Dielectric Properties and Oxidation Roasting of Molybdenite Concentrate by Using Microwave Energy at 2.45 GHz Frequency
- PDF / 2,767,579 Bytes
- 11 Pages / 593.972 x 792 pts Page_size
- 0 Downloads / 245 Views
RODUCTION
MICROWAVE heating has been applied extensively because of its excellent energy conduction properties in radiated materials. Microwave heating presents numerous advantages over traditional processing techniques. These benefits include faster ramp-up temperature, lower energy consumption, more precise and controlled volumetric heating, and enhanced quality and properties of the processed materials.[1] Microwave effects originate from absorption capacity and a microscopic polarization mechanism.[2] The former is evaluated with complex electronic permittivity[3] and magnetic permeability (lr ¼ l0r jl00r ).[4,5] A good impedance match results in complementarity between complex permeability and permittivity to ensure the strong electromagnetic loss
JIANG YONGLIN, LIU BINGGUO, LIU PENG, PENG JINHUI, and ZHANG LIBO are with the National Local Joint Engineering Laboratory of Engineering Applications of Microwave Energy and Equipment Technology, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan, China. Contact e-mail: [email protected]. Manuscript submitted Novermber 30, 2016.
METALLURGICAL AND MATERIALS TRANSACTIONS B
capability of absorbing media. Space charge, dipole, and interfacial polarization are three polarization types in the microstructure of an absorber[6,7]; they are generated within the microwave region and are believed to affect the resonance of permittivity. A large number of experimental studies have identified microwave absorption performance and its relation to the electromagnetic properties of various materials. Tang[8] reported that the dielectric dispersion mechanism in Sr3Co2Fe24O41 hexaferrite is independent of temperature at low frequencies and dependent on temperature at high frequencies because of the dominant resonance behavior. Maurya[9] investigated the dielectric properties of multilayer ceramic heterostructures with constituent compositions and presented a novel approach to achieve high dielectric responses over wide temperature ranges. Zhou[10] revealed the complex permittivity, permeability, and corresponding microwave absorption performance of NiCo2O4 nanoflakes with different thickness. A novel route to regulate complex permittivity and microwave absorption in nanomaterials was established. Molybdenite concentrate (about 90 pct MOS2) is a typical anisotropic mineral that belongs to the family of hexagonal crystals.[11] This concentrate possesses a weakly bonded, layered crystal structure, and exhibits excellent properties in catalysis, lubrication, and
stainless steel manufacturing. In addition, molybdenite concentrate is the essential ore mineral of the molybdenum industry for the production of technical-grade molybdenum trioxide, which is further used to produce molybdenum dioxide, molybdenum, ferromolybdenum alloy, and pure molybdenum compounds, such as ammonium paramolybdate, sodium, and calcium molybdate. Oxidation roasting of molybdenite concentrate has been industrially performed in multiple hearts and flui
Data Loading...
