One of the many environmentally friendly features of calcium sulfoaluminate (CSA) cements is represented by the possibility of using in their manufacturing process several industrial by-products as raw materials in place of limestone, bauxite and gypsum. As substitutes for the latter, (1) flue gas desulfurization gypsum, (2) fluorogypsum, (3) titanogypsum, (4) phosphogypsum, (5) light- and (6) heavy-fractions of fluidized bed combustion waste (fly ash and bottom ash, respectively) were experienced in this investigation. Seven CSA clinker-generating raw mixes, separately containing (together with limestone and bauxite) each of the six by-products and natural gypsum (as a reference term), were heated in a laboratory electric oven at temperatures ranging from 1150° to 1300°C. In terms of selectivity toward and C2S, optimum synthesis temperatures were 1250° and 1300°C. As far as ettringite-generating ability was concerned, all by-products showed a satisfactory behavior. The best results were obtained with cements derived from phosphogypsum- and titanogypsum-based raw mixtures.
Calcium sulfoaluminate cement from chemical gypsum
TELESCA, ANTONIO;CALABRESE, DANIELA;MARROCCOLI, Milena;PACE, MARIA LUCIA;VALENTI, Gian Lorenzo
2013-01-01
Abstract
One of the many environmentally friendly features of calcium sulfoaluminate (CSA) cements is represented by the possibility of using in their manufacturing process several industrial by-products as raw materials in place of limestone, bauxite and gypsum. As substitutes for the latter, (1) flue gas desulfurization gypsum, (2) fluorogypsum, (3) titanogypsum, (4) phosphogypsum, (5) light- and (6) heavy-fractions of fluidized bed combustion waste (fly ash and bottom ash, respectively) were experienced in this investigation. Seven CSA clinker-generating raw mixes, separately containing (together with limestone and bauxite) each of the six by-products and natural gypsum (as a reference term), were heated in a laboratory electric oven at temperatures ranging from 1150° to 1300°C. In terms of selectivity toward and C2S, optimum synthesis temperatures were 1250° and 1300°C. As far as ettringite-generating ability was concerned, all by-products showed a satisfactory behavior. The best results were obtained with cements derived from phosphogypsum- and titanogypsum-based raw mixtures.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
