Synthesis of Zeolites from Fly Ash by Microwave Assisted Hydrothermal Alkaline Activation
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摘要: 着重选用NaOH水溶液为反应前驱物, 通过改变反应温度、NaOH浓度与合成时间等参数, 在水热条件下利用微波加热直接对粉煤灰进行晶化, 合成得到了浊沸石、菱沸石、NaP1沸石3种沸石.粉煤灰转化为沸石率约15%~40%.研究表明: (1) 反应体系在15min左右即有合成沸石产生, 30min左右合成沸石转化率达到最佳; (2) 为保证沸石晶核生成和晶体的生长, 反应体系的溶液/粉煤灰比不应低于2.5; (3) 在溶液/粉煤灰比为2.5时, 应控制加热时间在30min左右.Abstract: NaOH water solution is chosen as an original reactant by changing the parameters such as activation temperature, thickness of NaOH water solution and synthesis time. In addition, the fly ash can be heated up and directly crystallized, on the condition of hydrothermal alkaline activation, by using microwave. As a result, three kinds of zeolites are synthesized: laumontite, chabazite and NaP1 zeolites. The ratio of translating fly ash into zeolites is 15%-40%. The research shows the following three results: (1) zeolites can be synthesized for about 15 min, and the best ratio of translating fly ash into zeolites can be achieved for about 30 min. (2) In order to pretest the formation of crystalline nucleus and the growth of crystallize, the ratio of solution and fly ash should be more than 2.5. (3) The heating time should be controlled for about 30 min with the ratio of solution and fly ash 2.5.
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Key words:
- fly ash /
- hydrothermal alkaline activation /
- microwave assisted /
- synthesis of zeolites.
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图 1 利用微波加热从粉煤灰合成沸石实验反应体系温度随时间的变化
Fig. 1. Change of reaction system temperature with heating time of synthesis of zeolites from fly ash by microwave assisted hydrothermal alkaline activation
图 2 利用微波加热水温随时间的变化
Fig. 2. Change of water temperature with heating time by microwave assisted
表 1 粉煤灰的化学组分
Table 1. Chemical composition of fly ash used in this experiment
表 2 第1组与第2组的实验参数与实验结果
Table 2. Experiment parameters and results of groups 1 and 2
表 3 第3组与第4组的实验参数与实验结果
Table 3. Experiment parameters and results of groups 3 and 4
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