The modified Landfill Ordinance of 2021 provides for an Austria-wide landfill ban on artificial mineral fibres from 2027. Artificial mineral fibres include mineral wool, which is primarily used as an insulating material in the construction industry. Waste from mineral wool, which includes glass wool and rock wool, is currently mainly sent to landfill in Austria due to a lack of alternatives. Utilisation or recycling processes must therefore be developed for this waste stream by 2027. Research is being conducted in this area at the University of Leoben as part of the "BitKOIN" project. One work package involves investigating the possibility of utilising this waste in the cement industry. The idea is to use thermochemical treatment to convert it into a secondary grinding material with similar properties to granulated blast furnace slag. For this reason, glass wool and rock wool are mixed with corrective substances, melted and then wet granulated in this study. This approach produces a glassy solidified granulate, which is analysed for its chemical oxide composition and structural requirements. The results of the analyses show that the requirements for the output material are met in terms of chemical composition, glass content and hydraulic reactivity. A granulated mixture of fly ash, glass wool and rock wool with a modified chemical composition can therefore potentially be used as a secondary cementitious material in the cement industry.