Green Conversion of Coal Fly Ash into Soil Conditioner: Technological Principle and Process Development

White mud is residue discharged during the acid method in aluminum extraction process from coal fly ash, and this material harmful to environment. The implementation of an environmentally friendly valuable way use white a key factor restricting commercial application ash alumina technology. An analysis revealed following: (1) it was highly enriched SiO2 (70–80%) while concentrations acid-soluble elements, such as Na, Al, Fe, some hazardous heavy metals, including Pb Cr, were significantly lower than raw ash; (2) approximately 80% had relatively high reaction activity because foregoing Al-extraction treatment. Through ingenious green chemical process, complete conversion into silicon–calcium fertilizer (SCF) achieved under very mild conditions (approximately 100 °C atmospheric pressure). Waste liquor totally recycled, no secondary solid waste generated. SCF available silicon content (ASC) 35%, higher standard (20%). Converting them soil conditioners or ecological remediation materials with lowest possible energy consumption pollution may be most promising approach for future disposal aluminosilicate industrial wastes.