Mechanism on reduction swelling of pellets prepared from Bayan Obo iron ore concentrate

ABSTRACT

The composition of Bayan Obo iron ore concentrate is complex. If a large proportion is used to prepare pellets, abnormal swelling will occur during blast furnace smelting. This paper studies the swelling behavior of pellets prepared from Bayan Obo iron ore concentrate in stages during the reduction process; XRD and SEM-EDS analysis and calculates the crystal parameters of the reduction products in each stage. The results show that the total RSI of pellets prepared from Bayan Obo iron ore concentrate is as high as 35%, and the third stage of reduction has the maximum swelling rate, which is 24%. The mechanisms of the three stages reduction swelling of pellets are the crystal transformation, the effect of slag phase and the growth of iron whiskers. The results can enrich the reduction swelling theory of pellets prepared from complex intergrowth minerals.

KEYWORDS:

• Ironmaking
• Bayan Obo iron ore concentrate
• pellets
• reduction in stages
• reduction swelling
• iron oxide
• crystal transformation
• iron whisker

Disclosure statement

No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

The authors acknowledge the financial support of National Natural Science Foundation of China [grant number 51904161], Special Project on Transformation of Scientific and Technological Achievements in Inner Mongolia [grant number 2019CG073], National Key Research and Development Program of China [grant number 2020YFC1909105], Natural Science Foundation of Inner Mongolia Autonomous Region [grant number 2019LH05006] and Scientific Research Foundation of the Higher Education Institutions of Inner Mongolia Autonomous Region [grant number NJZZ19123].