酸碱回收对粉煤灰合成沸石性能的影响

Research of recycling of waste acid or alkali and its impacts on the properties of zeolites synthesized from fly ash

针对粉煤灰合成沸石合成成本较高及废酸碱外排污染环境的问题,对粉煤灰合成人工沸石工艺中废酸碱回收的可行性及其对合成沸石产品性能的影响进行了试验研究,研究设置3个废酸碱回收利用比例条件(1:1,2:1,3:1),其他合成条件与初始粉煤灰合成沸石完全相同.利用SEM、XRD、BET等技术对合成产品进行表征,结果表明回收酸合成沸石(WAC-ZFA)、回收碱合成沸石(WAL-ZFA)表面存在大量孔隙结构,XRD图谱也存在尖锐的沸石衍射峰,表征结果与粉煤灰合成沸石(ZFA)相似;在BET方面,与ZFA相比,WAC-ZFA有所下降,而WAL-ZFA明显增大;废碱回收比例对合成沸石除氨的效果影响不大,而废酸回收比例对合成沸石除氨的效果影响较明显,综合考虑,建议在实际生产中废酸回收比例宜≤1:1,废碱回收比例宜≤3:1.

In order to reduce the production cost and control the environmental pollution caused by waste acid and alkali discharge, the process experiments of waste acid and alkali recycling and the relevant impacts on the properties of zeolites synthesized from fly ash were carried out. Under the similar experimental conditions, three recycling ratio 1：1,2：1,3：1were tested The physical-chemical characteristics of products was analyzed through SEM, XRD and BET. The results show that waste acid-zeolites synthesized from fly ash （WAC-ZFA） and waste alkali-zeolites synthesized from fly ash （WAL-ZFA） has the similar physical-chemical properties of zeolites synthesized from fly ash （ZFA）, sharp diffraction peaks and a large number of pore structure characterization on the surface observed as well. Compared with ZFA, the BET of WAC-ZFA is slightly lowered, but WAL-ZFA increased obviously. The waste acid＆amp;alkali recycling ratio have different effects on the removal of ammonia. Based on these results, the recovery ratio of waste acid and alkali should be less than 1：1and 3：1 respectively.