Abstract
Alite–ye’elimite–ferrite (AYF) cement is a more sustainable alternative to Portland cement (PC) that may offer improved mechanical, rheological, and chemical performance. Using traditional raw materials and conventional clinker processing conditions, alite (C3S) and ye’elimite (C4A3$), the major phases in PC and calcium sulfoaluminate (CSA) cements, respectively, cannot be coproduced. The typical formation temperature in the kiln for alite is >1350°C, but ye’elimite normally breaks down above 1300°C. However, with careful composition control and in the presence of fluoride, alite can be mineralized and formed at lower temperatures, thus enabling the production of AYF clinkers in a single stage. In this study, the production of AYF cement clinkers with different chemical compositions is attempted at 1250°C. The sensitivity of the fluoride content is initially assessed with a fixed target clinker composition to determine the optimal requirements. The effect of altering the target ferrite (C4AF) and alite (C3S) contents is also assessed followed by the effect of altering the target C4AF and C4A3$ contents. It is shown that AYF clinkers can be produced in a single stage through the careful control of the fluoride content in the mix; however, the formation/persistence of belite and mayenite could not be avoided under the conditions tested. It is also shown that ∼10 wt% ferrite in the target composition provides sufficient AYF clinker burnability and the amount of fluoride needs to be controlled to avoid stabilization of mayenite.
Highlights
Concrete is the most used building material worldwide, and its production is rising due to population growth and urbanization
The calcium oxide (CaO) content of clinkers needs to be reduced to minimize the chemical CO2 required for clinkering, while the process energy needs to be minimized to reduce the CO2 emissions stemming from fossil fuel combustion
The target AYF composition was not achieved in any of the clinkers as the formation/persistence of belite and mayenite could not be avoided in the presence of sulfur, the belite phase is forming and appears to consume SiO2 and CaO that were targeted for the alite formation
Summary
Concrete is the most used building material worldwide, and its production is rising due to population growth and urbanization. The most used binder is Portland cement (PC), the production of which, due to large demand, is a major contributor to global CO2 emissions that are threatening human life on Earth. The majority of these emissions are from the calcination of limestone (mostly CaCO3) to obtain calcium oxide (CaO), which is a key ingredient in cement clinker production. The second major contributor is the burning of fossil fuels. The CaO content of clinkers needs to be reduced to minimize the chemical CO2 required for clinkering, while the process energy needs to be minimized to reduce the CO2 emissions stemming from fossil fuel combustion. Raw-material CO2 reduces when lower CaO-bearing phases are used in the order of C4A3$ < C4AF < C3A < C2S < C3S (Gartner, 2004; Barcelo et al, 2014)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
