The Effects of Firing Temperatures on the Performance of Insulating Firebricks Containing Different Proportions of Alumina and Sawdust

Davies Oladayo Folorunso,Peter Olubambi,Joseph Olatunde Borode,Fatai Olufemi Aramide

doi:10.4236/jmmce.2015.34033

Abstract

This work studied the effects of firing temperatures on the refractory properties of insulating firebricks produced from a blend of hydrometallurgically purified clay, high alumina cement and sawdust. Twenty grams out of a bulk (1000 Kg) of clay obtained from Ipetumodu in Nigeria was analyzed for size range, consequent upon which the remaining bulk was sieved to 100 µm, being the average size. The bulk was there after leached under a predetermined condition (1.6 mol/dm3 of oxalic acid at 70˚C for 150 min and 200 rev/min agitation speed) and cylindrical samples (5 cm diameter by 5 cm high) containing different quantities of high alumina cement (5% - 20%) and sawdust (1% - 5%) were prepared, dried at 110˚C and subsequently fired at 900˚C, 1100˚C, 1300˚C and 1500˚C, at the rate of 4˚C/min and soaked for 2 hrs. These samples were subjected to different refractory tests (permanent linear change, modulus of rupture, bulk density, cold crushing str- ength and apparent porosity). Even though samples containing more than 20% alumina crumbled at elevated temperatures, it was still observed that the bricks performed to expectations at lower alumina contents, even at 1500˚C. The sample containing 3% sawdust and 10% alumina cement however, gave the desired requirement for preparing good insulating firebricks with reliable phase integrity, as revealed by scanning electron microscopy (SEM).

Highlights

Insulating fire bricks, though specially designed for high heat environment, will eventually start to fail and break down over time
Composite refractory brick has been identified as a solution to obtain both chemical and physical properties needed to be possessed by a good refractory brick
The scanning electron microscopy (SEM)/EDS analysis shows the SEM micrographs of the relative sizes of the clay particles at X500 magnification and the spectra depicting the peaks of the elements present

Summary

Introduction

Insulating fire bricks, though specially designed for high heat environment, will eventually start to fail and break down over time. This necessitates a periodical replacement of the firebricks with new ones in order to ensure that the bricks work as intended, which in turn accounts, for the regular demands for firebricks by the industries and outfits where the bricks are used [1]. Composite refractory brick has been identified as a solution to obtain both chemical and physical properties needed to be possessed by a good refractory brick This is achieved by a blend of clay with either synthetic or organic additives [2]

Methods

Results

Conclusion