CHEN Guan-Jhou National Cheng Kung University

Spoluautoři Weng-Sing Hwang, Shih-Hsien Liu and Jia-Shyan Shiau

In this study, carbothermic reduction experiments with different laterite ores mixed with bio-coal were conducted. Different reduction temperatures (900-1400 oC) were also used with the carbothermic reduction process to study the direct reduction mechanism. Results show that major phase were Fe1.833(OH)0.5O2.5 and Fe2SiO2 before reduction of limonite. After reduction, the phase was Fe. The major phases were Fe(CO3)、Fe3O4、Fe2SiO4 and Al3S4 before reduction of saprolite. After reduction, the phases were Fe、Fe0.64Ni0.36 and α-Fe10.08Ni. For the reduction, bio-coal had become the reductant. Nickel content of limonite had been raised from 1.18 to 1.64 % and the nickel content of saprolite from 3.43 to 4.93 %. The observations show that for the carbothermic reduction mechanism of pellet, the outer layer of pellet formed a dense area and the core of pellet had loose area in the initial reduction reaction. When the pellet was produced in the two-phase region at 1200 oC, the pellet had a significant shrink. The shrinking rate is 30 %. Finally, the pellet formed nickel-iron alloy phase and iron was separated from the oxide phase.