Effect of cullet on firing temperature and dielectric properties of porcelain insulator

Andualem Merga Tullu; Tatek Temesgen Terfasa; Enyew Amare Zerfe; Miresa Tadese; Eaba Beyene; Adane Muche Abebe; Dinsefa Mensur Adoshe

doi:10.1016/j.heliyon.2022.e08922

Effect of cullet on firing temperature and dielectric properties of porcelain insulator

Heliyon. 2022 Feb 8;8(2):e08922. doi: 10.1016/j.heliyon.2022.e08922. eCollection 2022 Feb.

Authors

Andualem Merga Tullu^{1

2}, Tatek Temesgen Terfasa³, Enyew Amare Zerfe⁴, Miresa Tadese¹, Eaba Beyene⁵, Adane Muche Abebe⁵, Dinsefa Mensur Adoshe⁵

Affiliations

¹ Department of Chemistry, College of Natural and Computational Sciences, Ambo University, P.O. Box 19, Adama, Ethiopia.
² Faculty of Chemistry, Silesian University of Technology, Marcina Strzody 9, 44-100 Gliwice, Poland.
³ Department of Chemical Engineering, School of Mechanical Chemical and Material Engineering, Adama Science and Technology University, P.O. Box 1888, Adama, Ethiopia.
⁴ Department of Chemistry, School of Natural Science, Adama Science and Technology University, P.O. Box 1888, Adama, Ethiopia.
⁵ Department of Materials Science and Engineering, School of Mechanical Chemical and Material Engineering, Adama Science and Technology University, P.O. Box 1888, Adama, Ethiopia.

Abstract

Porcelain insulators prepared from locally available ceramic materials, such as Hosaena clay, quartz, partially replaced feldspar by cullet (rich in alkaline materials). The physical and electrical properties, such as water absorption, apparent porosity, bulk density, linear shrinkage, and dielectric strength as a function of firing temperature, were evaluated. The XRD and AAS measurement results show Hosaenna clay mainly belongs to kaolinite minerals with a sufficient SiO2 (45.60wt. %), Al2O3 (35.52wt. %), and it possesses reasonable plasticity nature. The SEM and Electrical properties measurement shows the porcelain insulators fired at 1150 °C & 1200 °C showed homogenized primary and secondary mullite with optimum glassy phase and good dielectric strength for practical applications. The primary & secondary mullite and glassy phases were grown early at a firing temperature of 1150 and 1200 °C, due to the partial replacement of feldspar by cullet. The porcelain insulator prepared from the composition of 45%clay, 35%feldspar, 10%quartz and 10%cullet and fired at 1200 °C showed dielectric strength 8.9kv/mm, water absorption (0.459%), apparent porosity (1.530%), bulk density (4.29 g/cm³), and linear shrinkage (4.18%). Therefore, incorporating economic alkaline materials such as cullet to improve the alkalinity of the locally available clay materials, Hosaenna clay, Arero feldspar, and Arero quartz reduces the firing temperature with excellent dielectric strength.

Keywords: Cullet; Dielectric strength; Glassy phase; Mullite; Porcelain insulator.