Interaction of sodalite and cancrinite with NH4NO3 solution. First case of low-temperature synthesis of buddingtonite

Abstract

Hydroxyl sodalite and sulfate cancrinite were synthesized from fly ash from TPP Varna, Bulgaria. The interaction of the two feldspathoids with NH4NO3 solution at 90 °C was investigated. Because of the reaction, sodalite is dissolved and ammonium feldspar (buddingtonite) is formed, which is the first case of low-temperature synthesis of this mineral. The interaction of cancrinite with NH4NO3 induces ion exchange and the formation of cancrinite with composition (NH4)5.4Na3.6(NO3)1.45(SO4)0.25(OH)0.05[Al6Si6O24]·2H2O, suggesting potential for the use of this form as a slow-acting fertilizer.