Effects of EAF Slag’s Milling Time and Firing Temperature to EAF Slag Added Ceramic Tile’s Properties

Abstract

Significant quantity of solid wastes, especially electric arc furnace (EAF) slag is generated by the growing Malaysia’s steel industries. Recycling them offer a more sustainable solution and also added value to the solid wastes. Therefore, in this project, an attempt was made to recycle the EAF slag waste as one of raw materials in ceramic tile. In our preliminary study of assessing the suitability of the slag in ceramic tile, it was found that at fixed firing temperature of 1150°C, increasing of EAF slag added (wt.%) would deteriorate the properties of tile produced. Meanwhile, introduce an additional silica and feldspar led to better properties of the tile. Optimum composition of the ceramic tile was found to be 40 wt.% EAF slag – 30 wt.% – 20 wt.% silica – 10 wt.% feldspar. Hence, this study aims to further improve the properties of the tile by varying EAF slag’s milling time (15 minutes and 30 minutes) and firing temperature (1075°C, 1100°C, 1125°C and 1150°C). Results obtained show that as milling time was increased from 15 minutes to 30 minutes, average particle size, X50 of the slag was reduced from 53 µm to 3 µm. When the particles size of EAF slag added was smaller, the tile had a higher modulus of rupture (MOR), higher bulk density, lower apparent porosity and water absorption. The improved MOR was due to increase in total anorthite and wollastonite crystalline phases (wt.%) in the tile. The MOR was the highest at firing temperature of 1100°C for 3µm EAF slag particle whereas for larger particle size (53µm), the MOR was highest at 1150°C. This suggests possible improvement in reduction of firing temperature when smaller particles are used.