SiC-based porous ceramic carriers for heat-conductive phase change materials through carbothermal reduction method

摘要

Iron tailings remain the environment-damaging waste from the iron ore, and high porosity porous ceramics are an attractive material to "turn waste into treasure." To improve the thermal conductivity, porous ceramics with high silicon carbide content have been prepared by carbothermal reduction sintering process using argillaceous fine-grained iron tailings with high silica content. The carbothermal reduction reaction mechanism and the components and properties of samples in sintering process are investigated. The results show that reaction components in the tailings are mainly SiO(2)and Fe(2)O(3)and liquid phase is generated rapidly between 1200 degrees C and 1300 degrees C, producing foaming effect and significantly improving the porosity. Moreover carbothermal reduction of SiO(2)occurs above 1300 degrees C. After sintering at 1600 degrees C for 2 hours, the apparent porosity and thermal conductivity of porous iron tailing ceramics are 81.1% and 0.58 W/(m center dot K), respectively. Compared with the ordinary porous iron tailing ceramics with the same porosity, the thermal conductivity of those herein is increased by 6.6 times. This study is instructive for the development of low-cost preparation technology of phase change material carriers.