The present work has evaluated Kalalani vermiculite as a potential raw material for the production of high strength porcelain insulators. Three porcelain compositions were prepared to contain 0, 20 and 30 wt% of Kalalani vermiculite. Porcelain samples were fabricated using a semi-drying method. The chemical, mineralogical phases and microstructural characterization of the raw materials were carried out using XRF, XRD, and SEM techniques, respectively. Water absorption, bulk density, dielectric and bending strengths were performed on porcelain samples fired up to 1300 o C. However, at the sintering temperature of 1250 o C, the porcelain sample with 20 wt% of Kalalani vermiculite gave the dielectric strength of 61.3 kV/mm, bending strength of 30.54 MPa, bulk density of 2.21 g/cm 3 and low water absorption value of 0.21 % which is the prerequisite properties for high strength porcelain insulators. It was therefore concluded that Kalalani vermiculite has the potential to be used for the production of high strength porcelain insulators.

This study evaluated the potential of locally sourced-ceramic raw materials in Tanzania, Pugu kaolin, Same clay, vermiculite and feldspar, for production of high voltage porcelain insulators. The chemical, mineral phases and microstructural characterization of raw materials and porcelain samples were carried out using the X-ray fluorescence, X-ray diffraction, and scanning electron microscopy techniques, respectively. The mineral phases of the fired porcelain sample identified were mullite and quartz. The porcelain bodies were fabricated using the dry pressing method by varying the composition of the selected ceramic raw materials. The physical-mechanical properties and dielectric strength were measured for each porcelain sample. The sample with the composition of 20% Pugu kaolin, 20% Same clay, 20% vermiculite and 40% feldspar was found to have the dielectric strength of 50.8 kV.mm-1, bending strength of 20 MPa and water absorption of 0.46%, which satisfies the main requisite properties for high voltage porcelain insulators.