Preparation of High-Carbon Metallic Briquette for Blast Furnace Application

Abstract

Developments in blast furnace (BF) ironmaking have long focused on low-coke operation. In this study, high-carbon metallic briquettes (HCMB) were prepared using ultrafine iron oxide powders and coal fines for BF application. The preparation conditions were optimized, and the binding mechanism of the briquette was analyzed. The gasification behavior of the optimally prepared HCMB was investigated under conditions simulating the in-furnace environment of the BF, and its application in BF was evaluated through numerical simulations. The results showed that the optimal preparation condition was m_hematite/m_coal = 2.0. The optimally prepared HCMB had a carbon content of 25.6 wt%, cold strength (CS) of 1300 N/briquette, and crushing strength after reaction (CSR) of 2500 N/briquette. The high strength of the briquette was attributed to the iron network binding. The threshold temperature and activation energy of the briquette gasification in the blast furnace were 973 K and 166 kJ/mol, respectively. Simulation results on the HCMB application in a BF of 2500 m³ indicated that mixing HCMB of 5% into the ore burden could save approximately 12.5 kg of coke for producing one ton hot metal from the ore.