Utilization of Mineral Wools as Alkali-Activated Material Precursor.

Juho Yliniemi,Pasi Karinkanta,Mirja Illikainen,Paivo Kinnunen

doi:10.3390/ma9050312

Abstract

Mineral wools are the most common insulation materials in buildings worldwide. However, mineral wool waste is often considered unrecyclable because of its fibrous nature and low density. In this paper, rock wool (RW) and glass wool (GW) were studied as alkali-activated material precursors without any additional co-binders. Both mineral wools were pulverized by a vibratory disc mill in order to remove the fibrous nature of the material. The pulverized mineral wools were then alkali-activated with a sodium aluminate solution. Compressive strengths of up to 30.0 MPa and 48.7 MPa were measured for RW and GW, respectively, with high flexural strengths measured for both (20.1 MPa for RW and 13.2 MPa for GW). The resulting alkali-activated matrix was a composite-type in which partly-dissolved fibers were dispersed. In addition to the amorphous material, sodium aluminate silicate hydroxide hydrate and magnesium aluminum hydroxide carbonate phases were identified in the alkali-activated RW samples. The only crystalline phase in the GW samples was sodium aluminum silicate. The results of this study show that mineral wool is a very promising raw material for alkali activation.

Highlights

Alkali-activated materials (AAM), called geopolymers or inorganic polymers, have received a lot of attention lately because they have the potential to partly replace ordinary Portland cement (OPC) as a construction material
In addition to the amorphous material, sodium aluminate silicate hydroxide hydrate and magnesium aluminum hydroxide carbonate phases were identified in the alkali-activated rock wool (RW) samples
Two types of virgin mineral wool were purchased from a hardware store for this study: rock wool (RW, Paroc, Paroc eXtra) and glass wool (GW, Saint Gobain, Isover KL37-100)

Summary

Introduction

Alkali-activated materials (AAM), called geopolymers or inorganic polymers, have received a lot of attention lately because they have the potential to partly replace ordinary Portland cement (OPC) as a construction material. Studies have shown that AAMs have mechanical properties as good as, or even better than, OPC concrete [1]. Other beneficial properties, such as fire resistance and their typically light weight, make it possible to use them for such purposes as constructing panels or making ceramics [2,3]. In 2012, OPC production was estimated to account for 8% of global CO2 emissions [4], and government policies worldwide strongly encourage reducing OPC use. This explains the recent interest in finding alternative construction materials and binders

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Conclusion