Recovery of silica‐rich precursor from sugarcane bagasse ash through thermochemical activation: Physicochemical characterization and hydrothermal evaluation

The valorization of sugarcane bagasse ash (SCBA) as a secondary silica resource was investigated using sequential thermochemical and hydrothermal treatments. SCBA was calcined at 500–800°C and subsequently treated with 1–3 M NaOH to identify suitable processing conditions within the investigated range. Structural, chemical, and morphological changes were characterized using XRD, XRF, FTIR, SEM/EDS, TEM, and particle‐size analysis. Calcination at 600°C followed by treatment with 2 M NaOH was selected for subsequent processing based on the combined experimental observations. Bulk XRF analysis showed an increase in SiO 2 content from 45.72 wt.% in raw SCBA to 63.00 wt.% in the selected precursor. Mass‐balance analysis showed a dry precursor yield of 41.80% and a SiO 2 recovery efficiency of 57.60%. Hydrothermal treatment produced a partially crystalline aluminosilicate material containing crystalline and amorphous fractions, although a specific zeolite framework could not be conclusively assigned. An exploratory machine‐learning analysis was additionally performed as a supporting assessment; however, the limited dataset did not provide reliable predictive capability. The results demonstrate laboratory‐scale recovery of a silica‐rich precursor from SCBA and provide a basis for further process development and quantitative scale‐up assessment.