Foundry Wastes as a Potential Precursor in Alkali Activation Technology

Abstract

The 2 nd International Conference on Technologies & Business Models for Circular Economy (TBMCE) was devoted to presentations of circular economy concepts, technologies and methodologies that contribute to the shift of business entities and society as a whole to a more responsible, circular management of resources. In the framework of TBMCE 2019, we presented the Strategic Research and Innovative Partnership -Network for the Transition to Circular Economy (SRIP-CE) as a platform for establishing a successful long-term public-private partnership. The conference program included panel discussions, plenary and keynote sessions, oral and poster presentations on the following topics: Sustainable energy, Biomass and alternative raw materials, Circular business models, Secondary raw materials and functional materials, ICT in Circular Economy, Processes and technologies. TBMCE 2019 was organized by Faculty of Chemistry and Chemical Engineering, University of Maribor and held in Portorož, Slovenia at the Grand Hotel Bernardin from October 24th to October 25th, 2019. The event was under the patronage of Ministry of Economic Development and Technology.

Socratic lectures 10 - Part I

“…efflorescence took place (thermonatrite formed). Alkali-activated glass wool had 3 times lower shrinkage, 4 times higher bending strength and 2 times higher compressive strength (Horvat et al, 2018).…”

Green Transition in Slovenian Building and Civil Engineering Industry: 10 Years of Research on Alkali-Activated Materials and Alkali-Activated Foams

“…efflorescence took place (thermonatrite formed). Alkali-activated glass wool had 3 times lower shrinkage, 4 times higher bending strength and 2 times higher compressive strength (Horvat et al, 2018). Although waste foundry sand is not a promising material for alkali activation, its usefulness for the reaction has been evaluated by the addition of KOH/NaOH and K/Na-silicate solution in different ratios, as well as the addition of extra water and molarities of KOH/NaOH.…”

“…Volumetric drying (microwave irradiation) was, regarding the shrinkage, faster than drying at 110 °C, which was faster than drying at room conditions. However, faster drying causes bigger cracks and a decrease in bending strength but increases compressive strength (Horvat et al, 2019a). The potential of different local foundry wastes was evaluated regarding their usefulness in alkali activation at room conditions.…”

“…Compressive strengths for all other samples were from 5 to ~10 MPa. Therefore, these materials can be used as reactive fillers (Horvat et al, 2019b). Another potential precursor, which has not been widely researched up to date (Soriano et al, 2023), was local green ceramics waste that was activated using NaOH and Na-silicate, but in calculated ratios following molar ratios of Al, Si and the sum of the chemical elements of the first group of the periodic system, as also the mass of whole water (from all sources) content present in the mixture.…”

“…Using this fraction resulted also in the smallest total porosity of alkali-activated slags (Traven et al, 2019). The influence of curing/drying methods was further researched on alkali-activated waste casting cores that did not solidify in more than 2 years at room conditions no matter their particle size (Horvat et al, 2019b). Both granulations (below 600 µm and 90 µm) were activated with 10 M NaOH and Na-silicate solution, all in a mass ratio (2.5/3.3/3.75):1:1, respectively, and cured for 24 h at 70 °C.…”