Hi Gang,
An acquaintance has shown me a quantity (apparently several ounces)
of silver “powder”, apparently recovered from some photographic
processing operation several years back. Has anyone ever dealt with
this stuff before?
-
Can I just melt it down in a crucible and pour an ingot? Any idea
of the purity?
-
Any residual chemicals or toxic elements I need to be aware of?
-
Something best sent to legitimate refiner?
Thanks again, in advance. You people are awesome!
Dave
Dave Sebaste
Sebaste Studio and
Carolina Artisans’ Gallery
Charlotte, NC (USA)
dave@sebaste.com
Dave,
I bought some from a guy several years ago, two or three pounds, as I
recall. Melted it down and poured it into water to make casting grain,
and have used it for casting as well as rolled it into wire and sheet.
It’s .999 as best I can figure. I don’t know about any toxicity. The
stuff I received was black when I got it, which I presume was oxide or
sulphide but it poured out clean and silvery.
Jerry in Kodiak
An acquaintance has shown me a quantity (apparently several
ounces) of silver "powder", apparently recovered from some
photographic processing operation several years back. Has anyone
ever dealt with this stuff before? - Can I just melt it down in a
crucible and pour an ingot? Any idea of the purity? - Any residual
chemicals or toxic elements I need to be aware of? - Something best
sent to legitimate refiner?
Hi, Dave
The purity and contaminants will depend on just how it was obtained.
I would guess the most likely possibility is that it was recovered
from a photographic fixer solution. This can be done either by
electro-plate (used in most large-scale operations), in which case it
would be fairly pure; or by precipitating it from the solution using
something like metallic zinc dust. In this case it comes out as a
brownish sludge.
From your description it is most likely electrolytical.
But either way – unless you have some way of assaying it yourself –
it really should be sent to a refiner, such as Handy & Harman. The
problem here would probably be finding someone who is willing to do
such a small amount.
Margaret
An acquaintance has shown me a quantity (apparently several ounces)
of silver "powder", apparently recovered from some photographic
processing operation several years back. Has anyone ever dealt with
this stuff before?
G’day; shops and firms which do photographic processing on a fairly
large scale use sodium or ammonium thiosulphate - and lately other
chemicals - to ‘fix’ the image, and this dissolves unused silver from
negatives and photographs. There are a number of methods of
recovering this waste silver which over a year or so can amount to a
considerable amount of money. Concentration is necessary, but to heat
and evaporate the waste is expensive, and other methods are used.
Deionising columns are often used to concentrate silver ions then
treating the columns with other chemicals can release the
concentrated silver salts, which can be reduced to silver by
electrolysis, and this method would result in fairly pure silver
metal.
- Can I just melt it down in a crucible and pour an ingot? Any idea
of the purity?
to arrive at a decisive figure for purity the silver would have to
undergo assay by a competent laboratory
- Any residual chemicals or toxic elements I need to be aware of?
Without complete knowledge of the recycling of the silver in
question, the answer can be no more than a guess, but I personally
believe it should be free from toxic substances.
- Something best sent to legitimate refiner?
Silver is a relatively cheap metal and refining and assay are
expensive. It could be that sending it to a refiner might not turn
out to save much money relative to the cost of silver from an
established company.
I personally would be inclined to melt a small quantity and cast a
rod ingot around 5mm diameter, then use that to make thin wire. Very
careful examination of the wire and it’s annealed properties would
expose ‘jags’ due to unwanted alloying elements. In the words of the
prophet, suck it and see! However, if one were to make jewellery with
this metal, it would be unethical to quality stamp it without assay.
Cheers, –
John Burgess; @John_Burgess2 of Mapua Nelson NZ
Dave,
The material you have is called silver sludge or silver chip. It is
the product of electroplating the silver out of the fixer solution
used to stabilize the image on photographic film. High levels of
silver may be found in x-ray processing solution and far less in color
film processing. If the current leveling the plating process is
correct at all times the CHIP produced will be bright and hard and 999
fine. As a black or brown powder the color is sulfide also extracted
from the ammonium thiosulfate " Fixer " . If you assay after each Melt
you may find you will have to melt several times to get to 999 fine.
Other than that, It smells bad.
I have been in the X- Ray business since 1969
Art Smith
69253 Lariat
Sisters, Oregon 97759
541-549-8096
@Art_Lucy_Smith
Thanks, Art. It is the black powder. I think I’m just going to give
him the names of a couple refiners and let him work it out! I’ve go no
stake in it, other than the possibility he’d want me to make him
something from the silver.
Dave
Dave Sebaste
Sebaste Studio and
Carolina Artisans’ Gallery
Charlotte, NC (USA)
dave@sebaste.com mailto:dave@sebaste.com
http://www.CarolinaArtisans.com http://www.CarolinaArtisans.com
Hello,
Like John Burges says. your silver would be rather clean if it is
recovered from photo chemicals. It is mostly 99-99.5 percent pure
silver. A simple way to see, is the monks test. Heat up a bit silver (
a knife point) in some charcoal. Burn this really hot so that the
silver will evaporate and burn. If you see at the edges around the
burned silver, no discolouration from condensing (silver condenses
black) from other material. it is pure and clean. If you see an orange,
colour is contains some lead, you see some yellow colour this can mean
cadmium. green yellow can mean sulphur/chromium and so on. If this is
so, try to melt some silver with some borax like melting powder ( for
cleaning melts) and you do this test again. I think now the sliver is
clean enough to use.
Martin Niemeijer
Another thing about SILVER recovered from Photographic chemicals. I
have in the past ( long past ) requested from Rio - Grande and sent
in many pounds of this material to be refined. At that time they would
either pay for it or CREDIT it to my account and then I could buy what
ever I wanted. Call some of your suppliers and see what they can do for
you. Thanks for listening.
Art Smith
69253 Lariat
Sisters, Oregon 97759
541-549-8096
@Art_Lucy_Smith