Conversion of lignite fly ash into synthetic zeolite by hydrothermal, fusion‐hydrothermal and hydrothermal ‐sonochemical processes

Abstract The purpose of this study was the conversion calcareous lignite fly ash (LFA) into synthetic zeolite by hydrothermal, fusion‐hydrothermal and hydrothermal ‐sonochemical processes. Experiments were carried out using raw washed (5 N HCl) ash. Initially, fractional factorial experimental design used to plan experiments assess process parameters such as solid liquid ratio (S/L), silica aluminum oxide (SiO 2 /Al O 3 ), calcium content (% CaO), time temperature process. optimized conditions then applied a two‐stage process, while influence sonication on efficiency tested before after Mineralogical analysis performed X‐ray diffractometer (XRD) detect formation. Further characterization conducted fluorescence (XRF), specific surface area laser particle efficiency. results indicated formation four types crystals. LFA yielded maximum yield, when it hydrothermally treated for 6 h at 150 o C, S/L=1:2, SiO =6.3. In conditions, phillipsite synthesized 27%. yield improved 32% followed 30 min At same processing use produced 72% crystalline tobermorite. hydrothermal‐late can effectively convert waste valuable products. This article is protected copyright. All rights reserved.