Introduction to Particle Size Analysis                                                 Ian Treviranus                     ...
What we’ll talk about          Featured technologies          Defining particle size          Understanding size metric...
Featured technologies         LA-950                   Laser Diffraction         SZ-100                   Dynamic Light ...
LA-950: Laser Diffraction         Particle size performance leader         Ninth generation         Ultra durable      ...
SZ-100: Dynamic Light Scattering         Particle size: 0.3 nm – 8 µm         Zeta potential: -200 – +200 mV         Mo...
Image Analysis    Dynamic:                               Static:    particles flow past camera             particles fixed...
CAMSIZER Series         High resolution size & shape         Intelligent sieve correlation         Patented dual captur...
PSA300         High resolution size & shape         Referee technique for micronized powders         Turnkey, automated...
More Information          Best Practices/Training                           Understanding Laser Diffraction PSA Results ...
Who Cares About Particle Size?                Minerals Grinding                         10                               ...
What we’ll talk about          Featured technologies          Defining particle size          Understanding size metric...
Size Terminology                                             0.1µm 1.0µm     10µm 100µm10-10             10-9             ...
Poll!                Which size ranges do you measure?© 2013HORIBA, Ltd. All rights reserved.
Particle Diameter (m)                                           0.01              0.1               1              10    ...
The Basics                Which is the most meaningful size?                               different          different   ...
The Basics                What sizes can be measured?© 2013 HORIBA, Ltd. All rights reserved.
Size Definitions          Martins’s Diameter: The distance between opposite           sides of a particle measured on a l...
Particle Orientation                                                                 Equivalent Spherical   Equivalent Sph...
The Basics       Particle                            Particle Distribution© 2013 HORIBA, Ltd. All rights reserved.
The Basics       Particle Size Particle Size Distribution                        4 µm© 2013 HORIBA, Ltd. All rights reserv...
Monodisperse vs. Polydisperse                           Monodisperse                                    PolydisperseVOLUME...
Logarithmic vs. Linear Scale                                Logarithmic X-Axis                              Linear X-Axi...
Distribution Display                                                           Cumulative Distribution                    ...
Your Analyzer’s Displays                          Frequency               Frequency + cumulative (undersize)              ...
What we’ll talk about          Featured technologies          Defining particle size          Understanding size metric...
Central ValuesMeanWeighted Average                                  MeanCenter of Gravity                                 ...
What does “Mean” mean?                          Three spheres of diameters 1,2,3 units                                    ...
Many possible Mean values                                1 2  3                X nl  D[1,0]            2.00          ...
Volume-based Mean diameterD[4,3] which is often referred to as the Volume Mean Diameter [ VMD ]                           ...
Central Values revisited                                                                    Mean                          ...
Most Common Statisticshalf are smaller than this diameter half are larger than this diameter                              ...
Standard Deviation                                                                        Normal (Gaussian)              ...
Distribution Width                                            Polydispersity Index                                       ...
For Your Reference           Note: Span typically = (d90 – d10)/ d50© 2013 HORIBA, Ltd. All rights reserved.
For Your Reference© 2013 HORIBA, Ltd. All rights reserved.
For Your Reference                                           Error Calculations in LA-950 only© 2013 HORIBA, Ltd. All righ...
Skewness© 2013 HORIBA, Ltd. All rights reserved.
Kurtosis (Peakedness)                                           From highest to lowest peak:                              ...
Number vs. Volume Distributions  r = 1 µm                   r =2 µm            r = 3 µm  v=4                          = 32...
Beans!© 2013 HORIBA, Ltd. All rights reserved.
Equivalent Volume Distributions© 2013 HORIBA, Ltd. All rights reserved.
Equivalent Volume Distributions© 2013 HORIBA, Ltd. All rights reserved.
Equivalent Volume Distributions© 2013 HORIBA, Ltd. All rights reserved.
Equivalent Volume Distributions© 2013 HORIBA, Ltd. All rights reserved.
