Briquetting : A new approach to recycle the waste iron-bearing materials generated in steel plants

Iron and steel industry generates huge quantities of waste iron fines containing Iron ore, mill scale, flue dust and sludge etc. Accumulations of steel plant dust and its disposal have become a concern worldwide. Recycling of these waste iron-bearing materials become more and more important due to environmental as well as economical
reasons and one of the ways to recycle this waste is by agglomeration technique i.e. Briquetting. The efforts has been made to study the properties of bentonite bonded
briquettes for charging in MBF were prepared using various iron bearing materials generated in the Usha Martin Limited at room temperature and when subjected to high
temperature reduction. In this study the effect of various processing parameters on the properties e.g. degree of reduction, degree of swelling, cold crushing strength (CCS) on the bentonite-bonded briquettes has been studied. Green briquettes were shown the strength of 113 Kg CCS at room temperature and reduced to 25.3 Kg CCS when heated
to 1000"C under reducing conditions. The strength loss may be due to loss of binder between the iron particles during heating, swelling and pores formation in the briquettes.
It was also observed that the strength increased to 61 Kg CCS when the briquettes were subjected to 1200"C. Highest strength of 139 Kg CCS was obtained when the reduced
briquettes were given to 60-min sinter time at 1200°C. This behavior is may be due to fusion of iron whiskers and formation of eutectic slag bond between newly formed iron
grains.