微波场中锰矿物微结构及物料组成与其吸波性能的相关性研究

发布时间：2019-02-16 00:20

【摘要】：矿物吸收微波能力及吸波机理是矿物能否应用微波进行处理以及处理工艺选择、处理设备开发的关键因素。本论文从矿物在微波场中的升温速率、矿物的电磁参数、矿物吸收微波能量三个角度探讨矿物吸收微波能力；并运用热重差热、扫描电镜、XRD精修等分析方法来研究矿物自身微结构对其吸波能力的影响；最后探讨不同组成的混合矿物吸收微波能量与其宏观性能的相关性。结果表明：(1)升温速率法、介电常数法、中间介质量热法三种方法从三个角度探讨矿物对微波的敏感性。对纯矿物而言,三种评价方法获得的结论差别不大；对混合矿物而言,存在显著差异；升温速率法较为直观的反应物料在微波场中实际温度的变化规律；介电常数法从物料电磁特性的角度揭示物料对微波的敏感性；中间介质量热法从能量角度分析微波场中物料对微波能量的利用规律。(2)升温速率法、介电常数法、中间介质量热法等三种方法研究矿物吸波能力时,除了大新二氧化锰矿和锰金属单质粉末,三种方法的测试的基本规律基本一致。γ-MnO2对微波的敏感性最强,其次是台山MnSO4·H2O和MnCO3,之后是Mn2O3和Mn3O4, MnO和天津MnSOH2O的对微波的敏感性最弱。(3)矿物的成分和结构是影响矿物吸收微波能量相对值的关键因素。研究发现,台山MnSO4H2O和天津MnSO4-H2O,γ-MnO2和β-MnO2其成分相同,但其吸收微波能量相对值差异较大,说明矿物微观结构对吸收微波能量相对值影响显著。(4)热重差热分析及XRD结构精修等分析结果表明,结晶水及其结合方式、晶粒尺寸、晶格畸变是影响矿物吸收微波能量的主要原因。(5)天津MnSO4·H2O的晶粒尺寸和晶格畸变都比台山的大,而β-MnO2晶粒尺寸小于γ-MnO2,但其晶格畸变却大于γ-MnO2;晶粒尺寸小的台山MnSO4·H2O和β-MnO2都表现出了强的吸波能力。(6)混合物料微波吸收能量规律表明,物料混合后依然保持各自的吸波特性,不吸收微波或吸波弱的物质的存在并不会影响强吸波物质自身的吸波特性。(7)自身的吸波能力对混合物料在微波场中吸收微波能量有显著影响。随着强吸波物质的质量百分比的增加,混合物料吸波能量呈非线性上升。(8)对于强吸波物质MnO2和弱吸波物质MnCO3来说,更换中间介质后相对微波能变化趋势相似,但其吸收微波能量的相对值不同。物料吸收微波能量相对值与中间介质吸波能量呈负相关。(9)不同的物质放入微波腔体,当体积足够大时,都会不同程度影响腔体内微波的有效利用率。强吸波物质存在腔体时,腔体损耗小,微波利用率高；弱吸波物质存在腔体时,腔体损耗大,微波利用率低。
[Abstract]:The microwave absorption ability and absorbing mechanism of minerals are the key factors for the treatment of minerals by microwave, the selection of treatment process and the development of treatment equipment. In this paper, the microwave absorption capacity of minerals is discussed from three aspects: the heating rate of minerals in microwave field, the electromagnetic parameters of minerals, and the absorption of microwave energy by minerals. Thermogravimetric differential thermal analysis, scanning electron microscopy and XRD refinement were used to study the effect of mineral microstructure on their microwave absorption ability. Finally, the correlation between microwave energy absorption and macroscopic properties of mixed minerals was discussed. The results show that: (1) the sensitivity of minerals to microwave is discussed from three aspects: (1) heating rate method, dielectric constant method and mesomorphic mass calorimetry method. For pure minerals, the conclusions obtained by the three evaluation methods are not different; for mixed minerals, there are significant differences; The dielectric constant method reveals the sensitivity of the material to microwave from the point of view of the electromagnetic characteristics of the material. The use of microwave energy by materials in microwave field is analyzed from the angle of energy. (2) three methods, I. e., heating rate method, dielectric constant method and intermediate dielectric mass calorimetry method, are used to study the microwave absorbing ability of minerals. Except for Daxin manganese dioxide ore and manganese metal powder, the basic rules of the three methods are basically the same. 纬-MnO2 is the most sensitive to microwave, followed by MnSO4 H2O and MnCO3, in Taishan, Mn2O3 and Mn3O4,. MnO and Tianjin MnSOH2O have the weakest sensitivity to microwave. (3) the composition and structure of minerals are the key factors affecting the relative value of microwave energy absorbed by minerals. It is found that the components of Taishan MnSO4H2O and Tianjin MnSO4-H2O, 纬-MnO2 and 尾-MnO2 are the same, but the relative values of absorbing microwave energy are quite different. The results of thermogravimetric differential thermal analysis and XRD structure refinement show that the crystalline water and its bonding mode, grain size, and so on, have a significant effect on the absorption of microwave energy. Lattice distortion is the main reason affecting mineral absorbing microwave energy. (5) the grain size and lattice distortion of Tianjin MnSO4 H2O are larger than that of Taishan, while 尾-MnO2 grain size is smaller than 纬-MnO2, but its lattice distortion is larger than 纬-MnO2;. The small grain size of Taishan MnSO4 H2O and 尾-MnO2 showed strong absorbing ability. (6) the microwave absorption energy law of mixed materials shows that the materials still have their own absorbing characteristics after mixing. The existence of non-absorbing or weakly absorbing materials does not affect the absorption characteristics of the strong absorbing materials. (7) the absorbing ability of the mixture material has a significant effect on the absorption of microwave energy in the microwave field. With the increase of mass percentage of strong absorbing materials, the absorbing energy of mixed materials increases non-linear. (8) for MnO2 and MnCO3, the change trend of microwave energy is similar after replacing intermediate medium. But the relative value of absorbing microwave energy is different. The relative value of microwave energy absorbed by materials is negatively correlated with the absorbing energy of intermediate medium. (9) when different substances are put into the microwave cavity, when the volume is large enough, the effective utilization rate of microwave in the cavity will be affected to some extent. When the strong absorbing material exists in the cavity, the cavity loss is small, and the microwave utilization ratio is high, while the weak absorbing material exists in the cavity, the cavity loss is large and the microwave utilization ratio is low.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD912

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