开放系统中CaCO_3的溶解与沉淀对水溶液的成分及其性质的影响

THE EFFECTS OF DISSOLUTION AND PRECIPITATION OF CaCO_3 ON THE COMPOSITIONS AND PROPERTIES OF WATER IN AN OPEN SYSTEM

作者在对开放系统条件下ＣａＣＯ_３溶解与沉淀过程中水样的ｐＨ值及溶液中各组份存在形式含量的变化情况进行计算的基础上，讨论了天然水中阴阳离子间的络合作用对水溶液的成分及矿物饱和指标计算结果的影响，分析了ＣａＣＯ_３的溶解与沉淀对水溶液的成分及其性质的影响。

On the basis of a brief introduction of calculation method of pH values and equilibrumdistribution of species for natural water,in this paper,the authors calculated the concentra-tion percentages of species in total concentration of corresponding constituents for 4 watersamples.The changes of water compositions and their properties with the dissolution andprecipitation of CaCO_3 were also calculated.According to all these calculation results,theauthors discussed the effects of complexation of cations and anions in natural water on thewater compositions and the calculated results of saturation indices of calcite.The effects ofdissolution and precipitation of CaCO_3 on the water compositions and their properties werealso discussed and analyzed.In the end,the authors got the following conclusions.(1)Com-plexation makes the concentrations of free ions in natural water decline,its effects on the cal-culated results of saturation indices of calcite can not be neglected.(2)In an open system,with the dissolution of CaCO_3,the pH values of the solution will increaes and the CO_2 willdissolve;whereas with the precipitation of CaCO_3,the pH values of the solution will de-crease and CO_2 will escape from the solution.