# Particle Technology

THE DEFINITION OF MECHANICAL PROCESS TECHNOLOGYTHE PURPOSE OF MECHANICAL PROCESS TECHNOLOGYMAIN TOPICS AND PROCESSESThe characteristics of systems and their changes of stateDISPERSE SYSTEMSREPRESENTING THE CHARACTERISTICS OF PARTICLE ASSEMBLIESMeasures of dispersity: fineness parameters(a) Geometrical measures of dispersity(b) Settling velocity(c) Optical measures of dispersity(d) DensityEquivalent diameterParticle shapeGeneral representation of particle assemblies (a) Definition of distribution functions for various measures of populations(b) Moments(c) Conversion of distributions(d) Specific statistical values of the measure of dispersity(e) The spread of a distribution: measures of scatter(f) Specific surfaceThe Gaussian or normal distributionParticle distributions and distribution functions approximating to them(a) Examples of particle distributions(b) The log-normal distribution(c) The Gaudin-Schuhmann or power-law distribution function(d) The RRSB distributionSimilar distributionsTHE SEPARATION OF DISPERSE SYSTEMSMaterial balancesGrade efficiency and grade efficiency curve, cut size and sharpness of cutMIXING OF DISPERSE SYSTEMSThe state of a mixture and the degree of mixingtThe variance of the concentration distribution during the mixing processEvaluation of mixing experiments(a) Mixture of known composition(b) Mixtures of unknown composition(c) The distribution of the composition of the samples from a uniform random mixture(d) Sample sizePACKING OF GRANULAR SOLIDSThe states of packing systemsThe particle and void systemPacking structureLiquid filling of voidsCapillary pressure and porosimetryForces transmitted in the packingFundamental physical processes and particle metrologyTHE MOTION OF PARTICLES IN A FLOWING MEDIUMThe forces on a single particle(a) Synopsis(b) The drag force on a sphere in a fluid moving with a constant and uniform velocity of approach(c) The influence of turbulence in the bulk of the fluid and of surface roughness(d) The influence of compressibility and the mean free path of the fluid(e) The influence of acceleration and particle rotation(f) The influence of particle shape(g) Wall effectsThe motion of a single particle(a) The equations of motion(b) Uniform motion of a particle(c) Accelerated particle movementThe dynamic interaction of particles in a fluid(a) The interaction between individual particles(b) Interactions between particles settling in suspensionsFLOW THROUGH PACKINGSDimensional analysisEmpirical perfusion lawsTHE MECHANICS OF THE FLUIDIZED BEDPhenomenologyPerfusion lawThe stability of the fluidized bedTHE CONTINUUM MECHANICS OF PACKINGS: POWDER MECHANICSCoefficient of pressure at restState of stressYield criteria for packings(a) The Coulomb yield criterion used in soil mechanics(b) Yield behaviour of bulk solidsThe design of bunkers using Jenike’s methodDEFORMATION AND FRACTURE OF SOLIDSFracture criteriaDeformation and fracture of particles under stressComminutive properties of materialsADHESIONLiquid bridgesvan der Waals forces (dispersion forces)Electrostatic forcesSolid bridgesComparison of the first three adhesive mechanisms and the influence of the surface roughnessPARTICLE METROLOGYSampling and sample splittingDispersionCounting methods(a) Indirect (pictorial) counting methods(b) Direct counting methodsSedimentation methodsSeparation processes(a) Sifting(b) Air classificationTechniques for measuring surface area(a) Photometric surface measurement(b) Permeability methods(c) Sorption methodsPore size measurement(a) Pore size distribution using sorption methods(b) The determination of pore size by capillary pressureProcessesSEPARATION PROCESSESSeparations in streams of fluids(a) Cross-current separation processes(b) Counter-current separation processes (equilibrium separation)(c) Combined cross-current-counter-current separation processes(i) The cyclone(ii) Recirculating air classifier (with distributing plate)(iii) Disc centrifuge and plate separator(d) Inertial deflecting separation(e) Separation in pulsating flowSink-and-float sortingElectrical and magnetic separation processes(a) Electrical separation processes(b) Magnetic separation processesSeparation processes using wall frictionSiftingCake filtrationMIXING PROCESSESMixing of gasesMixing of a gas into a liquid (aeration)Dispersing of a liquid into a gas (nebulization)Mixing of liquidsDispersing of solids in gasesDispersing of solids in liquidsMixing of solidsAGGLOMERATING AND COAGULATING PROCESSESCumulative granulationAgglomeration by compactionSinteringCoagulationCOMMINUTION PROCESSESCrushersRoller millsMills with loose milling implementsImpact-grinding machinesCutter millsWet millingCONVEYING, STORING AND FEEDING OF BULK SOLIDSConveyingStoring and feeding