Eco-efficient transformation of mineral wool wastes into lightweight aggregates at low firing temperature and associated environmental assessment

Waste recycling is one of the key elements to mitigate the environmental problems that threaten our society. Mineral wool is currently the most widely used insulation material in the European Union, so the amount of waste generated in the demolition and restoration of buildings has increased alarmingly. This work investigates for the first time the use of glass wool (GW) and rock wool (RW) as a component in the manufacture of lightweight aggregates, showing that both can be suitable raw materials considering the density (1.3-1.5 g/cm(3)) and mechanical strength (2-6 MPa) obtained. In addition, the use of GW would help to reduce the firing temperature significantly (700 degrees C) compared to that normally used in the manufacture of these materials (around 1200 degrees C), which would imply significant energy savings. Considering that thermal insulation materials and lightweight aggregates are among the most widely used materials in the construction sector, the work presented here also evaluates the environmental impact associated with the manufacture of lightweight aggregates with RW and GW in comparison with the traditional process, using the Life Cycle Assessment (LCA) methodology. A significant environmental improvement has been observed in almost all the analyzed impact categories of the artificial aggregates manufactured with mineral wool with respect to traditional LWAs.

Automated summary

Waste recycling is an important means to mitigate environmental problems. This study found that glass wool and rock wool can be used as raw materials for lightweight aggregates, with suitable density and mechanical strength. The use of glass wool significantly reduces energy consumption in the manufacturing of lightweight aggregates, and there is a significant environmental improvement compared to traditional artificial aggregates.