Many ashes contain heavy metals, which hampers the utilization as secondary resources. In this PhD project heavy metals were removed from co-combustion ashes (wood and straw) and MSWI fly ash prior to using the ashes as partly substituting clay in brick manufacturing.
The goal was to upgrade the ashes by washing and electrodialytic treatment so the bricks with ash both had good material properties and sufficiently low heavy metal leaching.
The goal was obtained. Most challenging was to reach the limiting value for Cr leaching from bricks with MSWI fly ash. However, through an optimization process, bricks were produced, which had good material properties and low leaching of all heavy metals, including Cr. In these bricks, 5 wt% of the clay was replaced by electrodialytically treated MSWI fly ash.
Supervisors: Lisbeth M. Ottosen, Pernille E. Jensen, Gunvor M. Kirkelund, Jacob W. Schmidt
Download the PhD thesis
You can find more work by Wan Chen