CaCO_3软垢的成因

Study on Soft Scale Mechanism of CaCO_3

依据实验观察和理论计算分析,研究了添加化学阻垢剂使水垢软化的物理机理.实验研究表明:方解石晶粒聚集时形成坚实的硬垢,球霰石聚集时形成松软的软垢;根据球霰石聚集形成的垢体结构,首次提出了球霰石间的聚集是软垢形成的主要机制.实验观察表明:添加阻垢剂有效地抑制了方解石晶核的生成几率,从而提升了球霰石在析出物中所占的比例,因而促成了水垢的软化.分子模拟研究和结构分析揭示,阻垢剂只能有效地抑制具有层状生长机制的晶面,即F平面的生长,而不能有效地抑止K晶面的生长,这为阻垢剂促成球霰石生成几率提高提供了理论根据.

The physical mechanism for inhibitor to make scale soft is studied on the basis of experimental observation and theoretical computation analysis. Experimental results show that calcites aggregate to form hard scale, and vaterites aggregate to form soft scale. Based on scale structure of vaterite aggregation, this paper proposes for the first time that aggregation between vaterites is the main mechanism of soft scale. Experimental observation also shows that inhibitor greatly blocks the possibility of calcite precipitating from solutions, thus increasing proportion of vaterite to precipitate and causing soft scale to occur. Based on the molecular modeling computation and crystal structure analysis, it was revealed that the inhibitor does not block the growth of kinked faces（K-faces）, but the growth of flat flaces （F-faces）, providing theoretical explanation for the phenominon that the inhibitor increases the proportion of vaterite precipitating from solutions.