The effect of bio-coal on the carbothermic reduction of laterite ores

Abstract

In order to investigate the effect of bio-coal on the carbothermic reduction of laterite ores, carbothermic reduction experiments of two type laterite ores mixed with bio-coal were conducted in this research. The reduction experiments were carried out at 11731673K for 1800 s in Ar. Compared reduction results of coal and bio-coal show increasing the nickel content with increasing temperature. Bio-coal had become the reductant, the nickel content of limonite specimens and saprolite specimens had been raised from 1.18 mass% (before reduction) to 1.64 mass% (after reduction at 1373K for 1800 s) and from 3.43 mass% (before reduction) to 4.93 mass% (after reduction at 1473K for 1800 s), respectively. The major phases of limonite specimens were Fe 1.833 (OH) 0.5 O 2.5 and Fe 2 SiO 2. After the reduction at 1473K for 1800 s, the major phase was metal Fe. The major phases of the saprolite specimens were Fe(CO 3), Fe 3 O 4, Fe 2 SiO 4 and Al 3 S 4. After the reduction at 1473K for 1800 s, the major phases were Fe, Fe 0.64 Ni 0.36 and α-Fe 10.8 Ni. The morphological observation of limonite and saprolite specimens shows that the pelletshaped specimen became a dense area and the core of the pellet had loose structure at 11731374K for 1800 s. The core of pellet was produced small spherical metal phase at 1473K for 1800 s, this temperature was the soft melting temperature. Finally, the pellet produced nickel-iron alloy phase and iron was separated from the oxide phase at 1673°C for 1800 s.