Technological processes intensification in devices with magneto-fluidized bed

Ivan Egorov,Nikolay Egorov,T Abbasian Najafabadi,K Yeghiazaryan,I Sevostianov,V Mladenovic,A Nguyen Dong

doi:10.1051/matecconf/201713203001

Abstract

The paper shows the efficiency of application of magneto-fluidized bed formed of ferromagnetic materials in press-forms dosed filling and milling devices. For powders without natural fluidity, dosing device is situated between electromagnets creating constant magnetic field with horizontal induction lines and alternating gradient magnetic field with vertical induction lines and higher induction gradient in the lowest part of chamber with powder. This configuration allows development of uniform efflux speed of ferromagnetic powders from 2 mm diameter opening. For example, mass efflux speed of strontium ferrite powder with 1 μm average particle size in magneto-fluidized bed reached 181.1 mg/s and the dosing time of 2000 mg of this powder was 11.1 s. For practical usage of magneto-fluidized bed in the milling device, beater mill is situated between electromagnet poles in the way that induction lines of constant and alternating gradient magnetic fields were mutually perpendicular and parallel to the plane of rotating beaters. Milling of particulate strontium ferrite with 1558.5 μm average particle size during 120 minutes in magneto-fluidized bed allows increasing milling degree in 16.2 times by comparison with processing without electromagnetic effect.

Highlights

Powder metallurgy uses various particulate metals and alloys as raw materials
Presented dependencies show that ferrite powders mass efflux speed grows with increase of induction gradient at fixed constant magnetic field induction
This can be explained by considering that in gradient alternating magnetic field the force proportional to the induction gradient acts on particles of ferromagnetic material

Summary

Introduction

Powder metallurgy uses various particulate metals and alloys as raw materials. Particle size decrease increases interparticle interaction leading to changing of particulate system technological characteristics [1]. Considerable theoretical and experimental material about influence of magnetic fields on rheological state of magnetic fluids [2-4] and particulate materials in fluidized state [5-7] was accumulated. There is a wide range of devices that fluidize particulate medium by means of hydration, aeration, ultrasonic, electrodynamic and electromagnetic effects [8-11]. In case of ferromagnetic materials electromagnetic effect on particulate medium (uniform alternating magnetic field, rotating magnetic field, superposition of alternating gradient and constant magnetic fields [12-15]) is the most effective way of obtaining dynamically stable weighted state of particulate system – magneto fluidized bed. Using of magneto-fluidized bed can largely intensify technological processes of mixing, milling, dosing, drying etc. Using of magneto-fluidized bed can largely intensify technological processes of mixing, milling, dosing, drying etc. [16-19]

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