Study On The Dielectric Properties Of Microwave-thermally Reduced Chromite Ore Powder

Ferrochromium,as essential material,is added to the production of stainless and high-alloy ferritic steel.The method of traditional smelting is smelting by converter and electric smelting.However,the former mainly have high energy-consuming(1800℃～2000℃)and higher requirements on refractory material;The latter is easy to increase the carbon content with loss of carbon electrode.Thus,it is necessary to explore a process to smelt the low carbon ferrochrome efficiently.In recent decades,microwave,as a new type of heating technology,gradually replaces the traditional heat,because there are some characteristics of the selective heating,rapid heating,,good controllability,environment pollution-free and it can avoid the phenomenon of uneven in the traditional heating.Therefore it have extensive application in metallurgical.It can avoid the step of pelletizing in microwave heating.Meanwhile,Silicon-containing chromite ore fines can be directly into the chamber for reaction and not only reduce the reaction temperature but also improve the reduction rate of chromite ore fines.Significant advantages of microwave depends mainly on its dielectric loss generating heat of the heating mode.This paper has analyzed chromite ore fines,ferrosilicon alloy,flux,mixed material dielectric properties and discussed the particle sizes,ratio of Si and O,apparent density and alkalinity on the influence of material dielectric properties,which provides the theoretical foundation for the next step of chromite smelting.1.The paper take the chromite ore fines as raw material,ferrosilicon alloy as reductant,CaO as fluxing agent,then mix the materials into the microwave resonant cavity,observe the change of the microwave resonant frequency(f)and the quality factor(Q)and measure material dielectric properties can be obtained,the microwave absorbing properties can be measured.2.This paper mainly studied the dielectric properties of the experimental materials(including different particle size of chromium iron ore powder,silicon powder,ferrosilicon alloy,siliceous lime,magnesium lime)in 2450MHZ.The experimental results show that with the particle size decreases,the dielectric properties of the chromium iron ore powder is better;The dielectric properties of ferrosilicon alloy powders and calcium lime is better than that of silicon powder and magnesia lime.3.The paper has studied the influence of silica ratio to the dielectric properties.The silica ratio is design from 0.36 to 0.62,finally it is concluded that when silica ratio is 0.50,the dielectric properties material is best.4.The paper has studied the influence of alkalinity to the dielectric properties.Several groups of alkalinity contrast test designed from 1.60 to 1.80,finally it is concluded that when silica ratio is 1.80,the material dielectric properties is best.5.The paper studied the influence of apparent density to the dielectric properties.And found that with the increasing of apparent density,dielectric properties of materials increases.Above all,we have known that the particle size of the chromite ore fines and the apparent density,Si:O and alkalinity of silicon-containing chromite ore fines have effects on dielectric properties of material,this paper has provided some theoretical basis for the reduction of chromite.