Adjusting the melting and crystallization behaviors of ferronickel slag via partially replacing of SiO₂ by B₂O₃ for mineral wool production

Utilization of ferronickel slag as a raw material for mineral wool production not only conserves natural resources, but also achieves the sustainable development for the ferronickel industry. In order to utilize the ferronickel slag more efficiently, the melting and crystallization behaviors of the slag with the partial replacement of SiO₂ by B₂O₃ were investigated in this paper. The results show that the initial and complete melting temperatures decreased with B₂O₃ substitution for SiO₂, which indicates that the addition of B₂O₃ can reduce the energy consumption during the melting process. The incubation time of the slag in the Time Temperature Transformation (TTT) diagram increased, whereas the initial crystallization temperature in the Continuous Cooling Transformation (CCT) diagram decreased when SiO₂ was substituted by B₂O₃. In addition, the main crystalline phases precipitated in the slags were columnar MgSiO₃ and Mg₂SiO₄. The weakening of crystallization ability caused by the substitution of B₂O₃ for SiO₂ will be beneficial for the improvement of fiber quality when the ferronickel slag is used as a raw material for mineral wool production.