Alkali-activated aluminium-silicate composites as insulation materials for industrial application

Abstract

The article reports on the study of thermal stability of alkali-activated aluminium- silicate composites (ASC) at temperature 800 –1100°C. ASC were prepared by using calcined kaolinite clay, aluminium scrap recycling waste, lead-silicate glass waste and quartz sand. As alkali activator, commercial sodium silicate solution modified with an addition of sodium hydroxide was used. The obtained alkali activation solution had silica modulus M s =1.67. Components of aluminium scrap recycling waste (aluminium nitride (AlN) and iron sulphite (FeSO 3 )) react in the alkali media and create gases – ammonia and sulphur dioxide, which provide the porous structure of the material [1]. Changes in the chemical composition of ASC during heating were identified and quantitatively analysed by using DTA/TG, dimension changes during the heating process were determined by using HTOM, pore microstructure was examined by SEM, and mineralogical composition of ASC was determined by XRD. The density of ASC was measured in accordance with EN 1097 - 7. ASC with density around 560 kg/m 3 and heat resistance up to 1100°C with shrinkage less than 5% were obtained. The intended use of this material is the application a s an insulation material for industrial purposes at elevated temperatures.