LABORATORY-SCALE MAGNETOHYDROSTATIC SEPARATOR FOR HIGH RESOLUTION DENSITY ANALYSIS OF PLASTIC AND OTHER WASTES

摘要

Recycling and reuse of different plastic wastes is still a current problem to solve for process engineersrnand it is true for seeking industrial applications as well as for smaller laboratory-scale, where a givenrnwaste sample, plastic or even metallic, has to be precisely separated into narrow density fractionsrnto gain data for industrial design or for scientific research. The principle of magnetohydrostaticrnseparators are known even there are industrial size machines but our primary aim was therndevelopment of a laboratory-scale separator for analysis of particles of densities up to 6 kg/L andrnsizes up to 8 mm.rnMain parts of the built experimental equipment are the ferrite core with two high power coils. Thernshape of the ferrite core at the two sides of the separator channel was specially designed to producernisodynamic magnetic field. In these places the ferrite core was constructed from laser cut ferriternsheets. The development of the high power electric supply for the two coils was a real challengernbecause the high voltage and current (400 V, 30 A) and because it had to be precisely regulated forrnbeing able to set discrete relative forces on the particles. Two separator channels were made fromrntransparent plastic. The magnetic fluid is circulated by a centrifugal pump, fresh feed is supplied byrna vibrated feeder and products can be taken by built in samplers. The velocity profile in the separatorrnchannel is measured by an ultrasonic Doppler velocity meter.rnPaper reports about the development and itself of the magnetohydrostatic separator and aboutrnsome fundamental and applied laboratory experiments with different reference particles and wastesrnfrom used cars and electrical appliances.