Thermodynamic studies on selective oxidation of Nb, P and C in dephosphorization of low niobium hot metal
The main problem with the efficient utilization of Nb resource in the Boyan Obo Ore lies in the selective oxidation of Nb, P and C. In this work, thermodynamic studies have been conducted to determine the conditions of selective oxidation of Nb, P and C in low niobium hot metal in the process of oxidizing dephosphorization. The thermodynamic condition for dephosphorization was determined as: 1ga(P2O5)≤38754/T-27.82+51gaO+21GaP The condition for retaining Nb from oxidation is: 1gaO-Nb≤1/51ga(Nb2O5)-2/51gfNb-2/51g％Nb-70425/T+28.14 The oxygen activity for oxidation of Nb, C and P is relevant to the initial C content in hot metal. The equilibrium oxygen activity of Nb-O reaction increases with an increase of the C content, whereas the equilibrium oxygen activity of C-O and P-O reactions varies oppositely with the C content. The reduction of52OParesults in a decrease of the C content required for removing P and retaining Nb, as well as makes the process of dephosphorization more feasible. The increase of temperature decreases the C content of selective oxidation of Nb and P, but is unfavorable to dephosphorization.Under the conditions of T>1650K，C=4.0％，Nb=0.02％，αP2O5=10-24,αNb2O5=10-10,P in hot metal can be removed to 0.01％ while 0.02％ of Nb can be retained in hot metal without oxidized.
Dephosphorization selective oxidation niobium phosphorus thermodynamics
Yongli JIN Zengwu ZHAO Jieyu Zhang Baowei LI
School of Materials Science and Engineering, Shanghai University, Shanghai, 200072, China Inner Mong Inner Mongolia Key Laboratory for Utilization of Bayan Obo Multi-Metallic Resources，Elected State Ke School of Materials Science and Engineering, Shanghai University, Shanghai, 200072, China
国际会议
Ninth International Conference on Molten Slags,Fluxes and Salts(第九届国际熔渣、溶剂与熔盐学术会议 MOLTEN12)
北京
英文
1-10
2012-05-27（万方平台首次上网日期，不代表论文的发表时间）