Mineralogical characteristics of siliceous potassic mineral fertilizers

Abstract

Siliceous potassic mineral fertilizer made from coal fly ash is a slow-release fertilizer for rice paddy that supplies Si and K to soil for a long time. In this study, I investigated the material characteristics of this fertilizer and found that it consists of kaliophilite (KAlSiO4), which forms by replacing glass particles derived from fly ash, and akermanite (Ca2MgSi2O7), which fills the spaces between the kaliophilite grains. It was also demonstrated that mineral formation occurs through solid phase reactions without melting. The dissolution of chemical components from this fertilizer in the soil begins with akermanite, while the release of K, Al, and Si from kaliophilite is relatively gradual and continues over a longer period.