Gasification Behavior of Phosphorus during Hydrogen-rich Sintering of High-phosphorus Iron Ore

• Published in: ISIJ International Vol. 62; no. 3; pp. 496 - 503
• Main Authors: Chen, Yanbiao, Liu, Wenguo, Chen, Jiansheng, Zuo, Haibin
• Format: Journal Article
• Language: English
• Published: The Iron and Steel Institute of Japan 15-03-2022
• Subjects: hydrogen-rich sintering; phosphorus gasification; reaction mechanism; reduction temperature
• ISSN: 0915-1559; 1347-5460
• DOI: 10.2355/isijinternational.ISIJINT-2021-468

In order to realize the efficient utilization of high phosphorus iron ore resources, a new method of phosphorus gasification removal in hydrogen-rich sintering process was proposed. In this paper, the gasification behavior of phosphorus in hydrogen-rich sintering process of high-phosphorus iron ore was studied. Thermodynamic calculation of possible reactions is carried out by using FactSage6.1 software, and the phase transformation and distribution of phosphorus in the process of roasting reduction were analyzed by XRD, SEM-EDS and EPMA. The experimental results show that in hydrogen-rich atmosphere, the dephosphorization rate increased from 9.9% to 29.51% and then decreased to 8.62% in the temperature range of 900°C–1200°C, and the maximum value appeared at 1100°C. Compared to the carbon reduction, the dephosphorization rate in hydrogen-rich atmosphere increased significantly in the whole temperature range, and the maximal dephosphorization rate could be improved from 15.03% to 29.51%. The results of thermodynamic analysis showed that the initial temperature of direct reduction of apatite by hydrogen is higher, and adding SiO2 and Na2CO3 allowed to decrease the reduction temperature of apatite by hydrogen to about 946.50°C. With the increase of reduction temperature, the reduced phosphorus gas was absorbed by metallic iron to form stable iron phosphorus compounds, resulting in the decrease of dephosphorization rate. Therefore, in order to realize the gasification removal of phosphorus, the selective reduction of iron oxide and apatite should be realized, and the formation of liquid iron should be avoided as far as possible in the reduction process.