phangue - 5-11-2006 at 17:29
KFC with his question on phenol really saved me from forum HELL. I am not much of a chemist, and my principal interest is colorants for ceramic
glazes. This involves metal oxides. Now it’s no doubt cheaper to just go buy them ready to use, but when I see a mess around the yard—like an old
copper pipe; I have this urge to make it useful.
The books I have read say to heat copper to low red heat to derive copper oxide, but when I tried that in a capped iron pipe over a blast in the back
yard; I got a big mess in the bottom of the pipe. Same thing when I tried quarter dollars together with KNO3 to get nickel oxide—welded quarters.
What the hell are quarters made out of now anyway? So I was all set to post a question as to the action of an acid on the copper leading to the oxide.
Then I saw the reaction to KFC and hesitated. Boy, would I have caught it!
Thanks be to BeerChloride with his post on “weird copper compound” for solving my issue about. Copper oxide. Now what do I do by way of an acid
process to derive a nickel oxide?
bereal511 - 5-11-2006 at 17:58
Heat the copper in the open, it needs the oxygen to form a copper oxide coating. Also, it is better to have copper sheet, mesh, or wire because it
takes too long to heat a block of copper to form copper oxide as it flakes off.
Quarters are made of a nickel/copper alloy, 8.33% nickel and 91.6% copper. It would be better to find a different source of nickel to make your
nickel oxide.
12AX7 - 5-11-2006 at 18:43
You might have luck with Canadian nickels, which were once made out of nickel, owing to their nickel mine in Sudbury.
Unreactive metals like copper and nickel are best decomposed electrolytically. A concentrated salt solution with the metal as anode will oxidize it
to oxide or hydroxide. This is washed and calcined to give the respective black oxide.
Lead forms an insoluble chloride or dioxide layer, but a solution of say, sodium perchlorate or nitrate ought to handle it well. I don't know about
sodium acetate, but being a weak acid it probably doesn't conduct real great.
These are going to be more efficient and convienient than oxidizing in air and processing the crunchy mixed, impure oxide.
FYI, you probably melted the copper.
Tim
Elawr - 5-11-2006 at 21:27
I had good success using muriatic acid to turn scrap copper into useful chloride salt. It was some oxidized copper plumbing pipe salvaged from the
debris of a burned-down house. I simply cut the pipe up, discarding the soldered ends, and covered the metal with 27% HCl. Over several days the
copper slowly digested, throwing down Cu2Cl2 (Cuprous Chloride) as a sparkling white microcrystalline precipitate. From time to time, I added small
amounts of 27 % H2O2 in order to accelerate the process. The solution turns immediately brown with various oxychlorides and great heat is generated.
You must be careful with H2O2 as an accelerant for this kind of thing, lest your reaction get away from you and come boiling up out of its vessel and
all over everything! Areation acheives similar end, and given enough chloride, you'll end up with an acidic solution of cupric chloride ( CuCl2),
which can be boiled down until dry. My end product was nice, fine blue-green acicular crystals.
From the chloride, many colorful and toxic copper-based pigments are easily made, including the basic chloride, carbonate, acetoarsenate (paris
green), etc.
The_Davster - 5-11-2006 at 21:49
I second the use of electrolysis for this, I have in the past used electrolysis of KNO3 solutions with copper electrodes to produce CuO/Cu(OH)2
depending on temp. I found KNO3 preferable to the other electrolytes I tried.
Ni should go about the same, but the hydroxide is more stable then the corresponding copper one, so you will likely have to calcine it after to get
the oxide.
not_important - 6-11-2006 at 00:09
there is no good scrap source of nickel that I know of, outside of 12AX7's suggestion of older Canadian coins. US nickels are 3/4 copper, 1/4 nickel,
the US dime, quarter, and half dollar are a copper core clad in nickel-copper alloy - 91% copper and 8% nickel overall
http://www.missico.com/personal/tidbits/us_coins.htm
http://www.frbatlanta.org/invoke_brochure.cfm?objectid=83FD4...
Eons ago I used the air oxidation route for converting scrap copper to the oxide. Set up a gas flame at an angle to heat the copper, a glass pan below
it, and suspended the copper from an arm that was being lifted by a cam with a sharp drop so as to shake the copper and encourage the oxide to drop
off.
Copper pipe and wire are fairly pure, if you do as you did and avoid the soldered sections. Some of the ceramic CuO (black oxide) is made in just
that fashion - air oxidation of scrap copper, followed by crushing, screening, second air roast to get full oxidation, and a final crushing and
grading.
I doubt it's worth trying for nickel from coins, and scrap nickel is rather uncommon. Iron works well, and most iron colour aren't terribly sensitive
to contamination. Manganese is another, wash the contents of batteries with water a few times to remove the KOH and zinc salts, after that possibly
roast it in air at 400 C to burn off organics and carbon - although it seems to work OK without that.
I once did a glaze using a US nickel as the colourant. I'd hammered it thin, then air oxidised and ground the mixed oxides. It gave a nice green-blue,
the nickel pulling the normal copper blue more green. But it was just for fun, nickel tends to be such a frustrating colour source, working well for
many times then deciding instead of green it will be zombie green-grey or a horrible yellow-brown. The only nickel glaze I had luck with getting
consistent colour was an alkaline one fairly high in lithium.
phangue - 6-11-2006 at 14:58
Thank you bereal511, 12AX7, Elawr, The-Davster, and not-important. You have been very kind and helpful. Now I know how to proceed safely.
Baphomet - 22-11-2006 at 18:32
I've had success with the same process Elawr used.. I did it with HCl and H2O2 on copper wire. Upon drying, you will know you have CuCl2 if it appears
brown and turns white then green upon exposure to air. It's interesting to observe. Note that a lot of H2O2 contains sequesterants that will
contribute some impurities if you choose this route.
The direct oxidation via blowtorch then chlorination with high quality HCl will yield the most pure product.