SOURCE:

Faculty: Engineering
Department: Metallurgical And Materials Engineering

CONTRIBUTORS:

Chima, O. M
Nnuka, E. E

ABSTRACT:

This study investigated the performance enhancement of the refractory properties of Nguzu – Amaiyi clay blended with different agro wastes-(groundnut shell, rice husk and sawdust) at varied compositions. The chemical and mineralogical compositions were determined using X-ray fluorescence technique and X-ray diffraction spectrometer respectively while the micro structural examinations were done using scanning electron microscope (SEM). Nguzu and Amaiyi clays were blended at ratio 40:60 to get the experimental control sample. This sample was blended with the individual different additives and also with their blends of three and two at different formulations specified in the experimental design. The test samples were moulded, dried, fired to 12000C and thereafter subjected to physiomechanical tests. Response surface methodology based on central composite design was used to evaluate and optimize the effect of the composition of clay and the additives on the responses. Results obtained showed that Nguzu and Amaiyi clays had low alumina composition of 21.8 and 22.9% with silica composition of 54% and 48.9% respectively. The refractory properties of bricks made with Nguzu clay, Amaiyi clay and the control sample had respective values of ( 4, 4.4 and 6.59)%, (20, 11.59 and 15.63)%, ( 2.13, 2.15 and 1.77)g/cm3, (38.8, 33.5 and 32.7)MPa, (28, 29 and 30) cycles, (0.00265, 0.00397 and 0.00318)W/mm0C and (1490, 1520 and 1550)0C for linear shrinkage, apparent porosity, bulk density, modulus of rupture, thermal shock resistance, thermal conductivity and refractoriness respectively. Percentage enhancement of (85, 57, 71, 85, 57 and 28)% in these properties were achieved in the blend with groundnut shell, rice husk, sawdust, combination of the three additives, combination of groundnut shell with rice husk and combination of groundnut shell with sawdust respectively. The optimum production conditions to achieve maximum performance of the properties were determined to be 5 and 95% composition of additive and clay respectively. Good agreement between the model predicted and experimental results confirmed the adequacy and soundness of the developed model. The highly insulating composite bricks developed are suitable for high temperature applications.