Study On The Influence Of Inorganic Anions On The Flotation Behavior Of Three Typical Calcium Minerals And Its Mechanism Of Action

Scheelite abounds in resources, which are essential materials of industry, agriculture and national defense. However, scheelite, fluorite and apatite commonly constitute mineral intergrowth, the similarity among the natures of the minerals, the complicated interactions among the dissolved species and the mutual transformation between the mineral surfaces, which could account for the difficulty of the separation of calcium salt minerals and high-efficiency. In this thesis, three typical calcium salt minerals regarded as the research object, namely, scheelite, fluorite and calcite, by doing single mineral flotation tests, scheelite ore flotation tests, Zeta potential measurement, determination of adsorption magnitude and flotation solution chemical calculation in the system that using sodium oleate as collector, the investigation that different modules of F", CO32-, WO42- and SiO32-(module 1 and module 2.4) could responsible for the vary flotation behavior of scheelite, fluorite and calcite has been carried out, which also exploded the interrelation between those anions and the surfaces of these three minerals.According to the results of the single mineral flotation tests, F-, CO32-, and WO42- could activate the scheelite and calcite within a certain range of concentration, while they don't have distinct activation to fluorite. With low concentration of SiO32-(module 1), the activation takes place to all these three minerals to some degree, while enhancing the concentration of SiO32- (module 1), it shows depression to those minerals. With low concentration of SiO3- (module 2.4), the activation to scheelite takes place, while depression to scheelite is shown with high concentration of SiO32-(module 2.4). Meanwhile, SiO32-(module 2.4) shows strong depression to fluorite and calcite within the whole range of concentration. The depressive capability of SiO32-(module 1 and module 2.4) to these three minerals is accordant:fluorite> calcite> scheelite.Another conclusion could be drawn from the single mineral flotation teats is, during scheelite ore flotation, the scheelite could be successfully separated from fluorite and calcite by adding proper amount of sodium carbonate and sodium silicate (module 2.4). By adopting this way of flotation, the scheelite concentrates which grade of WO3 is 60.08% and recovery is 70.38% are finally being obtained.The tests of zeta potential and the adsoption magnitude of collector at the mineral surface show that:the adsorption of F- to the calcium minerals is relatively weak and it only has slight influence over the surface charge and the adsorption of collectors of the mineral surface. CO32-,WO42- and SiO32-(module 1 and module 2.4) generate relatively strong specific adsorption to all the three minerals. Within a certain concentration range of CO32-,WO42- and SiO32-(module 1), the adsorption between sodium oleate and these three calcium minerals could be enhanced, while the adsorption of sodium oleate to fluorite and calcite would be rapidly reduced with the enhance of concentration of SiO32-(module 2.4).The dissolution behavior research and the calculation of solution chemistry of flotation of these three calcium minerals show that:sodium oleate float these calcium minerals mainly by the chemical-bond between sodium oleate and Ca2+ at the mineral surface in the highly alkaline conditions. The activation of inorganic anions to the flotation behavior of the calcium minerals is due to the chemical reaction which declined the capability of Ca2+ as precipitator of collectors, enhanced the interaction between the collectors and the mineral surface, and increased the recovery of minerals. While SiO32- is used as depressor, its main ingredient is active silica colloid. It reduces the minerals'floatability by the adsorption at the mineral surface which could improve the hydrophilic property of mineral surface.