柠檬酸对石灰岩溶蚀动力模拟及岩溶意义

SIMULATION EXPERIMENT ON DISSOLUTION OF CALCITE BY CITRIC AND ITS KARST IMPORTANCE

柠檬酸对未清洗的石灰岩颗粒 (直径 0 .15～ 0 .2 5 mm)的溶蚀模拟试验表明 ,石灰岩溶蚀释放的钙离子量呈对数式增加。随柠檬酸浓度 (10 mg/ l,5 0 mg/ l,10 0 mg/ l)的增加 ,溶液的初始 p H依次降低 ,而石灰岩颗粒溶出的钙离子依次升高 ,它们分别是去离子水溶出量的 1.77、4.2 5、5 .0 3倍。 10 0 mg/ l柠檬酸 ,10× 10 - 2atm CO2 和 5 0 mg/ l柠檬酸 + 5× 10 - 2 atm CO2 对石灰岩微颗粒的溶蚀释放的钙离子量大致相当。

The simulation experiment of calcite grains eroded by citric was carried out. The calcite was ground into grains with the diameter 0.15～0.25mm. Labile calcium in the soil and limestone powders on the interface of soil rock were taken into account, therefore, the fresh calcite grains were not washed. The concentrations of citric solutions were 10mg/l, 50mg/l, and 100mg/l respectively. The results showed that the amount of released calcium from calcite increased in logarithm. High contents of citric solution could result in more calcite dissolution.The amount of released calcium from the calcite in 10mg/l, 50mg/l, 100mg/l citric solutions was 1.77, 4.25, 5.03 times as much as that in deionized water respectively. The dissolution amount of 100mg/l citric was matched with those of 10×10 -2 atm CO 2 and 50mg/l citric+5×10 -2 atm CO 2. Consequently, organic acid is one of the important driving forces in karst dynamic systems.