การพัฒนาวัสดุเชิงประกอบจีโอพอลิเมอร์จากกากตะกอนเหล็กเป็นวัสดุกำบังรังสีแกมมา

Abstract

In this study, iron sludge geopolymer composite materials were developed as a gamma radiation shielding material instead of cement that produces carbon dioxide from the high-temperature calcination process. The influence of industrial iron sludge content on the physical properties and radiation attenuation of the resulting geopolymer composite material was studied. The experiment used the main raw material is clay from Nakhon Si Thammarat Province, a concentrated alkaline solution containing sodium silicate solution (Na2SiO3) with sodium hydroxide solution (NaOH) is 2 : 1 ratio. With a solution of sodium hydroxide with a concentration of 10 M and iron sludge was used at amounts of 0, 10, 20, 30, 40 and 50% by mass of clay. Mixing and forming by compression, then incubated at room temperature for 28 days. They were then tested for different properties. The results showed that the geopolymer's density increased with increasing iron sludge content. The density ranges from 2.026 to 2.207 g/cm3. The water absorption was the lowest of 11.7% at 20% iron sludge. While the compressive strength of the geopolymer is as high as 80 MPa at 20% of the iron sludge. This corresponds to the effect of water absorption and SEM effect showing the dispersion and infiltration of the iron sludge in the geopolymer. The microstructure study of the geopolymer with the XRD technique showed that after the geopolymer has a semi-crystalline structure and the Quartz crystals in clay do not change the structure. In contrast, Kaolinite has changed its structure. In addition, radiation attenuation properties of Geopolymer from clay mixed with iron sludge at energy levels of 1.172 and 1.330 MeV from a 60Co gamma source, it was found that the linear gamma attenuation coefficient was directly proportional to the iron sludge content. However, the radiation resistance is not solely dependent on the density of the material. It also depends on the distribution of the filler in the material. The linear gamma attenuation coefficient was the highest at 50% iron sludge, which was 0.8428 ± 8.5 × 10−2 cm-1 at an energy level of 1.330 MeV and 0.8285 ± 2.8 × 10−2 cm-1 at the energy level 1.172 MeV. The half-thickness (HVL) is the thickness that halves the radiation intensity, which decreases as the iron sludge content increases. As the percentage of radiation that passes through the radiation shield, it was found that the geopolymer can block 35.5 - 64.5% of radiation. From this research, it can be concluded that iron sludge has the ability to reduce gamma radiation. And it can also help strengthen the Geopolymer.