Glass Wool Recycling by Water-Based Solvolysis

Abstract

Glass wool is an insulation material used in large quantities; despite its popularity, it is still surprising that around 2.5 million tons of mineral wool waste is generated every year in Europe. Waste management faces numerous challenges because, with current technologies, waste cannot be cleaned and melted again for repurposing, so even the recollected glass wool ends up in landfill. Herein, we present a hydrolysis technology that decomposes the binder applied to glass fibers using exclusively water. We succeeded in decomposing the resin from the surfaces of the end-of-life fibers, originating from different sources like industrial furnace insulation and two demolition-sourced building insulation wastes. The effects of temperature, pressure, the mass flow of the water, and the applied fluid ratio were investigated. The most important parameters are the temperature and the time for the decomposition, but to minimize glass loss through the solubility of glass, the fluid ratio plays an important role as well. The fibers were efficiently cleaned after only 20 min at 300 °C by the optimized parameters, with a mass recovery of 70 wt.%.