ESTIMATION OF TUNGSTEN IN COMPLEX MATRICES USING TOLUENE 3,4-DITHIOL AND THIOCYANATE

A rapid less labour-intensive procedure for complete decomposition of tungsten bearing complex matrices by potassium pyrosulphate and its de termination using toluene 3, 4-dithiol and thiocyanate is reported. Th e analytical results of various standard reference materials are prese nted (Jasperoid GXR-1, Deposit GXR-3, copper mill head GXR-4, tin-tung sten ore IGS-26, Mo-W ore IGS-27, tungsten concentrate SRM-277, scheel ite ore SRM-2430, reference tungsten ore TLG-1, CT-1, BH-1 and Mo-W or e MP-2) along with two manganese nodules (GSPN-2 and GSPN-3) recently introduced by the Chinese Academy of Geological Sciences and one Polis h soil sample (SRM-2710). For most of the samples the agreement betwee n the observed value and the published data have been found to be extr emely good. Derivations have been noted in some samples where publishe d concentrations are indicative values only, indicating that more data are still required to upgrade the status from proposed/unspecified to the certified level. Results of various statistical analyses (interme thod comparison, F-test and regression analysis) reveal that the metho ds are matrix dependent. Separation of tungsten from molybdenum is str aightforward, hence can be used for a quality control programme and in the evaluation of reference materials.