The characteristics of ZnO–Bi2O3-based varistor ceramics doped with Y2O3 and varying amounts of Sb2O3

Bernik, Slavko; Maček, Srečko; Ai, Bui

doi:10.1016/s0955-2219(03)00412-6

Cited by 60 publications

(27 citation statements)

References 7 publications

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“…Antimony oxide is used in the varistor to reduce the average size of the ZnO grain [17][18][19]. The microstructure of the MOV contains three phases, the most dominant phase being that of the zinc oxide grains.…”

Section: And Toni Karlssonmentioning

confidence: 99%

Recovery of Antimony: A Laboratory Study on the Thermal Decomposition and Carbothermal Reduction of Sb(III), Bi(III), Zn(II) Oxides, and Antimony Compounds from Metal Oxide Varistors

Karlsson

Forsgren

Steenari

2018

J. Sustain. Metall.

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As antimony is typically present in industrial and commercial products only in small amounts, the concentration of antimony in waste types is low and a limited amount of antimony is currently recycled. One product relatively rich in antimony is the metal oxide varistor (MOV) used for overvoltage protection in electric circuits. To increase the antimony concentration, the MOV was pulverized (\ 65 lm) and leached, resulting in an insoluble MOV residue containing 186 ± 2 mg/g of antimony. This work investigates the thermal decomposition and carbothermal reduction of pure metal oxides (Sb 2 O 3 , Bi 2 O 3 , and ZnO) and MOV residue. Thermogravimetric (TG) analysis was used in order to propose a temperature range in which it is possible to separate antimony oxide from the MOV residue. TG results indicate that during thermal decomposition of pure metal oxides, sublimated antimony oxide can be recovered at 650°C, leaving Bi 2 O 3 and ZnO unreacted. The addition of carbon caused mainly volatilization, with some reduction, of Sb 2 O 3 and reduction of Bi 2 O 3 to occur at nearly the same temperature, approximately 600°C. However, volatilization of Bi was not troublesome below 800°C due to slow kinetics. Thermal decomposition of antimony from the MOV residue was not possible in the temperature range studied (\ 1000°C), while carbothermal reduction to the MOV residue revealed antimony volatilization occurred near 800°C.

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Section: And Toni Karlssonmentioning

confidence: 99%

Recovery of Antimony: A Laboratory Study on the Thermal Decomposition and Carbothermal Reduction of Sb(III), Bi(III), Zn(II) Oxides, and Antimony Compounds from Metal Oxide Varistors

Karlsson

Forsgren

Steenari

2018

J. Sustain. Metall.

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“…During this reaction, the trivalent Y 3+ ion replaced a divalent Zn 2+ ion on the lattice through the liberation of a net electron to the conduction band and the formation of positively charged 2Y`Z n . This reaction mechanism assumed that the Y 2 O 3 doping effect on the non-Ohmic properties was related to electronic state at the grain boundary [5], [6]. Figure 5 shows the dielectric constant and the dielectric loss with respect to the frequency of the Y 2 is decreased with increasing amounts of Y 2 O 3 , which was mainly attributed to the high resistivity of the segregation layers 1.42 [M-ohm].…”

Section: Resultsmentioning

confidence: 99%

“…ZnO varistors are essential fir surge protection devices and have dominated the market because of their highly non-linear characteristics. ZnO varistors can generally be divided into two categories, called Bi 2 O 3 -based and Pr 6 O 11 -based varistors, in terms of the oxides that induce the nonlinear properties of the varistors [2]. In general, the current-voltage characteristics of the varistors are defined by the power law; I = kV α (k, constant, V, Voltage), where alpha represents the degree of nonlinearity of the conduction.…”

Section: Introductionmentioning

confidence: 99%

Voltage Enhancement of ZnO Oxide Varistors for Various Y₂O₃Doping Compositions

Yoon¹,

Lee²,

Lee³

et al. 2009

Transactions on Electrical and Electronic Materials

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The microstructure and the electrical properties of a ZnO varistor, which was composed of a ZnO-Bi 2 O 3 -Sb 2 O 3 -CoO-MnO 2 -NiO-Nd 2 O 3 system, were investigated at various Y 2 O 3 addition concentrations. Y 2 O 3 played a role in the inhibition of the grain growth. As the Y 2 O 3 content increased, the average grain size decreased from 6.8 ㎛ to 4 ㎛, and the varistor voltage(V 1mA ) greatly increased from 275 to 400 V/mm. The nonlinearity coefficient (α) decreased from 72 to 65 with increasing Y 2 O 3 amount. On the other hand, the leakage current (I L ) increased from 0.2 to 0.9 ㎂. These results confirmed that doping the varistors with Y 2 O 3 is a promising production route for production of a higher fine-grained varistor voltage (V 1mA ) which can dramatically reduce the size of the varistors.

