给水管网中金属离子化学稳定性分析

Analysis on Chemical Stability of Metal Ion in Water Distribution System

为防止给水管网结垢和腐蚀造成的危害,对北方某市给水管网中钙离子与碳酸盐系统、镁离子、铝离子和铁离子等的化学稳定问题进行了分析,发现钙离子与碳酸盐系统在温度<12℃时是稳定的,在温度>18℃时CaCO3 有沉淀的趋势;镁离子与铝离子是稳定的;铁离子是不稳定的,Fe(OH)3 有较强的沉淀趋势,是水质化学不稳定的主要原因。管垢的主要成分是铁,管网中的铁不稳定是由于管垢向水中释放铁引起的。在给水管网中铁的不稳定会引起用户水浊度的升高。

In order to prevent the hazard incurred by scaling and corrosion in water distribution system, analysis was made on the chemical stability of metal ion including calcium-carbonate system, magnesium ion, aluminium ion, and iron ion in distribution system in a northern city. It is found that calcium-carbonate system is stable at temperature lower than 12 ℃, while CaCO 3 precipitation tendency occurs at temperature higher than 18 ℃; magnesium and aluminium are stable; and iron is not stable with high Fe(OH) 3 precipitation tendency, which is the primary reason why water quality is chemically unstable. The main composition of the scale is iron, and iron unstable is due to the release of iron from scale in the distribution system. Iron unstable brings about increased turbidity in tap water.