Development of novel refractory ceramic continuous fibers of fly ash and comparison of mechanical properties with those of E-glass fibers using the Weibull distribution

This study aimed to develop manufacturing technology for high-strength refractory ceramic fibers (RCFs) using fly ash, which is a highly promising material for the exterior and thermal insulation industry. The technology also contributes to reducing the environmental pollution caused by landfilling fly ash after coal is burned. Fly ash discharged from a thermal power plant, which had aluminosilicate chemical compositions, was used as the main material. As auxiliary materials, basalt, anorthite, feldspar, dolomite, and calcite were used to adjust the melt flowability, and frit, silica sand, and burr stone were used to lower the melting temperature. Moreover, the development of aluminosilicate fly ash fiber has the advantages of lower cost for raw materials and processing. Fly ash and natural rocks are inexpensive, and most of all, unlike the case for glass fiber production, the high cost of B2O3 is not a necessary expense. Fly ash is retrieved in powder form, which is advantageous compared to the starting materials for glass; the grinding process of raw materials can be skipped. From the fibrilization index calculation, we showed that the spinnability was influenced by the chemical composition of the salt-forming oxides in the fly ash compounds. We also found a correlation between the winding speed and the fiber diameter. The mechanical properties of a series of fly ash fibers were assessed by the Weibull distribution and then compared with those of the E-glass fibers that were melt-spun under an analogous condition.