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“…The end of life surge arrestors can be disassembled, separating the MOVs from the surge arrestor housing. The MOV is composed mainly of zinc oxide ([90 wt%) [5][6][7] and also contains antimony (3-5 wt%), bismuth (3-5 wt%), cobalt (*1 wt%), nickel (*1 wt%), and manganese (*1 wt%) [5,6]. Currently, there are no processes to recycle zinc from MOVs.…”

Section: Introductionmentioning

confidence: 99%

Recycling Zinc from Metal Oxide Varistors Through Leaching and Cementation of Cobalt and Nickel

Gutknecht

Colombus

Steenari

2016

J. Sustain. Metall.

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Metal oxide varistors (MOVs) are housed in a surge arrestor and composed of zinc oxide ([90 wt%) and other metal oxides such as antimony, bismuth, cobalt, manganese, and nickel. Due to the high concentration of zinc in MOVs, it is a better choice to recycle them as opposed to landfilling. This research set out to determine if cementation could be used as a purification step to remove co-leached metals, leading to a purified leachate suitable for zinc electrowinning. Zinc was leached from crushed MOVs using dilute sulfuric acid, which avoided co-leaching of antimony and bismuth but required further purification to remove co-leached cobalt and nickel. In further purification of the leachate, cementation was investigated. Initial findings suggest that the cobalt concentration can be reduced by over 50 % (200 mg/L) and nickel concentration reduced by over 90 % (90 mg/L), by optimizing the activator (Sb/Cu) concentration, temperature, pH, and surface area of zinc dust. Further investigations into optimized batch addition of zinc and copperantimony activators verified that nearly 92 % ([390 mg/L) of the cobalt and all nickel (100 mg/L) can be removed from the acidic varistor leachate. These results suggest that cementation by addition of zinc dust can be used for purification of zinc solutions containing over 400 mg/L cobalt and 100 mg/L nickel and thus preparation of the solutions for zinc electrowinning.

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The characteristics of ZnO–Bi2O3-based varistor ceramics doped with Y2O3 and varying amounts of Sb2O3

Cited by 60 publications

References 7 publications

Recovery of Antimony: A Laboratory Study on the Thermal Decomposition and Carbothermal Reduction of Sb(III), Bi(III), Zn(II) Oxides, and Antimony Compounds from Metal Oxide Varistors

Recovery of Antimony: A Laboratory Study on the Thermal Decomposition and Carbothermal Reduction of Sb(III), Bi(III), Zn(II) Oxides, and Antimony Compounds from Metal Oxide Varistors

Voltage Enhancement of ZnO Oxide Varistors for Various Y₂O₃Doping Compositions

Recycling Zinc from Metal Oxide Varistors Through Leaching and Cementation of Cobalt and Nickel

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The characteristics of ZnO–Bi2O3-based varistor ceramics doped with Y2O3 and varying amounts of Sb2O3

Cited by 60 publications

References 7 publications

Recovery of Antimony: A Laboratory Study on the Thermal Decomposition and Carbothermal Reduction of Sb(III), Bi(III), Zn(II) Oxides, and Antimony Compounds from Metal Oxide Varistors

Recovery of Antimony: A Laboratory Study on the Thermal Decomposition and Carbothermal Reduction of Sb(III), Bi(III), Zn(II) Oxides, and Antimony Compounds from Metal Oxide Varistors

Voltage Enhancement of ZnO Oxide Varistors for Various Y2O3Doping Compositions

Recycling Zinc from Metal Oxide Varistors Through Leaching and Cementation of Cobalt and Nickel

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Voltage Enhancement of ZnO Oxide Varistors for Various Y₂O₃Doping Compositions