Characterization of Argentine dolostones with potential application in the manufacture of refractory materials

Abstract

The chemical, mineralogical, mechanical, thermal and textural characterization of two samples of dolostones of Argentine origin has been carried out. In this work the samples were: rock fragments approximately 10 cm on a side, rock fragments approximately 1 cm on a side, powder <7200 μm (obtained from rock 1 cm by trituration) and powder <100 μm (obtained from powder <7200 μm by ball mill grinding). For the characterization of the rocks, analytical techniques were used. Particle size distributions were performed by sieving (for the samples <7200 μm) and laser granulometry (for the samples <100 μm) and the specific surface was determined by BET method. The chemical composition was determined by XRF technique. The mineralogical analysis was performed by XRD technique and complemented with Rietveld analysis for the quantification of the mineralogical phases. In addition, the FTIR technique was used to complement the previous spectroscopic technique. The pycnometric density was measured using kerosene as immersion liquid. The bulk density and porosity (open, close and total porosity) of the rocks were carried out on rock fragments 3 cm on a side, using Archimedes method employing kerosene as immersion liquid and complemented with the mercury porosimetry technique. The ceramic texture analysis was carried out by SEM. The mechanical strength to diametrical compression of the rocks was determined on cylindrical specimens, taking into account the ASTM D-3967-16 standard. Finally, the thermal behaviour of the rocks was carried out by thermogravimetric and differential thermal analysis (TGA/DTA); the setting was: 1300 °C in the air atmosphere. The loss on ignition (LOI) was calculated with four thermal techniques: ISO 10058:1992 standard, TGA technique, muffle test (ad hoc method), and a designed method. The results have shown that the rocks studied fall into the classification of “dolostones” with the majority constituent mineral being “dolomite”. The chemical profiles analysed and the content of impurities are within potential range for refractory application.