Research On Flotation Properties Of Iron Sulfide Minerals Based On Crystal Chemistry

In this paper, several common iron sulfide minerals were taken for flotation study, including pyrite, pyrrhotite, arsenopyrite and pentlandite. Basing on the mineral crystal chemical feature, the surface properties of iron sulfide minerals, the floatability of iron sulfide minerals from different areas and the influence of flotation reagents on mineral floatability have been studied in this paper. By flotation solution chemical calculation, zeta potential measurement and XPS analysis, it was found out that the relationship between the flotation crystal chemical feature, the surface properties and the floatability of sulfide iron minerals is very important.In the butyl xanthate flotation system, the natural floatability and the surface electrical properties of sulfide iron minerals have been studied. Studies show that the natural floatability of pyrite and arsenopyrite is better than pyrrhotite and pentlandite, and that of pyrrhotite is the most worst. The points of zero charge of pyrrhotite, pentlandite, pyrite and arsenopyrite are 6.2,2.95,2.0 and 1.5.The influences of metal cation, inorganic anion regulator and organic regulator have been studied on the floatability of sulfide iron minerals in the butyl xanthate flotation system. Studies show that Ca2+ and Fe3+ have an inhibitory effect on the iron sulfide minerals. Cu2+ can inhibit those iron sulfide minerals under the condition of acidic pH value and activate them under the condition of alkaline pH value. Na2S and K2O2O4 have inhibitory effects or activations on pyrite and arsenopyrite. Na2CO3, Na2SO3 and Na2S2O3 have inhibitory effects on pyrite and arsenopyrite. All kinds of the inorganic anion regulators have inhibitory effects on pyrrhotite and pentlandite. H2C2O4 has inhibitory effects on pyrite, pyrrhotite and arsenopyrite, but has activation effects on pentlandite.In the butyl xanthate flotation system, the floatability differences of pyrite and pyrrhotite have been studied, which have been obtained from different areas. Studies show that the natural floatability of the two kinds of pyrite and pyrrhotite is different, with the similar variations of pH value influence. Ca2+ and Fe3+ have an inhibitory effect on the two kinds of pyrite and pyrrhotite, but the inhibitory intensities are different according to the pH values. Cu2+can inhibit those two kinds of minerals under the condition of acidic pH value and activate them under the condition of alkaline pH value. Na2S, Na2SO3 and Na2S2O3 have inhibitory effects on the two kinds of pyrite and pyrrhotite. Na2CO3 have different effects on the pyrite and pyrrhotite from Hunan, but week effects on the pyrite and pyrrhotite from Yunnan. K2Cr2O4 has different effects on the two kinds of pyrite and pyrrhotite at different pH values. H2C2O4 has activation effects on both the two pyrites and pyrrhotites in a certain pH value condition.The relationship between the crystal chemical characteristics, surface properties and its floatability of iron sulfide mineral has been studied. Studies show that the lattice defects existing in the crystals of iron sulfide mineral can produce different effects on the numbers and states of the exposed atoms. S is relatively high concentration on pyrrhotite surface, while Fe is relatively high concentration on pyrite surface, which make the reaction different between the butyl xanthate and the pyrite and pyrrhotite minerals. The relative concentrations of metal atoms including Fe, As and Ni are related to the floatability of sulfide minerals, that is to say, the higher concentration, the better floatability. The tariff of metal cations exposed on pyrite surfaces is higher, the electropositive of mineral surface is stronger, which can make influences on the iron sulfide minerals floatability.With XPS analysis, the relationship between the iron sulfide mineral surface properties and floatabilities has been studied before and after the effects of reagents. Studies show that either metal cation or inorganic anion regulators and organic regulators can have influences on the relative concentrations and the valence states of some elements on the surface of iron sulfide minerals, and then also have influences on the action mode between the mineral surface and collector. For example, after the action of Cu2+, the relative concentrations of S of mineral surface have been lower, which shows that Cu2+ acted with S can absorb on the mineral surface, and with the flotation solution chemistry analysis, it is considered that Cu(OH)2 can be formed on the mineral surface preferentially and when the collector has been added, Cu(OH)2 can react with the collector and have activation effects on both the minerals. After the action of H2C2O4 with pentlandite, the valence states of mineral surface components have been changed and the relative concentrations of C is higher, which shows that H2C2O4 components have absorbed on the mineral surface and blocked the absorption of collector, and have the inhibitory effects on pentlandite.The study results of this paper have been revealed the relationship between the iron sulfide mineral crystal chemical characteristics and surface properties and the floatability, and enriched the iron sulfide mineral flotation crystal chemical theory system, which could provide guiding significance for flotation separation of iron sulfide minerals to some extent.