Study On Preparation Of SiO₂(?-Fe₂O₃)from Blast Furnace Slag And Its Electromagnetic Absorption Properties

At present,the utilization rate of blast furnace slag is close to 100%,but the traditional extensive utilization accounts for a large proportion,mainly in the field of building materials.However,the silicon-based refined utilization technology of blast furnace slag cannot be widely used in the end due to the influence of the trace iron component.If the trace iron component that is difficult to remove can be used as a functional component instead of an impurity,and form a ferrite structure with the silicon element in the system,the iron removal process with a long process and high energy consumption can be omitted,and at the same time,two Silicon oxide wave absorption function.Based on this,this article uses blast furnace slag as the main raw material,after adding an external iron source,two methods of conventional aging and microwave aging are used to prepare Si O₂(?-Fe₂O₃)composite materials,using XRD,FT-IR,XRF and VNA,etc.Modern analytical methods have carried out systematic research on the phase structure,chemical bond changes,and microwave absorbing properties of samples.The main conclusions are as follows:(1)The crystallinity of the precursor under conventional aging is greatly affected by the mass ratio of iron slag,the mass fraction of sulfuric acid,the p H value of aging and the aging temperature,and is less affected by the aging time;except for the mass ratio of iron slag Except for positive correlation,it is negatively correlated with others.Taking the conversion rate as the evaluation criterion,the optimal process conditions for preparing the precursor are:iron slag mass ratio 1:1,sulfuric acid mass fraction 14.29%,aging p H value 2.9,aging temperature 100?,aging time 12 h,At this time,the conversion rate can reach 42.1%.The optimal process conditions for the precursor calcination are:the organic reducing agent is citric acid,and the calcination temperature is 400?.At this time,the target product Si O₂(?-Fe₂O₃)can be obtained.(2)The crystallinity of the precursor under microwave aging is greatly affected by the mass ratio of iron slag,the mass fraction of sulfuric acid,the p H value of aging,and the microwave power,but is less affected by the microwave time;except that it is positively correlated with the mass ratio of iron slag Besides,it is negatively correlated with others.The conversion rate is also used as the evaluation standard.The optimal process conditions for the preparation of precursors under microwave conditions are:iron slag mass ratio 1:1,sulfuric acid mass fraction 14.29%,aging p H value 2.9,microwave power 90 W,microwave time 5 h,The conversion rate reached 43.34%at this time.(3)Due to the selective heating characteristics of microwave,the fluctuation range of the crystallinity of the precursor obtained by microwave aging is higher than that of conventional aging samples;due to the instant heating characteristics of microwave,when the same conversion rate is reached,the time required for microwave aging is Shortened by2.4 times.(4)The dielectric properties of Si O₂(?-Fe₂O₃)prepared by conventional aging methods are lower than that of single Si O₂,and the permeability performance is higher than that of single Si O₂,and it exhibits obvious wave absorption in 12?13GHz;microwave aging method The prepared Si O₂(?-Fe₂O₃)electric field energy absorption performance is lower than that of a single Si O₂,and the electric field energy loss is slightly higher than that of a single Si O₂the magnetic field energy absorption performance is equal to that of a single Si O₂,and the magnetic field energy loss performance is higher than that of a single Si O₂;And it shows obvious wave absorption in 8?10GHz.The change of the aging method will basically not affect the reflection loss ability of Si O₂(?-Fe₂O₃),but will only change the frequency band of the absorbing effect.