Comparing Distribution Bases                                    Same material shown as volume, number and area           ...
Statistical Issues with Distributions    L Neumann, E T White, T Howes (Univ.     Queensland) “What does a mean size     ...
Does the Mean Match the Process?          Particle size measurements often made to           monitor a process           ...
Size Reduction Scenario     10 x1 m                              10 x 1 m                                            79....
Size Reduction: Number Mean   Ten particles of size 1; one of size 100 unitsNumber mean = D[1, 0] = (10*1 + 1*100)/11 = 10...
Size Reduction: Volume Mean                Ten particles of size 1; one of size 100 units                           Volume...
Can You See the Problem?                            Number mean = 10    Number mean = 14                            Volume...
Size Growth Scenario                                           10 1 m                                     10 1 m        ...
Growth: Number Mean             Ten particles of size 1; ten of size 46.42                   D[1, 0] = (10*1 + 10*46.42)/2...
Growth: Volume Mean             Ten particles of size 1; ten of size 46.42            D[4, 3] = (10*14 + 10*46.424)/(10*13...
Can You See the Problem?                             Number mean = 24   Number mean = 10                             Volum...
Practical Implications          Not just a “party trick” topic!            “Do you know you can break particles and      ...
What we’ll talk about          Featured technologies          Defining particle size          Understanding size metric...
PSA Method is ImportantWhy should one consider various methods of particle size analysis?    Material suppliers and user...
Size Range by Technique                                                   ELECTROFORMED MESH         SIEVES               ...
What Size is Measured?         Laser Diffraction                  Equivalent Spherical Diameter         Dynamic Light Scat...
Particle Shape Definitions         Acicular:                         Needle-shaped, rigid         Angular:                ...
Poll!           What are the shapes of your particles?© 2013HORIBA, Ltd. All rights reserved.
Poll!          Do you use multiple sizing techniques?© 2013HORIBA, Ltd. All rights reserved.
Hegman Gauge          Used in paint and coatings industry               Device has tapered center                channel...
SievesWeigh % sample caught on known screen sizesSolid particles 30 m – 30 mm (and larger)  Advantages:                ...
Electrical Sensing ZoneCoulter Principle     Based on change in      conductivity of aperture      as particle traverses...
Light Obscuration          Light Obscuration:                             Liquid Flow                                    ...
Sedimentation                                                               Sedimentation of same density     Stokes Law ...
Sedimentation Issues          Comparison of Brownian Motion and           Gravitational Settling                         ...
Dynamic Light Scattering     Most common technique for sub-micron sizing     Range: 1 nm – 1 m*                        Fr...
Manual Microscopy Count particles in a given  field of view Use graticule to obtain size Repeat this process for a  num...
Automated Microscopy     Static:                               Dynamic:     Particles fixed on slide,             Particle...
Automated Microscopy                                                      Advantages:                                    ...
Acoustic Spectroscopy Acoustic signal sent into  concentrated sample Detector measure  attenuation f (frequency,  distan...
Laser Diffraction                                           •Converts scattered light to                                  ...
Poll!                             Which techniques do you use?© 2013HORIBA, Ltd. All rights reserved.
What we’ll talk about          Featured technologies          Defining particle size          Understanding size metric...
ありがとうございました                                                       ขอบคุณครับ                                              ...
www.horiba.com/particle                                                         Ian Treviranus                            ...
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Essentials of Particle Size Analysis

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Ian Treviranus from HORIBA Scientific provides an introduction to particle size analysis. This talk will be useful for anyone using laser diffraction, dynamic light scattering, or dynamic image analysis instruments. The information will be suitable for any instrument from any manufacturer of these technologies.

Topics covered include:

Why is particle size important
Defining particle size
Understanding size metrics
Differences between particle size technologies

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Essentials of Particle Size Analysis

  1. 1. Introduction to Particle Size Analysis Ian Treviranus ian.treviranus@horiba.com www.horiba.com/us/particle© 2013HORIBA, Ltd. All rights reserved.
