Research On The Relationship Of Microstructure And Composition Of Manganese Mineral With Microwave Absorption Characterizes

Microwave absorbing ability of mineral and microwave absorption mechanism are the key factors that decide whether or not microwave can be used to heat mineral and what technology and how equipment development shall be used. In this paper the microwave absorbing ability of mineral was investigated by the heating rate of mineral, electromagnetic parameter and microwave energy absorption of mineral. More over, thermal gravimetric and differential thermal, scanning electron microscopy and XRD refinement etc. had been used to study the effect of mineral microstructure on microwave absorbing ability of mineral. Finally, we discussed the relationship between microwave energy absorption of mixed mineral and their macro performances. The results show that:(1)Heating rate method, permittivity method and intermediate medium calorimetry method were used to investigate the sensitivity of the mineral to microwave in three contexts. For pure minerals, three evaluation methods have little difference for the conclusion, but for mixed minerals, there was significant difference; Heating rate method intuitively reflects the changing rule of the actual temperature of minerals in the microwave field; permittivity method reveal the sensitivity of mineral to microwave from the perspective of electromagnetic properties; intermediate medium calorimetry method analyze the law of using microwave for minerals in the microwave field from the perspective of energy.(2)The basic law of the results by three kinds of test methods are basically the same except daxin manganese dioxide and manganese metal powder. γ-MnO2 is most sensitive to microwave, the second are taishan MnSO4·H2O and MnC03, after that are Mn2O3 and Mn3O4. MnO and tianjin MnSO4·H2O are the weakest absorbers of microwave energy.(3)Composition and structure of mineral are the key factors that influence the relative absorbed microwave energy of mineral. The results showed that TaiShan MnSO4·H2O and TianJian MnSO·-H2O, γ-MnO2 and β-MnO2 have a big difference in absorbing microwave energy although they have the same composition, which indicate that micro-structure of mineral have a significance influence on microwave absorption characteristics of mineral.(4)The results of thermogravimetric-differential thermal analysis and XRD structure refinement analysis showed that water crystallization and binding mode, grain size, and lattice distortion are the main causes that influence mineral absorption of microwave energy.(5)Both grain size and lattice distortion of TianJin MnSO4·H2O are bigger than that of TaiShan. The grain size of β-MnO2 is smaller than γ-MnO2, but lattice distortion of β-MnO2 are bigger than γ-MuO2. TaiShai MnSO4·H2O and β-MnO2 which have small grain size shown a strong ability in absorbing microwave energy.(6)The law of microwave absorption of mixed material shows that the material still kept their own microwave absorption characteristics. The material which is transparence to microwave or weak in absorbing microwave was not able to influence microwave absorption characteristics of sensitive materials.(7)Microwave absorption characteristics have a significance effect on mixed material in absorbing microwave. Energy absorbing of mixed material increases non-linearly with increasing the quality percentage of strong absorbent material.(8)For strong and weak microwave absorbing materials, tendency of relative microwave energy change was similar when replaced the middle medium. But the relative value of the absorbed microwave energy was difference. The relative value of materials in absorbing microwave energy was negatively correlated with absorbing energy of intermediate medium.(9)Placing different materials into the microwave cavity, when the volume is large enough, the utilization efficiency of microwave cavity would be influenced in varying degrees. When there was a strong microwave absorbing materials, the utilization efficiency of cavity was high because of low loss caused by cavity. When a weak microwave absorbing materials in the cavity, the utilization efficiency of cavity was low since the loss caused by cavity became high.