Data from: Synthesis of zeolites Na-A and Na-X from tablet compressed and calcinated coal fly ash

Zeolites Na-A and Na-X are important synthetic zeolites widely used for separation and adsorption in industry. It is of great significance to develop energy-efficient routines that can synthesize zeolite Na-A and Na-X from low-cost raw materials. Coal fly ash (CFA) is major remaining from combustion of coal and biomass containing more than 85 % SiO2 and Al2O3, readily to replace the conventionally used sodium silicate and aluminate for zeolite synthesis. We used Na2CO3 to replace the expensive NaOH used for the calcination of CFA and showed that tablet compression can enhance the contact with Na2CO3 for the activation of CFA through calcination for synthesis of zeolites Na-A and Na-X under mild conditions. We optimized the control variables for zeolite synthesis and showed that phase-pure zeolite Na-A can be synthesized with CFA at reactant molar ratio, hydrothermal reaction temperature and reaction time of 1.3Na2O: 0.6Al2O3: 1SiO2: 38H2O at 80 oC for 6 h, respectively, while phase-pure zeolite Na-X can be synthesized at 2.2Na2O: 0.2Al2O3: 1SiO2: 88H2O at 100 oC for 8 h, respectively. The composition, morphology, specific surface area, vibration spectrum and thermogravimetry of synthesized Na-A and Na-X were further characterized.Na-A型与Na-X型沸石是重要的合成沸石，广泛应用于工业分离与吸附领域。开发以低成本原料合成Na-A型与Na-X型沸石的节能工艺，具有重要的研究价值与应用意义。粉煤灰（coal fly ash, CFA）是煤炭与生物质燃烧后的主要残渣，其二氧化硅（SiO₂）与氧化铝（Al₂O₃）总含量超过85%，可直接替代传统沸石合成所用的硅酸钠与铝酸钠原料。本研究采用碳酸钠（Na₂CO₃）替代价格高昂的氢氧化钠（NaOH）用于粉煤灰焙烧预处理，并发现压片工艺可增强碳酸钠与粉煤灰的接触效果，从而在温和条件下通过焙烧活化粉煤灰，用于合成Na-A型与Na-X型沸石。本研究优化了沸石合成的调控变量，结果表明：以粉煤灰为原料，当反应物摩尔比为1.3Na₂O:0.6Al₂O₃:1SiO₂:38H₂O、水热反应温度为80℃、反应时长6小时时，可合成纯相Na-A型沸石；而当反应物摩尔比为2.2Na₂O:0.2Al₂O₃:1SiO₂:88H₂O、水热反应温度为100℃、反应时长8小时时，可合成纯相Na-X型沸石。研究人员进一步对合成得到的Na-A型与Na-X型沸石的组成、形貌、比表面积、振动光谱及热重特性进行了表征。