This study reports the kinetic experimental results of albite in water and inKCl solution at 22 MPa in the temperature range of 25 to 400 deg C. Kinetic experiments have beencarried out in an open flow-through reactio...This study reports the kinetic experimental results of albite in water and inKCl solution at 22 MPa in the temperature range of 25 to 400 deg C. Kinetic experiments have beencarried out in an open flow-through reaction system (packed bed reactor). Albite dissolution isalways incongruent in water at most temperatures, but becomes congruent at 300 deg C (close to thecritical point 374 deg C). At temperatures from 25 to 300 deg C, the incongruent dissolution ofalbite is reflected by the fact that sodium and aluminum are easily dissolved into water; from 300to 400 deg C it is reflected by silicon being more easily dissolved in water than Al and Na. Maximumalbite dissolution rates in the flow hydrothermal systems have been repeatedly observed at 300 degC, independent of flow rates. The kinetic experiments of albite dissolution in a KCl aqueoussolution (0.1 mol KCl) indicate that the dissolution rate of albite increases with increasingtemperature. Maximum silicon release rates of albite have been observed at 400 deg C, while maximumaluminum release rates of albite at 374 deg C. The reaction rates of albite also depend on thepotassium concentration in the aqueous solution. These results can be used to interpret themechanism for forming hydrothermal alteration. The kinetic experiments of mineral-aqueous solutionsinteractions in the hydrothermal system from 25 to 400 deg C and at 22 MPa indicate that theformation of the feldspar-mica-kaolinite zoning occurring in some ore deposits may depend not onlyon the mineral stability but also on the kinetics of feldspar hydration, which is affected by thewater property variation when crossing the critical point.展开更多
基金the financial support of GTB basicr esearch fund 9502215,20010302,DK2001022,the support of 2001DEA20023,2001DEA30041,G1999043212also the Nationa1 Natural Science Foundation of China Grant 4003011.
文摘This study reports the kinetic experimental results of albite in water and inKCl solution at 22 MPa in the temperature range of 25 to 400 deg C. Kinetic experiments have beencarried out in an open flow-through reaction system (packed bed reactor). Albite dissolution isalways incongruent in water at most temperatures, but becomes congruent at 300 deg C (close to thecritical point 374 deg C). At temperatures from 25 to 300 deg C, the incongruent dissolution ofalbite is reflected by the fact that sodium and aluminum are easily dissolved into water; from 300to 400 deg C it is reflected by silicon being more easily dissolved in water than Al and Na. Maximumalbite dissolution rates in the flow hydrothermal systems have been repeatedly observed at 300 degC, independent of flow rates. The kinetic experiments of albite dissolution in a KCl aqueoussolution (0.1 mol KCl) indicate that the dissolution rate of albite increases with increasingtemperature. Maximum silicon release rates of albite have been observed at 400 deg C, while maximumaluminum release rates of albite at 374 deg C. The reaction rates of albite also depend on thepotassium concentration in the aqueous solution. These results can be used to interpret themechanism for forming hydrothermal alteration. The kinetic experiments of mineral-aqueous solutionsinteractions in the hydrothermal system from 25 to 400 deg C and at 22 MPa indicate that theformation of the feldspar-mica-kaolinite zoning occurring in some ore deposits may depend not onlyon the mineral stability but also on the kinetics of feldspar hydration, which is affected by thewater property variation when crossing the critical point.
