Zirconia-based refractories are ceramics that serve as furnaces for the production of high-quality speciality glasses. These materials are obtained by cooling a melt composed of different oxides and oxide precursors. The microstructure of these refractories consists of monoclinic zirconia embedded in a three-dimensional interconnected amorphous phase. Using mesoscopic Monte Carlo simulations, the present paper addresses the effect of the amount of amorphous phase and temperature on the microstructure of the material. The simulated microstructures resemble those obtained using tomography experiments. A theoretical model describing the electrical behavior of the material as a function of temperature and composition is also reported. In this model, the conductivity of the ZrO2 particles is assumed to be constant, but the overall conductivity of the sample depends on its tortuosity s. Comparison with experimental data suggests that the present model provides a realistic picture of the electrical behavior of zirconia-based ceramics and leads to quantitative predictions.