地下水混合作用的碳酸钙溶解沉淀效应

以水溶液平衡化学模型为基础,使用实际地下水样的水质分析结果,对相对CaCO3处于未饱和、过饱和状态地下水的混合进行了模拟计算,发现两种天然地下水的混合,不但可以发生混合溶蚀作用,而且还可发生混合沉淀作用。混合溶蚀(沉淀)作用分为严格意义下的混合溶蚀(沉淀)类型和广义的混合溶蚀(沉淀)作用类型。实际中两种地下水的混合是产生溶蚀还是沉淀作用,取决于端元混合水样的化学成分。

Mixing Effects of Groundwater on CaCO3 Dissolution and Precipitation

The methods of aqueous speciation calculation,pH calculation as well as the calculation of solubility(precipitability) of CaCO3 in natural water were used to study the effects of mixing of groundwater on the dissolution(precipitation) of CaCO3.Mixing were made for three groups of natural groundwater,one is the mixing between unsaturated(with CaCO3) water,the second group is the mixing between supersaturated water,and the last group is the mixing of unsaturated water with supersaturated water.Results show that mixing of natural groundwater can not only lead to increase the dissolution of CaCO3,but also increase the precipitation of CaCO3 according to the composition of the groundwater.Both the mixing dissolution and mixing precipitation can be classified into two kinds,that is an increased mixing dissolution(precipitation) in strict sense and an increased mixing dissolution(precipitation) in broad sense.Furthermore,mixing of two kinds of groundwater can also lead to increase the dissolution of CaCO3 in certain mixing proportion and to increase the precipitation of CaCO3 in other mixing proportion.In practice,which kind of mixing effects will happen is mainly determined by the composition of end-member mixing water.