A Study on Recycling and Application Waste Ceramic Shell Mould by Using Geopolymer Technology
| Autor: | Yi-Fong Wu, 吳一峰 |
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| Rok vydání: | 2015 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 103 Lost wax casting is one of the common methods for investment casting. An investment casting mould consists of individual layers of fine zircon particles and granular mullite particles by using silica gel as binder to form a shell mould. However, the whole process was too complicated and setting times required several days normally. In addition, the waste ceramic shell mould needed further disposal. In this study, outer layers of casting mould were replaced by geopolymer, which was fabricated by mixing waste ceramic shell mould, metakaolin, and the ground calcium carbonate in alkali solution. Physical/mechanical properties, viscosity, setting time, microstructure of geopolymer with different amount of powders, concentration of KOH, SiO2/K2O molar ratio, liquid-solid ratio and dipping time in water after sintering were investigated. After initial test, geopolymer casting mould was used as outer layers and was applied in the investment casting process. For green modulus strength, dried shell mould was tested directly after drying 24 h. Before test the fired strength, shell mould was sintering at 1125 ℃. The permeability properties of fired shell mould were also tested by measuring pressure-decayed time. Finally, the casting tolerance was calculated. The experimental results showed that the waste ceramic shell mould based geopolymer can reduce the setting time. The microstructure of geopolymer (G5MK5) is a three-dimensional aluminosilicate framework. When the geopolymer was used as substituted outer layers of casting mould, the properties of specimen show a better green strength, fired strength and permeability performances. In comparison with the original ingredients, it can be found that geopolymer used as outer layers for casting mould (3L-G2HL) will save 76 NT dollars and 13 h of drying time. Therefore, reutilization of the waste ceramic shell mould by using geopolymer technology could be a potential way to apply in investment casting process. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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