Triboelectrostatic separation for granular plastic waste recycling: A review

Wu, Guiqing; Li, Jia; Xu, Zhenming

doi:10.1016/j.wasman.2012.10.014

Cited by 192 publications

(80 citation statements)

References 73 publications

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“…In addition, excessively charged particles cause an electrostatic discharge, which can pose the risk of fire and explosion hazards [9]. On the other hand, charged particles can be used for many industrial applications, including electrophotography [10], electrostatic powder coating [11], electrostatic separation [12,13], self-assembly [14], and various measurements [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Advanced characterization of particles triboelectrically charged by a two-stage system with vibrations and external electric fields

Mizutani

Yasuda

Matsusaka

2015

Advanced Powder Technology

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a b s t r a c tIn this study, we propose a new method to effectively characterize particle tribocharging caused by repeated contact with a wall in an external electric field. We perform experiments using a two-stage system consisting of two inclined vibrating plates and electrodes. The mass flow rate and charge of particles were controlled at the first vibrating plate, and the charge that was transferred from the plate to the particles was obtained from the difference between the charges on particles at the lower and upper ends of the second vibrating plate. In addition, electric currents generated by the charge transfer were simultaneously measured at the second vibrating plate. From these measurements, we verified that the charge balance in this system holds. Furthermore, we found that the charge transfer depends on various factors, such as the initial charge, chemical and electrical properties, travel length of particles, and the external electric field. We also found that the equilibrium charge of particles depends on the chemical property and external electric field. The equilibrium charge and the rate of tribocharging were evaluated analytically from the relationship between the initial and transferred charges without changing the travel distance of particles. This method enables the rapid and reliable analysis of the particle tribocharging process.

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Section: Introductionmentioning

confidence: 99%

Advanced characterization of particles triboelectrically charged by a two-stage system with vibrations and external electric fields

Mizutani

Yasuda

Matsusaka

2015

Advanced Powder Technology

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“…By processing only lowquality products it can be realized if the whole waste stream is used at the same time, which is called 'downcycling'. More than half of polymer materials are discarded every year despite their durability, so it is necessary to separate and recycle polymers because of social pressure and environmental aspects (Alter, 2005;Bezati et al, 2011;Wu et al, 2013). Thus, it would be desirable to establish a new, alternative separation method, which enables the sorting of assorted waste products into individual substances from the waste stream possible in one step, regardless of the materials (Zhang et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Alternative polymer separation technology by centrifugal force in a melted state

Dobrovszky

Ronkay

2014

Waste Management

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Abstract:In order to upgrade polymer waste during recycling, separation should take place at high purity. The present research was aimed to develop a novel, alternative separation opportunity, where the polymer fractions were separated by centrifugal force in melted state. The efficiency of the constructed separation equipment was verified by two immiscible plastics (polyethylene terephthalate, PET; low density polyethylene, LDPE), which have a high difference of density, and of which large quantities can also be found in the municipal solid waste. The results show that the developed equipment is suitable not only for separating dry blended mixtures of PET/LDPE into pure components again, but also for separating prefabricated polymer blends. By this process it becomes possible to recover pure polymer substances from multi-component products during the recycling process. The adequacy of results was verified by differential scanning calorimetry (DSC) measurement as well as optical microscopy and Raman spectroscopy.

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“…Each wall consists of 8 half-cylinders, which form 8 inner parallel chambers with axis orthogonal to the flow main direction. The chambers are labeled according to their position along the flow direction (Cn, with n = 1, ..., 8). Figure 1a shows the longitudinal section of the instrument and most relevant measures.…”

Section: Experimental Apparatusmentioning

confidence: 99%

“…Nowadays the most common techniques employed in mechanical recycling plants to separate plastics are based on optical, fluorescent and infrared properties [5,6], electrostatic forces [7,8], flotation by hydrophilic character [9,10], thermal treatment [11], and density differences [12]. All processes present drawbacks related to cost, performance and environmental hazards such as the influence of moisture, surface status, and low feeding speed of particles in electrostatic separation; the need for an additive in separation by flotation and density; the wide range of density values for the same typology of plastic materials makes the choice of the density for sink and float separation challenging.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of the Productivity of a Wet Separation Process of Traditional and Bio-Plastics

et al. 2018

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Abstract:The separation process within a mechanical recycling plant plays a major role in the context of the production of high-quality secondary raw materials and the reduction of extensive waste disposal in landfills. Traditional plants for plastic separation employ dry or wet processes that rely on the different physical properties among the polymers. The hydraulic separator is a device employing a wet technology for particle separation. It allows the separation of two-polymer mixtures into two products, one collected within the instrument and the other one expelled through its outlet ducts. Apparatus performance were analyzed as a function of fluid and solid flow rates, flow patterns developing within the apparatus, in addition to the density, shape, and size of the polymers. For the hydraulic configurations tested, a two-way coupling takes place where the fluid exerts an influence on the plastic particles and the opposite occurs too. The interaction between the solid and liquid phases determines whether a certain polymer settles within the device or is expelled from the apparatus. Tests carried out with samples of increasing volumes of solid particles demonstrate that there are no significant differences in the apparatus effectiveness as far as a two-way interaction takes place. Almost pure concentrates of Polyethylene Terephthalate (PET), Polyvinyl Chloride (PVC), and Polycarbonate (PC) can be obtained from a mixture of traditional polymers. Tests conducted on Polylactic Acid (PLA) and Mater-Bi ® samples showed that the hydraulic separator can be effectively employed to separate bio-plastics from conventional plastics with remarkable grade and recovery.

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Triboelectrostatic separation for granular plastic waste recycling: A review

Cited by 192 publications

References 73 publications

Advanced characterization of particles triboelectrically charged by a two-stage system with vibrations and external electric fields

Advanced characterization of particles triboelectrically charged by a two-stage system with vibrations and external electric fields

Alternative polymer separation technology by centrifugal force in a melted state

Experimental Investigation of the Productivity of a Wet Separation Process of Traditional and Bio-Plastics

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