was able to return the Cd/Pb melt and dross to the recycler and get my $ back. I had my blood levels checked for Pb and Cd and they were below threshold.

If you come across sheet "lead" that seems a just little less flexible and just a tad lighter than it should be, then be warned, it could be cadmium. I related this whole story to my recycler guy and he now intends to shoot any lead that comes in with the assay gun. Cd is a bit valuable than lead, it turns out.

[sargenv]

I was just out melting bullet lead excavated from the backstop at my range and encountered a small amount of yellow smoke.. like just the size of a bullet maybe.. There were some traces of clay targets (pigeons) in the mix of stuff that I tried to get out before things melted, but just could not get to. I had the forethought today to have a fan blowing moderately strong across the pot to keep the smoke out of my face and all of the smoke went off in another direction.. When I saw yellow smoke, I stayed well away from it and now I'm wondering if it was sulfer or cadmium.. it poofed up one more time, and there appeared to be this black, tarry substance that burned off on the side of the pot.. I'm still thinking sulfer compound, thoughts? (didn't mean to hijack the thread, just seemed like it had come to an end and I thought this might be somewhat related). The final lead after I'd skimmed the bullet jackets and dust came out nice and clean with no smoke evident..

[Woodsroad]

Asphalt from the clay birds, or other **** in the dirt. Highly unlikely to be Cd.

[lwknight]

Yup, backstop ore can be nasty for sure. My club range uses some plastic cardboard kin sheets for target boards. Thats really nasty to process.

[Woodsroad]

Yeah, it's some other ****, other than Cd.
Doesn't mean that it will not kill you, it will just kill you differently.