Natural Fluorite from Órgiva Deposit (Spain). A Study of Its Pozzolanic and Mechanical Properties

• Published in: Crystals (Basel) 2021-11, Vol.11 (11), p.1367
• Main Authors: Martín, Domingo A., Costafreda, Jorge Luis, Estévez, Esteban, Presa, Leticia, Calvo, Alicia, Castedo, Ricardo, Sanjuán, Miguel Ángel, Parra, José Luis, Navarro, Rafael
• Format: Article
• Language: English
• Subjects: Cement; Compressive strength; Energy costs; Fluorite; Graphite; Laboratories; Mechanical properties; mechanical strength; Mineralogy; mortar; Mortars (material); Portland cements; pozzolan; Raman spectroscopy; reduction of CO2 emissions; Scanning electron microscopy; Spectrum analysis; X-ray diffraction
• ISSN: 2073-4352; 2073-4352
• DOI: 10.3390/cryst11111367

This work presents the results of the partial substitution of Portland cement (PC) by natural fluorite (NF) and calcined fluorite (CF) in mortars, at 10%, 25% and 40%. To meet these objectives, a sample of fluorite was initially studied by XRD, SEM and Raman Spectroscopy (RS). A chemical quality analysis (CQA) and a chemical pozzolanicity test (CPT) at 8 and 15 days were carried out in a second stage to establish the pozzolanic properties of the investigated sample. Finally, a mechanical compressive strength test (MCST) at 7, 28 and 90 days was carried out on specimens made up with PC/NF and PC/CF mixes, at a ratio of 10%, 25% and 40%. XRD, SEM and RS results indicated fluorite as the major mineralogical phase. The CPT and CQA showed an increase in the pozzolanicity of the samples from 8 to 15 days. The MCST showed an increase in compressive strength from 7 to 90 days for both PC/NF and PC/CF specimens. The results obtained establish that fluorite produces positive effects in the mortar and contributes to the gain of mechanical strength over time, being a suitable material for the manufacture of cements with pozzolanic addition with a reduction of CO2 emissions, and by reducing the energy costs of production.