Khater Gamal A, El-Kheshen Amany A, Farag Mohammad M
Glass Research Department, National Research Centre, Cairo 12622, Egypt.
Materials (Basel). 2022 May 14;15(10):3534. doi: 10.3390/ma15103534.
Industrial waste is one of the primary sources that harm the environment, and this topic has occupied many scientists on how to take advantage of these wastes or dispose of them and create a clean environment. By-pass cement dust is considered one of the most dangerous industrial wastes due to its fine granular size and its volatilization in the air, which causes severe environmental damage to human and animal health, and this is the reason for choosing the current research point. In this article, eight samples of glass-ceramics were prepared using by-pass cement dust and natural raw materials known as silica sand, magnesite, and kaolin. Then melted by using an electric furnace which was adjusted at a range of temperatures from 1550 to 1600 °C for 2 to 3 h; the samples were cast and were subjected to heat treatment at 1000 °C for 2 h based on the DTA results in order to produce crystalline materials. Various techniques were used to study the synthesized glass-ceramic samples, including differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscope (SEM), and thermal expansion coefficient (CTE). X-ray analysis showed that the phases formed through investigated glass-ceramic samples consisted mainly of β- wollastonite, parawollastonite, diopside, anorthite, and cordierite. It was noticed that β- the wollastonite phase was formed first and then turned into parawollastonite, and also, the anorthite mineral was formed at low temperatures before the formation of the diopside mineral. SEM showed that the formed microstructure turned from a coarse grain texture to a fine-grained texture, by increasing the percentage of cordierite. It also showed that the increase in time at the endothermic temperature significantly affected the crystalline texture by giving a fine-grained crystalline texture. The linear thermal expansion measurements technique used for the studied glass-ceramic samples gives thermal expansion coefficients ranging from 6.2161 × 10 to 2.6181 × 10 C (in the range of 20-700 °C), and it decreased by increasing cordierite percent.
工业废物是危害环境的主要来源之一，这一话题吸引了众多科学家探讨如何利用这些废物或对其进行处理，以创造一个清洁的环境。旁路水泥粉尘因其细颗粒尺寸以及在空气中的挥发性，被认为是最危险的工业废物之一，它会对人类和动物健康造成严重的环境破坏，这也是选择当前研究点的原因。在本文中，使用旁路水泥粉尘以及硅砂、菱镁矿和高岭土等天然原料制备了八个微晶玻璃样品。然后使用电炉在1550至1600°C的温度范围内熔化2至3小时；根据差示热分析（DTA）结果，将样品浇铸并在1000°C下进行2小时的热处理，以制备晶体材料。采用了多种技术来研究合成的微晶玻璃样品，包括差示热分析（DTA）、X射线衍射（XRD）、扫描电子显微镜（SEM）和热膨胀系数（CTE）。X射线分析表明，所研究的微晶玻璃样品形成的相主要由β-硅灰石、副硅灰石、透辉石、钙长石和堇青石组成。注意到β-硅灰石相首先形成，然后转变为副硅灰石，并且钙长石矿物在低温下形成，早于透辉石矿物的形成。扫描电子显微镜（SEM）显示，通过增加堇青石的百分比，形成的微观结构从粗晶粒结构转变为细晶粒结构。它还表明，在吸热温度下时间的增加通过产生细晶粒晶体结构，对晶体结构有显著影响。用于所研究的微晶玻璃样品的线性热膨胀测量技术给出的热膨胀系数范围为6.2161×10至2.6181×10°C（在20 - 700°C范围内），并且随着堇青石百分比的增加而降低。
