X-ray tomography of refractory bricks

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Kemian tekniikan korkeakoulu | Master's thesis
Degree programme
Master's Programme in Chemical, Biochemical and Materials Engineering
This thesis explores the application of X-ray tomography (XRT) combined with image analysis software to locate and quantify the porosity and metal content of refractory brick samples obtained from converter s. The versatile approach of XRT and PerGeos software assists in obtaining 2D and 3D representations of bricks different phases. The aim is to visualize and quantify the distribution of porosity and metal content within the brick samples and to extract valuable insights from the results. The experimental setup involved drilling tubular brick samples with a carefully chosen diameter and placing them in an acrylic glass tube for subsequent XRT analysis. The XRT machine was configured with specific parameters such as voltage, current, resolution, and filter, to obtain high-quality images with minimal artifacts. The software approach, especially the threshold limit selection, played a crucial role in accurately segmenting porosity and metal phases in the obtained images. The analysis of the brick samples using PerGeos software showcased impressive precision in phase separation. The results indicated that metal content was significantly higher at the hot end of the samples, while the cold end exhibited lower metal penetration. Furthermore, the positioning of the refractory brick within the converter also impacted the eventual penetration of molten metal and mate. The software analysis provided precise data on the volume fraction change with each slice of the image for each sample, which complemented with the observations from 3D image analysis. Furthermore, PerGeos enabled the identification and characterization of closed and interconnected pores, aiding in the comprehensive evaluation of the samples porosity. However, the study also encounters limitations, including operator dependency during phase selection and the trade-off between image resolution and file size. Beam hardening artifacts in some samples posed hurdles, but the software and accurate machine input helped mitigate this impact.
Jokilaakso, Ari
Thesis advisor
Pankka, Iida
Kleemola, Lotta
x-ray tomography, porosity, metal content, computed tomography, software analysis
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