| URN | etd-0118110-122728 | Statistics | This thesis had been viewed 699 times. Download 21 times. |
| Author | Shang-Yi Chou | ||
| Author's Email Address | s59604017@mail2u.tnu.edu.tw | ||
| Department | hazards | ||
| Year | 2009 | Semester | 1 |
| Degree | Master | Type of Document | Master's Thesis |
| Language | English | Page Count | 157 |
| Title | Removal of water-soluble chloride ion in bottom ash from municipal solid waste incinerator | ||
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| Abstract | Bottom ash was derived from the incineration processes of municipal solid wastes. Its properties were similar to the natural aggregates. Due to the excessive amount of water-soluble chloride ion in bottom ash which will increase the corrosion rate on steel bar of reinforced concrete, leading to crack the protective layer of reinforced concrete. Subsequently, the strength of building will be weakening. As a result, the bottom ash requires proper pretreatment to remove chloride ion before be reused as construction material. In accordance with the official announcement by Environmental Protection Administration in Taiwan, to reuse bottom ash as aggregates of reinforced concrete must diminish water-soluble chloride ion content down to 0.0240% (w/w). This research studied the removal efficiencies of water-soluble chloride ion in bottom ash by both Shaking treatment (ST) and Ultrasound Sonication Treatment (UST). The optimal operation conditions were evaluated included shaking strength, L/S, extraction time, extraction temperature, extraction solutions, and test stages. The results showed the optimal operation conditions were four-stage of ST, shaking speed of 75 rpm, total extraction time of 50 minutes (30, 10, 5, 5 minutes for each stage), total L/S of 5/1 (2/1, 1/1, 1/1, 1/1 mL/g for each stage), extraction solution of the first stage used 2 N NaOH solution, the second to the fourth stage used deionized water, and operation temperature of 50 ℃. Under these conditions, 98% removal of chloride ion was achieved, and the average concentration of water-soluble chloride ion remained in bottom ash was 0.0160%. On the other hand, while extraction with H2SO4 solution would restrain chloride ion dissolved out. The main factors for removal of soluble chloride ion in bottom ash presume that related to the acid-base reactions between extratction solution and the surface of bottom ash. In addition, the removal efficiencies of chloride ion were not effect by the wet or dry state of bottom ash. All expermints showed that the ST had better dissolved efficiencies of chloride ion then the UST. |
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| Files | indicate access worldwide | ||
| Date of Defense | 2010-01-13 | Date of Submission | 2010-01-18 |