Investigation of the Properties and Microstructure of Direct Bonded Dolomite Refractory with Fe۲O۳ -Cr۲O۳ nanoparticles: A Comparative Study

In this research, the properties and microstructure of direct bonded dolomite refractory (having) Iron oxide (Fe۲O۳) and Chrome oxide (Cr۲O۳) nanoparticles have been investigated. For this reason ۰, ۰.۵, ۱, ۱.۵, ۲, ۲.۵ and ۳ wt. % of Fe۲O۳ and Cr۲O۳ nanoparticles have been added to the composition. After forming the samples as cylinders (۵۰*۵۰ mm۲), they were fired in an electric furnace at ۱۶۵۰ °C for ۳ hr. The measured parameters were bulk density, apparent porosity, hydration resistance and cold crushing strength. Also, microstructural investigation and phase’s analysis of the selected samples was performed by scanning electron microscopy (SEM/EDX) and X-ray diffraction (XRD) devices; respectively. Results showed that the use of Cr۲O۳ nanoparticles lead to formation of CaCr۲O۴ and MgCr۲O۴ phases, which improved the sintering process of the samples thorough the solid state sintering mechanism. Also, the use of Fe۲O۳ nanoparticles leads to creating CaO.Fe۲O۳ (CF) and ۲CaO.Fe۲O۳ (C۲F) phases which improved the sintering process of the specimen thorough the liquid phase sintering mechanism. Also, it showed that Cr۲O۳ nanoparticles additive has a greater effect on improving the properties of direct bonded dolomite specimens compared to Fe۲O۳ nanoparticles additive.

Keywords:

Dolomite , Refractory , Fe۲O۳ , Cr۲O۳ , nanoparticles