Dielectric Properties of Zinc Sulfide Concentrate during the Roasting at Microwave Frequencies

Microwave technology has a potential application in the extraction of zinc from sulphide ores, knowledge of the dielectric properties of these ores plays a major role in the microwave design and simulation for any process. The dielectric properties of zinc sulfide concentrate for two different apparent densities—1.54 and 1.63 g/cm3—have been measured by using the resonance cavity perturbation technique at 915 and 2450 MHz during the roasting process for the temperature ranging from room temperature to 850 °C. The variations of dielectric constant, the dielectric loss factor, the dielectric loss tangent and the penetration depth with the temperature, frequency and apparent density have been investigated numerically. The results indicate that the dielectric constant increases as the temperature increases and temperature has a pivotal effect on the dielectric constant, while the dielectric loss factor has a complicated change and all of the temperature, frequency and apparent density have a significant impact to dielectric loss factor. Zinc sulfide concentrate is high loss material from 450 to 800 °C on the basis of theoretical analyses of dielectric loss tangent and penetration depth, its ability of absorbing microwave energy would be enhanced by increasing the apparent density as well. The experimental results also have proved that zinc sulfide concentrate is easy to be heated by microwave energy from 450 to 800 °C. In addition, the experimental date of dielectric constant and loss factor can be fitted perfectly by Boltzmann model and Gauss model, respectively.

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Effects of Sodium Peroxide Additives on Dielectric Properties and Microwave Roasting Mechanism of Zinc Sulfide Concentrate

JOM ◽

10.1007/s11837-020-04050-6 ◽

2020 ◽

Vol 72 (5) ◽

pp. 1920-1926 ◽

Cited By ~ 2

Author(s):

Guangjun He ◽

Wenwen Qu ◽

Libo Zhang ◽

C. Srinivasakannan ◽

Chenhui Liu ◽

...

Keyword(s):

Dielectric Properties ◽

Zinc Sulfide ◽

Sodium Peroxide ◽

Microwave Roasting ◽

Sulfide Concentrate

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Dielectric Properties of Zinc Sulfide Concentrate during the Roasting at Microwave Frequencies

10.20944/preprints201702.0044.v2 ◽

2017 ◽

Author(s):

Guangjun He ◽

Shiwei Li ◽

Kun Yang ◽

Jian Liu ◽

Peng Liu ◽

...

Keyword(s):

Dielectric Constant ◽

Dielectric Properties ◽

Dielectric Loss ◽

Zinc Sulfide ◽

Apparent Density ◽

Loss Tangent ◽

Loss Factor ◽

Microwave Energy ◽

Dielectric Loss Factor ◽

Sulfide Concentrate

Microwave technology has a potential application in the extraction of zinc from sulphide ores, knowledge of the dielectric properties of these ores plays a major role in the microwave design and simulation for any process. The dielectric properties of zinc sulfide concentrate for two different apparent densities—1.54 and 1.63 g/cm3—have been measured by using the resonance cavity perturbation technique at 915 and 2450 MHz during the roasting process for the temperature ranging from room temperature to 850 °C. The variations of dielectric constant, the dielectric loss factor, the dielectric loss tangent and the penetration depth with the temperature, frequency and apparent density have been investigated numerically. The results indicate that the dielectric constant increases as the temperature increases and temperature has a pivotal effect on the dielectric constant, while the dielectric loss factor has a complicated change and all of the temperature, frequency and apparent density have a significant impact to dielectric loss factor. Zinc sulfide concentrate is high loss material from 450 to 800 °C on the basis of theoretical analyses of dielectric loss tangent and penetration depth, its ability of absorbing microwave energy would be enhanced by increasing the apparent density as well. The experimental results also have proved that zinc sulfide concentrate is easy to be heated by microwave energy from 450 to 800 °C. In addition, the experimental date of dielectric constant and loss factor can be fitted perfectly by Boltzmann model and Gauss model, respectively.

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Compilation of the Dielectric Properties of Body Tissues at RF and Microwave Frequencies.

10.21236/ada303903 ◽

1996 ◽

Cited By ~ 637

Author(s):

Camelia Gabriel

Keyword(s):

Dielectric Properties ◽

Microwave Frequencies ◽

Body Tissues

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Dielectric properties of a low-loss (1-x)(Mg0.95Zn0.05)2TiO4-x(Ca0.8Sr0.2)TiO3 ceramic system at microwave frequencies

Journal of Electroceramics ◽

10.1007/s10832-020-00228-1 ◽

2021 ◽

Author(s):

Shih-Sheng Liu ◽

Yuan-Bin Chen

Keyword(s):

Dielectric Properties ◽

Tio3 Ceramic ◽

Ceramic System ◽

Low Loss ◽

Microwave Frequencies

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Nondestructive Sensing of Water Activity From Measurement of the Dielectric Properties at Microwave Frequencies

IEEE Sensors Letters ◽

10.1109/lsens.2020.3042749 ◽

2020 ◽

Vol 4 (12) ◽

pp. 1-4

Author(s):

Samir Trabelsi

Keyword(s):

Dielectric Properties ◽

Water Activity ◽

Microwave Frequencies ◽

Nondestructive Sensing

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Distinct Roles of Acidophiles in Complete Oxidation of High-Sulfur Ferric Leach Product of Zinc Sulfide Concentrate

Microorganisms ◽

10.3390/microorganisms8030386 ◽

2020 ◽

Vol 8 (3) ◽

pp. 386 ◽

Cited By ~ 3

Author(s):

Maxim Muravyov ◽

Anna Panyushkina

Keyword(s):

Microbial Community ◽

Zinc Sulfide ◽

Elemental Sulfur ◽

Waste Product ◽

Sulfur Oxidation ◽

Low Grade ◽

Sulfide Concentrates ◽

Sulfide Concentrate ◽

Elemental Sulfur Oxidation ◽

Ferric Leaching

A two-step process, which involved ferric leaching with biologically generated solution and subsequent biooxidation with the microbial community, has been previously proposed for the processing of low-grade zinc sulfide concentrates. In this study, we carried out the process of complete biological oxidation of the product of ferric leaching of the zinc concentrate, which contained 9% of sphalerite, 5% of chalcopyrite, and 29.7% of elemental sulfur. After 21 days of biooxidation at 40 °C, sphalerite and chalcopyrite oxidation reached 99 and 69%, respectively, while the level of elemental sulfur oxidation was 97%. The biooxidation residue could be considered a waste product that is inert under aerobic conditions. The results of this study showed that zinc sulfide concentrate processing using a two-step treatment is efficient and promising. The microbial community, which developed during biooxidation, was dominated by Acidithiobacillus caldus, Leptospirillum ferriphilum, Ferroplasma acidiphilum, Sulfobacillus thermotolerans, S. thermosulfidooxidans, and Cuniculiplasma sp. At the same time, F. acidiphilum and A. caldus played crucial roles in the oxidation of sulfide minerals and elemental sulfur, respectively. The addition of L. ferriphilum to A. caldus during biooxidation of the ferric leach product proved to inhibit elemental sulfur oxidation.

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