Reduction Behavior of Carbon Composite Pellets Including Alumina and Silica at 1273 K and 1373 K

Abstract

The effect of alumina and silica on the reaction behavior of carbon composite pellet was investigated by thermogravimetric analysis at 1 273 K (1 000°C) and 1 373 K (1 100°C). X-ray diffraction was used for the phase analysis of iron oxide changing from hematite to reduced iron. The overall reaction was divided into three stages according to phase transformation of iron oxide. CO and CO2 from off-gas data was used for kinetic analysis and for understanding reaction mechanism. The Boudouard reaction was largely influenced by alumina and silica that changed CO gas concentration resulting in different reduction behavior of the pellets. Alumina increased the reaction rate of carbon composite pellet while silica decreased the overall reaction rate.

Experiments and Kinetic Modeling for Reduction of Ferric Oxide-biochar Composite Pellets

“…[13][14][15][16] This process provides an advanced utilization opportunity for the high volatile coals as well as biomass materials. [17][18][19][20][21][22][23][24][25][26][27][28] Gupta et al 17) have investigated the behavior of water hyacinth char addition in iron ore pellet. The results shown that the biomass char could be a potential for making iron ore pellet.…”

Effect of Silica on Reduction of Calcium Ferrite with CO–N₂ Gas Mixtures

“…2,3) Hyunsik 4,5) explored the effect of silica on the reduction kinetics of carbon composite pellets and found that silica decreases the reduction rate by lowering…”

Reduction Behavior of Dolomite-Fluxed Magnetite: Coke Composite Pellets at 1573 K (1300 °C)

“…Determination of the reduction mechanism for Stage 2 was unnecessary since the kinetics of the Fe 3 O 4 to FeO reaction within this region is comparatively fast and was not the rate-determining factor for the overall reaction. Details on the reaction mechanism of carbon composite hematite pellets have also been described by Park and Sahajawalla, [16,17] where the solid-solid reaction, intermediate gaseous reduction as well as the Boudouard reaction takes place during the overall reaction. Although the present study utilized magnetite concentrates, the basic reduction mechanism can also be incorporated similar to the case of reagent grade hematite.…”

“…The present authors have also studied the effect of minerals on the reduction of carbon composite pellets in terms of the reducibility and physical property. [14][15][16][17] However, carbonaceous material was limited to synthetic graphite in the previous studies and the effect of carbon content and mineral phases during the reduction process has yet to be fully understood. In particular, utilization of process by-products including coke breeze and waste dolomite in excess of 5 pct and more and its effect on the reducibility and physical strength has not been studied to the knowledge of the present authors.…”