23 research outputs found

    Thermodynamics of Portland Cement Clinkering

    Get PDF
    Acknowledgements The authors would like to thank Gulf Organization for Research and Development (GORD, Qatar) for funding.Postprin

    Production of belite calcium sulfoaluminate cement using sulfur as a fuel and as a source of clinker sulfur trioxide : pilot kiln trial

    Get PDF
    The authors gratefully acknowledge the financial support provided by the Gulf Organization for Research and Development (GORD), Qatar, through research grant number ENG016RGG11757. The authors would also like to acknowledge Thomas Matschei and Guanshu Li for the stimulating and fruitful discussions concerning the development of this work. The continuous support prior to, during and after the pilot kiln trial from Vadym Kuznietsov and the entire team at IBU-tec is also greatly appreciated.Peer reviewedPublisher PD

    Advances in clinkering technology of calcium sulfoaluminate cement

    Get PDF
    Acknowledgement The authors gratefully acknowledge the financial support provided by the Gulf Organisation for Research and Development (GORD), Qatar, through University of Aberdeen research grant number ENG016RGG11757. Funding Information: Gulf Organisation for Research and Development (GORD) (ENG016RGG11757)Peer reviewedPostprin

    Alite calcium sulfoaluminate cement: chemistry and thermodynamics

    Get PDF
    Calcium sulfoaluminate (CA)cementisabinderofincreasinginteresttothecementindustryandisundergoingrapiddevelopment.Currentformulationsdonotcontainalite;however,alitecalciumsulfoaluminate(aCA) cement is a binder of increasing interest to the cement industry and is undergoing rapid development. Current formulations do not contain alite; however, alite calcium sulfoaluminate (a-CA) cements can combine the favourable characteristics of Portland cement (PC) with those of CAcementwhilealsohavingalowercarbondioxidefootprintthanthecurrentgenerationofPCclinkers.ThispaperpresentstworesultsontheformationofaCA cement while also having a lower carbon dioxide footprint than the current generation of PC clinkers. This paper presents two results on the formation of a-CA clinkers. The first is a thermodynamic study demonstrating that the production of a-CAclinkerispossiblewithouttheuseofmineralisers,dopingwithforeignelements,orusingmultiplestagesofheating.ItisestablishedthataCA clinker is possible without the use of mineralisers, doping with foreign elements, or using multiple stages of heating. It is established that a-CA clinker can be readily produced in a standard process by controlling the oxygen and sulfur dioxide fugacity in the atmosphere. This allows for the stabilisation of ye’elimite to the higher temperatures required for alite stability. The second result establishes that when using fluorine to mineralise a-C$A clinker production, the iron content in the clinker is also an important variable. Although the exact mechanism of alite stabilisation is not known, it is shown that alite formation increases with the combination of calcium fluoride and iron (III) oxide in the mix

    Estimation of standard molar entropy of cement hydrates and clinker minerals

    Get PDF
    It is not straightforward to experimentally measure the standard molar entropy of cement hydrates or clinker minerals. This is further compounded by the controversies surrounding the entropy values reported in established thermodynamic datasets for cements. The purpose of this study is to assess the reliability of standard entropies compiled in those datasets. To this end, a simple but robust method is used in which the standard entropy of an inorganic solid is correlated to its formula unit volume via a linear equation. The results of this analysis show that the standard entropies and/or molar volumes (and in cases solubility products) of the following phases deserve closer scrutiny: meta-ettringite phases; magnesium/aluminium layered double hydroxide solid solutions; almost all iron-bearing monosulfate and hydrogarnet phases; and several calcium silicate hydrate solid solution end-members. In addition, this study reports the provisional estimates for the standard entropies of minerals ternesite and ye'elimite

    Enthalpy of formation of ye’elimite and ternesite

    Get PDF
    Calcium sulfoaluminate clinkers containing ye’elimite (Ca4Al6O12(SO4)) and ternesite (Ca5(SiO4)2SO4) are being widely investigated as components of calcium sulfoaluminate cement clinkers. These may become low energy replacements for Portland cement. Conditional thermodynamic data for ye’elimite and ternesite (enthalpy of formation) have been determined experimentally using a combination of techniques: isothermal conduction calorimetry, X-ray powder diffraction and thermogravimetric analysis. The enthalpies of formation of ye’elimite and ternesite at 25 °C were determined to be − 8523 and − 5993 kJ mol−1, respectively
    corecore