Micromeritics SediGraph® III Plus Particle Size Analyzer

SediGraph III Plus 5125 is a unique, dependable, and proven particle size analyzer based on scientific principles.

  • Established global standard for over 50 years in sedimentation-based particle size analysis
  • Fully automated operation with control through a modern software interface
  • Utilizes Stokes’ Law for accurate determination of particle size
  • Real-time monitoring of particle settling and immediate access to size analysis results
  • High throughput capabilities with MasterTech autosampler
  • Complies with ASTM B761-06 and Committee C28 on Advanced Ceramics requirements
  • Recognized as an industry standard in key sectors such as mining, geology, and ceramics


The SediGraph III Plus employs direct mass concentration detection to determine particle size distributions and statistics, including D10, D50, and D90. It has basic and advanced reporting capabilities that are accessible at the touch of a button.

For continuous monitoring of a production process, and transfer of data to a network or cloud for remote access, the SediGraph III Plus can be coupled with the optional MasterTech autosampler.

Features and Benefits

Intelligent Design Features:

The advanced instrumentation features of the SediGraph III Plus guarantee repeatable and easily performed measurements.

Enhanced functionalities facilitate smoother operation and maintenance of the instrument, ensuring that results can be consistently replicated by SediGraphs at different locations.

Design Improvements Include:

  • Comprehensive particle accountability ensures that every component of the introduced sample is considered, including fractions below 0.1 µm.
  • Fully automatic operation for increased sample throughput, reduced operator involvement, and minimized human error.
  • Capability to merge data with other particle sizing methods, expanding reported data range to 125,000 µm (125 mm), ideal for geological applications.
  • Scanning the sedimentation cell from bottom to top for an accurate inventory of fast-settling particles while minimizing resolution time for fine particles.
  • Temperature-controlled analyses to maintain liquid properties throughout the analysis, ensuring accurate and reproducible results.
  • Multiple analysis speeds for customizable speed and resolution based on specific needs.
  • Plot overlays for visual comparisons of analysis results from multiple analyses. For example a reference/baseline analysis, or a superposition of two different types of plots of the same data.
  • Real-time display for monitoring the cumulative mass plot, allowing immediate procedural adjustments if necessary.
  • Statistical process control (SPC) reports for tracking process performance, enabling quick responses to fluctuations.
  • Data comparison plots offer graphical displays of the mathematical difference between two data sets (difference from the reference plot) or the extent of data point values above or below tolerance. boundaries (out of the specification plot).
  • Multiple analyzer control allows simultaneous operation of two SediGraph III devices from a single computer, saving laboratory space and simplifying data storage.



The Micromeritics SediGraph is the preferred standard instrument for particle size analysis in laboratories worldwide, excelling in both rugged production environments and controlled laboratory settings. It continues to produce accurate results with superior reliability.

Particle mass is measured by X-Ray absorption directly. Particle size distribution is measured with the sedimentation method. The SediGraph employs Stokes’ law (that is, the rate at which particles fall under gravity through a liquid with known properties) to determine the equivalent spherical diameter of particles ranging from 300 to 0.1 micrometers.

The new-generation SediGraph III Plus integrates this proven technique with advanced technology, ensuring reproducible and highly accurate particle size information, typically completing analyses within minutes.



The particle size range and mass distribution within each size category significantly impact the ability to sinter ceramic powders. It also influences their forming properties and the pore size distribution in the final product.

Information on particle size distribution is crucial for determining curing and bonding procedures, controlling pore structure, ensuring sufficient green body strength, and achieving the desired strength, texture, appearance, and density in the end product.

Metal Powders

Precise control of particle size allows for the design of specific pore characteristics into a product, with porosity often being a key factor in product performance. Similar to ceramics, particle size distribution plays a critical role in determining the strength and density of both the green body and the final metal product.

Geological/Soil Science

Grain size directly influences the moisture-holding capacity of the soil, drainage rate, and the soil's nutrient retention ability. The size of grains is closely linked to sediment transport in geological contexts.


Particle size distribution in base powders, such as talc, and pigments used for coloring has a significant impact on the appearance, application, and packaging of cosmetics.


The particle size alone can influence the tinting strength of a color, which affects the quantity of pigment needed for the required color intensity. As tinting strength increases, the quantity of pigment required to produce the necessary color intensity goes down. Particle size distribution also affects gloss, texture, color saturation, and brightness.


Particle size directly affects the catalytic activity of metals in structure-sensitive catalytic reactions.

Construction Materials

The particle size of cement influences the setting time and the strength characteristics of finished concrete and cement.

Minerals and Inorganic Chemicals

The reactivity of materials is contingent upon the exposed surface area, making particle size distribution a vital consideration.


