I have a pot that is hardened (I ran out of Propane!) that I know is Zinc contaminated. When I remelt, at what temperature should I try this sulphur treatment? At Lead melting temp or zinc melting temp???
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I have a pot that is hardened (I ran out of Propane!) that I know is Zinc contaminated. When I remelt, at what temperature should I try this sulphur treatment? At Lead melting temp or zinc melting temp???
Well Markbo... Both. I start at 600 or around 550 and flux saw dust.... then hit it with the sulfur.... Now, Zinc melts in the 700s so, why do I do it now? "Cuz". If the smelt is really contanimated, this is my attempt to capture the already combined zinc bits. Then... heat up to above the zinc melt point and hit it again with saw dust. Then..you guessed it.... the sulfur. I get a good dross with each flux with sulfur and really, do it twice at high temp. Dunno why...just do.... Sometimes I may sulfur flux there or four times. The dross does change over attempts and finally finish with wax. Then I add my tin and mix.... Sometimes...it works really well. Good Luck.
Nose Dive
Cheap, Fast, Good. Kindly pick two.
I found some sulfur at the local plant supply place pretty cheap and a 5 gallon bucket of sawdust free at Home Depot. Finally got a day off today, but it is unusually for this time of year here, absolutely dead calm. I think I will wait till we get some breeze back and try it then. In the meantime I have lots of buckets to separate. I think in the end the manual separation will be worth it.
Try using copper sulfate instead of sulfur to get the zinc out. Doesn't make a fire and does the same thing. Cost is about the same, toughens the CBs. It will also remove tin but not antimony. Check the thread under adding copper.
Finally had time and perfect weather and the same time. Breezy to waft away the fumes! Got a lot more dross out using sawdust and sulfur. Probably 10-12 ladles full of oatmeal looking stuff out of roughly 40 lbs of lead. Real colorful too. Lots of blues in spots. Must have been the sulfur - never seen it like that before.
Anyway, the test will be in the casting. Now I have to wait for time and weather again. :) I DID take the opportunity though to filter all my wheel weights. From 6 x 5 gallon buckets I got 3 full of lead only and will sell the 3 full of zinc, steel & aluminum. Maybe they'll trade me for some lead. ;)
I am familiar with all the different wheel weight markings, thanks lizard. I am 100% sure I have found some aluminum weights. Very few, but they are out there!
As a chemistry teacher, I want to point out that Hydrochloric Acid (pool supply houses call it muriatic acid) will work as well, and is marginally safer to work with. In either case, beware of the fumes.
I've been reading this thread with great interest. I don't have any WW, but I might pick some up from a local tire place. I can get a lot of sawdust, but that's mostly chainsaw shavings which I think I might have to dry before using. Wouldn't sawdust alone remove zinc? Would that just be too slow or require too much sawdust? Also, would venison tallow be an acceptable substitute for suet or lard? Would it have to be rendered first to remove the water from it? It would be good to find a use for it.
Good info. I was wondering what to do with some WW ingots i bought that i think are contaminated. I'll give it a try when the weather clears up.
Relsom, FWIW I used a respirator that I keep for using with a blaster. It did NOT help much! Those sulfur fumes are no joke. I wore my respirator, stayed up wind and held my breath when I had to get close to spoon off the dross. I just used a long 1x2 for stirring so I could stay away from the pot. I must say though that following advice of low temp sawdust, then sulfur, then repeat at higher temp got a lot more dross out of the pot than I thought was still in there!
You need to use a positive airflow respirator / hood. They are relatively easy to make and you can use a garden hose for the forced air supply so that it can be coming from an area well away from the toxic environment where you are working. The air supply can be just part of a shop vac if you hook the hose to the exhaust port on it. The first one I made MANY years ago was made from a paper grocery sack with a view port cut out and a clear panel taped inside of it for a view port. I had seen plans for this on the web and decided that it was simple enough that I would give it a try. I was working with some chemicals that produced some rather hazardous fumes and I was in a relatively enclosed space. Even with just the paper hood, I could not smell the chemicals.
Since then, I have adapted an Israeli surplus gas mask to do the same thing. Here's a link to a Finish one for $20 that would also work:
http://www.sportsmansguide.com/net/c....aspx?a=641202
To convert it to a forced air supply, you need to modify the screw-on gas cartridge to have a connector for whatever air supply you are using. Another advantage of this is that you can have your air source inside the air-conditioned part of your house and you'll have cooler air that you are breathing in.
If you don't have a shop vac or if you want something that is not quite so powerful, the 120VAC air mattress type inflators also will work and will produce plenty of air supply for your breathing needs.
When using the modified gas mask, I leave the facepiece slightly looser so that the air doesn't all have to exit through the designated air port. It's more comfortable that way anyway.
I picked up some Sulfur today to try to get zinc out of alloy I purchased, Thanks to everyone on this thread. I thought I was going to have to throw the alloy away or mix it 25% to 75% new alloy. At 800lbs of possible contaminated alloy, I dont have the money to buy 2400lbs of good alloy.
Doc
Grumman, I was thinking about that gas mask you linked to. I get enough funny looks from neighbors already. I can just imagine what the gossip would be if they saw me walking around wearing one of those with a long hose attached to it! :mrgreen:
Just make sure that you wear the proper protective clothing also...
http://www.latexbay.com/ebay/germany/god-102115.jpg
Uhhh... Maybe not...
What is the bes way to detect zinc before messing up?
tallow98
In my case it was wheel weights. There are already some advice listed about not letting get in there in the first place, which is sure a lot easier than getting it out once it is already contaminated. :mrgreen: