particle shape of micronized powders

Measuring the Particle Shape of

Micronized Powders

Jeffrey Bodycomb, Ph.D.Jeff.Bodycomb@horiba.comwww.horiba.com/us/particle

What we’ll talk about

Importance of particle shape

Dynamic image analysis principles

Case studies

Starting point

Somewhat familiar with particle technology

Particle sizes over 1-5 microns and up to many millimeters

Stay current with free webinarsParticle size essentials

Featured technologies

LA-950Laser Diffraction

SZ-100Dynamic Light Scattering & Zeta Potential

CAMSIZER & CAMSIZER XTDynamic Image Analysis

PSA300Static Image Analysis

SA-9600Flowing Gas BET Surface Area

CAMSIZER XT: Fine Image Analysis

High resolution size & shapeExtends lower detection rangeCohesive & free-flowing powders,

suspensions1 micron – 3 millimeter

Examples

Why is Shape Important?

Most (all?) particles are not perfectly behaving spheres

Shape can influence almost everything Particle processes, making products Product performance Making measurements

So in other words, shape can affect almost everything

Particle Processes

Powder flow; spheres flow easily, needles do not

Liquid flow; increased aspect ratio will increase viscosity

Powder mixing; blend time may change with shape

Also VERY associated with size, hard sometimes to separate size and shape

Powder Flow

Understand that spheres flow more easily than needles

How to quantify? Need to first know something about powder flow testing

Won’t go into great detail in today’s talkJust show results including particle

Powder Flow*

Qc =hopper angle

BC = outlet diameter

Angle of internal friction

Powder Flow

Unconfined Yield Strength

Major principle stress that causes an unconfined bulk material to fail in shear

Directly proportional to arching & formation of rat holes

Influences by # contact points From: Johansen, Effect of Particle Shape on

Unconfined Yield Strength, Material Flow Solutions,Inc.

Powder Flow*

Glass spheres CaCo3 Talc

Similar size ~ 5 µm But different shape

*Bumiller, et. al., A Preliminary Investigation Concerning the Effect of Particle Shape on a Powder’s Flow Properties, Proceeding from WCPT4, July 2002

Powder Flow

BC: minimum outlet diameter to prevent archingQc: hopper wall angle (from verticle) to achieve mass flowCritical flow rate: predicted flow from outlet d : effective angle of internal friction

Powder Flow*

*Podczeck & Miah, The influence of particle size and shape on the angle of internal friction and the flow factor of unlubricated and lubricated powders, International Journal of Pharmaceutics 144 (1996) 187 194

Rheology/Viscosity

0.01 0.025 0.050

Volume Fraction

100 200 300 nm

Complex relationship between size/shape and rheology

More spherical shape = lower viscosity

Small particle size = higher viscosity

Wider particle size distribution = lower viscosity

spheres

fibers

Mixing

Shape affects mobility and therefore causes segregation

Smaller effect than size Shape differences could still be substantial

*Koller et. al.,Continuous quantitative monitoring of powder mixing dynamics by near-infrared spectroscopy

Powder Technology, Volume 205, Issues 1–3, 10 January 2011, Pages 87–96

Shape Effects Size Measurements

Inherent effect since light scattering instruments report equivalent spherical diameter

Sieve vs. laser diffraction vs. image analysis

Consider cylinder vs. sphere

=V = pr2h

V = 4pr3

Sieve = 50 mmLaser = 72 mm IA = full description

Modeling/Predicting Differences

In particle size; choose a technique, influence the answer

Well explained in this paper

Presented at the Spring Meeting of the Parenteral Drug Association in Philadelphia, June 1977

Defining Size

Measurement Results

xc min

“width”

A‘ = A

“diameter overprojection surface”

“length”

xFe max

CAMSIZER results are

compatible with

sieve analysis

x [mm]0.1 10

Tinovetin-B-CA584A_BZ_xc_min_002.rdfSyngenta-1mm-2min-Sieb.ref

Meßwertdiagramm:D:\...-Demo-Muenchwillen\CAMSIZER-Messungen\Tinovetin-B-CA584A_BZ_xc_min_002.rdfMeßaufgabe: Syngenta-BZ.afg

Width Sieving

--- width measurement

-*- Sieving

comparison

CAMSIZER-measurement xc min (red)and sieving * (black)

xc min

“width”

Want to Measure Shape?

