The Comparison of the Environmental Impact of Waste Mineral Wool and Mineral in Wool-Based Geopolymer

Abstract

Waste generated in fine wool production is homogeneous and without contamination, which increases its chances of reuse. Waste mineral wool from demolition sites belongs to the specific group of waste. However, the storage and collection require implementing restrictive conditions, such as improper storage of mineral wool, which is highly hazardous for the environment. The study focuses on the leachability of selected pollutants (pH, Cl−, SO42−) and heavy metals (Ba, Co, Cr, Cu, Ni, Pb, Zn) from the waste mineral wool. As a solution to the problem of storing mineral wool waste, it was proposed to process it into wool-based geopolymer. The geopolymer, based on mineral wool, was also assessed regarding the leaching of selected impurities. Rock mineral wool is very good for geopolymerisation, but the glass wool needs to be completed with additional components rich in Al2O3. The research involved geopolymer prepared from mineral glass wool with bauxite and Al2O3. So far, glass wool with the mentioned additives has not been tested. An essential aspect of the article is checking the influence of wool-based geopolymer on the environment. To investigate the environmental effects of the wool-based monolith and crushed wool geopolymers were compared. Such research has not been conducted so far. For this purpose, water extracts from fragmented geopolymers were made, and tests were carried out following EN 12457-4. There is no information in the literature on the influence of geopolymer on the environment, which is an essential aspect of its possible use. The research results proved that the geopolymer made on the base of mineral wool meets the environmental requirements, except for the pH value. As mentioned in the article, the geopolymerisation process requires the dissolution of the starting material in a high pH (alkaline) solution. On the other hand, the pH minimum 11.2 value of fresh geopolymer binder is required to start geopolymerisation. Moreover, research results analysed in the literature showed that the optimum NaOH concentration is 8 M. for the highest compressive strength of geopolymer. Therefore, the geopolymer strength decreases with NaO concentration in the NaOH solution. Geopolymers glass wool-based mortars with Al2O3 obtained an average compressive strength of 59, the geopolymer with bauxite achieved about 51 MPa. Thus, Al2O3 is a better additional glass wool-based geopolymer than bauxite. The average compressive strength of rock wool-based geopolymer mortar was about 62 MPa. The average compressive strength of wool-based geopolymer binder was about 20–25 MPa. It was observed that samples of geopolymers grout without aggregate participation are characterised by cracking and deformation.

Municipal Solid Waste Incineration Fly Ash: From Waste to Cement Manufacturing Resource

“…Although immobilization in the hardened binders (SCB1 and SCB2) is not total for some metals (e.g., Cr), the concentrations are below the highest permissible values according to the Urban Waste Water Treatment Directive [ 80 , 81 ]. Due to the differences observed between SCM2 and the binders, it can be concluded that the heavy metals were fixed during hardening.…”

Is the Concept of Zero Waste Possible to Implement in Construction?

“…Table 1 shows that the sourcing and reuse of reused materials is a simple way to generate less waste and a dominant trend in deepening the ecological aspect of architecture and construction. Reusing non-obvious materials such as glass [31], concrete pavement [32], mineral wool [33,34], and rubble [35] is reflected in the scientific research and literature of the twenty-first century.…”

“…Buildings 2024, 14, x FOR PEER REVIEW 6 of 20 manual labour injury cial protection shredding, stacking, cutting Reusing non-obvious materials such as glass [31], concrete pavement [32], mineral wool [33,34], and rubble [35] is reflected in the scientific research and literature of the twenty-first century.…”

The Effect of Mineral Wool Fiber Additive on Several Mechanical Properties and Thermal Conductivity in Geopolymer Binder

“…The mechanical processing of this waste is also a challenge. Mineral fibers, despite their low density, are very abrasive, which causes abrasion to shredding equipment [5]. Moreover, the large volume relative to the low mass makes it economically unjustifiable to transport this waste over long distances.…”