粉煤灰提取液的絮凝效应

为了回收利用粉煤灰，采用盐酸浸提法制备粉煤灰提取液（CFAL）用作絮凝剂。通过单因素实验优化CFAL的制备条件，并在高岭土模拟体系内研究CFAL的絮凝效应。研究在不同CFAL投加量下浊度的去除率，确定最佳的投加剂量及在此剂量下絮体的大小与沉降性能。对原浊度为100 NTU的高岭土悬浊液，当CFAL为0.44 mg·L-1（以Al的含量计）时，浊度去除率达到90%以上。在同等剂量下，聚合氯化铝（PAC）和氯化铝（AlCl3）的浊度去除率均低于CFAL，分别为78.7%和79.2%。CFAL的絮体大小约为400 μm，沉降较快，在20 min后，去除率达到90%以上；PAC和AlCl3的絮体分别为260和330 μm，分别沉降60和40 min后，去除率稳定在80%左右。在实验剂量范围内，CFAL絮凝后对高岭土悬浊液的pH不会造成明显影响，且余铝满足《生活饮用水卫生标准》（GB 5749-2006），CFAL是一种廉价、高效、安全的混凝剂。

Flocculation effects of coal fly ash leachate

To investigate a method for reusing coal fly ash (CFA),hydrochloric acid was used to leach the CFA to prepare coal fly ash leachate (CFAL) as an effective flocculant.The leaching protocol was optimized via single-factor experiments.The dosage effect of CFAL on turbidity removal in a kaolin suspension was studied.When CFAL was 0.44 mg·L-1 (in terms of Al concentration),the turbidity removal of kaolin was over 90%,which was higher than that of PAC and AlCl3 at the same dosage.The flocs of CFAL were approximately 400 μm in size and larger than those created with PAC and AlCl3.The sedimentation of the flocs formed by CFAL was faster and achieved a removal rate of 90% in 20 min.In contrast,the removal rates of PAC and AlCl3 reached approximately 80% in 60 and 40 min,respectively.CFAL did not significantly affect the pH before or after flocculation,and the Al residuals did not exceed the Chinese drinking water standard (GB 5749-2006).CFAL was an effective,cheap,and safe flocculant.