What happens to lead then you overhead it beyond its melting point

  1. What happens to lead then you overheat it beyond its melting point, and what metal or chemical does it become then?
     
    Last edited: Jan 29, 2007
  2. jcsd
  3. Gokul43201

    Gokul43201 11,141
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    It becomes molten lead. If you continue to heat the liquid beyond its boiling point, you get lead vapor.
     
  4. So see then you heat lead and it melt then it makes like a bubble, it’s like mercury, but then you heat it to much then suddenly it drops down and becomes red almost like your heating iron or something and it’s strong but very brittle

    What does this molten lead actually means, does it have a Molecular formula beside Pb
     
  5. disregardthat

    disregardthat 1,841
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    does it make bubbles if it was heated in a vacuum?
     
  6. D H

    Staff: Mentor

    The chemical formula for water is H20, regardless of whether the water is ice, liquid, or steam. Why would you expect the frozen/liquid/vapor form of lead to have a different chemical formula? They are all lead.
     
  7. Well belief me that lead must have a dioxide after it or something, because it’s pretty much screwed, ash
     
  8. Gokul43201

    Gokul43201 11,141
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    That makes absolutely no sense at all. Care to clarify?
     
  9. If you over heat lead over its melting point, it changes it self to some messed up substance, now that’s what I’m not sure of it’s like then you overheat Aluminium it does the same thing, it make some kind of substance.

    It’s probably like Sulfur you can melt sulfur bit if you over heat it, it start to burn and produce Sulfur dioxide SO2
     
  10. chemisttree

    chemisttree 3,721
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    If you got your "lead" from wheel weights or lead acid batteries, the hard brittle stuff left over when you distill out the lead is antimony. Antimony is hard, silver to gray and brittle. It will cause contact dermatitis, conjunctivitus (pink eye), nasal ulceration. Bad JU JU! Keep it away from any of your hydrogen experiments since it will form extremely toxic, volatile hydrides.

    Find the Merck Index at your local College library and make friends with it.

    Just a note... I hope that when you are doing this kind of stuff you aren't inhaling or you are using a good hood. A garage with a few open doors really won't cut it.
     
  11. Gokul43201

    Gokul43201 11,141
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    I've cast both lead and aluminum, but I've never taken them very much past their melting points. Are you (jacques) talking about the layer of dross that forms over the melt? That, as you guessed, is predominantly the oxide of the metal, but also includes other impurities (as pointed out by c-tree). If you skim off the dross, you have nice, clean melt below.
     
  12. Integral

    Integral 7,351
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    I have ran Al way past its melting point (~900C) IIRC we saw no strange material form. How hot are you talking about. The more specifics you can provide the better.

    You may be reacting with your crucible, with the atmosphere and/or with any impurities in the original metal. There is no way we could tell what he dross is since you have not provided even the basic info needed.
     
  13. ~1700C but this is done by a oxy-torch, it starts to make white sparks, but never mind that, it just basically starts to ignite the Al, but I’m more into the lead one, did you test out the lead ?
     
  14. Gokul43201, I think you understand my setup, Yip I’m Jacques, my lead is almost pure lead, it’s in a bars, I’ve found 3 of them, and I get the same results from my soldering lead, I’ve got 2 types, on is plain hard and the other one is a alloy with Tin to lower the melting point and it also stays cleaner for longer.

    I’m also heavy into electronics.
     
  15. russ_watters

    Staff: Mentor

    If you're mixing something, you'll need to tell us what you are doing because we can't guess. But elements do not transmute into other elements just by heating them. That's called alchemy and a lot of alchemists died trying to make that happen...
     
  16. Nope, I’m not mixing anything, just want to know why lead suddenly change to some weird burnout lead, it look like lead, but it’s strong in a way and brittle.
     
  17. chemisttree

    chemisttree 3,721
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    It is obviously not lead... at least pure lead. It is very likely that the "pure" lead bars you "found" (?????) are not pure lead but rather a lead alloy. The alloys give lead wetablity toward steel and copper (in electronics) and increase hardness. Changing the ratio of lead to alloying metal by removing some of the lead through volatilization could result in a hard, brittle alloy depending on the alloying metal(s). These alloying metals include one or more of the following: antimony, calcium, aluminum, barium, silver, tin, arsenic, strontium, indium, lithium, cadmium and copper.

    Did the bars have any stamping identifiers? For example "L-52500".

    You might want to test the residue futher.

    The Merck Index has some tests that might help. I quote:

    "Antimony - reacts with slight excess of HCl with aid of HNO3; Pour soln. in large vol of water; white ppt forms which becomes orange-red on addn of H2S and is sol in ammonium sulfide."

    Under the same conditions, lead will be gray to black. A mixture of the two might look black, however.

    You might try a flame test too. Read more here:

    http://chemistry.about.com/library/weekly/aa110401a.htm

    Antimony will have a green flame and lead a blue one. A mix will appear greenish. If it is contaminated with sodium, you won't see anything but yellow.
     
  18. Gokul43201

    Gokul43201 11,141
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    At 1700C you're at the BP of most any high lead alloy.

    What is strong and brittle. If you cooled the melt back down, you might easily have a microstructure resembling some high temperature phase that is frozen in. This will depend on things like composition and cooling rate.

    As of now, there are too many variables and unknowns in your experimental setup to say anything definite.

    C-tree: Do you believe you can tell something of the order of 1% Sb from a flame color?
     
  19. Boiling point, lead is 1749C

    I know this color flame tests, gold leaf makes a white flame then heated / melted, I look nice

    This lead makes no color and no smell, it only changes from a silvery bubble to a suddenly a drop down and become red in color then further on heated, the color behaves like a heated piece of iron

    I mostly cool down my metals in water and never melt it again.


    Here’s another weird this somebody can hopefully answer:
    If you heat a empty cola can with a heat source of ~1700C then you get some weird black skin falling of from the can surface, I’m not sure if it’s Teflon, all I know is that is a protective layer in the inside of the can, to stop the metal from rusting, HCL don’t eat is but the metal goes, it looks like transparent plastic, but if you heat it with ~1700C, it becomes black and can be picked up by a magnet?
     
  20. chemisttree

    chemisttree 3,721
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    Gokul,

    Nope! I also failed to realize that if any distillation occurred, it would be the antimony that would distill out first and a lead-enriched residue would result. By my logic, it should have been softer rather than harder...
     
  21. chemisttree

    chemisttree 3,721
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    Jacquesl,

    You have discovered the can liner. I'm sure that googling "steel can coating" will provide you an answer. The residue is interesting.... Ferromagnetic?

    Maybe you have discovered a "buckycan" form of carbon!
     
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