RE: [Histonet] Re: Ammoniacal silver nitrate disposal
I find it more cost effective to precipitate silver with sodium chloride -
not reagent grade, just ordinary table salt from the market.
> From: email@example.com on behalf of John
> A. Kiernan
> Sent: Tuesday, September 20, 2005 8:56 AM
> To: Featherstone, Annette
> Cc: 'firstname.lastname@example.org'
> Subject: [Histonet] Re: Ammoniacal silver nitrate disposal
> 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
> "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
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