1070-4272/05/7810-1709 + 2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 10, 2005, pp. 1709!1711. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 10, 2005,
Original Russian Text Copyright + 2005 by Kononov, Golounin, Pashkov, Kuklina, Mikhailenko, Tsupinin.
Sorptive Recovery of Gold(I) from Cyanide-containing Aqueous
Alkali with Resins Containing Guanidinium Sorption Sites
Yu. S. Kononov, A. V. Golounin, G. L. Pashkov, U. F. Kuklina,
M. A. Mikhailenko, and D. V. Tsupinin
Institute of Chemistry and Chemical Technology, Siberian Division,
Russian Academy of Sciences, Krasnoyarsk, Russia
Purolite Int. Ltd. Agency, Moscow, Russia
Received June 9, 2005
Abstract-A technique was developed for desorption of gold(I) from a strongly basic resin containing
guanidinium sorption sites with aqueous-organic alkalis.
Strongly basic resins containing quaternary am-
monium cations as sorption sites are widely used for
industrial recovery of gold(I) from cyanide-contain-
ing aqueous alkalis. Gold(I) is desorbed from these
resins with acidic aqueous thiourea. This procedure
is hazardous and expensive. Furthermore, these resins
must be treated before sorption with acid to remove
cyanide complexes of nonferrous metals and iron .
Anion exchangers containing basic nitrogen sorp-
tion sites, among them guanidine derivatives, sorb
gold(I) from cyanide-containing aqueous alkalis. How-
ever, desorption of Au(I) from these sorbents with
aqueous alkali is inefficient. For example, in eluting
Au(I) from a resin containing N-(6-aminohexyl)-N`-
butylguanidinium sorption sites (pK
~ 12) with 10%
aqueous alkali, only 40% of gold passes into the elu-
ate. Under the same conditions, the degree of gold
desorption from a resin containing 1,5,7-triazabicyclo-
[4.4.0]decene-5 sorbing groups (pK
~ 16) is only 1%.
From resins with different sorbing amino groups sep-
arated by di- and triatomic hydrocarbon bridges con-
taining alcoholic groups, 35365% of gold is desorbed
with 0.0134 M aqueous alkali .
These data show that a significant fraction of gold(I)
sorbed on resins under consideration cannot be eluted
from them with aqueous alkali.
It is known that the acid ionization constants of
organic compounds depend on the solvent. For ex-
of ammonium salts in water3alcohol mix-
tures decreases linearly with increasing alcohol con-
centration and sharply decreases (by two pK
at alcohol concentrations of 60370% . Assuming
that similar correlations occur for resins containing
guanidinium cations, we can expect that, in going
from aqueous alkali to solutions of alkali in water3
alcohol mixtures or other appropriate aqueous-organic
solvent with relatively low permittivity, the pK
the resin sorption sites decreases and, as a result,
the desorption of gold(I) from the resins is facilitated.
In our experiments, we used a strongly basic anion
exchanger Purolite A-180 widely accepted in the hy-
drometallurgy of gold. This resin has the form of
a poly(styrene3divinylbenzene) matrix modified with
guanidinium cation as sorbing groups. To elucidate
the acid3base behavior of Purolite in aqueous alkali,
we carried out its potentiometric titration with aque-
The potentiometric titration curve (see figure)
shows that, in alkaline medium, guanidinium cations
Potentiometric titration curve of Purolite A-180 resin
with aqueous alkali. (a) NaOH consumption.