Diffusion tests were performed with solid diffusants of iron oxides in porous silico-aluminous refractory castables in high temperature conditions. A non-destructive X-ray computer microtomography technique with digital 3D reconstruction (3DCT) was used for spatial monitoring the diffusion into the media. A particle tracking (PT) method was applied to predict diffusion through porous materials and to quantify its diffusive properties based on 3D images over time. The influence of temperature was examined ranging from 1100°C to 1300°C, at exposure time of 100h. High alumina-silicate refractory materials were used: M1 (non-doped). The high-density components (HDC) and Pores were extracted in the images from the cross-sections of the microtomography process and converted into monochromatic 8-bit image to quantify the concentration of the diffusants and pores.

The sequential junction of all microtomographic digital slices shows the diffusion concentration profile along the depth of the samples. There are approximately 350-400 digital microtomographic slices for each temperature (1100°C, 1200°C, 1250°C. 1275°C and 1300°C). Thus, this process provides the diffusion penetration profile (diffusivity) in the medium as a function of temperature and, therefore, a diffusional mathematical model.