Having about an ounce of 26% ammounium dichromate to dispose of
in an environmentally responsible manner, & having read contributions to
this list about adding strong alkali & filtering.......
I added an equal quantity of household ammonia, which made no impression,
except for the perfume. (I know household is only 4 or 5% but I was trying to
get rid of it because it made prints smell like low-grade bordello.)
Next I added maybe a tablespoon of sodium carbonate. This foamed up, like
orange sherbert, and was still bright orange, which I took to mean it still
possessed hexavalency. I couldn't find litmus paper, but it was about pH 6
on Hydrion paper.
So I added about 2 teaspoons sodium hydroxide -- all, remember, for an
ounce of original solution. At this point the test color didn't match
any of the squares on the chart. The difference on the chart from 6.5 to 8
was pretty indistinguishable anyway (maybe it faded?).
Anyway, I decided to wait for precipitation to happen, & indeed soon
there was a thin ring of brownish sludge & the rest of the solution
became a dirty, rather watery-looking orange. This I propose to now
filter, sloshing it down the drain, then wiping the sludge out of the
container with a paper towel for future disposal.
The reason I describe all this is that I can't imagine treating say,
a gallon, if it took a proportionate amount of chemical -- which would
simply substitute one problem for another (& probably burn holes in my
Maybe it works better if you have used developer to mix it with? (I
didn't have any on hand.)
Any comments/advice would be cherished.