Influence of additions on the preparation of ye’elimite from natural phosphate
Loading...
Date
2025
Journal Title
Journal ISSN
Volume Title
Publisher
UNIVERSITE MOHAMED BOUDIAF - M’SILA
Abstract
Cement production is considered a fundamental element in the construction industry,
but it contributes significantly to environmental pollution, as it emits one ton of carbon dioxide
for every ton of cement produced, representing 5% of global carbon emissions. To address this
environmental challenge, scientists are researching the development of more environmentally
sustainable alternatives such as ye’elimite-based cement, which is characterized by low carbon
emissions and reduced need for limestone in the production process. In the research presented
in this thesis, we prepared multi-phase composites based on ye’elimite, using natural phosphate
(fluorapatite) from Djebel El Onk in Algeria as an alternative source of CaO instead of
limestone. This study also investigates the effect of oxide additives such as natural quartz and
magnesium oxide on the behavior and decomposition characteristics of fluorapatite.
The study examined the influence of varying SiO2 content (0-5.4 wt%) on the reactive sintering
of mixtures containing fluorapatite, bauxite, and gypsum. The resulting composites included
multiple phases such as calcium hexaluminate, fluorapatite, ye’elimite, and gehlenite.
Quantitative Rietveld analysis revealed that increased quartz content promoted gehlenite
formation over ye’elimite at 1300-1350 °C, while also significantly modifying the
microstructure-leading to the development of hexagonal and circular grains after heat treatment
at 1400 °C. In addition, we examined the effect of MgO on the decomposition of natural
fluorapatite during the synthesis of spinel-ye’elimite-based multiphase composites. Using
advanced analytical techniques (XRD, Rietveld method, SEM-EDS, FTIR, and TG/DTG), we
investigated the influence of temperature (1000-1500 °C) and MgO content (0-6 wt%) on phase
formation, including fluorapatite, ye’elimite, spinel, hibonite, beta-tricalcium phosphate, and
grossite. The results demonstrate that higher MgO content promotes spinel formation and
stabilizes ye’elimite at elevated temperatures.
Description
Keywords
Cement, Natural Phosphate, Fluorapatite, Calcium Sulfoaluminate, Ye’elimite, Rietveld Method.