Flue gas desulfurization gypsum and coal fly ash as basic components of prefabricated building materials

► Use of industrial by-products in the manufacture of prefabricated building materials. ► Study on hydrothermal reactions of flue gas desulfurization gypsum, fly ash and lime. ► Both ettringite and calcium silicate hydrate formed as useful binding products. ► Within the investigated ranges 55-85 °C and 2 h-7d, ettringite formed at a higher rate. ► Conversion toward binding products was highest at 70 °C and increased with curing time.