Reaction kinetics of fluorite in flow systems and surface chemistry

• 作 者: 张荣华 胡书敏
• 机 构: Open Research Laboratory of Geochemical Kinetics, Institute of Mineral Deposits, Chinese Academy of
• 出 处: Science in China,Ser.D
• 发表日期: 1996年06期
• 关键词: dissolution kinetics attach react occupied adsorbed dissociation accumulated pac

The kinetic experiments of fluorite in water-HCl solution in an open-flow system at the temperatures ≤100℃ reveal that the variation of flow rate (U) can change the reaction rate orders from 0 to 2 or higher. In the far from equilibrium systems, the dissolution rates of fluorite in aqueous solutions have a zero order.The reaction rates are controlled by pH values of input solutions. In fact, the reaction rates are related to the concentrations of the active sites occupied by H+ on fluorite surface [SOH]. X-ray photospectroscopy observations on fluorite surface before and after reaction indicate that surface chemical processes control the reaction rates: Cl- cations attach on and enter into surface of fluorite besides H+ when fluorites react with HCl solutions, which affect the reaction rates.

The kinetic experiments of fluorite in water-HCl solution in an open-flow system at the temperatures <100 ° C reveal that the variation of flow rate (U) can change the reaction rate orders from 0 to 2 or higher. In the far from equilibrium systems, the dissolution rates of fluorite in aqueous solutions have a zero order. The reaction rates are controlled by pH values ​​of input solutions. In fact, the reaction rates are related to the concentrations of the active sites occupied by H + on fluorite surface [SOH X-ray photospectroscopy observations on fluorite surface before and after reaction indicate that surface chemical processes control the reaction rates: Cl-cations attach on and enter into surface of fluorite besides H + when fluorites react with HCl solutions, which affect the reaction rates.