Influence of Fe_xO_y and Al₂O₃ Contents on the Thermal Stability of Iron Ore-Waste Fibers: Key Mechanisms and Control

Traditional rock wool fibres are susceptible to crystallization and pulverization. To mitigate this, glass fibres were produced from iron ore waste (IOW). When the ratio of Fe²⁺ and Fe³⁺ is 1:3 and the Al₂O₃ content is 10 wt.%, increasing the Fe_xO_y content enhances the thermal stability.At an Fe_xO_y content of 17-19% and an Al₂O₃ content of 10-13%, the glass transition temperature (Tg) peaked. Increasing the Fe_xO_y content from 10% to 20% enhanced the stability of Si-O and Al-O bonds and increased bridged oxygen, stabilizing the structure. Here, Fe²⁺ balances structural charges, while Fe³⁺ replaces some Al atoms in the network. When the Al₂O₃ content is 10-13% and the Fe_xO_y content is 17-19%, the thermal stability of the IOW rock glass reaches its optimal level. At 20% Fe_xO_y content, the structure becomes three-dimensional and cyclic, increasing polymerization. Consequently, incorporating Fe_xO_y alongside a 10% Al₂O₃ content improves thermal stability, supporting the development of high-stability rock wool from IOW. This approach also enhances the refractory properties of rock wool fibres within the Fe_xO_y-Al₂O₃-SiO₂-MgO-CaO system.