Reprocessing of coal fly ash through desilication and dealumination methods for the synthesis of silica and alumina nanoparticles

This research discusses the extraction of Si and al through various methods for the synthesis of silica and alumina nanoparticles. To extract Si from CFA, three methods were employed: (1) NaOH leaching, (2) H₂SO₄ leaching followed by NaOH leaching and (3) Thermochemical treatment of CFA followed by NaOH leaching. In order to remove Al from the coal fly ash, four methods were employed: (1) H₂SO₄ leaching, (2) NaOH leaching followed by H₂SO⁴ leaching, (3) Thermochemical treatment and (4) NaOH leaching followed by thermochemical treatment.

After Si and Al extraction, sodium silicate and aluminium sulphate solutions were formed, from which silica and alumina nanoparticles were produced, respectively.