Use image analysis ! Direct measurement of size + shape Get not only size but also shape distribution

CAMSIZER PSA300

Summary

Particle shape a critical physical parameter

Affects the product, the process and lab measurements

Understand how shape affects your business

Understand how shape influences your measurements

Examples

Dynamic:particles flow past camera

1 – 3000 um

Static:particles fixed on slide,stage moves slide

0.5 – 1000 um2000 um w/1.25 objective

Image Analysis: Two Approaches

Static or Dynamic Image Analysis? Dynamic

Broad size distributions (since it is easier to obtain data from a lot of particles)

Samples that flow easily (since they must be dropped in front of camera)

Powders, pellets, granules

StaticSamples that are more difficult to disperse (there

are more methods for dispersing the samples)Samples that are more delicatePastes, sticky particles, suspensions Precious samples

Data Evaluation

BinarizeFind Edges

Analyze Each Particle

Output Distribution

Raw Image

Features

Use gravity, or, better, vacuum (from a compressed air supply and venturi) in order to draw particles through instrument. Vacuum helps keep the windows clean.

27© Retsch Technology GmbH

Dynamic Image Analysis:

Moving Particles

Why Dynamic Image Analysis? Robust measurement….the interaction between the instrument and the particle is optical, so there is no wear and change in calibration.

High resolution size distribution resultsFast

Also, these are all reasons to use Dynamic Image Analysis instead of sieves.

Solid particles 20 mm – 125 mm Low equipment cost Some automation/calculation available

More information available through www.retsch.com

Sieves

Difficult to tell when sieve results are “drifting” due to wear

Results depend on nature of “shaking” leading to operator to operator variations in results.

Limited information

Advantage of Image Analysis

Better size analysis due to understanding of particle shape:Length, Width, Average Diameter

Shape Analysis with CAMSIZER XT

area of the particle

perimeter of the particle

circle with same area as

particle

diameter of circle of same

b/l0.4 0.5 0.6 0.7 0.80

Q3 [%]

Pharma-Product-1-30kPa-bonne-forme-_xc_min_009.rdfPharma-Product-1-30kPa_Vitesse-Adaption_xc_min_008.rdf

lactose-30kPa_xFemax_003.rdfPharma-Product-2-460_xc_min_008.rdf

SPHT0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.90

Q3 [%]

Pharma-Product-1-30kPa-bonne-forme-_xc_min_009.rdfPharma-Product-1-30kPa_Vitesse-Adaption_xc_min_008.rdf

lactose-30kPa_xFemax_003.rdfPharma-Product-2-460_xc_min_008.rdf

X-Jet Dry Powder Dispersion

Sample: PMMA Beads

Detection of oversized particles

x c _ m i n [ µ m ]8 1 0 1 2 1 4 1 60

Q 3 [ % ]

C A 1 0 F e e d 4 5 0 k p a _ x c _ m i n _ 0 0 7 . r d fC A 1 0 F e e d 4 5 0 k p a _ x c _ m i n _ 0 0 8 . r d fC A 1 0 T 1 8 C 4 5 0 k p a _ x c _ m i n _ 0 0 4 . r d fC A 1 0 T 1 8 C 4 5 0 k p a _ x c _ m i n _ 0 0 5 . r d fC A 1 0 T 1 8 F - A 4 5 0 k p a _ x c _ m i n _ 0 0 1 . r d fC A 1 0 T 1 8 F - A 4 5 0 k p a _ x c _ m i n _ 0 0 2 . r d fC A 1 0 T 1 8 F - B 4 5 0 k p a _ x c _ m i n _ 0 0 1 . r d fC A 1 0 T 1 8 F - B 4 5 0 k p a _ x c _ m i n _ 0 0 2 . r d f

G r a p h o f m e a s u r e m e n t r e s u l t s :C : \ . . . C a m s i z e r 4 3 1 9 X T \ C A M D A T \ R T 1 6 9 4 M i c r o b e a d s \ C A 1 0 F e e d 4 5 0 k p a _ x c _ m i n _ 0 0 7 . r d fT a s k f i l e : R T 1 6 9 4 P M M A 4 5 0 . a f g

Particle size [µm]

4 Samples:RedGreenBlueViolet

x c _ m i n [ µ m ]1 3 1 4 1 5 1 6 1 7 1 8

9 9 . 0

9 9 . 2

9 9 . 4

9 9 . 6

9 9 . 8

1 0 0 . 0

Q 3 [ % ]

C A 1 0 F e e d 4 5 0 k p a _ x c _ m i n _ a v . r d fC A 1 0 T 1 8 F - B 4 5 0 k p a _ x c _ m i n _ a v . r d fC A 1 0 T 1 8 C 4 5 0 k p a _ x c _ m i n _ a v . r d fC A 1 0 T 1 8 F - A 4 5 0 k p a _ x c _ m i n _ a v . r d f

G r a p h o f m e a s u r e m e n t r e s u l t s : M e a n v a l u e s , t a s k R T 1 6 9 4 P M M A 4 5 0 . a f g C : \ . . . C a m s i z e r 4 3 1 9 X T \ C A M D A T \ R T 1 6 9 4 M i c r o b e a d s \C A 1 0 F e e d 4 5 0 k p a _ x c _ m i n _ 0 0 8 . r d f , C A 1 0 F e e d 4 5 0 k p a _ x c _ m i n _ 0 0 7 . r d f

Δ ~ approx 0.5% Vol.

Red with oversized particlesGreen without oversizeBlue with oversized particlesViolet without oversize

Dispersing a SampleWant to spread particles out so that they

don’t touch.No Yes

Want to spread particles out so that they don’t touch.

Use % of field of view that is covered in order to control feed rate. Try 1% at first.

Control feed rate.

Feeding Too fast Good

SMALL PARTICLESPOTENTIALLY SMALL

EXTRACTION ERRORS (A)POTENTIALLY LARGE

SAMPLE PREP ERRORS (C)

LARGE PARTICLESPOTENTIALLY LARGE

EXTRACTION ERRORS (B)POTENTIALLY SMALL

SAMPLE PREP ERRORS (D)

INSTRUMENT ERROR IS SMALL AND RELATIVELY CONSTANT

PARTICLE SIZE

SAMPLE PREPARATION SAMPLE EXTRACTION

INSTRUMENT ERROR

Measurement Error Sources

Want to spread particles out so that they don’t touch.

Small and sticky particles will stay clumped together. Need to use energy to separate particles. That means air dispersion or liquid dispersion.

Micronized Powders

Feeding Too fastNot enough dispersion energy Good

Modular "X-Change" ConceptFlexible configuration for a wide application range

simple • safe • fast

Measurement principle – X-Jet

X-Jet Measurement ResultsInfluence of dispersion on shape parameters

Milk powder with X-Jet at 30, 60, 120, 200, 300 kPa

Milk powder_30kPa_xc_min_001.rdfMilk powder_60kPa_xc_min_002.rdfMilk powder_120kPa_xc_min_003.rdfMilk powder_200kPa_xc_min_004.rdfMilk powder_300kPa_xc_min_005.rdf

CCD - Basic CCD - Zoom

Measuring Principle

CAMSIZER XT 14µm 1µm

CAMSIZER

Resolution Difference

30 µm -> 30 mm1 µm-> 3 mm

Size Range

Detection of particles

One pixel is element of a projection when at least half of the pixel is covered.

Measurement Range

Large particles cannot been measured properly even they fit in the frame.

Measurement RangeThe probability of large particles touching the edge of the frame is higher than for smaller particles.

=> Large particles cannot been measured sufficiently

Upper limit of measurement range

Two-Camera-System

Basic-Camera Zoom-Camera

comparison

CAMSIZER-measurement xarea (red)and sieving * (blue)

A‘ = A

“diametervia projection surface”

Digital Image ProcessingArea Measurement Sieving

Feret diam. 1

Feret diam. 2

Longest diam.

to longest┴

Equivalentsphericaldiam

Size Descriptors

Feret diam. 1

Feret diam. 2

Longest diam.

to longest┴

Aspect ratio

= shortest diam longest diam

= to longest diam longest diam

= shortest Feret diam longest Feret diam

= three different numbers!

Shape: Aspect Ratio

More Shape Descriptors

Optical Process Controlanalysis for size and shape

Measurement Results

Number of Particles

Error bars are one standard deviation from repeated measurements of the same number of particles from different parts of the sample.

The error bars get smaller as you evaluate more particles.

Measurement of very broad particle distributions (due to speed and two cameras)

Direct particle definition by width (analogue to sieving) by length or projection surface

Two camera system for more accuracy and reproducibility

Easy operation Fail-safe, robust Ideal for particle shape analyses Measurement of density, counting of

particles

Measurement Results

CAMSIZER Advantages

Watch out for:

Sample preparationImage qualityMeasure enough particles

Examples

Product PerformanceSome products perform better when

more sphericalGlass beads for highway paintProppants

Some products perform better when less sphericalAbrasivesCatalysts

Finding particles by shape

Glass Beads for Highway Paint

Size and shape critical to reflective properties

More round = more reflectivity back to source

CAMSIZER uses b/l ratio to quantify roundness

Dry In paint

Defects from round particles

Satellites

Pointed

Aggregates

Glass Beads for Highway Paint

Quantified by Camsizer

Proppant Packing

Shape Comparison

A s p c t R a t i o0 . 3 0 . 4 0 . 5 0 . 6 0 . 7 0 . 80

Q 3 [ % ]C e r a m i c - P r o p - E P - 2 0 - 4 0 - M e s h - 4 0 . r d fC e r a m i c - P r o p - S B - 2 0 - 4 0 - M e s h 1 . r d fC e r a m i c - P r o p - S G - V - 1 . r d fS a n d - P r o p - S I B - 2 0 - 4 0 - M I S - 9 . r d fN a t u r a l - B r o w n - S a n d - C - 2 0 - 4 0 . r d fW h i t e - S a n d - P r o p - U N F - 2 0 - 4 0 - 1 7 . r d fW h i t e - S a n d - P r o p - S I B - 2 0 - 4 0 - C H F - 1 0 . r d fW h i t e - S a n d - P r o p - U N F - 2 0 - 4 0 - 1 . r d fW h i t e - S a n d - P r o p - U N F - 2 0 - 4 0 - 8 . r d f

G r a p h o f m e a s u r e m e n t r e s u l t s : M e a n v a l u e s , t a s k P r o p p a n t s - C a d r e . a f g D : \ . . . - P r o p p a n t \I m e r y s - E l - P r o p - # 2 0 - # 4 0 - 1 8 m m - Z _ x c _ m i n _ 2 0 1 2 _ 0 2 _ 1 4 _ 2 3 _ 5 5 _ 5 3 _ 0 4 2 . r d f , I m e r y s - E l - P r o p - # 2 0 - # 4 0 - 1 8 m m - Z _ x c _ m i n _ 2 0 1 2 _ 0 2 _ 1 5 _ 0 0 _ 3 0 _ 3 4 _ 0 4 1 . r d f

Shape comparison between natural sand proppants and ceramic proppants. There are two clearly different ranges of Aspect Ratio (Krumbein’s Sphericity). Analysis of other shape parameters are possible as well (Convexity for ceramic bead twins, Symmetry for good and broken ceramic beads, Krumbein’s Roundness etc.)

Proppants

Traditional method CAMSIZER

Abrasion Mechanics

Difference in hardness between the two substances: a much harder abrasive will cut faster and deeper

Grain size (grit size): larger grains will cut faster as they also cut deeper

Grain shape: sharp corners help some mechanisms

Compactness helps in others

Dynamic Image AnalysisBy choosing proper size parameter, Xc min, results can match historic sieve Data. Also generates shape data provenTo correlate with abrasive performance.

Sand: Round vs. “Edgy”

Similar in size.Shape difference seenin b/l and sphericity.Edgy would makebetter abrasive.

Sphericity

Breadth/length (b/l)

Catalysts Size/Shape by CAMSIZER

Spherical catalysts Easy, no special effort

Cylindrical catalystsLength, width

Bended extrudatesUse other parameters 2

max )()( cFelength xxx

mincstretch x

Catalysts Size/Shape by CAMSIZER

Tri & quadralobePossible to distinguish

between different diameters

Shorter green distribution = length

Taller maroon distribution= width

Size helps define shape

Quadralobe catalysts

Trilobe catalysts

xFe max

xc min

Measurement Results

Q3 (round particles) =

Find the componentsof Ion Exchanger

and Charcoal in a mixture

Examples

Danke Merci

Gracias

Большое спасибо

Grazie<اُشْك? ر

Σας ευχαριστούμε

감사합니다 Obrigado

Tacka dig

谢谢 ขอบคุ�ณคุรั�บ

Thank youありがとうございました

धन्यवा�दநன்ற

www.horiba.com/particle

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Jeff Bodycomb, Ph.D.Product Manager

Jeff.Bodycomb@horiba.com

particle shape of micronized powders

effect of particle shape

spheres shape

mixing shape

size shape differences

influence of particle

spherical shape

different shape

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