Woops - metal smelting

[Realgar]

Tried a test smelt of some of my galena in a clay crucible, didn't get any lead but the ore reacted with the clay to produce a glaze with a curious yellow tint. I stuck it under UV and it glows like a firefly.
I must take the crucible into work and wave it under a geiger tube - thorium or uranium? Uranium is pyrophoric, I could make myself a fire stick from it.

Realgar

 

[Stuart]

ooh sounds intresting

 

[Ed]

crushed or powdered galena has been used to glaze pottery for years. There are some good examples of medieval pottery in the british meuseum. There are many glazes out there which are lead compounds including lead oxide, lead sulphide and lead carbonate.... the coulour you get depends on the iron content of the clay so the glaze will be a slightly different colour on different clays.


Ed

 

[Keith_Beef]

Tried a test smelt of some of my galena in a clay crucible, didn't get any lead but the ore reacted with the clay to produce a glaze with a curious yellow tint. I stuck it under UV and it glows like a firefly.
I must take the crucible into work and wave it under a geiger tube - thorium or uranium? Uranium is pyrophoric, I could make myself a fire stick from it.

Realgar

Apparently, you should use a cast iron crucible for melting lead, and you'll probably need some sort of reducing compound to reduce the metal from the oxides.

Once you get the metal, it will oxidise easily at liquid temperatures, so you need to keep it covered with linseed oil or rosin.


Keith.

 

[Realgar]

Apparently, you should use a cast iron crucible for melting lead, and you'll probably need some sort of reducing compound to reduce the metal from the oxides.

Once you get the metal, it will oxidise easily at liquid temperatures, so you need to keep it covered with linseed oil or rosin.


Keith.

I was using charcoal with a touch of clay binder. Lead glazes - I try to avoid them them as people aren't too happy when you use them on pipes or bowls or cups. I should have though about the source of galena though - lead's a decay produce of assorted radioisotopes so the ore's often associated with the parent nucleides and I dug it out myself with little regard for the surrounding matrix. I'll stick to tin, no nasty suprises there just eight hours at the bellows..

 

[dtalbot]

Galena is lead sulphide (according to geochemist SWMBO) hence the yellow

 

[Realgar]

I'd taken it way past sulphur - the ore is roasted first to burn it out leaving lead oxide, sulphur fouls all sorts of things especialy lungs ( not that lead oxide dust is any better ). What I ought to do is figure out a way of extracting the sulphur for making sulphur matches but it's a lot easier just to buy some.
I stuck the crucible under one of the counters - it's hot allright but not horrendous ( a mere 8x background ), I've got some U2 glass bowls that kick out more. Ah well there goes my dream of a bushcraft fast breeder, I'm sure Ray would have liked it.

 

[dtalbot]

Well,
I was a natural radiochemist in my last job, 8xbg dosn't sound a whole lot if you had some particularly active ore. Assuming of course you have a reasonably low background.
Yep lead is a decay poduct but galena is a chemical formulation of lead specifically, so it had got as far as lead in the decay chain before it became galena. Have you tried a crucible on its own under the counter, labware can have some strange radiochemical properties! Like the batch of kilner jars that I had which emitted thoron! Turns out some monazite black sands had been used to make the glass, but had us puzzling for a long while!
Where was the galena from, I can think of some places round here where there are closley spaced galena and yellow cake occurances?
Cheers
David

 

[Realgar]

I got it from somewhere up derbyshire way, it's not the best quality - mostly small galena crystals in a matrix of some other crystaline mineral ( barite I think ) with some sulphur yellow material at the junction between the two.

Realgar

 

[dtalbot]

I got it from somewhere up derbyshire way, it's not the best quality - mostly small galena crystals in a matrix of some other crystaline mineral ( barite I think ) with some sulphur yellow material at the junction between the two.

Realgar

Barite if it dosn't look like calcite almost certainly
If it was round Ashover I would'nt be to sure it wasn't yellow cake!
Cheers
David

 

[den]

I've always wanted to have a go at smelting. Any metal not fussed really.
Is tin the easiest ? Does anyone have any good links to get me started?

 

[Keith_Beef]

I got it from somewhere up derbyshire way, it's not the best quality - mostly small galena crystals in a matrix of some other crystaline mineral ( barite I think ) with some sulphur yellow material at the junction between the two.

Realgar

There were lead mines up round Buxton/Castleton way, and that area is a bit of a hotspot, I seem to remember. Some radioactive gas (radon?) comes up through the caverns in the limestone rock.

Keith.

 

[dtalbot]

There were lead mines up round Buxton/Castleton way, and that area is a bit of a hotspot, I seem to remember. Some radioactive gas (radon?) comes up through the caverns in the limestone rock.

Keith.

Yep,
At one point the reading I and some colegues took in a cave near Castleton (not one of the show caves) was the highest natural level of radon in any cave system worldwide!.
But it is mostly down to average concentrations of uranium series elements in very permiable rock which lets the radon out rather than spectacularly high uranium levels.
Cheers
David

 

[Realgar]

Was was expecialy bothering was the way all the water running from the lead mines was channeled down to the willage to supply drinking water.
Mind you if they'd had piped water in those days they'd have used lead pipes anyway...