磷矿石中白云石晶体化学特性研究

选取贵州两个典型磷矿区中具有代表性的海相沉积型磷矿石中的白云石纯矿物, 对其进行晶体化学特性研究, 从而为有效分选白云石和胶磷矿的浮选工艺提供理论指导。采用化学分析和X射线衍射分析分别对两种白云石纯矿物进行测试, 并应用价键理论对白云石矿物结构中的化学键特征进行计算, 在此基础上对白云石矿物解离后表面特性及可浮性进行了推测, 结果表明: 白云石矿物解离后表面必定暴露大量的Ca²⁺、Mg²⁺离子, 而C⁴⁺暴露较少, 在水溶液中零电点相对较高, 负电性相对较弱, 表面存在大量的金属阳离子, 表明其在阴离子捕收剂浮选体系中可浮性较好, 当溶液酸性减弱、碱性增强时, 白云石表面带负电, 此时用阳离子捕收剂浮选时可浮性较好。

Study on Crystal Chemistry Characteristics of Dolomite in Phosphate Ores

Pure dolomite samples selected from representative marine sedimentary phosphate ores in two different typical phosphorus mining areas in Guizhou were used to study chemical crystal properties of dolomite so as to provide theoretical guidance for the flotation process for effective separating dolomite from collophane. Chemical analysis and X-ray diffraction(XRD) analysis were adopted to investigate the two pure dolomite samples. The chemical bonding features of the crystal structure of the dolomite samples were calculated using valence-bond theory. The surface properties and floatability of the liberated dolomite minerals were speculated based on these data. The results showed that a large number of Ca²⁺、Mg²⁺ and relatively less C⁴⁺ were exposed at the surface of dolomite after dissociation. In the aqueous solution the point of zero charge (PZC) was relative higher and the electronegativity relatively weaker. The presence of a large amount of metal cations at the surface indicated that they got better floatability in anion collector floatation system. As the pH value of the solvent increased, the surface of the dolomite bore a negative charge and using a cation collector could bring a good floatability.