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kine
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Identifying a metal oxide
Hi there i am new here and very nice forum congratulations!
I recentrly bought a metal oxide from a paint shop for experimental purposes with therm;ite formulations, but i am not sure what oxide it is.
It is for sure an oxide because it is writen on the label.
I need a way to identify what metal it is. The most possible must be iron oxide Fe2O4 (magnetite) or Cuo (copper oxide) because of the totaly black
color.
I am not that good in chemistry so i thought i could use some help from you all.
Are there any simple methods to experiment with this oxide without too much aparatus or chemicals?
Thanks in advance.
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chemoleo
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If it is magnetite Fe3O4, get a magnet out and see if it attracts.
If not, then add dilute hydrochloric acid, and dissolve it. Does it dissolve? What colour? Then add NaOH to the dissolved oxide, until you get a
precipitate. What colour again?
That should sort out most possibilities, as there aren't THAT many cheap black oxides.
NiO is black, too, btw.
Anyway, do that, and tell us the results, it should be an easy one.
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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kine
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Guess it is magnetite Fe2O4 because it sticks on the magnet. Although i wish it was CuO because of more impresive thermite formulation but it is more
expensive to manufacture and especialy for paint use. So it is reasonable that this oxide is used for black paint.
At the store i found also many other oxides like cobalt oxide but there are many colors - powders that state on their label "cobalt color".
Could there be impurities?
I got 600 mesh flake aluminium wax coated because it is pyroforic. Is this suitable for thermite?
Both powders are extremly fine so should i expect a very fast burning mixture? Will the raming in the container increase the speed of deflagration due
to solid byproduct?
[Edited on 8-8-2005 by kine]
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12AX7
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Magnetite is Fe3O4.
The lower oxygen content will cause it to burn slower, whether the particle size is microns, or half an inch! (Some day I'll have to do an anvil
with thermite, I figure a good charge to get it burning good, then go to alternating aluminum plate and taconite ore for the bulk of it, plus some
calcium fluoride, magnesia and silica to get the slag good and soupy.)
You'll gain a little reaction speed with the fine powder but for the most part, all you're doing is allowing smaller charges to burn. Go
with cheap aluminum or magnesium filings.
You'll know cobalt when you see it. Not by appearance but by price: cobalt oxide from the pottery supply runs around $40/lb. Cobalt is not a
common metal, and what little exists would rather be used in high speed steel and nickel/cobalt super alloys 
Tim
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kine
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In that case copper oxide seems suitable but how can i be sure before i buy it? I mean there are a lot of kind of "black powder" colors and
some don't have the indication "oxide" but they are not Fe3O4 since they have different indications, like other name or serial number
but still the same black.
I saw a bottle containing "red iron oxide" with an orangish color will this give a "faster" thermite?
Is there a posibility for CuO to be in other color than black?
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12AX7
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Fe2O3 will certainly work well. Standard thermite. Cuprous oxide, Cu2O, is yellow to orange to red and makes a thermite suitable for producing
copper metal. Black cupric oxide, CuO, makes a thermite which burns more like flash, and is impact sensitive (see energetic materials forum,
exploding targets have been made of this).
Tim
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kine
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I made a search at the "Energetic materials" forum for "exploding targets" byt there is nothing.
Anyway aboyt what sensitivity we are talking about, like droping 100grams and it goes of or something like hiting it with a hamer?
Is it possible to use a sleave of copper wire for high surface area in alectrolisis to make Cu(OH)2 and then heat it in case i don't find it?
What is the comercial use other than paint of Cuo so i can find it? Potery shops shell it for what?
Edit: I found one of the black powders was manganese oxide or dioxide? Can this replace CuO in therm;ite?
[Edited on 8-8-2005 by kine]
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neutrino
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Try finding the MSDS sheets for the pigments. These should tell you what's in them.
I wouldn't try MnO<sub>2</sub> thermite. MnO<sub>2</sub> is a strong oxidizer and might give you more of a flash powder.
Electrolysis will certainly work.
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kine
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I am not sure that the black is manganese dioxide it just says that it is manganese black, could it be MnO?
Actualy i want a flash like thermite so MnO2 it is good for me. There is a problem with me only if it is too shock sensitive or friction. Does a MnO2
and Al make a shock/friction sensitive mix?
Edit: Also i wanted to know if it is ok to store therm;ite. Iknow that iron oxide therm;ite is very safe to store but does this apply to CuO or MnO2
combos?
[Edited on 8-8-2005 by kine]
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Axt
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CuO/Al targets @ http://ww1.webtop100.net/~62552/xmovies.webtop100.net/banner...
Even though I've never tried to hit it with a hammer, I think it pretty insensitive. You can try precipitating it from boiling Cu sulphate
solution with NaOH, though Im not sure how much water it holds onto.
MnO2/Al is pretty tame compared to CuO. But then the tamest of all, for me, is brown PbO2  Both precipitated from Pb acetate with NaOCl, and extracted from new (never seen acid) batteries always burn very slowly. Even if
heated (dried) in the oven for an extended period. Very frustrating, considering its supposedly one of the most violent. Yellow/red HgO &
yellow(?) Bi2O3 should be nice as well (lower boiling points).
