Toyohisa Fujita

Combination of sink-float separation and flotation technique for purification of shredded PET-bottle from PE or PP flakes

Abstract In this contribution, the separation of polyethylene terephthalate (PET)–polyethylene (PE) and polyethylene terephthalate (PET)–polypropylene (PP) mixtures was studied in order to improve the grade of the raw input used in PET bottle recycling. First, PET bottles and their caps (made of PE or PP) were shredded and the floatability of each polymer was tested. Even with the addition of the wetting reagents dodecylamine acetate (DAA) or polyvinyl alcohol (PVA), the results did not suggest that the required 99.995% purity of PET plastic could not be achieved by floatation. Second, the mixtures were separated with a sink–float process using a drum separator. Finally, as the required purity of PET could not be obtained by either technique alone, a system utilising a combination of the two processes was developed. This system easily achieved the desired PET grade. At last, some sink–float experiments were performed with a medium of magnesium sulphate (dense medium separation).

Progress in Separating Plastic Materials for Recycling

In order to deal with the problems facing the plastics processing industry research, work is focused primarily on designing, developing and testing a variety of separation and sorting techniques able to recover plastics from wastes, which can be re-used or re-processed to form new products. In this regard, technologies developed in mineral processing can be of great help. Various techniques for separating plastics materials have been recently developed. These techniques can be divided in two main categories, i.e. wet separating techniques and dry separating techniques. This paper presents the recent progress in separating plastics reviewing the potential of the available techniques.

Characteristics of magnetic compound fluid (MCF) in a rotating rheometer

As a new intelligent or smart fluid, we propose a magnetic compound fluid (MCF). This fluid has nm size magnetite and μm size iron particles in a solvent. The magnetic field effect on flow characteristics of MCF can demonstrate midpoint between magnetic fluid (MF) and magneto-rheological fluid (MRF). For example, the magnitude of shear stress to shear rate under a steady magnetic field in MCF can be larger than MRF by varying the compound rate of the magnetite and iron particles. This report shows an experimental data of shear stress to shear rate of MCF in rotating rheometers of cone and concentric cylinder types under transverse and longitudinal magnetic fields.

ELECTROSTATIC SEPARATION OF THE SHREDDED PLASTIC MIXTURES USING A TRIBO-CYCLONE

In this experimental work, artificial plastic mixture of two kinds of components (i.e. PET and PE mixture) is tribo-electrostatically separated. The mixture is charged by friction in a tribo-cyclone.

New microscopic polishing with magnetic compound fluid (MCF)

We propose a magnetic compound fluid (MCF) as a new smart fluid. This fluid includes nm size magnetite and mm size iron particles in a solvent. The magnetic effect can be expected to demonstrate between the magnetic fluid (MF) and magneto-rheological fluid (MRF). Moreover, the magnitude of the shear stress to the shear rate under steady magnetic field can be larger than MRF by varying the compound rate of the MF and MRF. This report shows an experimental application of microscopic polishing with the MCF. We examined the surface roughness of flat titanium material to the attached rotating plate with 15 rpm under magnetic field. By comparing the roughness between the MCF and the MR, the polished plate is more uniformly over the plate with the MCF than the MR. Further the roughness of Ry and Ra are larger under fluctuating magnetic field than steady magnetic field. The more effective polishing can be explained with the cluster model of particles.

Extraction of magnetic particle clusters self-assembled by a magnetic field

For the purpose of particle assembly on a nano- or microscale produced by metal particles, we proposed a method of extracting magnetic clusters in the shapes of rods or needles that have been produced in sizes ranging from macroscopic to microscopic. We also succeeded in freely controlling the scale of the magnetic cluster in this size range, with the form remaining stable without the presence of a magnetic field through the use of hydrophilic monomers of oleic acid. We discovered an algebraic rule governing the relation between the scale of the magnetic cluster and the strength of the applied magnetic field.

Basic study of heat convection pipe using the developed temperature sensitive magnetic fluid

Abstract Magnetic fluids, produced using highly temperature-sensitive ultrafine ferrites coprecipitated in alkaline solution containing zinc and calcium ions, were used in the heat convection pipe. When the magnetic field was applied to the vertical pipe near the heat source, the regulated free convection made the magnetic fluid flow and transferred the thermal energy effectively.

Preparation, viscosity and damping of functional fluids that respond to both magnetic and electric fields

A fluid that can be controlled both by magnetic and electric fields, will lead to applications such as dampers, separators, light scattering in a thin film, actuators, etc. In this paper, the preparation, viscosity and damping characteristics of three types of functional fluids that responses to magnetic and electric fields, are presented. These fluids have qualities of magnetic and electrorheological fluids.

Viscosity of electrorheological magneto-dielectric fluid under electric and magnetic fields

Abstract The viscosity of a stable mixture of magnetic and dielectric fluids under magnetic and electric fields was measured and discussed. The electric field was more effective than the magnetic field in increasing the viscosity. Also, this mixture has the merit of stable retention under the magnetic field.

Separation Performance of PVC and PP Plastic Mixture Using Air Table

The aim of the research presented in this article was to investigate separation performance of the air table when separating a binary mixture of plastics. Separation using the air table, i.e. a dry mechanical process that grades constituents of the mixture with differences in specific gravity, is employed for separation of the PVC/PP mixture. Moreover, the performance of the laboratory-scale air table is improved by increasing the height of riffles laid on the porous deck.