CMA

50 Table 9. Composition of the MSWI Fly ash (FA), washed fly ash (WFA), and dried-washed fly ash (DWFA)- Yan et al, 2018 Compositions FA WFA DWFA Salt Moisture (%) 6.63 37.77 0.72 0.66 LOI (%) 23.00 57.63 23.45 5.84 Ash (%) 79.12 42.34 76.99 95.68 Cl (%) 14.47 0.50 1.04 59.91 Na (%) 2.46 0.32 0.82 33.58 K (%) 3.32 0.21 0.5 0.37 SO3 (%) 4.64 1.80 3.92 0.11 Al2O3 (%) 3.64 2.36 3.88 – Fe2O3 (%) 1.19 0.89 1.2 – MgO (%) 3.06 1.98 3.19 – CaO (%) 34.87 29.25 48.84 – SiO2 (%) 9.82 6.60 11.27 – ‘-’ means no detectable; LOI and Ash are given in dry-basis, and the other variables are given in wet basis. MSWI-FA from a municipal solid waste incinerator with grate-based technology and a daily disposal capacity of 1000 tonnes was used in this eld study. The major useful components of the original y ash (FA), which accounted for 49.52% of the total, were CaO, SiO2, Fe2O3, and Al2O3 , while Cl, Na, and K accounted for 20.32% of the total (see table 9). After water washing and drying process, the major useful components of the dried washed y ash (DWFA) accounted for 65.19%, and the detrimental components accounted for 2.36% of the total content. The system consists of a pre-treatment facility and a pre-heating–pre-calcining cement kiln. The plant is equipped with state-of-the-art air pollution control devices, and has a daily clinker production capacity of 2700 t. The pre-treatment is designed to remove the NaCl and KCl dissolved salts without extracting the dissolvable HMs contained in the MSWI-FA. Table 10. Operating conditions during the pre-treatment and in the cement kiln system Test 0 Test 1 Test 2 Input streams RM consumption (t/h) 178.8 175.5 171 Coal consumption (t/h) 14.8 14.3 13.6 FA feeding rate (t/h) 0 4.8 4.8 Intermediate streams DWFA feeding rate (t/h) 0 3.1 1.7 CKD production rate (t/h) 10.9 10.9 10.5 Output streams CK production rate (t/h) 113.5 113.8 110.3 Salt production rate (t/h) 0 1.3 1.2 Flue gas volume- at stack after Dryer (NM3/hr) 0 26 000* 66 850** Flue gas volume- at Kiln back-end stack (NM3/hr) 270 500 277 500 310 000 *The gas for heating was generated by a furnace burning diesel **The gas was introduced from the clinker cooler at kiln inlet