A study on thermal conductivity of six unexplored Nigerian clays for possible refractory and insulating materials

• Main Author: Ajala, , Amkpa Job
• Format: Thesis
• Language: English; English; English
• Published: 2017
• Subjects: TA715-787 Earthwork. Foundations
• Online Access: http://eprints.uthm.edu.my/310/1/24p%20AMKPA%20JOB%20AJALA.pdf; http://eprints.uthm.edu.my/310/2/AMKPA%20JOB%20AJALA%20COPYRIGHT%20DECLARATION.pdf; http://eprints.uthm.edu.my/310/3/AMKPA%20JOB%20AJALA%20WATERMARK.pdf; http://eprints.uthm.edu.my/310/

Refractories are mineral and chemical based materials, with high heat resistance properties. Refractory manufacturing typically uses clay as the main raw material. The study aims to investigate six unexplored Nigerian clay based on the suitability of their chemical, physical, mechanical and thermal properties as refractories. Six clay deposit locations in Nigeria were selected namely Kpata, Riyom, Gombe, Aloji, Barkin-lade and Quan’pan. The samples were obtained through a two meters depth excavation method. Experimental specimens were produced from these samples through dry-pressing methods followed by firing at 900-1200°C. All specimens were tested to identify the chemical, physical, mechanical and thermal properties of ASTM standards. X-ray fluorescence (XRF) and X-ray diffraction (XRD) analysis show that all specimens contain alumino-silicates as the dominant composition, with 10% loss on ignition. Through the Archimedes test, the percentage of porosity is found in the range of 20-30%, with bulk densities about 1.7-2.3g/cm3. Cold crushing strength (CCS) and modulus of rupture (MOR) give readings of 15-59 MPa and 6.2-9MPa respectively. Meanwhile, the analysis on thermal properties found specimens having thermal shock resistance on a 20-30 scale cycle, pyrometric cone equivalence (PCE) at a temperature range of 1500-1700°C and thermal conductivity at a range of 0.01-0.9W/m.K. The overall experiment results are within the range of ASTM standards and this illustrates that all of the clay is potentially a refractory material.