The effect of activators on the dissolution characteristics and occurrence state of aluminum of alkali-activated metakaolin

•The effect of different activators on the dissolution characteristics of aluminum in metakaolin (MK) is discussed.•The distribution and occurrence state of aluminum in hydration products strongly depend on the type of activators.•The sulfate accelerates the dissolution of Al ions from MK.•In MK-CH system, the formation of stratlingite is more favored than that of C-A-S-H.