[Histonet] Re: Ammoniacal silver nitrate disposal

[John A. Kiernan]

Ammoniacal silver nitrate solutions must not 
evaporate to dryness because the deposit contains 
silver azide and silver amide, a mixture known
as fulminating silver that is a touch-sensitive
explosive. Add some hydrochloric acid to the
solution. this will precipitate all the silver
as white silver chloride. This darkens on
exposure to light; it is not hazardous. 

When you have a big bottle of silver chloride,
decant off most of the supernatant (which contains
ammonium chloride and dilute hydrochloric acid) and
add metallic zinc to the sludge. After a few days
the silver chloride changes to a heavy deposit of
dark grey silver powder. Decant again and rinse 
with dilute hydrochloric acid to extract excess
zinc, then wash the deposit with several changes
of water, filter and dry.

I've got two jars of silver powder made in this
way, but have yet to find out who would buy it
for refining. Any ideas? 
-- 
-------------------------------
John A. Kiernan
Department of Anatomy and Cell Biology
The University of Western Ontario
London,   Canada   N6A 5C1
   kiernan[AT]uwo.ca
   http://publish.uwo.ca/~jkiernan/
   http://instruct.uwo.ca/anatomy/530/index.htm
_______________________________
"Featherstone, Annette" wrote:
> 
> I would like to know how everyone is disposing of the ammonium-silver
> nitrate waste and DAB. Any and all responses would be of great help.
> Thanks
> Annette Featherstone HT/MLT
> Supervisor Anatomic Pathology
> Kaleida Health
> Buffalo General Hospital
> 100 High St
> Buffalo NY 14203
> 716-859-2625
>