软化-混凝预处理高矿化度矿井水的试验研究

Experimental Study on Pretreatment of High Salinity Mine Water by Soften-coagulate

高矿化度矿井水可回用,常采用膜技术脱盐,但运行过程中Ca^(2+)、Mg^(2+)造成的膜污染极大地影响了膜性能。开展矿井水预处理降低硬度及浊度,对减轻膜污染、提高出水水质、降低运行费用起着重要的作用。采用氧化钙-偏铝酸钠软化法耦合PAC(聚合氯化铝)混凝法降低矿井水的硬度及浊度,采用单因素试验考察了药剂投加量、反应时间、沉淀时间对去除效果的影响。试验结果表明,投加30 mg/L CaO、15 mg/L NaAlO_(2)及20 mg/L PAC,反应60 min,沉淀20 min的条件下,水样的总硬度为56.622 mg/L,总硬度去除率为46.10%,浊度去除率为88.86%,吨水药剂费用为2.4元。

Membrane technology has a good desalination effect in high mineralization mine water that can be reused,but the precipitation contamination caused by Ca~(2+)and Mg~(2+)during operation greatly affects the membrane performance.Pretreatment to reduce hardness and turbidity plays an important role in reducing membrane contamination,improving effluent quality and reducing operating costs.The calcium oxide-sodium metaaluminate softening method coupled with PAC (polyaluminum chloride) coagulation were selected to remove the hardness and turbidity of mine water,and the effects of chemical dosage,reaction time and precipitation time on the removal effect were investigated using single-factor experiments.The optimum conditions were:the dosage of CaO was 30 mg/L,the dosage of NaAlO_(2) was 15 mg/L,the dosage of PAC was 20 mg/L,the reaction was 60 min,and the precipitation time was 20 min.The total hardness content of the water sample at this time was 56.622 mg/L,with a total hardness removal rate of 46.10%and a turbidity removal rate of 88.86%.The cost of the chemical for the ton of water was 2.4 yuan.