China
Africa
Explore chapters and articles related to this topic
Insulators for Overhead Lines
Published in Amitava Sil, Saikat Maity, Industrial Power Systems, 2022
Porcelain is the most commonly used material for overhead insulator in present days. The porcelain is aluminum silicate. The aluminum silicate is mixed with plastic kaolin, feldspar and quartz to obtain final hard and glazed porcelain insulator material. The surface of the insulator should be glazed enough so that water should not be traced on it. Porcelain also should be free from porosity since porosity is the main cause of deterioration of its dielectric property. It must also be free from any impurity and air bubble inside the material which may affect the insulator properties. Dielectric strength of Porcelain is 6.5 kV/mm, tensile strength is 2 kg/mm2 and composite strength is 30 kg/mm.
Moth proofing of wool fabric using nano kaolinite
Published in The Journal of The Textile Institute, 2018
Seiko Jose, Shanmugam Nachimuthu, Sekhar Das, Ajay Kumar
Nano particles are special group of materials with unique features and have extensive applications in diverse fields (Matei, Cernica, Cadar, Roman, & Schiopu, 2008). The formation of nano particles changes the properties of many conventional materials (Samanta, Bhattacharyya, Jose, Basu, & Chowdhury, 2016). Recent advances in the field of nanotechnology lead to the preparation of highly ordered nano particulates of any size and shape. Bio mechanical treatment to textiles can improve the functional finishing of natural fibre-based products (Esfandiari, 2008; Esfandiari, Firouzi-Pouyaei, & Aghaei-Meibodi, 2014). Kaolinite is one of the most common clay minerals found on the surface of the earth. Kaolinite is originally produced by chemical weathering of igneous rocks containing the feldspar and is an abundantly available clay mineral. Chemically, it is a hydrated Aluminium Silicate having a chemical composition Al2Si2O5(OH)4 (Zsirka, Horváth, Makó, Kurdi, & Kristóf, 2015). Kaolinite has physical and chemical properties which make it useful in a great number of applications like as paper filler and coating pigment. The nano kaolinite powder is commercially available for 1.5 $/kg, which means it is much cheaper than any of the commercial anti moth agents. Reports are available on imparting anti moth finishing of wool using nano silver (Ki, Kim, Kwon, & Jeong, 2007). However, there is no literature is available on anti moth finishing using nano kaolinite. Hence, in the reported work, an attempt has been made to coat nano kaolinite on wool fabric for getting anti moth properties. The characterization of nano coating on wool fabric, textile properties of fibre and fabric, and contact toxicity of moth (A. verbasci) was also analysed.
Sustainable utilization of ultrafine rice husk ash in alkali activated concrete: Characterization and performance evaluation
Published in Journal of Sustainable Cement-Based Materials, 2022
Shaswat Kumar Das, Jyotirmoy Mishra, Syed Mohammed Mustakim, Adeyemi Adesina, Cyriaque Rodrigue Kaze, Debadutta Das
The XRD spectrum of 0URHA and 5URHA is presented in Figure 17. As the two mixtures have similar compositions except for the content of URHA, it can be seen from Figure 17 that they exhibited similar diffraction peaks. Sodium aluminum silicate (N-A-S) (PDF#01-089-6428), quartz (PDF#00-003-0427), and calcium aluminum silicate (C-A-S) (PDF#00-034-1236) were dominantly found in both mixtures. The presence of N-A-S and C-A-S confirms the alkali activation of the precursors.
Effect of temperature on bioleaching of iron impurities from kaolin by Aspergillus niger fungal
Published in Journal of Asian Ceramic Societies, 2019
Jalal Hajihoseini, Mahsa Fakharpour
Kaolin is among the most important minerals, mainly in the mineral composition of aluminum silicate (Al2Si2O5(OH)4) [1–3]. The mineral properties, morphology and physical and chemical properties of kaolin make it suitable for many industrial applications, such as production of ceramics, paper, paints, fillers, cosmetics and pharmaceuticals [3–6]. These applications are heavily influenced by the condition of the soil and its content of impurities, including iron. The presence of iron in kaolin decreases its brightness and refractoriness [1,4,7,8], and causes a significant reduction in its value [9]. Even 0.4% of oxide and iron hydroxides may cause red and yellow colors in the soil [10]. These iron oxide/hydroxides may be hematite (red), maghemite (reddish brown), goethite (brownish yellow), lepidocrocite (orange), ferrihydrate (brownish red), etc. Similarly, iron ores such as hematite may contain clays like kaolin as contamination that can cause problems in the operation of blast furnaces [10]. The first beneficial step in the production of commercially available raw materials is to effectively remove iron oxides from kaolin. The iron removal process can be conducted physically, chemically or in a combination of both [1,11]. Most industries have employed potent chemical reductants such as dithionite or hydrazine to remove iron impurities, but these chemicals are associated with of iron reduction in nature [5]. Chemical techniques for the removal of iron have economical, technological and environmental disadvantages. Sodium hydrosulfite, in particular, is an expensive and dangerous chemical requiring specific and costly storage and transport arrangements. Iron leaching with this chemical is also fairly complex, requiring careful monitoring of the pH, density of the kaolin slurry, oxygen level and amount of added sodium hydrosulfite, as the Fe (III) reduction reaction may be impaired by concurrent reactions [12]. Its use also produces large amounts of effluents containing high concentrations of dissolved sulfates that require chemical treatment, often in large ponds, before disposal.