EFFECT OF DADIN-KOWA ZIRCON SAND ADDITION ON THE REFRACTORY PROPERTIES OF IJAPO CLAY TOWARDS FURNACE LINING PRODUCTION

Abstract

The effect of Dadin-kowa Zircon Sand addition on the refractory properties of Ijapo Clay for furnace lining was investigated. The clay and zircon sand samples werecharacterized using X-Ray Fluorescence Spectrometer (XRF) for chemical composition determination. Moisture content of the refractory raw materials were determined using speedy moisture tester. Sample bricks in ratios 100:0:0, 90:5:5, 85:10:5, 80:15:5, 75:20:5, 70:25:5, 65:30:5, 60:35:5, 0:100:0 of clay, zircon sand and binder (bentonite) were prepared using the hydraulic press. Thereafter, sample bricks were tested for such properties as refractoriness, thermal shock resistance, crushing strength, porosity, bulk density, linear shrinkage and microstructure study. The microstructure was investigated with the aid of a scanning electron microscope (SEM). The chemical analysis results showed that Ijapo clay composed of silica 51.60%, alumina 34.90%, iron oxide 10.24%, calcium oxide 0.061%, potassium oxide 0.777%, titanium oxide 1.60% and other oxides in traces. While, the zirconia content in Dadin-Kowa zircon sand was 61.69%. The results obtained indicated that the binder used has the highest moisture content value of 13.2%. The results further showed that refractoriness, thermal shock resistance, bulk density and cold crushing strength increased on addition of zircon sand, while, shrinkage and porosity of the bricks reduced on the addition of zircon sand. From the microstructure analysis, it was revealed that particles were uniformly distributed in the matrix structure with the addition of 35% zircon sand. It was also observed that the pores in clay decreased on the addition of zircon. Generally, the results showed that Dadin-Kowa zircon sand additive was suitable for blending Ijapo clay in the production of high-quality refractory bricks. The refractory bricks produced from the blend of Ijapo clay with Dadin-kowa zircon sand and bentonite as binder at 60:35:5 gave the best refractory properties. They are therefore, recommended for lining of rotary furnaces and crucible furnaces for the melting of ferrous and non-ferrous alloys in the industries operating below 1500oC. They could also find application in casting ladle.