  2. 2. What we’ll talk about  Featured technologies  Defining particle size  Understanding size metrics  Differences between techniques  Q&A© 2013 HORIBA, Ltd. All rights reserved.
  3. 3. Featured technologies LA-950 Laser Diffraction SZ-100 Dynamic Light Scattering & Zeta Potential CAMSIZER & CAMSIZER XT Dynamic Image Analysis PSA300 Static Image Analysis SA-9600 Flowing Gas BET Surface Area© 2013 HORIBA, Ltd. All rights reserved.
  4. 4. LA-950: Laser Diffraction Particle size performance leader Ninth generation Ultra durable Lowest total cost of ownership Suspension, emulsion, powder, paste, gel 10 nanometer – 3 mm© 2013 HORIBA, Ltd. All rights reserved.
  5. 5. SZ-100: Dynamic Light Scattering Particle size: 0.3 nm – 8 µm Zeta potential: -200 – +200 mV Molecular weight: 1x103 – 2x107 Da Patented ultra long-life graphite electrodes Lowest total cost of ownership Optional autotitrator© 2013 HORIBA, Ltd. All rights reserved.
  6. 6. Image Analysis Dynamic: Static: particles flow past camera particles fixed on slide, stage moves slide© 2013 HORIBA, Ltd. All rights reserved.
  7. 7. CAMSIZER Series High resolution size & shape Intelligent sieve correlation Patented dual capture CAMSIZER 30 µm – 30 mm Free-flowing powders CAMSIZER XT 1 µm – 3 mm Cohesive or free flowing© 2013 HORIBA, Ltd. All rights reserved.
  8. 8. PSA300 High resolution size & shape Referee technique for micronized powders Turnkey, automated image analysis 1 µm – 1,000 µm Cohesive or free flowing powders Optional Powder Disperser accessory© 2013 HORIBA, Ltd. All rights reserved.
  9. 9. More Information  Best Practices/Training  Understanding Laser Diffraction PSA Results TR008  Troubleshooting Laser Diffraction Data TR010  Understanding Dynamic Light Scattering Results TR012  Help! How Can I Trust My Size Results? TR015  Refractive index selection, sampling, dispersion, system verification, method development and more  Technology  Intro to CAMSIZER TE002  Find the Best Analyzer for Your Application TE006  Intro to Static Image Analysis TE008  Intro to Dynamic Image Analysis TE009  Intro to Laser Diffraction TE010  Intro to Dynamic Light Scattering TE012  Intro to CAMSIZER XT TE015© 2013 HORIBA, Ltd. All rights reserved.
  10. 10. Who Cares About Particle Size?  Minerals Grinding 10 Pharmaceutical  Portland Cement 5 25 Chemical  Glass Beads 5 Ceramics Cement  Abrasives 5 Food Abrasives  Foods 5 Cosmetics Mining  Cosmetics 5 Powder Metals University  Pharmaceuticals 5 5 25 Other 5  Paint and Coatings  Metals and Ceramics  Explosives and Fireworks© 2013 HORIBA, Ltd. All rights reserved.
  11. 11. What we’ll talk about  Featured technologies  Defining particle size  Understanding size metrics  Differences between techniques  Q&A© 2013 HORIBA, Ltd. All rights reserved.
  12. 12. Size Terminology 0.1µm 1.0µm 10µm 100µm10-10 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 10-0 100 nm nanometer micrometer millimeter meter nm Micron or µm mm mAngstrom (Å) The most common designation is micrometers or microns. When very small, in colloid region, measured in nanometers, with electron microscopes or by dynamic light scattering. © 2013 HORIBA, Ltd. All rights reserved.
  13. 13. Poll! Which size ranges do you measure?© 2013HORIBA, Ltd. All rights reserved.
  14. 14. Particle Diameter (m) 0.01 0.1 1 10 100 1000 Ultrafine Fine Coarse Size Ranges Inhalable Tobacco Smoke Spores Beach Sand Relative Size of Common Viruses Bacteria Material Carbon Black Paint Pigment Human Hair Electron Microscope Optical Microscope Common Static Angular Light Scattering Methods Dynamic Light Scattering for Particle Electrozone Sensing Size Analysis Sedimentation Methods Field Flow Fractionation Light Obscuration Ultrasonic Spectroscopy© 2013 HORIBA, Ltd. All rights reserved.
  15. 15. The Basics Which is the most meaningful size? different different size definitions results© 2013 HORIBA, Ltd. All rights reserved.
  16. 16. The Basics What sizes can be measured?© 2013 HORIBA, Ltd. All rights reserved.
  17. 17. Size Definitions  Martins’s Diameter: The distance between opposite sides of a particle measured on a line bisecting the projected area. To ensure statistical significance all measurements are made in the same direction regardless of particle orientation. Equivalent Spherical  Feret’s Diameter: The distance between parallel Diameter tangents on opposite sides of the particle profile. Again to insure statistical significance, all measurements are made in the same direction regardless of particle orientation. Martin’s Diameter  Note: Both Martin’s and Feret’s diameters are generally used for particle size analysis by optical and electron microscopy.  Equivalent Circle Diameter: The diameter of a circle having an area equal to the projected area of the particle in random orientation. This diameter is usually determined subjectively and measured by oracular micrometers called graticules.  Equivalent Spherical Diameter: The diameter of a sphere that has the same volume as the irregular Feret’s Diameter particle being examined.© 2013 HORIBA, Ltd. All rights reserved.
  18. 18. Particle Orientation Equivalent Spherical Equivalent Spherical Diameter  Martin’s and Diameter Martin’s Feret’s Diameter’s Diameter will vary as Martin’s particles are Diameter viewed in different orientations. The result will be a DISTRIBUTION from smallest to largest. Feret’s Diameter Feret’s Diameter© 2013 HORIBA, Ltd. All rights reserved.
  19. 19. The Basics Particle Particle Distribution© 2013 HORIBA, Ltd. All rights reserved.
  20. 20. The Basics Particle Size Particle Size Distribution 4 µm© 2013 HORIBA, Ltd. All rights reserved.
  21. 21. Monodisperse vs. Polydisperse Monodisperse PolydisperseVOLUME VOLUME Particle Size Particle Size  Monodisperse Distribution:  Wide Distribution:  All particles are the same size  Particles of Many Sizes  Latex standards  Everything else © 2013 HORIBA, Ltd. All rights reserved.
  22. 22. Logarithmic vs. Linear Scale  Logarithmic X-Axis  Linear X-Axis Distribution DistributionVOLUME VOLUME 0 10 100 0 10 20 30 40 50 60 70 80 90 100 Particle Size Particle Size © 2013 HORIBA, Ltd. All rights reserved.
  23. 23. Distribution Display Cumulative Distribution Histogram VOLUME Differential Distribution Particle Size  Represented by series of segments or channels known as histogram.  Number of channels based on design, practicality and aesthetics© 2013 HORIBA, Ltd. All rights reserved.
  24. 24. Your Analyzer’s Displays Frequency Frequency + cumulative (undersize) Histogram Multiple frequency + cumulative (undersize)© 2013 HORIBA, Ltd. All rights reserved.
  25. 25. What we’ll talk about  Featured technologies  Defining particle size  Understanding size metrics  Differences between techniques  Q&A© 2013 HORIBA, Ltd. All rights reserved.
  26. 26. Central ValuesMeanWeighted Average MeanCenter of Gravity Median and ModeMedian50% PointModePeak of the distributionMost common value Size© 2013 HORIBA, Ltd. All rights reserved.
  27. 27. What does “Mean” mean? Three spheres of diameters 1,2,3 units 1 2 3 What is the average size of these spheres? Average size = (1+2+3) ÷ 3 =2.00 This is called the D[1,0] - the number mean© 2013 HORIBA, Ltd. All rights reserved.
  28. 28. Many possible Mean values 1 2  3 X nl  D[1,0]   2.00 3 1 4  9 None of the answers X ns  D[ 2,0]   2.16 3 are wrong they have just been calculated using 1  8  27 different techniques X nv  D[ 3,0]  3  2.29 3 1  8  27 X sv  D[ 3,2]   2.57 1 2  3 1  16  81 X vm  D[ 4,3]   2.72 1  8  27© 2013 HORIBA, Ltd. All rights reserved.
  29. 29. Volume-based Mean diameterD[4,3] which is often referred to as the Volume Mean Diameter [ VMD ] D [4,3] = D n 4 i i D n 3 i i Monitoring the D[4,3] value in your specification will emphasize the detection of large particles © 2013 HORIBA, Ltd. All rights reserved.
  30. 30. Central Values revisited Mean Weighted Average Mode Center of Gravity Median Mean Median 50% Point D[4,3] Mode Peak of the distribution Most common value Size Remember: D[4,3] is sensitive to large particles© 2013 HORIBA, Ltd. All rights reserved.
  31. 31. Most Common Statisticshalf are smaller than this diameter half are larger than this diameter D(v,0.5) median10% of the particles lie 90% of the particles lie below this diameter below this diameter D(v,0.1) D(v,0.9) D(v,1.0) Never use the D100! Size µm D(4,3) sensitive to large particles D(3,2) sensitive to small particles © 2013 HORIBA, Ltd. All rights reserved.
  32. 32. Standard Deviation  Normal (Gaussian) Distribution Curve -1 STD DEV +1 STD DEV   = distribution mean 68.27%   = standard deviation  Exp = base of natural logarithms-2 STD DEV +2 STD DEV 95.45% Mean 1 - (x - )2 Y=  2 Exp [ ] 22 © 2013 HORIBA, Ltd. All rights reserved.
  33. 33. Distribution Width  Polydispersity Index (PI, PDI)  Span  Geometric Std. Dev.  Variance  Etc…© 2013 HORIBA, Ltd. All rights reserved.
  34. 34. For Your Reference Note: Span typically = (d90 – d10)/ d50© 2013 HORIBA, Ltd. All rights reserved.
  35. 35. For Your Reference© 2013 HORIBA, Ltd. All rights reserved.
  36. 36. For Your Reference Error Calculations in LA-950 only© 2013 HORIBA, Ltd. All rights reserved.
  37. 37. Skewness© 2013 HORIBA, Ltd. All rights reserved.
  38. 38. Kurtosis (Peakedness) From highest to lowest peak: red, kurtosis 3 orange, kurtosis 2 green, kurtosis 1.2 black, kurtosis 0, cyan, kurtosis −0.593762… blue, kurtosis −1 magenta, kurtosis −1.2© 2013 HORIBA, Ltd. All rights reserved.
  39. 39. Number vs. Volume Distributions r = 1 µm r =2 µm r = 3 µm v=4 = 32 = 108 V = 4  r3 3V*3 = 12 96 324 Total = 12+96+324 = 43212/432=2.8% 96/432=22.2% 324/432=75% © 2013 HORIBA, Ltd. All rights reserved.
  40. 40. Beans!© 2013 HORIBA, Ltd. All rights reserved.
  41. 41. Equivalent Volume Distributions© 2013 HORIBA, Ltd. All rights reserved.
  42. 42. Equivalent Volume Distributions© 2013 HORIBA, Ltd. All rights reserved.
  43. 43. Equivalent Volume Distributions© 2013 HORIBA, Ltd. All rights reserved.
  44. 44. Equivalent Volume Distributions© 2013 HORIBA, Ltd. All rights reserved.
  45. 45. Comparing Distribution Bases  Same material shown as volume, number and area distribution 12 Number Volume Distribution 10Percent in Channel Volume Mean = 12.65µm Area Median=11.58 µm 8 SA=13467 cm2/cm3 Std Dev.=8.29 6 Number Distribution Mean = 0.38µm 4 Median=0.30 µm SA=13467 cm2/cm3 2 Std Dev.=0.40 0 0.58 2.27 8.82 34.25 0.34 1.15 4.47 Particle Size 17.38 © 2013 HORIBA, Ltd. All rights reserved.
  46. 46. Statistical Issues with Distributions  L Neumann, E T White, T Howes (Univ. Queensland) “What does a mean size mean?” 2003 AIChE presentation at Session 39 Characterization of Engineered particles November 16 - 21 San Francisco Other references:  L Neumann, T Howes, E T White (2003) Breakage can cause mean size to increase Dev. Chem. Eng. Mineral Proc. J.  White E T, Lawrence J. (1970), Variation of volume surface mean for growing particles, Powder Technology,4, 104 - 107© 2013 HORIBA, Ltd. All rights reserved.
  47. 47. Does the Mean Match the Process?  Particle size measurements often made to monitor a process Size reduction (milling) Size growth (agglomeration)  Does the measured/calculated mean diameter describe the change due to the process?  It depends on which mean used…© 2013 HORIBA, Ltd. All rights reserved.
  48. 48. Size Reduction Scenario 10 x1 m 10 x 1 m 79.4 m 79.4 m 100 m breaks into two smaller particles© 2013 HORIBA, Ltd. All rights reserved.
  49. 49. Size Reduction: Number Mean Ten particles of size 1; one of size 100 unitsNumber mean = D[1, 0] = (10*1 + 1*100)/11 = 10 units .. Largest particle (100) breaks into two of 79.37 (conserves volume/mass: 2 @ 79.373 = 1 @ 1003) Have broken one What happens to the number mean? Mean = (10*1+2*79.37)/12 = 14.06 units Surprise, surprise a 40.6% increase!© 2013 HORIBA, Ltd. All rights reserved.
  50. 50. Size Reduction: Volume Mean Ten particles of size 1; one of size 100 units Volume Moment Mean D[4, 3] = (10*14 + 1*1004)/(10*13 + 1*1003) ~ 100 units .. Largest particle (100) breaks into two of 79.37 (conserves volume/mass: 2 @ 79.373 = 1 @ 1003) Have broken one What happens to the D[4, 3]? New D[4, 3] = (10*14+2*79.374)/(10*13 +2*79.373) ~ 79.37 units This shows the expected behavior© 2013 HORIBA, Ltd. All rights reserved.
  51. 51. Can You See the Problem? Number mean = 10 Number mean = 14 Volume mean = 100 Volume mean = 79© 2013 HORIBA, Ltd. All rights reserved.
  52. 52. Size Growth Scenario 10 1 m 10 1 m 10 46.4 m 1 100 m Ten 46.4 m particles agglomerate into one 100 m particle© 2013 HORIBA, Ltd. All rights reserved.
  53. 53. Growth: Number Mean Ten particles of size 1; ten of size 46.42 D[1, 0] = (10*1 + 10*46.42)/20 = 23.71 units . Ten of 46.42 agglomerate into one of 100 (conserves volume/mass: 10 @ 46.423 = 1 @ 1003) Have agglomerated half; does mean increase? Mean = (10*1+1*100)/11 = 10 units Over a 50% decrease!© 2013 HORIBA, Ltd. All rights reserved.
  54. 54. Growth: Volume Mean Ten particles of size 1; ten of size 46.42 D[4, 3] = (10*14 + 10*46.424)/(10*13 + 10*46.423) ~ 46.4 units (Note again the volume moment mean is dominated by the large particles) . Ten of 46.42 agglomerate into one of 100 (conserves volume/mass: 10 @ 46.423 = 1 @ 1003) Have agglomerated half; does mean increase? D[4, 3] = (10*14+1*1004)/10*13 + 1*1003 ~ 100 units This shows the expected behavior© 2013 HORIBA, Ltd. All rights reserved.
