|
Title
|
|
|
|
Towards co-utilization of CO2 and Fe-rich sources to prepare clinker-free carbonate-bonded monoliths
| |
|
Author
|
|
|
|
| |
|
Abstract
|
|
|
|
| The main objective of this work was to contribute towards the co-utilization of CO2(g) and residues from metallurgical industries to produce Fe-carbonate bonded monoliths that are free from cement clinker. While excessive CO2 is considered a significant problem due to the increased global warming and its associated effects, Fe-rich metallurgical wastes are still used for low-value applications or are landfilled. Moreover, due to the volume of their use, construction materials production accounts for 7-8% of total CO2-emissions. Therefore, the co-utilization of slag and CO2 to produce construction materials has significant potential to contribute towards achieving future sustainability goals. In this study, Fe(0) is initially chosen as a model system to understand the feasibility of producing FeCO3-bonded monoliths under the desired reaction conditions (<100 °C, and <25 bar CO2-pressure). In addition to demonstrating the feasibility of FeCO3-cementation, the underlying reaction mechanisms are also discussed. Since the dissolution of Fe-sources is usually known to be the rate-limiting step, Fe-dissolution in dilute conditions is studied as a function of temperature, CO2-pressure, and time. Similar to the dissolution studies on Fe(0), dissolution studies in dilute solutions are also extended to the Fe-Si rich non-ferrous slags as a function of temperature, CO2-pressure, and time. In both the studies, it is shown that high temperature and CO2-pressure are conducive towards the dissolution of Fe(0) and Fe-rich slags. To transfer the knowledge of FeCO3-cementation from the model Fe(0) system to the sources in which Fe co-exists with Ca, FeCO3-cementation in CO2-H2O-Fe(0)-Ca(OH)2 systems is also studied. The importance of microstructures of the products, and the formation of mixed (Ca, Fe)-carbonates is pointed in this study. Finally, it is shown that the non-ferrous slags can be co-utilized with ferrous metallurgical slags rich in Ca to produce carbonate-bonded monoliths with high mechanical strength. It is shown that the carbonation of the non-ferrous slags as mixes with ferrous slags can lead to a significant decrease in environmental leaching. With more than 575 million tonnes of metallurgical slags produced every year, they offer an opportunity for significant CO2-mineralization as well as to produce low-carbon construction materials. |
| |
|
Language
|
|
|
|
English
| |
|
Publication
|
|
|
|
Antwerp
:
University of Antwerp, Faculty of Science, Department of Chemistry
,
2021
| |
|
Note
|
|
|
|
:
Cool, Pegie [Supervisor]
:
Snellings, Ruben [Supervisor]
| |
|