Mini blast furnaces are reactors that traditionally produce pig iron from charcoal using granular ore with some agglomerate substitution. This work proposes metallic burden replacement by self-reducing agglomerates and reutilization of cleaned top gas injected into the shaft of the mini blast furnace where charcoal or small coke from a large blast furnace are used as the reducing agent. This technology was evaluated using a previously validated, blast furnace computational code based on the transport phenomena. Several scenarios combining the charging of the furnace with self-reducing agglomerates and reutilization of cleaned top gas were simulated. Based on the simulation results, it can be concluded that up to 45% of the metallic burden could be replaced by self-reducing agglomerate combined with the reutilization of the top gas. The best conditions indicated an increase in productivity of around 8% with charcoal as the reducing agent. Results showed that decreases of 30% and 40% of the reducing agent could be achieved for operations with charcoal and small coke, respectively.
Mini blast furnace; self-reduction; recycling gas