[Edited on 8-8-2005 by Axt]
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kine
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Ok i found a pottery industry close where i live and tomorow i will give a call and ask about CuO. How should i ask for it? It is an industry not a
shop so i am not sure how to give them understand what i am looking for. What exactly it is used for in those industries?
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12AX7
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Well duh, first of all ask if they'll sell pound quantities. Then ask for a pound (or however many you want) and price, then pay, thank the
person and get out.
Copper provides three colors, red as colloidial copper metal and/or cuprous oxide (dissolved or suspended in a silica glass melt), cupric produces a
pastel green (like malachite) and, in some cases, blue (like azurite).
Mn is quite reactive (near zinc) so MnO2, despite being an oxidizer, is comparable to iron.
Axt: my CuO or PbO + MgAl powders all have shown shock sensitivity. Ignited Pb thermite hasn't proven to be particularly active, it often likes
to strobe over a period of seconds.
Tim
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praseodym
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It is always better to start a thermit reaction with a Mg fuse.
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kine
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Today i found accidentaly a store that sells bricks in colors and some colored glasses. At a shelf i found some powders including black but the label
doesn't say anything about oxide it says this : "Colouring agent for concrete lime and plaster" Is this the CuO i am looking for? The
person that sells it does not know what it contains.
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neutrino
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Find the website of the company that makes your powders and look for MSDS sheets.
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unionised
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Chemoleo,
"NiO is black, too, btw."
Care to check on that?
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IrC
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A simple flame test can tell you which metal is involved. However, if I were trying to make something I would not play around with unknowns, you can
get copper oxides on ebay from a particular seller, at very cheap rates and 99.9 percent purities. You can also get other compounds. If you do not
find him by doing an ebay search for say "copper oxide", send me a U2U. I don't want to post his ebay name, as I am not sure how he
would feel about that.
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kine
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Well there is no site on the company that makes the black dust neither i can make a test in the store before i buy it.
Tomorow i will call the pottery industry and ask for CuO as colouring agent.
On the other hand what could it be a jar full of black powder in a pottery store stating on label "colouring agent for concrete lime and
plaster" are there many other chemicals that used as a colouring agent in clay?
The clerk told me that it is used to give color in bricks but had no idea if it was CuO.
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Cyrus
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You can make a test in the store with a magnet. But I wouldn't advise bringing in test tubes and flasks or anything.
You can also just call the pottery supplier. They can answer questions about their store better than we can. They have tons of chemicals, and they had
better know what copper oxide is, and while you're at it, you should stock up on some other stuff they have too, especially if there's a
min. order.
12AX7, I can't believe you.... in your description of the colors copper makes in glazes, you forgot (gasp) that beautifiul metallic copper color
seen mostly in reduction fired raku. (usually in conjunction with iron oxide). Surely that's not what you meant by mere "red"? 
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praseodym
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| Quote: | Originally posted by unionised
Chemoleo,
"NiO is black, too, btw."
Care to check on that? |
NiO is green while Ni2O3 is black or sometimes dark gray. I think chemoleo could have gotten them mixed up...
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kine
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I bought the colouring agent for lime and plaster and it has similar magnetic properties as Fe3O4. Up on heating test with flame it turned to dark
brown so probably it is magnetite too. Now i got over a kilo of magnetite powder.
I asked many pottery shops around and noone has any CuO. Although i found massive amounts of copper suflate (turquoise blue) and also massive amounds
of KOH. Can somebody give me a detailed conversion of copper suflate to CuO with those materials. I want to make around half a kilo (quarter of a
pound?) so i dont have to mess with all those chemicals again.
Edit: Magnetite on heating on open flame turns in to brown color right?
Also does the above mentioned method with the solutions of copper suflate and sodium hydroxide release any toxic sulfure fumes?
[Edited on 10-8-2005 by kine]
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neutrino
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The conversion is very simple:
CuSO<sub>4(aq)</sub> + 2NaOH<sub>(aq)</sub> --> Cu(OH)<sub>2(s)</sub> +
Na<sub>2</sub>SO<sub>4(aq)</sub>
Filter out the Cu(OH)<sub>2</sub> and heat in an oven:
Cu(OH)<sub>2</sub> -heat-> CuO + H<sub>2</sub>O
No dangerous gasses/fumes produced. Note that this will also work with any soluble hydroxide (NaOH, KOH...)
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The_Davster
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Just boil the Cu(OH)2 after it has precipitated. It turns to CuO without the added step of putting it in the oven. Also I have found CuO made this
way is superior to roasted CuO from Cu(OH)2 in thermite.
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neutrino
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Doesn't oven-drying help remove residual moisture, as well? I seem to remember someone saying that step produces a superior thermite.
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kine
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I will use a pyrex for drying the Cu(OH)2 after filtering it out
Is CuO/Al thermite storage safe when closed airtight?
Also since it is impact sensitive a charge of the same thermite could initiate it or it will scateri around?
[Edited on 10-8-2005 by kine]
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