27Al NMR Study on the Interaction between Aluminate and Silicate Ions in Alkaline Solution

Abstract

Abstract An interaction between aluminate and silicate ions in highly alkaline solution was investigated by a high-resolution 27Al NMR study. The interaction greatly varied with alkali concentration, and did not occur at 1.0 mol dm−3 NaOH. At 0.10 mol dm−3 NaOH, the formation of a monomeric species with an ≡Al–O–Si≡ bond (Si/Al=1) was suggested and the formation constant was estimated to be 22.8 dm3 mol−1. At 0.015 mol dm−3 NaOH, polynuclear species with ≡Al–O–Si≡ bond was expected to be formed.