给水管道水泥砂浆衬里溶出物的安全性评价

Safety evaluation of leachate of cement mortar lining in water supply pipeline

为评价水泥砂浆衬里在水环境下金属溶出物的变化情况,考察了砂浆溶出物对饮用水安全性的影响。结果表明,在水泥砂浆与纯水体积比为1∶3且长期浸泡的条件下,砂浆存在微量金属元素Fe、Mn、Cu、Zn、Pb、As、Hg、Cr、Cd溶出现象;砂浆在流动自来水、纯水浸泡条件下,溶液的浊度、耗氧量以及Fe、Mn、Cu、Zn的增加量均远低于《生活饮用水输配水设备及防护材料的安全性评价标准》(GB/T 17219—1998)限值要求,且没有检测出Pb、Hg、As、Cr、Cd等元素;砂浆衬里表面物相为硅酸盐水化产物、Ca(OH)2、钙钒石和少量石膏,无新的物相产生;石灰石水泥和粉煤灰水泥砂浆溶出物使水的硬度增高,pH值增大的原因是砂浆表面的Ca(OH)2溶解所致;当自来水流量大于20 mL/min时,矿渣水泥和矿粉水泥砂浆衬里对水质没有影响。

In order to evaluate the variation of leaehate of cement mortar lining in water, the influence of mortar leachate on drinking water safety was investigated. The results indicated that there were absolute trace amounts for Fe, Mn, Cu, Zn, Pb, As, Hg, Cr, Cd in immersing water from cement mortar when the volume ratio of cement mortar and pure water was 1 ： 3. The relative increasing amounts for turbidity, oxygen consumption, Fe, Mn, Cu, Zn of solution were lower than the requirements for Standard for Safety Evaluation of Equipment and Protective Materials in Drinking Water System （ GB/T 17219 - 1998） under the condition of immersing tap water and pure water from cement mortar, and the elements of Pb, Hg, As, Cr, Cd were not detected. The cement mortar lining surface phase was silicate hydrates, calcium hydroxide, ettringite and gypsum. The reason was dissolved Ca（OH） 2 that increasing amount of hardness of water and pH were high than standard for limestone cement and fly ash cement mortar lining leaching. The mortar lining of slag cement and mineral powder cement had no influence on water quality when the flow of tap water was higher than 20 mL/min.