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Solvent extraction of silver for pollution control of photographic fixing solutions

Stenström, Stig LU (1991) In Journal of Photographic Science 39(6). p.241-245
Abstract
Silver recovery from photographic fixing solutions is investigated by applying solvent extraction techniques. Amines were shown to be the most promising extractants and quaternary ammonium chlorides selected for further studies because of high distribution coefficients and low pH-sensitivity. The distribution coefficient for silver from a 0.5 M ammonium thiosulphate solution increases from 2.3 to 46 when the extractant concentration is increased from 0.05 M to 0.5 M Aliquat 336. Further, the distribution of silver decreases with the square of the thiosulphate concentration. By dilution of the fixing solution 1:5 outlet silver concentrations below 1 mg/l can be achieved with 4 to 5 mixer settler units. Stripping can be performed by changing... (More)
Silver recovery from photographic fixing solutions is investigated by applying solvent extraction techniques. Amines were shown to be the most promising extractants and quaternary ammonium chlorides selected for further studies because of high distribution coefficients and low pH-sensitivity. The distribution coefficient for silver from a 0.5 M ammonium thiosulphate solution increases from 2.3 to 46 when the extractant concentration is increased from 0.05 M to 0.5 M Aliquat 336. Further, the distribution of silver decreases with the square of the thiosulphate concentration. By dilution of the fixing solution 1:5 outlet silver concentrations below 1 mg/l can be achieved with 4 to 5 mixer settler units. Stripping can be performed by changing the thiosulphate concentration or by using an ammonium chloride solution. In order to recycle the organic phase between the extraction and stripping sections, co-extraction of other components in the solution, such as thiosulphate degradation products and halides, should be further studied. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Photographic Science
volume
39
issue
6
pages
241 - 245
publisher
Royal Photographic Society
external identifiers
  • wos:A1991HG66000004
ISSN
0022-3638
language
English
LU publication?
yes
id
e0422210-4c69-486d-929d-e61b969ecfd9 (old id 3914130)
date added to LUP
2013-07-01 11:04:15
date last changed
2016-04-16 03:25:48
@article{e0422210-4c69-486d-929d-e61b969ecfd9,
  abstract     = {Silver recovery from photographic fixing solutions is investigated by applying solvent extraction techniques. Amines were shown to be the most promising extractants and quaternary ammonium chlorides selected for further studies because of high distribution coefficients and low pH-sensitivity. The distribution coefficient for silver from a 0.5 M ammonium thiosulphate solution increases from 2.3 to 46 when the extractant concentration is increased from 0.05 M to 0.5 M Aliquat 336. Further, the distribution of silver decreases with the square of the thiosulphate concentration. By dilution of the fixing solution 1:5 outlet silver concentrations below 1 mg/l can be achieved with 4 to 5 mixer settler units. Stripping can be performed by changing the thiosulphate concentration or by using an ammonium chloride solution. In order to recycle the organic phase between the extraction and stripping sections, co-extraction of other components in the solution, such as thiosulphate degradation products and halides, should be further studied.},
  author       = {Stenström, Stig},
  issn         = {0022-3638},
  language     = {eng},
  number       = {6},
  pages        = {241--245},
  publisher    = {Royal Photographic Society},
  series       = {Journal of Photographic Science},
  title        = {Solvent extraction of silver for pollution control of photographic fixing solutions},
  volume       = {39},
  year         = {1991},
}