metalresearcher
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Nice carbide making experiment
Today I repeated an experiment making CaC2 by putting CaO and charcoal in a graphite crucible and putting carbon rods to a DC welder (127 A) onto it.
I let the arc running for 5 minutes which indeed generated immense heat (> 2000 C) and athen I let it cool down.
After cooling down (05:12) I poured some water in the crucible and it started bubblimg immediately. I ignited it and it catched a bright sooting flame
which means that it is really acetylene gas (C2H2).
And there was a typical 'carbide smell' which is actually PH3 according to some sources, as C2H2 or CaC2 are completely without any smell.
But why does phosphine occur in carbide ? The source of my CaO is lime from the hardware store which is Ca(OH)2 which I have burnt. And the carbon is
charcoal, so where is the PH3 (or other bad smell) from ?
Here the video.
https://www.metallab.net/jwplayer/video.php?v=L2NsaXBzL01ha2...
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GrayGhost-
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Hi I buy calcium carbide in hardward store ( in my country) for welding with acetylene and oxygen torch, and yes smell very bad. Is sell in rocks of
variable size for kilograms.
I dont know exact origin of bad smell but is like sulfured.
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Bezaleel
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If this is indeed phosphine, I expect to be from calcium phosphate. Calcium phosphate containing rock is industrially processed for the phosphate. I
guess lime is a side product and tiny amounts of phosphate are left in it.
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Bert
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Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".
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Nice experiment. I am interested in a couple of group IV carbides lately as fuels.
Where did the Phosphorus and/or Sulfur contaminants that gives acetylene from Calcium carbide the phosphine or sulfide odor come from?
Limestone
Cheap sources of Calcium for industry are often of organic origin- Limestones in particular. Sedimentary rocks formed from ocean floor deposits of
corral, shells and calcerous skeletons of microscopic organisms. Organic debris of that type always contains some Phosphorus (everything living on
earth does), plus limestones generally contain odd bits of other minerals such as pyrites (which are sulfide minerals).
Acetylene
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industrially, the gas is mostly produced from the cracking process used to break down large hydrocarbons in oil refineries, and by the partial
combustion of methane. In this pure form, the gas has what the US National Institute for Occupational Safety and Health describes rather beautifully
as a ‘faint, ethereal odour’, though particularly when obtained from calcium carbide, which often has impurities, it tends to have a strong,
unpleasant garlicky smell from phosphine derivatives, or the unmistakable rotten eggs stench of hydrogen sulphide.
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Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
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2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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Texium
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Thread Moved
27-11-2023 at 11:46 |
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