Article

Accelerated Carbonation of Municipal Solid Waste Incineration Fly Ash Using CO 2 as an Acidic Agent for Clinker Production

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Abstract

An accelerated carbonation pretreatment of municipal solid waste incineration (MSWI) fly ash was investigated for the efficiency of both heavy metal solidification and chloride release in MSWI fly ash. Carbonation was performed with a liquid-to-solid ratio of 5, 10, or 20, during which carbon dioxide was used as the acidic agent. Other properties that were evaluated were the clinker composition, compression strength of the clinker, and setting time of the clinker. Results indicated that the carbonation process was highly efficient for the release of chloride and that the process had a high efficiency for amphoteric heavy metals (Cu, Zn, Pb, and Cd) solidified in the fly ash. The leached amount of Pb, Cu, and Zn in the wastewater effluent after the carbonation process was reduced to 20, 110, and 470 mg/kg compared with the amounts in the wastewater effluent after the single washing process. Major components of ordinary Portland cement (OPC) clinkers are present in the produced clinkers. The properties of the clinker after the addition of the carbonated MSWI fly ash have no obvious changes compared with OPC. Compared with other technologies, this method is helpful in the utilization of MSWI fly ash and to save raw materials in the production of cement.

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... Experimental data for the PCA covered MSWI fly ash samples from both the present study and literature [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]. The dataset for the PCA consisted of 51 MSWI fly ash samples and a coal fly ash, from Greenland, Europe and Asia. ...
... The calculated contents of oxides are shown in Table 2, together with the chloride content and LOI for the five MSWI fly ash samples. Included in Table 2 are the requirements specified in EN 450-1 2012 [10] for using coal fly ash in cement-based materials, as well as the results found in other studies for MSWI fly ash [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] and coal fly ash [42]. The five MSWI fly ash samples evaluated in the present study only fulfilled the chemical requirements specified in EN 450-1 2012 [10], for MgO and P 2 O 5 . ...
... The five MSWI fly ash samples contained less SiO 2 than the limit of at least 25 wt% reactive SiO 2 , regardless if the determined SiO 2 content is reactive or not, and had a combined content of SiO 2 , Fe 2 O 3 and Al 2 O 3 of approximately one-seventh the lower limit of 70 wt%. The SiO 2 content was less than the range indicated for coal fly ash [42] and was in the low range of what was observed for MSWI fly ash [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. The Al 2 O 3 and Fe 2 O 3 content were within the range of both MSWI and coal fly ash, with the exception of the Arc samples that contained less Al 2 O 3 and the Nuuk samples that contained less Fe 2 O 3 than the range for coal fly ash [42]. ...
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