几种低分子量有机酸对石灰岩溶蚀作用的室内模拟试验  

SIMULATION EXPERIMENT ON LIMESTONE DISSOLUTION BY SOME LOW-MOLECULAR-WEIGHT ORGANIC ACIDS

作　　者：黄黎英[1] 曹建华[2] 何寻阳[3] 杨慧[2] 李小方[2] 申宏岗[2] 

机构地区：[1]广西师范大学生命科学学院,广西桂林541004 [2]国土资源部岩溶动力学重点实验室,广西桂林541004 [3]中国科学院亚热带农业生态研究所,湖南长沙410125

出　　处：《地球与环境》2006年第3期44-50,共7页Earth and Environment

基　　金：国家自然科学基金(40372116)

摘　　要：在室内进行了几种低分子量有机酸对石灰岩颗粒(粒径0.45～1mm)的溶蚀试验,同时用盐酸进行对比试验。结果表明:各有机酸对石灰岩颗粒溶蚀作用大小的顺序为:乳酸>乙酸>柠檬酸>甲酸>草酸>丙酮酸,同类型酸中如醇酸或羧酸中,酸性较弱的酸溶蚀力反而较大。这几种酸混合后对石灰岩颗粒的溶蚀作用并未比单个酸的作用强。乳酸、乙酸、柠檬酸的溶蚀力大于盐酸。不管是有机酸还是盐酸,溶蚀石灰岩后溶液中钙离子浓度都呈对数增长,且与溶液pH值呈极显著正相关(P<0.0001);草酸反应液中的钙离子浓度与电导值呈极显著负相关(P<0.0001),其他种类酸溶液钙离子浓度则与电导值呈极显著正相关;除乙酸外,其他酸溶液电导值在反应初始阶段稍微下降后迅速上升。有机酸对石灰岩的溶蚀能力不仅与溶液中的H+和有机配位体浓度有关,而且与酸的类型、酸的强弱及反应后形成的盐的溶解度有关。Simulation experiments were done at the lab on limestone dissolution by some low-molecular-weight organic acids. The experiment on limestone by hydrochloric acid was done for comparison. The effects of organic acids on the dissolution of limestone tend to decrease in the order： lactic acid 〉acetic acid 〉citric acid〉formic acid〉oxalic acid〉pyruvic acid. Among the same group of organic acid, such as alcohol acid or carboxylic acid, the lower the acidity of the acid, the stronger the effect on limestone. The effect of mixed solution composed of six kinds of organic acids with the same molarity was less stronger than that of a single organic acid. The effects of lactic acid, acetic acid and citric acid were stronger than those of hydrochloric acid. After limestone was dissolved by organic acid or hydrochloric acid, the concentrations of calcium ion in acid solutions showed a logarithm increase and had a remarkable positive correlation with pH, and a remarkable positive correlation with the electric conductivity of acid solution except in oxalic acid solution. The concentrations of calcium ion in oxalic acid solution had a remarkable negative correlation with the electric conductivity of solutions. The electric conductivity of acid solutions except that of acetic acid declined for a short time at the beginning of the experiment, then ascended till the reaction in solutions reached balance.

关 键 词：有机酸 石灰岩 溶蚀 模拟试验 

分 类 号：P599[天文地球—地球化学]