  55. 55. Can You See the Problem? Number mean = 24 Number mean = 10 Volume mean = 46 Volume mean = 100© 2013 HORIBA, Ltd. All rights reserved.
  56. 56. Practical Implications  Not just a “party trick” topic! “Do you know you can break particles and the mean will increase?”  Serious. “Did an experiment. I thought I broke particles but the mean has increased” (REAL experience)  Should be aware it can happen!  Analyse whole size distribution, not mean alone.© 2013 HORIBA, Ltd. All rights reserved.
  57. 57. What we’ll talk about  Featured technologies  Defining particle size  Understanding size metrics  Differences between techniques  Q&A© 2013 HORIBA, Ltd. All rights reserved.
  58. 58. PSA Method is ImportantWhy should one consider various methods of particle size analysis? Material suppliers and users employ many different types of instruments Use a different technique = get a different answer It is important to understand how analysis methods differ in order to know how to compare data © 2013 HORIBA, Ltd. All rights reserved.
  59. 59. Size Range by Technique ELECTROFORMED MESH SIEVES CENTRIFUGAL SEDIMENTATION ACOUSTIC SPECTROSCOPY OPTICAL MICROSCOPY / IMAGE ANALYSIS ELECTRICAL CONDUCTIVITY LIGHT OBSCURATION / ELECTRICAL SENSING ZONE DYNAMIC LIGHT SCATTERING LASER DIFFRACTION10 nm 100 nm 1 µm 10 µm 100 µm 1 mm© 2013 HORIBA, Ltd. All rights reserved.
  60. 60. What Size is Measured? Laser Diffraction Equivalent Spherical Diameter Dynamic Light Scattering Hydrodynamic Radius Image Analysis Lengths, Widths, Equivalent Spherical Acoustic Spectroscopy Equivalent Spherical Diameter© 2013 HORIBA, Ltd. All rights reserved.
  61. 61. Particle Shape Definitions Acicular: Needle-shaped, rigid Angular: Edgy, hard angles Fibrous: Thread-like, non-rigid Granular/Blocky: Irregular-shaped, low aspect-ratio Spherical: Regular-shaped, unity aspect ratio Aspect ratio: Breadth / length OR Length / breadth Sphericity: How spherical is the particle? Roundness: How round is the particle?© 2013 HORIBA, Ltd. All rights reserved.
  62. 62. Poll! What are the shapes of your particles?© 2013HORIBA, Ltd. All rights reserved.
  63. 63. Poll! Do you use multiple sizing techniques?© 2013HORIBA, Ltd. All rights reserved.
  64. 64. Hegman Gauge  Used in paint and coatings industry Device has tapered center channel Slurry is placed in channel, then straight edge is drawn across it “Hegman Number” is where particles disturb smooth surface of slurry Information from largest particles only – no distribution© 2013 HORIBA, Ltd. All rights reserved.
  65. 65. SievesWeigh % sample caught on known screen sizesSolid particles 30 m – 30 mm (and larger) Advantages: Disadvantages: Low equipment Limited lower cost range Direct Time measurement Consuming method High Labor Cost No practical upper Need Large limit Sample Available through www.retsch.com© 2013 HORIBA, Ltd. All rights reserved.
  66. 66. Electrical Sensing ZoneCoulter Principle  Based on change in conductivity of aperture as particle traverses.  Requires conducting liquid.  Directly measures particle volume and counts.  High resolution  Used for blood cell counting more than industrial applications © 2013 HORIBA, Ltd. All rights reserved.
  67. 67. Light Obscuration  Light Obscuration: Liquid Flow Sensing ZoneLight Source Light is blocked by single particles as Detector they traverse the light beam Advantages: Disadvantages:  Particle count available  Dilution required for  USP<788> testing particle size analysis  High resolution histogram  Prone to cell clogging© 2013 HORIBA, Ltd. All rights reserved.
