锑的地球化学行为以及锑同位素研究进展

火山和成矿地质现象表明硼可以在含水流体和气体中运移，本文应用离子选择电极法测定水热气体中硼的溶解度，以揭示硼的气态迁移能力。使用氟硼酸盐选择电极，测定了经氟硼酸化的硼酸标准溶液和含硼气体凝结水的电位，当硼含量处于地质流体的主要范围内（0.52～524.50 mg/L）时，电极电位与硼浓度的对数呈现出灵敏度很高的能斯特线性关系，标准曲线具有很好的稳定性和重现性。本方法测定硼的检出限为0.13 mg/L，低于饮用水标准规定的硼含量限值，适用于测定水热气体中的硼含量。硼酸挥发实验显示，硼在150℃、0.37 MPa水蒸气中的含量可达0.65%～0.72%，与富硼火山喷气的硼含量相符，显示硼在高温水热条件下可在气相中显著迁移，且H₃BO₃气态分子是硼的主要迁移形式之一。矿床地质特征和实验表明，硼的气态迁移和电气石化与稀有金属型伟晶岩的形成和矿化以及某些热液-气成型Sn-W、Mo矿床和斑岩型Cu、Au矿床的形成密切相关。

Research Progress on Sb Geochemistry and Sb Isotopes

Antimony (Sb) has been widely used in products such as fire retardants, glass, rubber, paint, ceramics and semiconductors. It is found throughout igneous rocks but can be enriched in sedimentary rocks such as abysmal clays, shales and clastic rocks. Sb commonly occurs in magmatic sulfide deposits related to gabbroic rocks, sulfide deposits related to granitic rocks, clastic rocks and carbonate rocks hosted in stratified W-Sb-Hg deposits, and hydrothermal Pb-Zn deposits. The analytical method of high precision determination of Sb isotopes is now available. Samples are commonly digested with different types of acids, and Sb is separated and concentrated by cation exchange column combined with Thiol cotton fiber or both anion and cation exchange columns. Sb isotopes are determined by MC-ICP-MS coupled with hydride generation. The mass discrimination of equipment is commonly corrected by sample standard bracketing, using In and Sn internal standards. Different geological reservoirs have variable Sb isotope compositions (up to 18‱), with seawater of about 3.7‱, silicate rocks of 0.9‱ to 2.9‱, and sulfides (stibnite, sphalerite, pyrite, marcasite) of -1.9‱ to 16.9‱. Moreover, stibnites from different countries have different Sb isotope compositions. Glass from different places of production also shows different Sb isotope compositions. Sb isotopes will fractionate up to about 9‱ and 4‱ during oxide-reduction process (or sulfide precipitation) and inorganic absorption process, respectively. Therefore, Sb isotopes may serve as a geochemical tracer, which play an important role in indicating the source of ore-forming materials, portraying the ore-forming process and revealing the ore-forming mechanism. This isotope system can also be used to trace heavy metal pollution and can be used in archaeology.