Preparation Process and Properties of Pellets from PFC1 Hematite Concentrate

The shortage of high-quality pellet feed has constrained the green transformation of blast furnaces, making it urgent to find economical alternative materials. This study investigated the effects of different blending ratios (0-30%) of Brazilian hematite concentrate PFC1 on the ballability, firing characteristics, and metallurgical properties of the mixed feed. The results showed that PFC1 had a relatively coarse particle size (59.1% passing -0.074 mm) and a low specific surface area (847 cm²/g), but exhibited a rapid capillary water migration rate (13.33 mm/min) and an optimal static ballability index (K_p = 0.26). At PFC1 blending ratios of 10-20%, the green balls achieved a drop strength >4 times/0.5 m, a compressive strength of approximately 18 N·P^-1, and a decrepitation temperature ≥ 480 °C, demonstrating the best balling performance. In firing tests, the pellet strength showed a decreasing trend with increasing PFC1 proportion; however, under the firing regime of 1220 °C for 9-15 min, the compressive strengths of finished pellets from all schemes exceeded 2700 N, meeting the requirements for blast furnace use. The addition of PFC1 significantly improved the reducibility (RI increasing from 52% to 66.4%), while the reduction swelling index remained controllable (RSI ≤ 12.44%). Pot-grate tests validated the laboratory results, and the recommended industrial blending ratio of PFC1 is 10-20%. These findings provide a theoretical basis and process reference for the economical utilization of hematite-type concentrates.