粉煤灰水热合成Y型沸石及其表征  

Synthesis and characterization of Y-type zeolite from coal fly ash by hydrothermal method

作　　者：王璐 王国栋[1] 李现龙[1] 刘勇[1] 

机构地区：[1]天津大学环境科学与工程学院,天津300072

出　　处：《环境工程学报》2018年第2期618-624,共7页Chinese Journal of Environmental Engineering

基　　金：国家自然科学基金资助项目(51478308);天津市自然科学基金资助项目(14JCYBJC23300)

摘　　要：针对固体废弃物粉煤灰的资源化利用问题,探索合成Y型沸石的实验方法。以燃煤锅炉产生的粉煤灰为实验对象,经过筛分、研磨、高温煅烧和酸浸等预处理方法来提高硅铝含量。将预处理后的粉煤灰加碱煅烧后与氢氧化钠水溶液混合,水热合成Y型沸石。结果表明:粉煤灰经过750℃煅烧1.5 h可以去除约15%的碳;用4 mol·L^(-1)的盐酸在90℃下处理2 h,粉煤灰中的铁、钙和硫等杂质可以分别减少约63.1%、87.3%和79.6%;粉煤灰预处理后的质量减少约51%;预处理后的粉煤灰经过加碱熔融处理,其中的石英和莫来石晶相物质被完全破坏,生成了新的晶相物质;当预处理粉末/碱的质量比为1∶1.2时,熔融产物经过水热反应(温度95~105℃、时间12~24 h)可以生成纯度良好、形貌规则的八面棱柱体Y型沸石;粉煤灰合成Y型沸石的BET等效比表面积可达389.44 m^2·g^(-1),孔容为0.348 mL·g^(-1),并具有优良的热稳定性。粉煤灰经过适当处理,可以在不外加硅、铝化学试剂以及模板剂情况下水热合成结晶度良好的Y型沸石。The experimental methods of synthesis of Y-type zeolite were studied in view of the utilization of solid waste of fly ash.The fly ash by coal fired boiler was used to improve the content of silicon and aluminum,after the pre-treatment methods such as screening,grinding,high temperature calcination and acid leaching.The fly ash,after the pre-treatment and alkali calcination,was mixed with Na OH aqueous solution to hydrothermally synthesize Y-type zeolite.The results show that about 15% of carbon in the fly ash can be removed after calcination at 750 ℃ for 1.5 h.By using 4 mol·L^-1 hydrochloric acid treatment for 2 h at 90 ℃,the impurities such as iron,calcium and sulfur in fly ash can be reduced by about 63.1%,87.3% and 79.6%,respectively.The mass of the fly ash was reduced by about 51% after pre-treatment.The pre-treated fly ash is treated by alkali melting,in which the crystalline phases of quartz and mullite are completely destroyed and a new crystalline phase is formed.When the mass ratio of the pre-treated powder/alkali is 1 ∶ 1.2,the molten product can be converted to an eight-side prismatic Y-type zeolite with good purity and regular morphology through hydrothermal reaction treatment（95 to 105 ℃,12 to 24 h）.The BET equivalent specific surface area of Y-type zeolite synthesized with fly ash can reach 389.44 m^2·g^-1,while pore volume can reach 0.348 mL·g^-1.And it has excellent thermal stability as well.Through this work,the Y-type zeolite with high crystallinity by hydrothermal synthesis without adding silicon,aluminum chemical reagents and templating agent can be synthesized if the fly ash is properly treated.

关 键 词：粉煤灰 资源化利用 预处理 水热反应 Y型沸石 

分 类 号：X705[环境科学与工程—环境工程]