A novel approach to enhance decrepitation temperature and reducibility of ultrafine iron ore concentrate pellets

Utilizing ultrafine iron ore concentrate for pellet production can expand domestic iron ore resources in China and promote the utilization of low-grade ores. However, a challenge arises with the low decrepitation temperature and reducibility in the preparation process of ultrafine iron ore concentrate pellets. To address the challenge, a novel approach was proposed, which incorporated straw powder as an additive to enhance pellet porosity, thereby improving the decrepitation temperature and reducibility of ultrafine iron ore concentrate pellets. The effect of varying proportions of straw powder (0.0–2.0%) on the characteristics of ultrafine iron ore concentrate pellets was examined. Results indicate that at a 2.0% straw powder ratio, pellet decrepitation temperature notably rises from 380 to 540 °C, while the reducibility index escalates from 25.7% to 48.1%. Nevertheless, the addition of straw powder results in diminished drop strength, compressive strength of green pellets, and cold crushing strength of fired pellets. In addition, enhanced pellet reducibility leads to exacerbated reduction swelling index and reduction degradation index. Despite these effects, all parameters remain within an acceptable range.