The potential for material processing by microwave energy
This paper presents the potential applications for material processing by microwave energy which is electromagnetic waves that penetrates material and cause its molecules to rotate and generate heat. In this paper, potential uses of microwave energy in iron and steel making processes will be discussed in detail. Actually, microwave energy has been in use for various applications for over half century. One of the most well known applications is drying and cooking of food. Currently, industrial uses of microwave energy include direct-reduced iron making, wood processing, sintering, coke making, and so on. And moreover, CO2 and CH4 can be decomposed by super heating effect of microwave energy which can also be called as high temperature plasma furnace. In conventional heating processes, the materialpsilas surface is heated first and then the heat moves inward, while the material is heated the entire volume at about the same time, in microwave heating processes. Microwave heating method can be used in addition to conventional heating techniques to enhance the reaction of the material processing.
Microwave Application in Carbothermic Reduction of Iron Ores
Reduction of hematite fines and magnetite concentrates containing carbon using microwave energy was investigated. The reduction rate was found to be very rapid under all conditions employed. The nature of the ore mineral and flux (lime and limestone) did not influence the reduction but the nature of carbon had an effect, with charcoal being superior to coke.Microwave reduction is a highly non-isothermal process and bearing this in mind, the effect of temperature on reduction was exponential. Difference between the reduction of identical samples with microwave and conventional heating (1000°C) was remarkable–in favour of microwave heating.
Application of Pulse High-Energy Electron Beams for Decomposition of Chlorofluorocarbon in Atmospheric-Pressure Air
It is experimentally shown that a pollutant (Freon) in at mospheric-pressure air can be decomposed by irradiation of pulse high-energy electron beams. Pulse electron beams having 100∼220 kV energy with about 500 ns pulse width and a current density of about 3 A/cm2 were injected into air contaminated with Freon-12 of 300∼4800 ppm. Freon-12 in the gas cell was reduced by about 5% per pulse. Freon might be decomposed to CO2, hydrides of Cl or F and intermediate large molecules through the chemical reaction between Freon, air and the mixed hydrogen or residual water vapor. The decomposition rate was almost constant even though the density of Freon was changed from 300 to 4800 ppm. The decomposition rate and the decomposed amount greatly increased upon increasing the beam energy (150 to 220 keV) and current (310 to 780 A). The efficiency of decomposition for beam power increased to 100 nmol/J upon increasing beam energy to 82 J per pulse.