Using Primene JMT or TOA, the extraction of thiocyanic acid and of Ag(I) th
iocyanato-complex from aqueous thiocyanate solution was studied. On extract
ion of thiocyanic acid using aqueous phase containing 1.0 M NH4SCN and an o
rganic phase containing 100-300 kg m(-3) Primene JMT or TOA, (RNH3+ SCN-)(o
) and (R3NH+.SCN-)(o) were formed with apparent equilibrium constants, log
K-ex.a, of 8.7 and 6.5, respectively, The extraction of 1 x 10(-3) M Ag(I)
from aqueous ammonium thiocyanate solutions by the thiocyanate salts of Pri
mene JMT or TOA at concentrations ranging from 100 to 300 kg m(-3), and in
the presence of ammonium thiocyanate at concentrations of 0.5-3.0 M can be
summarized as follows:
2(RNH3+.SCN-)(o) + Ag(SCN)(3)(2- Kex,3) = ((RNH3+)(2).Ag(SCN)(3)(2-))(o) 2SCN(-), logK(ex,3) = 1.6
2(R3NH+.SCN-)(o) + Ag(SCN)(3)(2-) (Kex,3) = ((R3NH+)(2).Ag(SCN)(3)(2-))(o)
+ 2SCN(-),logK(ex,3) = 2.5.
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