Abstract:

With environmental issue being increasingly emphasized, anti-scaling methods without chemical additives gradually raises more concern over researchers. Some researchers consider magnetic treatment as a physical anti-scaling method that has the advantages of non-pollution and low cost. However, its effectiveness and mechanism in industrial applications still remain controversial. Wide range and narrow range magnetic treatment devices are newly designed, taking calcium carbonate crystal system as research object, to study the coupling relationship between magnetic treatment effect and the volume of treating water which are both closely related to industrial application. The results show that when the amount of treating water is small, magnetic treatment can promote the homogeneous nucleation of calcium carbonate, resulting in more crystal particles with smaller size and greater total deposition. In a certain speed range, magnetic treatment effect is enhanced with the increasing speed of rotating magnetic field.There is a clear coupling relationship between the rotating magnetic field and water volume:when the magnetic treatment conditions remained unchanged and the amount of water to be treated increased,magnetic treatment effect would be weakened; when the water volume treated remained unchanged and magnetic treatment condition strengthens, magnetic treatment effect would be enhanced. Stepwise magnetic treatment experiment with a part of solution which is going through magnetic treatment first and then gradually adding more can improve the removal rate of calcium carbonate in a large amount of water, and make the magnetic treatment effect more obvious. At the same time, the importance that matching water volume with magnetic field was illustrated.

Key words: rotating magnetic field, nucleation, crystallization, scaling, desalination, coupling relationship

摘要：

随着环保问题越来越得到重视，无化学药剂添加的阻垢方法也愈加引起研究者的关注。磁处理被一些研究者认为是一种无污染、低成本的物理防垢方法，但其在工业应用中的有效性和作用机制仍存在很大争议。以碳酸钙结晶体系为研究对象，新设计了磁场作用范围宽窄两种形式的磁处理装置，着重考察了与工业应用密切相关的处理水量与磁处理效果间的耦合关系。结果表明，当处理水量较小时，磁处理可促进碳酸钙的均相成核，使生成的晶体粒径变小数量增多，总沉积量增大，并且磁处理效果在一定转速范围内随旋转磁场转速的增加而增强。此外发现，旋转磁场与水量有明显的耦合关系：当磁处理条件不变而处理水量增大时，磁处理效果就会减弱；当处理水量一定而强化磁处理条件时，磁处理效果就会增强。先磁处理一部分溶液再逐步添加溶液进行的分步磁处理实验表明，该法可提高大水量条件下碳酸钙的去除率，使磁处理效果更为明显，同时表明了处理水量与磁场相匹配耦合的重要性。

关键词: 旋转磁场, 成核, 结晶, 结垢, 脱盐, 耦合关系