Abstract:
Aiming at the controversy over affinity between anions and quaternary ammonium resin in tungsten metallurgy, the study investigated into the influences of NaOH, Na
2CO
3 and NaHCO
3 on anions elution in quaternary ammonium type column at different temperatures by ion chromatograph. Thus, order of affinity between the anions and the column, and the thermodynamic parameters of dynamic exchange were obtained. The results showed that with NaOH as eluent, the affinity order between anions and quaternary ammonium column was: MoO
42- > WO
42- > AsO
43- > PO
43- > SO
42- > Cl
- > F
-. When Na
2CO
3 or NaHCO
3 was used as eluent, phosphorus and arsenic were converted into the form of HPO
42- and HAsO
42-, respectively, resulting in a decrease of their affinity for the chromatographic column. Furthermore, the capability to elute anions ranked: NaOH > Na
2CO
3 > NaHCO
3. When NaOH was used as eluent, temperature had a significant effect on the peak time of each anion. Besides, when NaOH and Na
2CO
3 were used as eluents, the corresponding thermodynamic parameters could be calculated by Van′t Hoff equation, and the order of relative Gibbs free energy changes was consistent with that of affinity between anions and quaternary ammonium column.