Samenvatting
The recycling of Municipal Solid Waste Incineration Bottom ash (BA) with a size below 4 mm is often difficult, due to its high contmination and porosity. To increase its reuse, the manufacture of lightweight aggregates represents a suitable option, as it takes advantage of the BA porous structure and uses cement for the immobilization of harmful contaminants. For highly contaminated ashes, hydrothermal treatment (HT) is known for further improving the immobilization of some heavy metals in the cementitious matrix. However, not many studies have investigated it as a curing method for pellets. This study addresses the application of highly contaminated BA fines in the production of lightweight aggregates. Firstly, pellets containing up to 80%wt. BA are manufactured and classified as lightweight aggregates, according to EN 13055. In the absence of HT, the formation of Friedel's salt helps the Cl− retention, lowering the leaching by 65% compared to theoretical values. After HT, the formation of tobermorite on the pellet surface is beneficial for the flexural strength (+14%). However, the decomposition of phases such as Friedel's salt increases the leaching of Cl−, Cu, Mo, and Zn compared to standard cured samples.
| Originele taal-2 | Engels |
|---|---|
| Artikelnummer | 116947 |
| Aantal pagina's | 13 |
| Tijdschrift | Construction and Building Materials |
| Volume | 230 |
| DOI's | |
| Status | Gepubliceerd - 10 jan. 2020 |
Financiering
The authors would like to acknowledge the financial support provided by NWO domain Applied and Engineering Science, formally NWO ( Nederlandse Organisatie voor Wetenschappelijk Onderzoek ), the Netherlands, under the project number 13933: “Environmental concrete based on treated MSWI bottom ash.” Moreover, for equipment support, the authors would like to acknowledge the group of Chemical Engineering and Chemistry, Chemical Reactor Engineering, Eindhoven University of Technology. Appendix A Complete table for leaching of contaminants of loose pellets manufactured including MSWI BA. The leaching assessment is performed according to EN 12457-2, one batch leaching test. Values in bold overcome the concentration of the contaminants allowed by the Soil Quality Decree. Elements SQD Unshaped material P_0 P_10 P_30 P_50 P_10A P_30A P_50A mg/kg d.s. mg/kg d.s. mg/kg d.s. mg/kg d.s. mg/kg d.s. mg/kg d.s. mg/kg d.s. mg/kg d.s. pH – 11.45 11.55 11.6 11.5 11.24 11.25 11.05 Antimony (Sb) 0.32 0.1 <0.1 0.1 0.2 0.1 0.25 0.23 Arsenic (As) 0.90 <0.3 <0.3 <0.3 <0.3 <0.3 <0.3 <0.3 Barium (Ba) 22.00 6.0 9.105 13.9 12.6 10.18 2.36 0.87 Cadmium (Cd) 0.04 <0.02 <0.02 <0.02 <0.02 0.09 0.08 0.1 Chromium (Cr) 0.63 0.02 <0.02 0.02 <0.02 0.32 0.43 0.41 Cobalt (Co) 0.54 <0.02 <0.03 0.03 <0.02 0.25 0.18 0.41 Copper (Cu) 0.90 0.68 0.59 0.79 1.4 <0.6 2.0 12.16 Lead (Pb) 2.30 0.1 0.1 <0.1 <0.1 <0.1 <0.1 <0.1 Molybdenum (Mo) 1.00 0.22 0.33 0.34 0.4 0.39 0.42 0.68 Nickel (Ni) 0.44 <0.05 <0.05 0.06 <0.05 0.29 0.38 0.43 Selenium (Se) 0.15 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 Tin (Sn) 0.40 <0.1 <0.1 0.1 <0.1 <0.1 <0.1 <0.1 Vanadium (V) 1.80 0.1 0.1 <0.1 <0.1 <0.1 <0.1 <0.1 Zinc (Zn) 4.50 <0.01 <0.01 <0.01 <0.01 0.39 1.31 1.79 Chloride (Cl) 616 2510 1800 1690 1580 2484.9 2550.8 4081.09 Sulfate (SO 4 2− ) 2430 57.9 67.0 74.0 61.0 227.8 176.5 2203.8
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