Au在SiO2—HCl—H2O体系中200℃溶解度测定：硅化对金矿化的意义初探

实验标定了200℃时Au与SiO2间的络合反应：热力学计算表明，在具地质意义的物理化学条件下，AuH3SiO40的浓度远远高于AuCl2-,指出以硅络合对Au的活化迁移比氯重要得多。在含硫和硅的体系中，随着SiO2的增高，AuH3SiO40的作用将比Au（HS）2-更显重要。Au在SiO2水溶液中的溶解可表述为：SiO的沉淀是导致Au沉淀析出的有效机制，因此说明硅化与金矿化具有内在的联系。     

The Dynamical Model of Chemical Oscillaiton in CaF2—HCl—H2O Solid—Liquid Reaction System

Based on the physical chemistry principle ,this paper proposes that the surface adsorption catalytic mechanism of HF is the key to dissolving the oscillation of the CaF2-HCl-H2OL solid-liquid reaction system.Meanwhile the dynamical model of this system has been established in order to study its non-linear dynamical genesis.Although this mathematics model is based on CSTR reaction apparatus,it is applicable to the foliate flow reaction apparatus,too.     

Melt–Fluid and Fluid–Fluid Immiscibility in a Na2SO4–SiO2–H2O System and Implications for the Formation of Rare Earth Deposits

Liquid–liquid immiscibility has crucial influences on geological processes, such as magma degassing and formation of ore deposits. Sulfate, as an important component, associates with many kinds of deposits. Two types of immiscibility, including (i) fluid–melt immiscibility between an aqueous solution and a sulfate melt, and (ii) fluid–fluid immiscibility between two aqueous fluids with different sulfate concentrations, have been identified for sulfate–water systems. In this study, we investigated the immiscibility behaviors of a sulfate- and quartz-saturated Na2SO4–SiO2–H2O system at elevated temperature, to explore the phase relationships involving both types of immiscibility. The fluid–melt immiscibility appeared first when the Na2SO4–SiO2–H2O sample was heated to ~270°C, and then fluid–fluid immiscibility emerged while the sample was further heated to ~450°C. At this stage, the coexistence of one water-saturated sulfate melt and two aqueous fluids with distinct sulfate concentrations was observed. The three immiscible phases remain stable over a wide pressure–temperature range, and the appearance temperature of the fluid–fluid immiscibility increases with the increased pressure. Considering that sulfate components occur extensively in carbonatite-related deposits, the fluid–fluid immiscibility can result in significant sulfate fractionation and provides implications for understanding the formation of carbonatite-related rare earth deposits.