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<p>Hematite concentrates have gradually become one of the important pellet feeds. However, hematite pellets suffer from poor roasting performance, high temperature requirements, and severe reduction degradation and swelling. Therefore, it is of great importance to improve the reduction behavior of fired high-grade hematite pellets. The effect of basicity and reduction methods on the reduction behavior of hematite pellets has been studied, and it has been shown that increasing the binary basicity of pellets from natural basicity (R = 0.04) to 0.20 is beneficial to reduce the reduction swelling index from 44.36% to 22.13%. Moreover, modifying the coal feeding mode by step coal adding and temperature elevation led to the reduction of the swelling index further down to 15.42%. Meanwhile, the cold compressive strength of reduced pellets increased from 50 N/P to 545 N/P. Mechanistic analysis showed that the increase in basicity led to an increase in the liquid phase inside the reduced pellets and a decrease in the reduction rate, thereby improving the properties of the pellets. In addition, pilot tests were conducted and the final metallized pellets had an iron grade of 93.37%, metallization degree of 96.62%, a sulfur content of 0.012%, cold compressive strength of 507 N/P, and a magnetic powder rate of only 2.09%.</p>

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Improving Coal-Based Direct Reduction Behaviors of Fired High-Grade Hematite Pellets by Modifying Basicity and the Coal Feeding Mode

  • 期刊论文

  • 发表日期：

    2026年2月3日

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  • Bohua Li,
  • Zhengqi Guo,
  • Deqing Zhu,
  • Yue Shi,
  • Ming Wang,
  • Wuju Zhang

摘要

Hematite concentrates have gradually become one of the important pellet feeds. However, hematite pellets suffer from poor roasting performance, high temperature requirements, and severe reduction degradation and swelling. Therefore, it is of great importance to improve the reduction behavior of fired high-grade hematite pellets. The effect of basicity and reduction methods on the reduction behavior of hematite pellets has been studied, and it has been shown that increasing the binary basicity of pellets from natural basicity (R = 0.04) to 0.20 is beneficial to reduce the reduction swelling index from 44.36% to 22.13%. Moreover, modifying the coal feeding mode by step coal adding and temperature elevation led to the reduction of the swelling index further down to 15.42%. Meanwhile, the cold compressive strength of reduced pellets increased from 50 N/P to 545 N/P. Mechanistic analysis showed that the increase in basicity led to an increase in the liquid phase inside the reduced pellets and a decrease in the reduction rate, thereby improving the properties of the pellets. In addition, pilot tests were conducted and the final metallized pellets had an iron grade of 93.37%, metallization degree of 96.62%, a sulfur content of 0.012%, cold compressive strength of 507 N/P, and a magnetic powder rate of only 2.09%.