  68. 68. Sedimentation Sedimentation of same density Stokes Law material in a viscous medium 18 µ Vp D= (A - B) G Vp = Settling velocity of discrete particle G = Gravity constant A = Density of Particle B = Density of Carrier Fluid D = Diameter of discrete particle Time µ = Viscosity of Carrier FluidNote: assumes settling of spherical particleUnder-sizes compared to other techniques if non-spherical © 2013 HORIBA, Ltd. All rights reserved.
  69. 69. Sedimentation Issues  Comparison of Brownian Motion and Gravitational Settling (Movement in 1 second; Particle density of 2.0 grams/cc) Particle Diameter Movement due to Movement due to (In micrometers) Brownian Motion Gravitational Settling 0.01 2.36 >> 0.005 0.25 1.49 > 0.0346 0.50 1.052 > 0.1384 1.0 0.745 ~ 0.554 2.5 0.334 < 13.84 10.0 0.236 << 55.4  Below 1 micrometer, Brownian motion becomes an appreciable factor in particle dynamics. Gravity sedimentation may not be an appropriate measurement technique for very small particles.© 2013 HORIBA, Ltd. All rights reserved.
  70. 70. Dynamic Light Scattering Most common technique for sub-micron sizing Range: 1 nm – 1 m* Frequency Shifted Signal Frequency-Intensity DistributionParticles in suspension undergo Brownian kT Stokes-Einstein R H motion due to bombardment by solvent 6  Dmolecules in random thermal motion.* Density dependent, when does settling become prominent motion? © 2013 HORIBA, Ltd. All rights reserved.
  71. 71. Manual Microscopy Count particles in a given field of view Use graticule to obtain size Repeat this process for a number of fields At least hundreds of particles must be sized Advantages: Disadvantages: Simple Slow Inexpensive Measures very few particles Can see shape Very tedious© 2013 HORIBA, Ltd. All rights reserved.
  72. 72. Automated Microscopy Static: Dynamic: Particles fixed on slide, Particles flow past camera(s) stage moves slide© 2013 HORIBA, Ltd. All rights reserved.
  73. 73. Automated Microscopy Advantages: Quick size + shape infoObjective & Image Acquisition and enhancement Statistically validcamera High resolution Particle imagesSubjective or Thresholdingautomatic Disadvantages: ExpenseDecisions or Image Processing Knowing whichblack box numbers are important Measurements © 2013 HORIBA, Ltd. All rights reserved.
  74. 74. Acoustic Spectroscopy Acoustic signal sent into concentrated sample Detector measure attenuation f (frequency, distance from source) Signal Detector source Signal output Advantages: Disadvantages: Can accommodate high sample concentrations  Need at least 1 wt% particles (no dilution)  Need to know wt% Rheological properties  Minimum sample = 15 ml Also measure zeta potential© 2013 HORIBA, Ltd. All rights reserved.
  75. 75. Laser Diffraction •Converts scattered light to particle size distribution •Quick, repeatable •Powders, suspensions •Most common technique© 2013 HORIBA, Ltd. All rights reserved.
  76. 76. Poll! Which techniques do you use?© 2013HORIBA, Ltd. All rights reserved.
  77. 77. What we’ll talk about  Featured technologies  Defining particle size  Understanding size metrics  Differences between techniques  Q&A© 2013 HORIBA, Ltd. All rights reserved.
  78. 78. ありがとうございました ขอบคุณครับ 谢谢 Gracias ُْ ‫اشكر‬ Grazie Σας ευχαριστούμε धन्यवादTacka dig நன்ற Danke Obrigado 감사합니다 Большое спасибо© 2013 HORIBA, Ltd. All rights reserved.
  79. 79. www.horiba.com/particle Ian Treviranus Product Line Manager ian.treviranus@horiba.com Talk to us, ask questions labinfo@horiba.com Receive news of updates View application & technical notes (170+), webinars (60+), white papers.© 2013 HORIBA, Ltd. All rights reserved.
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