A comparative study on lightweight and dense periclase-magnesium aluminate spinel refractories from industrial preparation

Lightweight design and preparation of refractories can promote the energy saving and emissions reduction for the working linings of high temperature furnaces. In this work, two lightweight periclase-magnesium aluminate spinel refractories were prepared by using microporous aggregates under the industrial production condition and compared with commercial dense refractories. The effects of the microporous aggregates and compaction pressure on their microstructures and properties were studied. A comparison of the results indicates that the flexural strengths of the lightweight specimens were enhanced from 3.7 MPa to 6.8 MPa, and the thermal conductivities were reduced significantly, better microporous aggregate/matrix interface structures were formed in the lightweight specimens due to the pore structures in microporous aggregates. Meanwhile, increasing compaction pressure from 120 MPa to 160 MPa negatively affected the thermal shock resistance and refractoriness under load of the lightweight specimens. In summary, the lightweight specimen made using a compaction pressure of 120 MPa exhibited higher strength, excellent thermal shock resistance, lower thermal conductivity(3.47 W/m center dot K at 1200 degrees C) and high refractoriness under load (1661 degrees C), which can meet the requirements for the upper transition zone and burning zone of cement rotary kilns. (c) 2023 Elsevier B.V. All rights reserved.