jderimig
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Cleaning copper chromite from frit glass
I made some copper chromite and used the frit to pull water after the acedic acid wash.
I was able to clean the frit surface with soap and water and although it functional it still has some gray stain.
Any suggestions on what to try? HCL acid doesn't touch it and I tried sulphuric acid drain cleaner (pure is on the way) and that didn't it touch it
either.
Those are the only things I have tried so far. I plan to try Chromic Acid next but that will be a few days.
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DavidJR
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Try soaking in a solution of EDTA disodium.
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rockyit98
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what about con. HNO3? maybe it will oxidize it back to copper chromate .i guess con. Ammonia can be used to dissolve copper chromate if good luck
would have it even copper chromite itself.
"A mind is a terrible thing to lose"-Meisner
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jderimig
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That is on my list to try, trying to source some locally.
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jderimig
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Quote: Originally posted by rockyit98  | | what about con. HNO3? maybe it will oxidize it back to copper chromate .i guess con. Ammonia can be used to dissolve copper chromate if good luck
would have it even copper chromite itself. |
I have trying 30% aqueous ammonia and there didn't seem to be a reaction. I will try some HNO3 after I distill some.
I have some KMnO4 on the way as I found in another thread that it might convert Cr2O3 so its soluable in HCL or HNO3. So maybe if it acts on Cr3O3 it
might work on CuCr2O5?
Keep the suggestions coming.
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DavidJR
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In future don't use frits for filtering anything which you don't know how to dissolve again later. It can sometimes be completely impossible to get
them clean again.
A traditional Buchner funnel with filter paper does not have this problem (because the filter paper is disposable).
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jderimig
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| Quote: Originally posted by DavidJR | In future don't use frits for filtering anything which you don't know how to dissolve again later. It can sometimes be completely impossible to get
them clean again.
A traditional Buchner funnel with filter paper does not have this problem (because the filter paper is disposable). |
Yup, lesson learned. I saw the method for producing CuCr in a video and he used a frit filter in the final step that was white as the driven snow.
So I figured he'd done this before and cleaning the frit would not be a space shot.
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PirateDocBrown
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I often place a circle of filter paper on top of the frit, you get a double filtering effect, and much crap is kept out of the frit.
Phlogiston manufacturer/supplier.
For all your phlogiston needs.
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jderimig
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Update: Think I found a solution.
Soak frit in solution of KMn04 (I did overnight).
Then soak in concentrated HCL. Seems to be doing the trick.
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SuperOxide
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| Quote: Originally posted by jderimig | Update: Think I found a solution.
Soak frit in solution of KMn04 (I did overnight).
Then soak in concentrated HCL. Seems to be doing the trick. |
Sorry to bump an old thread - but can you confirm if this is a solution or not? I plan on doing this synth soon, and am planning the proper cleanup
(including of the frit).
Thanks.
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macckone
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yes, that will work for this combo.
bleach should work as well in place of KMnO4.
But bleach is going to generate some chlorine gas.
sodium chlorate might work better but bleach is more accessible.
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SuperOxide
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| Quote: Originally posted by macckone | yes, that will work for this combo.
bleach should work as well in place of KMnO4.
But bleach is going to generate some chlorine gas.
sodium chlorate might work better but bleach is more accessible. |
I have some EDTA Disodium Salt Dihydrate that I purchased just for this test. And I dissolved some into solution, and added some copper chromite to it
and let it sit for some time. The solution went from clear, to green, to blue. And there's still some black copper chromite at the bottom.
 .
I added about equal quantities of the EDTA disodium and copper chromite (one scoop of each), but now that I think about it, the EDTA disodium salt
molecule is bigger than a molecule of copper chromite, right? So maybe equal volumes isn't right, I need to do a 1-1 molar ratio (at least).
I'm going to test out how well free EDTA acid works to compare (as opposed to the disodium salt).
It seems I can get the free EDTA acid by adding HCl to a solution of the EDTA disodium salt, which will make free EDTA and sodium chloride. EDTA is
much less soluble in water than the disodium salt or sodium chloride.
I added 3g of the disodium salt to some distilled water in a test tube, then once dissolved, added some conc HCl, and eventually a lot of EDTA fell
out of solution :-)
here are some more pics of that little pilot synth.
It seems that free EDTA may be more useful than the EDTA disodium salt, so I'm going to make some in a larger run - which I'm doing now (processing
80g of the disodium dihydrate salt).
If anyones interested in a comparison between the two forms of EDTA (in terms of cleaning up metals), then lmk and I'll share the results :-)
Edit: Now that I think about it though... The free EDTA is much less soluble in water, so maybe it wouldn't be as easy to use... hmm.
Oh well. Still fun to test it out.
[Edited on 16-8-2021 by SuperOxide]
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AJKOER
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| Quote: Originally posted by macckone | yes, that will work for this combo.
bleach should work as well in place of KMnO4.
But bleach is going to generate some chlorine gas.
sodium chlorate might work better but bleach is more accessible. |
Better, first add vinegar to the dilute aqueous NaOCl/NaCl (aka, bleach). This creates HOCl which behaves like H2O2 in a fenton-type reaction. The
Chromium oxidation state increases and yes, in the presence of NaCl, expect some Chlorine liberation as well.
Do not leave the mix sitting around as you could get a nasty smelling (and problematic) chloro-acetate in time.
Safer, but perhaps less effective, use a mix of Chlorine bleach and Baking Soda. Again, HOCl at work but no chloro-organics!
[Edited on 17-8-2021 by AJKOER]
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