Hitoshi Ohya

Shape Estimation of Anisometric Particles Using Size Measurement Techniques

This study was conducted to establish a simple method for evaluating the morphology of fine anisometric particles using size measurement techniques. The size distributions of mica particles and carbon fibers classified into narrower size ranges were measured by gravitational sedimentation and laser diffraction techniques. The ratio of mean diameters determined for flaky particles strongly depended on the aspect ratio, i.e. flatness. The relationship between particle shape and diameter is discussed theoretically. The experimental results were similar to those predicted. The flatness of fine particles can be evaluated by the ratio of the median diameter determined by laser diffraction to that determined by sedimentation.

Particle shape of copper milled by swing-hammer-type impact mill

Abstract In order to apply a shape sorting technique to recover the copper component from printed wiring board (PWB) scrap, the particle shape of copper milled by a swing-hammer-type impact mill was experimentally investigated. Copper plate and PWB scraps were used as samples. The effects of mill operating conditions, i.e., hammer circumferential speed (vc) and screen aperture size (diam. ds), on shape and size distribution of milled products were examined. Sphericity and homogeneity in the shape of milled copper particles largely depended on mill operating conditions. In the cases of both copper plate and PWB scrap milling, the most effective operating conditions to obtain spherical copper particles were vc≃50 m s−1 and ds=1 mm, and to obtain homogeneous shaped copper particles vc≃70 m s−1 and ds=1 mm. The most effective operating conditions of the mill to recover the copper component from PWB scrap using an inclined vibrating plate (IVP) were vc≃70 m s−1 and ds=1 mm.

Recovering copper from electric cable wastes using a particle shape separation technique

A particle shape separation technique was used to recover copper from electric cable wastes used in computer devices from the point of view of resource recycling. After the electric cables were crushed by a cutter mill, small pieces of the cables were impact milled for the purpose of liberating the copper wire from the plastic covering. The shape of the copper wires was prepared for separation by shape at the same time. By impact milling, the copper wires were twined and became pill-like particles. However, the shape of the plastic covering was irregular. An inclined conveyor and an inclined vibrating plate were used as the particle shape separator, and the most effective operating conditions for these apparatus were experimentally investigated. As a result, it was possible to separate copper from the plastic covering with high efficiency.

Analysis of particle motion regarding shape separation using an inclined conveyor

Abstract An inclined conveyor was developed for the purpose of particle shape separation. This apparatus consists of an inclined moving belt whose direction of inclination is normal to the direction of movement. When particles are fed onto the belt, spherical particles roll down and non-spherical particles tend to stay on, resulting in their net displacement in the direction of conveyor movement. The purposes of this method are firstly to process a large amount of material and secondly to enable separation of several kinds of shape. The effects of inclination and belt speed were investigated theoretically and experimentally.

Development of Recycling Technology by Using Superheated Steam

The superheated steam has used in the field of food engineering when it has the remarkable character such as the operation in the ordinary pressure, the good efficiency for heat transfer and the treatment in the steam without oxygen. It must be applied for the recycling process to recover the metal and remove the impurity. The examples were introduced to apply the technology for the removal of oil attached to the magnesium cutting powder and the treatment of metal plated resin with painting. We succeeded to remove less than 0.1% of oil for magnesium cutting powder. It was a value enough to bring it to the reconstructive process. The painting was damaged for the metal plated resin to recover the nickel and copper in the plating dissolution process. The both were promising results of the research and development for industrial-government-academic complex in north Kyushu district.