Method for synchronously realizing decontamination treatment and recycling of aluminum ash as well as admixture and mortar thereof

An admixture comprises aluminium dross 60-30 parts, +100 Mesh coal fly ash or other non-reactive Fine Solid Waste aggregate 10-30 parts, Ordinary Portland cement or other pozzolanic reactive aggregates 20-30 parts, Rapid sulfoaluminate cement 9 parts, Lightweight concrete admixture (BU-095 from Guangzhou BUICHEM) 1 part; wherein the total parts by weight are 100. A method of using the admixture comprises adding water with a pH above 7 in a ratio 33-50:100 water:admixture and mechanically stirring for 10-30 minutes, pouring into a mould and ensure it only occupies half the volume, and leave to expand. Seal and cure with water twice, aluminium nitride will react with water and produce ammonia, which will dissolve with water while fluorine will leach into the water. A mortar comprises admixture and mortar or sand in a ratio of 100:40-50.