Vicente-M. Vizcay Castro (mapa@bitmailer.net)
Tue, 05 Oct 1999 01:30:02 +0200
Dear Judy:
A comments:
1: I suggest to you that you read slowly and with more attention the
procedure.
2: Not criticize, suggest improvements.
>The process requires the evaporation and absorption
3: (first: pouring of; second: absortion; third: evaporation,
fourth: drying by agent)
>of 116.9 gms of nitric acid.
4: Specific gravity of 54% (w) nitric acid solution: 1,34 g/ml
116.9 g (HNO3) + 100,3 g (H2O) = 162 ml
a) Pouring of ......... 17 ml
b) Absortion ......... 100 ml
c) Evaporation ......... 25 ml => 18g of HNO3
d) Drying .......... 20 ml
>This must be dried in the dark. There is no safe way to accomplish
>this for the typical alt photo practitioner.
4: You don't have any place in which you could put a closed hermetic
container ?
I'm sorry.
> The same issues as making aqua regia, except that the fumes are
encouraged.
5: I supose that in making aqua regia (because it has HCl, HNO3, Cl2, NOCl,
NO2, NO, N2O4)
Nitric acid has HNO3, but less NO2, NO and N2O4.
> Also, soaking up the acid in paper towels is not a great idea.
6: That other cheap option suggests you ?
>Read section 7 - this decanting takes 340 hours (with acid fumes present),
>but maybe 10-100 times longer. A centrifuge can help.
7: A centrifuge,...., a vacuum filtration system, ......, a chemical
hood, ...a....
A chemical laborathory well equiped...
> I can just imagine this beaker of nitric acid being flung around in a
darkroom.
8: Very good imagination.
>This procedure is referenced in Dick Stevens book.
9: In Dick Stevens book:
"Method 7.: Ferric nitrate plus oxalic acid dissolved in nitric
acid produces ferric oxalate."
The procedure isn't in Dick Stevens book because the procedure does not
dissolve
the oxalic acid in nitric acid.
> It's one of the procedures he does *not* recommend - the others are safer
and easier.
10: Mr. Stevens words are:
" These three methods have more advantages and fewer drawbacks than
the other
four. They are simpler, safer, cheaper, and quicker, and they
produce a cleaner, less
contaminated product"
It's Mr. Stevens opinion.
I suggest that you follows to the letter the procedure, obtains your own
powder oxalate,
test it and as of that moment forge your own opinion.
>It also will not produce as good of a grade of FO as the other Stevens
>process. Even the RS procedure (free, on the B&S website, no password) is
>safer, easier, and will produce a more pure FO. Much more pure.
When you said "more pure", have you analysis of both products?
If not, you can not say that that it has not demonstrated
Regards,
V. Vizcay
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