A Study of Insulating Properties of Refractory Bricks Produced from the Blend of Fireclay and Periwinkle Shell

Authors: Obidiegwu EO, Ochulor EF, Awojobi EO

DOI Info: http://doi.org/ 10.5281/zenodo.5805093

ABSTRACT

This paper studied the insulating properties of refractory bricks produced from a blend of fire clay and periwinkle shells to assess the possibility of developing a new material for lining furnaces with improved efficiency. Various samples were produced from 75 to 100 wt.% of clays with particle sizes of 300 µm, blended with 0-25 wt.% periwinkle shells of 150 µm. The samples were fired at temperatures ranging from 950 ^oC-1100 ^oC for 3 hours at the rate of 2.5 ^oC/minutes using an electric furnace. The chemical compositions of the clays and periwinkle shell were analysed using atomic absorption spectrometer (AAS). ASTM standard test methods were used to determine apparent porosity, bulk density, thermal conductivity, linear shrinkage and cold crushing strength (CCS) of the samples. The AAS result shows that calcium oxide and combustible material were the predominant compound in the periwinkle shells. Porosity increased with increase in periwinkle shell amount, the highest porosity being 40.2% at 950 ^oC and 25wt.% of periwinkle shell. There was a decrease in thermal conductivity from 0.32 W/mk to 0.088 W/mK with increase in the addition of periwinkle shell. Also, bulk density decreased from 5.2 to 1.57 g/cm³ at 1100 ^oC. As the firing temperature increases, the CCS increased from 2066 to 3250 kN/m² and linear shrinkage increased from 5.2 to 9.4%. It was deduced from the results that bricks with 20 – 25 wt.% of periwinkle shells fired at 1100 ^oC possessed enhanced insulating properties.

Download Full Text