Maintaining a properly balanced size distribution of abrasive grains and powders is fundamental for materials used in slurries, dry blasting, or bonded abrasive tools. Uniform particle size ensures precise flow rates through blast machines and is a critical factor in media management when recycling abrasive materials.


Versatile Data Presentation and Reporting System

The SediGraph III Plus comes equipped with a versatile and user-friendly interface, delivering the convenience expected from a Windows-based program. Featuring point-and-click menus, customizable reports with users’ laboratory logo graphics, editable graphs, cut-and-paste graphics and tables, data export capabilities, and more, the interface ensures ease of use.

Custom protocols aid in planning, initiating, and overseeing analyses, ensuring consistency regardless of the operator’s skill level.

The system allows for the collection, organization, archiving, and reduction of raw data, storing standardized sample information and analysis conditions for convenient retrieval in subsequent applications. Finished reports can be generated for screen or paper viewing and transferred in various formats to storage devices.

Data Reporting

The SediGraph III Plus automatically provides detailed analysis data for particles ranging from 300 to 0.1 µm. It allows the integration of data from other particle size analyses, spanning from 125,000 to 300 µm, facilitating effective reporting for particles ranging from 125,000 to 0.1 µm.

In addition to tabular data, various graphical analysis plot types are available, including:

  • Cumulative Mass, Area, and Number
  • Settling Velocity Distribution
  • Process Control Charts
  • Log Probability
  • Baseline/Full-Scale References
  • Regression Analyses
  • Difference From Reference
  • Frequency Distribution
  • Out of Specification
  • Rosin-Rammler

Plots can be overlaid to compare results from different samples or different plot types from the same sample. This enables a comparison of analysis results against a standard. Plots can be rescaled for scrutiny of graphical data.

A Phi unit column has been added to tables and x-axis selections in graphs, where Ф = -log2 (particle diameter in mm). Additionally, a column selection for settling velocity (cm/s) is available for tables. The x-axis of plots can be scaled in particle size or settling velocity.

Sedigraph III Plus - Product Overview

Video Credit: Micromeritics Instrument Corporation


Source: Micromeritics Instrument Corporation

. .
Particle Diameter Range 300 to 0.1 micrometers Equivalent Spherical Diameter
Wetted Materials Stainless steel, Teflon® impregnated anodized aluminum, nickel-plated aluminum, nylon, polypropylene, polystyrene, Tygon® and Pharmed® tubing, tungsten carbide, Ertalyte®, Viton®, Buna-n, and epoxy
Sample Size 50 mL of dispersed sample – precise concentration is not required
Suspending Liquids Any liquid compatible with sample cell materials and not highly absorptive of Xrays (typical liquids are water, glycols, mineral oils, SediSperse®, and alcohols)
Power Requirements 85 to 264 VAC, 47/63 Hz, 450 VA
Temperature Ambient +10 to 40 °C, operating; -10 to 55 °C, storing or shipping
Humidity 20 to 80 % (non-condensing)
Miscellaneous ISO 9001 manufacturer CE certified
Physical Height: 52 cm (20.5 in.)
Width: 50.5 cm (20 in.)
Depth: 58 cm (23 in.)
Weight: 43 kg (95 lbs)


Source: Micromeritics Instrument Corporation

Part Number Description
003-58601-00 Ultrasonic Bath 115 V, 60 Hz
003-58602-00 Ultrasonic Bath 230 V, 50 Hz
004-16814-00 Glass, Mass Median Diameter 1.5 micrometers, 15 g
512-27600-01 Filter, Air 10 PPI
512-27600-02 Filter, Air 25 PPI
051-58605-02 Ultrasonic probe tip, for use with units with serial number 151 and greater, which have only one connector that connects to the MasterTech.
512-33001-00 Operating software and operator's manual, SediGraph 5120
512-42801-00 Operator's manual, Sedigraph 5120
512-42805-00 SediGraph III Plus - operator manual
004-16838-00 Daxad 23 SediGraph 29 Dispersing aid
004-61021-01 Beaker, tall form, 100 ml, Glass
052-00051-00 MasterTech 052, for automatic sample preparation. Redisperses samples and transfers them to the SediGraph for analysis. Includes built-in mechanical stirrer and ultrasonic probe. For SediGraph model 5100 and 5120.
052-00052-00 MasterTech 052, . For SediGraph model 5200
512-32820-01 Tubing set, universal, pre-cut
004-25053-00 Spatula - Stainless Steel
003-20665-00 Interface cable, shielded
003-60101-06 Power cord, shielded
003-63801-01 Cable, Ethernet straight-thru

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