ABSTRACT

The zeolitisation of fly ash originating from hard coal combustion in a Polish power plant was conducted using the alkaline hydrothermal method with and without the application of ultrasound. The output ash primarily contained glass, mullite, quartz and hematite, and its dominant chemical components included SiO₂ (over 50 wt.%) and Al₂O₃ (over 28 wt.%). The synthesis of two zeolitic materials was conducted under the following conditions: 3 M NaOH solution, synthesis time – 8 hours, temperature – 80°C. For one of the syntheses, ultrasound with a frequency of 40 kHz and power of 480 W was applied for the first two hours. The identification of mineral components of initial ash and post-synthesis products was conducted using following methods: X-ray diffraction, X-ray energy dispersive spectroscopy, scanning electron microscopy, differential thermal analysis and thermogravimetric analysis. The obtained zeolitic materials varied greatly in phase composition. The product phase composition for the non-ultrasound-assisted synthesis was practically identical to the initial fly ash (mullite, quartz and hematite). The glass underwent minor chemical metamorphosis, recognizable by the presence of new phases in small quantities, typically mutually interlayered, mostly in the form of thin incrustation on the ash grains. The phases included: hydrosodalite, NaP-type zeolite, LTA-type zeolite and A-type zeolite. These phases, where Na⁺ cations should be dominant, contained K⁺, Ca²⁺ and Mg²⁺ cation substitutions. The zeolitic material obtained with the application of ultrasound, apart from initial fly ash phase residues, contained new phases in significant quantities, such as hydrosodalite and NaP-type zeolite, and A-type zeolite in smaller quantities.

摘要

使用碱性水热法对波兰发电厂产生的硬煤燃烧产生的飞灰进行沸石化，其中应用和不应用超声波。输出的灰分主要包含玻璃、莫来石、石英和赤铁矿，其主要化学成分包括SiO ₂ (超过50 wt.%)和Al ₂ O ₃（超过 28 wt.%）。两种沸石材料的合成在以下条件下进行：3 M NaOH 溶液，合成时间 – 8 小时，温度 – 80°C。对于其中一种合成，前两个小时应用了频率为 40 kHz、功率为 480 W 的超声波。使用以下方法对初始灰分和合成后产物的矿物成分进行鉴定：X 射线衍射、X 射线能量色散光谱、扫描电子显微镜、差热分析和热重分析。所得沸石材料的相组成变化很大。非超声辅助合成的产物相组成实际上与初始飞灰（莫来石、石英和赤铁矿）相同。玻璃经历了轻微的化学变态，可以通过少量新相的存在来识别，通常相互夹层，主要以灰粒上的薄壳形式存在。相包括：水方钠石、NaP型沸石、LTA型沸石和A型沸石。这些阶段，其中 Na⁺阳离子应占主导地位，包含 K ⁺、Ca ²⁺和 Mg ²⁺阳离子取代。通过应用超声获得的沸石材料，除了初始飞灰相残留物外，还含有大量的新相，例如水方钠石和NaP型沸石，以及少量的A型沸石。