Physicochemical properties of metallized pellets of high-chromium vanadium-bearing titanomagnetite
WU En-hui1,2, LI Jun1,2, XU Zhong1,2, HOU Jing1,2, HUANG Ping1,2
1. College of Vanadium and Titanium, Panzhihua University, Panzhihua 617000, Sichuan, China; 2. Vanadium and Titanium Resources Comprehensive Utilization Key Laboratory of Sichuan Province, Panzhihua 617000, Sichuan, China
Abstract：The iron, vanadium, titanium and chromium of high-chromium vanadium-bearing titanomagnetite can be comprehensively utilized by coal based direct reduction-electric furnace melting separation new process, which is one of the most promising non-blast furnace smelting processes. The physicochemical properties of high-chromium vanadium-bearing titanomagnetite metallized pellets have an important impact on the subsequent electric furnace melting and separation process. Based on this, the effects of reduction temperature, reduction time, coal-ore mass ratio and binary basicity on the physicochemical properties such as phase composition, metallization rate, carbon residue, resistivity and compressive strength of metallized pellets during coal based direct reduction were investigated. The magnetite and ilmenite were reduced to metallic iron and anosovite with increasing the reduction temperature and prolonging the reduction time, while higher coal-ore mass ratio and binary basicity have an adverse effect on the reduction process. The resistivity of the metallized pellets depends on the phase compositions, the content of different phase compositions and the combination form between each phase compositions of the metallized pellets. There was an obvious negative correlation between the metallization rate and resistivity of metallized pellets, while the degree of negative correlation decreased with the metallization rate increased. When the metallization rate was higher than 90%, the resistivity of metallized pellets was lower than 0.5 Ω/cm. The formation content of metallic iron and the connection form between metallic iron grains were the key factors affecting the compressive strength of metallized pellets. The increase of reduction temperature and reduction time was favorable to improve the compressive strength of metallized pellets, while the compressive strength of metallized pellets decrease with increasing the coal-ore mass ratio and binary basicity. Under the condition of reduction temperature of 1 300 ℃, reduction time of 35 min, coal-ore mass ratio of 25∶100, and binary basicity of 0.13, the metallization rate, carbon residue, resistivity and compressive strength of metallized pellets are 92.58%, 5.39%, 0.3 Ω/cm and 81.74 N/pellet respectively.
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2023, Vol. 58 
