Abstract

In this study, an olivine sample obtained as final tailing from a chromite enrichment plant was examined for its sintering properties and utilization potential as a refractory raw material. For this purpose, cylindrical specimens were first prepared and then sintered at the temperatures of 1300, 1400, 1450 and 1500 °C for 2 h in a laboratory furnace. Quality of the products was evaluated in terms of some physical and mechanical refractory specifications such as bulk density, water absorption, porosity, shrinkage and cold crushing strength. Furthermore, phase developments and microstructural changes due to the sintering were determined in detail with X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis, respectively. According to the experimental results, with increasing temperature, the bulk density and shrinkage values increased while the porosity and water absorption values decreased. Specifically, the bulk density and shrinkage values varied in the ranges of 2.33–2.60 g/cm3 and 1–5%, respectively. The porosity values of 24.10 and 15.68% were obtained after sintering at 1300 and 1500 °C, respectively. The cold crushing strengths slowly increased from 46.90 to 55.86 MPa after sintering between 1300 and 1450 °C. A sudden rise to 93.44 MPa was then observed at 1500 °C. Accordingly, the thermo-optical analysis indicates that the olivine exhibited a sintering point of 1478 °C and no softening up to 1500 °C. However, the formation of undesirable low-melting enstatite was detected by the XRD and SEM analysis which also specified the increasing amorphous phase and crystallizations of forsterite and spinels with rising temperature. Overall results have shown that the olivine sample used has a promising potential as a refractory raw material mainly due to its high MgO content, low loss on ignition (LOI) value and appropriate particle size.

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