Development of Innovative Recycling Processes for Mineral Wool Waste

Theresa Magdalena Sattler

Research output: ThesisDoctoral Thesis

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Abstract

The present doctoral thesis comprises recovery and recycling options for mineral wool waste along the waste hierarchy. The aim of this thesis was the development of innovative landfilling solutions through processing of the waste stream, recovery of mineral wool waste in backfilling and recycling in the cement industry, and a circular solution with a closed loop scenario for the waste in and glass/stone wool industries. Obtained results are presented in the five publications and the supplementary chapters found in the appendix. The recycling of mineral wool waste is not yet conducted in Austria due to economic inefficiency, technical challenges and suspected health issues. Some recycling and processing options already exist however; other options are investigated in the RecyMin project, which compares various recycling methods in regard to environmental and economic impact. In a study researching landfilling, three scenarios for the conditioning of rock wool for landfilling are compared. The performance of the different sample bodies under landfill conditions are simulated at the lab scale by cyclic loading along with the monitoring of the deformation during the experiment and the graphical derivation of the Young¿s modulus. The results show that a combination of comminution and cement-supported briquetting significantly increases the geotechnical performance of mineral wool waste with respect to landfilling. Mineral wool waste can be used together with an inorganic binder as backfill material. Corresponding recipes indicate the compliance with all requirements. Research on the recycling of mineral wool waste to produce a supplementary cementitious material shows that materials obtained from thermochemical treatment of mineral wool waste with other secondary raw materials fulfill the performance requirements regarding an alternative binder component. The circular route investigated to recycle mineral wool waste into new mineral wool showed that valuable and limited landfill volume can be conserved and the reduction of primary resource consumption and CO2 emissions is possible. The solubility-controlling mechanisms of mineral wools were investigated using pH-dependent leaching tests according to ÖNORM EN 14429 and hydrogeochemical models (LeachXS/Orchestra). For the Al-rich samples, the precipitation of the mineral phase wairakite is suggested to control the leaching, for the Al-poor sample, the precipitation of talc yields to leachable concentrations of Silicon at a pH value of 10. The thermochemical treatment using correction materials to adjust the chemical composition of the mineral wool that was followed by rapid cooling through a spinning process revealed the possibility of a closed loop scenario for mineral wool waste. The present doctoral thesis deepens the understanding regarding mineral wool waste in general and it´s recovery and recycling options in Austria on a broad and fundamental approach. The results gained through the RecyMin project open up numerous future paths facilitating recycling of mineral wool waste.
Translated title of the contributionEntwicklung innovativer Recyclingverfahren für Mineralwolleabfälle
Original languageEnglish
QualificationDr.mont.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Vollprecht, Daniel, Assessor B (external)
  • Pomberger, Roland, Supervisor (internal)
  • Melcher, Frank, Co-Supervisor (internal)
  • Galler, Robert, Assessor A (internal)
DOIs
Publication statusPublished - 2024

Bibliographical note

no embargo

Keywords

  • mineral wool waste
  • recycling
  • recovery
  • circular economy
  • waste management
  • closed loop scenario

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