Rapid-hardening and dimensionally stable calcium sulphoaluminate (CSA) cements, when compared with Portland cements, have very interesting properties and are also able to give a significant contribution to the sustainability of the cement manufacturing process, due to relatively low synthesis temperatures, reduced thermal input to the kiln and CO2 generation, easy grindability and utilization of solid industrial wastes in the technological cycle. By-products coming from a fluidized bed combustion (FBC) plant and a traditional coal-fired power station, both located in the industrial area of Sulcis-Sardinia (which also includes an aluminium plant based on the Bayer manufacturing process from commercial bauxite) were investigated as raw mix components for the synthesis of CSA cements. Mixtures containing limestone, bauxite as well as FBC bottom and/or fly ash (up to 22%), pulverized coal fly ash (up to 24%), flue gas desulphurization waste (up to 6%) were heated for two hours in a laboratory electric oven at temperatures ranging from 1200° to 1300°C. The conversion of reactants was generally complete and high selectivities towards the desired hydraulic phases (C4A3S and dicalcium silicate) were obtained, particularly at about 1250°C.
Use of Wastes Generated within Coal-Fired Power Stations for the Synthesis of Calcium Sulphoaluminate Cements
TELESCA, ANTONIO;MARROCCOLI, Milena;VALENTI, Gian Lorenzo
2008-01-01
Abstract
Rapid-hardening and dimensionally stable calcium sulphoaluminate (CSA) cements, when compared with Portland cements, have very interesting properties and are also able to give a significant contribution to the sustainability of the cement manufacturing process, due to relatively low synthesis temperatures, reduced thermal input to the kiln and CO2 generation, easy grindability and utilization of solid industrial wastes in the technological cycle. By-products coming from a fluidized bed combustion (FBC) plant and a traditional coal-fired power station, both located in the industrial area of Sulcis-Sardinia (which also includes an aluminium plant based on the Bayer manufacturing process from commercial bauxite) were investigated as raw mix components for the synthesis of CSA cements. Mixtures containing limestone, bauxite as well as FBC bottom and/or fly ash (up to 22%), pulverized coal fly ash (up to 24%), flue gas desulphurization waste (up to 6%) were heated for two hours in a laboratory electric oven at temperatures ranging from 1200° to 1300°C. The conversion of reactants was generally complete and high selectivities towards the desired hydraulic phases (C4A3S and dicalcium silicate) were obtained, particularly at about 1250°C.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
