Abstract:

The efficiencies of softening the deep wellwater having high hardness and low basicity with chemical drugs are compared. The softening efficiency of CaO is always negative. That of Na₂CO is only 49% - 60% when its excessiveness is 38% - 314%. That of NaPO₄ comes to 96.3% when its excessiveness is only 12%, but the deposition velocity is slower and the cost is higher. With the combination of CaO and Na₂CO, on condition that CaO dosage exceeds the theoretical dosage the softening results from three kinds of Na2CO3 dosages are different. When the Na₂CO dosage is less than the theoretical dosage,the Na₂CO dosage becomes the main factor in softening efficiency and the optimum efficiency is 67.4%. When Na₂CO dosage is near the theoretical dosage,the CaO dosage becomes the main factor in softening efficiency and the optimum efficiency is 78.9%. When the Na₂CO dosage is 12% excessive and the CaO dosage is at the optimum dosage of removing Ca²⁺, add a small amount of NaOH,and then, the best softening efficiency of 99% can be obtained.

Key words: high hardness and low basicity, deep wellwater, chemical softening

摘要：

针对一种高硬度低碱度深井水,比较了不同药剂的软化预处理效果。CaO除硬为负效应;Na2CO3除硬效率较低,投加过量38%￣314%时,总硬去除率为49%￣60%;Na3PO4除硬效率较高,过量12%的总硬去除率达96.3%,但沉淀速度较慢,成本较高。采用石灰-纯碱法,使CaO投加量>理论量,三种Na2CO3投加量下除硬效果不同。当Na2CO3投加量小于理论量时,Na2CO3用量是影响硬度去除的主要因素,总硬最佳去除率为67.4%;当Na2CO3用量接近理论量时,CaO用量是影响硬度去除的主要因素,总硬最佳去除率为78.9%;当Na2CO3过剩12%时,在钙硬去除率最大的CaO用量下,投加少量的NaOH,总硬去除率可达99%。

关键词: 高硬度低碱度, 深井水, 化学软化

CLC Number: 

• TU991.2