Enhanced Reduction Disintegration Index (RDI) and Reduction Swelling Index (RSI) of Iron Ore Cold-Bonded Briquettes Through Optimized Binder Percentage and Varying Briquetting Pressure Parameters
摘要
This study is focused on addressing the global issue of CO2 emissions from iron industries. The contribution of CO2 emissions by the Chinese steel sector is around 15% at the national level and 7% at the global level. A novel compound binder has been developed and incorporated in cold-bonded briquettes (CBBs) of magnetite iron ore fines to minimize this emission from blast furnaces (BFs). CBBs are prepared with 3–7 wt% compound binder under varying briquetting pressures ranging from 25 to 400 MPa. Results showed that CBBs with 5 wt% (CB-5) achieved a maximum compressive load of 5064 N at 350 MPa with drop count of 31 at 325 MPa, and powder generation rate (PGR) was reduced to 0.21% at 300 MPa. Reduction disintegration index (RDI) analysis revealed that the prepared CB-5 briquettes surpassed the critical threshold of 68% at pressures from 200 to 300 MPa, indicating strong structural integrity. Reduction swelling index (RSI) was reduced to approximately 7.57% at 300 MPa, signifying limited volumetric expansion during reduction. Uniform distribution of the binder was revealed by morphological studies. The concentration of harmful elements (Na and Zn) below its critical level was observed by energy-dispersive X-ray (EDX) analyses as per standard (YB/T 4803–2020). A cost reduction of 12% per ton was observed as compared with conventional sinter and 17% per ton for pellets. This ecofriendly and cost-effective process will provide an alternative to existing conventional iron burden material for BFs.
Graphical Abstract