Six elemental groups in the gold deposits in the study region have been distinguished:( 1 ) tungsten-antimony-gold; (2) tungsten-gold; (3) antimony-gold; (4) lead-zinosilvergold; (5) uranium-silver-gold; (6) simple gold. Discussed in the present paper are the distribution, source, mineralization, migration and concentration of gold. The resuhs show that the ore-controlling strata or source beds related to gold deposits all show high background values of gold; the gold and other associated ore-forming dements are obviously derived from the country rocks. Mineralization is related chiefly to regional metamorphism in the ore-controlling strata, or alkali-pervasing metasomatism. During metamorphism in the orecontrolling strata, gold was released into solutions, and then transported and deposited in some localities. Gold carried in hydrothermal solutions occurs mainly in the form of Na[Au(SH)2]. Native gold or electrum were precipitated from the ore solutions and concen.trated into ore deposits with the decrease of T, pH and fO2.
The adsorption of tungsten on ferric oxide, manganese dioxide, slate, carbonaceous slate,kaolinite and bentonite in the solutions of pH 4---9 at atmospheric temperatures and pressures has been examined. Experimental results show that acidic solution is in favour of the adsorption of tungsten on the adsorbents. The adsorptivities of these adsorbents for tungsten decrease with increasing pH values for the solutions. Of all the substances joining the expe-riment, Fe2O3 is possessed of the highest adsorptivity and clays of the lowest. Their adsorptivities reduce in the order of Fe2O3, MnO, carbonaceous slate, SiO2, slate and clay in neutral and acidic solutions and of Fe2O3, carbonaceous slate, MnO, slate, clay and SiO2 in alkaline solutions. The adsorption of tungsten on the adsorbents and its pH dependence can be explained by the presence of W(VI) complex cations. The increase of pH results in the reduction of their quantities in the solutions with concomitant diminution of adsorptivity.Experimental data indicate that W shows a strong tendency of concentration during supergene processes in tungsten geochemical provinces. Therefore, it is of particular significance in the formation of tungsten-bearing formations.
