Sammanfattning
Industrial waste materials, such as steelmaking slags, appear to be potential raw materials for reducing CO2 emissions by carbonation. The suitability of applying a carbonation route based on acetic acid leaching to produce carbonates from blast furnace slag is presented in this study. The effect of solution pH, temperature, and CO2 pressure on the precipitation of carbonates was experimentally studied. A simple thermodynamic model was used to verify our results. The feasibility of the process was also discussed, addressing energy input requirements and the consumption of chemicals. According to our experiments, the addition of NaOH, i.e. an increase in solution pH, is required for the adequate precipitation of calcium carbonate at temperatures of 30-70 °C and pressures of 1 or 30 bar. Preliminary process calculations showed that approximately 4.4 kg of blast furnace slag, 3.6 l of acetic acid, and 3.5 kg of NaOH would be required to bind 1 kg of CO2, resulting in 2.5 kg of 90% calcium carbonate. While the heat needed for the evaporation of the acetic acid could probably be acquired as waste heat by process integration with other processes, the electricity required for NaOH regeneration would make the process unsuitable for CO2 sequestration.
| Originalspråk | Engelska |
|---|---|
| Sidor (från-till) | 1461-1467 |
| Antal sidor | 7 |
| Tidskrift | Energy |
| Volym | 33 |
| Nummer | 9 |
| DOI | |
| Status | Publicerad - sep. 2008 |
| MoE-publikationstyp | A1 Tidskriftsartikel-refererad |
Finansiering
We would like to thank Rita Kallio, Kimmo Kinnunen, and Esko Pöyliö at Ruukki for generously providing us with XRF and XRD services and valuable discussions. We also wish to thank Hannu Revitzer at the Laboratory of Physical Chemistry and Electrochemistry for discussions and advice on the experimental rig. We want to thank the Laboratory of Energy Engineering and Environmental Protection for facilitating this work, as well as the Laboratory of Applied Thermodynamics and the Laboratory of Physical Chemistry and Electrochemistry for providing part of the equipment used in the experiments. We acknowledge the Finnish Funding Agency for Technology and Innovation (TEKES), Ruukki Productions, UPM-Kymmene, and Wärtsilä for their financial support.