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From selective dissolution to crystal chemistry of brownmillerite in sulfate resisting cement
Author(s) -
Mériot Alexis,
Noirfontaine MarieNoëlle,
Courtial Mireille,
Izoret Laurent,
TusseauNenez Sandrine,
Labourel Mélanie,
Gauffinet Sandrine,
Dunstetter Frédéric
Publication year - 2023
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.18764
Subject(s) - brownmillerite , electron microprobe , dissolution , chemistry , sulfate , crystal chemistry , nuclear chemistry , inorganic chemistry , mineralogy , materials science , crystal structure , crystallography , perovskite (structure) , organic chemistry
Abstract The aim of this study is to extract brownmillerite from sulfate resisting Portland cement (SRPC) in order to determine its crystal chemistry and the effects of dissolution protocols. Brownmillerites (C 4 AF) from four SRPC were extracted and systematically studied by X‐ray diffraction (XRD), electron probe microanalysis (EPMA), and X‐ray fluorescence spectroscopy. Two extraction steps were used. The first is the salicylic acid/methanol (SAM) protocol that leaves a residue rich in ferrite, C 3 A and sulfates. Precipitated hydrated sulfate minerals are also observed for clinker with high molar SO 3 /Na 2 O eq ratio. The second, developed in this paper, uses acetic acid (AcA) extraction to dissolve C 3 A and sulfates. The Rietveld refinements showed that all brownmillerites of this study crystallize in Ibm2 space group. Two families of brownmillerite were identified by their aluminum content and cell parameters, related to the presence of C 3 A in the clinker. EPMA indicated that ferrites from SR0 and SR3 cements have Al/Fe ratios about 0.7 and 0.8–1.0, respectively. XRD allows to predict the (Al+Mg+Si)/Fe ratio in brownmillerite in good agreement with EPMA. The SAM protocol is the best way to study crystal chemistry of brownmillerite and the AcA protocol is recommended to dissolve sulfates and C 3 A for further reactivity studies.