Carbothermic Reduction of Hematite Powders by Microwave Heating

Abstract

To examine the applicability of hematite ore to the ironmaking by microwave heating, the carbothermic reduction of hematite powders by microwave heating were elucidated using the gas analysis of exhausted gas, and were compared with that of magnetite powders. The temperature of the hematite -graphite mixed powders moderately increases at the beginning, and then, starts to increase abruptly at around 400°C owing to the thermal runaway of Fe2O3. Once the reduction reaction starts to take place, the reduction reaction rate of hematite is even faster than that of magnetite, which is the same behavior as that observed by conventional heating. Hematite ore could be a possible raw material for microwave ironmaking: When hematite ore is utilized, the ore should be preheated up to around 400°C prior to the feeding to a microwave furnace.

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.…”

“…Konishi et al [19][20][21][22] investigated the pellets containing biochar can reduce the use of carbonaceous reductant and cut CO 2 emission. Hayashi et al 23) compared different carbothermic reductions of hematite and magnetite powders under the condition of microwave heating and analyzed different procedures. Rashid et al 24) investigated the utilization of low grade iron ore and palm kernel shell (PKS) waste biomass as an alternative energy source in ironmaking.…”

Microwave Carbothermic Reduction of Oolitic Hematite

“…Microwave heating provides several advantages through savings in energy, space and time, and a reduction in the environmental impact of material processing. There are have lots of literatures referred to the microwave reduction of oxides ores, such as magnetite, 13) hematite, 14) vanadium titano-magnetite, 15) steel making slag and sludge, 16) nickeliferous silicate laterite, 17) malachite concentrate, 18) bauxite ore, 19) and so on. In the present work, the reduction of coke-bearing oolitic hematite pellets were conducted at temperature of 1 273-1 523 K in a temperature controllable microwave cavity with the output power of 0-1.5 kW.…”

Observation of localized heating phenomena during microwave heating of mixed powders using in situ x-ray diffraction technique

“…AT-5 graphite was used as to approximate the conditions and to enable comparison with microwave carbothermal pig iron reduction research, 1,3 in which that graphite powder is commonly employed. MgO and Al 2 O 3 were selected because of their high intensity XRD peaks in the vicinity of the strongest graphite XRD peak, and their comparatively low microwave absorptivity.…”

“…One example of such research is on microwave pig iron making, where iron ore powders mixed with graphite are reduced using microwave heating. [1][2][3] During microwave irradiation, the energy absorbed per volume is expressed as a function of the electric conductivity r, the complex relative electrical permittivity e 00 and the complex relative magnetic permeability l 00 . 4,5 For the pig iron making process mentioned above, materials could be heated using microwaves due to the high electric conductivity and permittivity of graphite, and the high magnetic permeability of magnetite iron ore.…”