Imerys Technical Centerimerys-carbonates.com/wp-content/...webpages_light.pdf · Analysis of weight loss in a sample over a specific temperature range/ heating rate. In mineral powders,

ImerysTechnical Center

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INTRODUCTION 003OPTICAL MICROSCOPY 004

SCANNING ELECTRON MICROSCOPY (SEM) 006TRANSMISSION ELECTRON MICROSCOPY (TEM) 008

ENERGY DISPERSIVE X-RAY SPECTROSCOPY 010DIGITAL IMAGE PROCESSING 012

BULK CHEMICAL ANALYSIS 013

X-RAY DIFFRACTION 014THERMAL ANALYSIS 015

FOURIER TRANSFORM INFRARED SPECTROSCOPY (FTIR) 018PARTICLE SIZE TECHNIQUES 020

COLOR AND BRIGHTNESS ANALYSIS 022OTHER PHYSICAL TECHNIQUES 023

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Introduction

Innovating for the futureWe thrive on innovating advanced solutions and developing industry changing processes. Our technical experts come from a wide variety of disciplines and backgrounds, providing Imerys with a unique perspective on addressing industry challenges and innovating for the future.

Alongside our geologists and mineralologists, we delight in finding the next best thing and bringing it to the surface.

Millions of years in the making.

Imerys’ team of technical experts have years of experience working with mineral applications. Working at state-of-the-art R&D facilities across the globe, our technical teams are dedicated to sharing their expertise and collaborating with customers and research partners to develop game-changing innovations for the industries we serve.

We are dedicated to devoloping solutions that help our customers optimize their products. By matching exactly the right mineral requirements to your performance needs, we help you to save time and bring enhanced performance to your applications.

In addition, our process engineers can study your production processes to ensure best use and handling of our minerals in your systems.

Collaborating with our R&D facilities and applications experts, customers are able to replicate their challenges in a controlled environment. This allows us the opportunity to provide experienced insight on the problems that keep you scratching your head.

Supporting our customers

004

300 µm

004

Dispersion Staining

Microscopy

Phase identification based on optical properties. Optical properties include

refractive index, birefringence, extinction angle and sign of elongation

OPTICAL MICROSCOPY

Binocular Stereoscopic Microscopy

Low magnification surface imaging of samples allows us to identify defects,

contaminants, flaws, and other issues within

our customers products.

Stereoscopic microscopy detail of a defect in a rubber stopper

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Allows us to charactarize the profile and phase of our ore bodies and provide mineral specific analysis.

Quantifying dispersion is important in predicting and improving mineral

composits and formulations.

Carbonate

Talc

50 µm

1000 µm

Dispersion Staining

Microscopy

Polarized Light Microscopy

Phase identification based on dispersion staining color. A mineral grain acts as a

prism, producing dispersion of the visible spectrum. The dispersion staining color is

achieved by selective elimination of certain wavelengths of the spectrum.

An elongated tremolite fragment is identified in a competitive mineral.

PLM image showing a carbonate particle with a rainbow effect indicating high birefringence next to a talc particle showing lower birefringence.

With a depth over 20 times larger than a conventional optical

microscope, EDF allows accurate 3D observation of the surface

topography.

Extended Depth of

Field (EDF)Microscopy

3D image showing the roughness created between two fibers in order evaluate poor ink transfer.

006

Secondary Electron Imaging (SEI)

Surface imaging with magnification

range of 20x to 100,000x.

Secondary electron imaging produces a very

clear surface image with a large depth of focus.

Enables us to look at samples in extreme detail,

allowing us to gain insights in the morphology and the microstructure of our own

minerals and our customers formulations.

SCANNING ELECTRON MICROSCOPY (SEM)

Macrocrystalline talc

Microcrystalline calcium carbonate

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50 µm

50 µm

Back-Scattered Electron (Z-Contrast) Imaging

This complementary imaging technique gives us additional insight into the different densities in the various phases of the sample. This helps us to build a detailed picture of the composition of the product we are evaluating.

Paper Surface: Z-contrast Image

Paper Surface: Secondary Electron Image

Surface imaging technique where contrast is due to compositional difference i.eheavier materials produce a brighter signal.

Compare Z-contrast imaging(top) of a paper surfaceshowing filler distribution, with conventional secondary electron imaging (left).

100 µm

008

Transmission Electron Imaging

TEI is used to identify different minerals to fully characterize ores and

reserves.

TEI resolution helps to characterize the structure of the material down to the

nanometer scale.

TRANSMISSION ELECTRON

MICROSCOPY (TEM)

Highest magnification imaging of electron transparent materials

(thin particles). An optimum resolution of 0.5 nm can be achieved, allowing

for atomic lattice imaging.

b*

a*

[130][20]

[110][200]

1 µm

009

Electron Diffraction

Scanning Transmission Electron Imaging

Scanning images similar to those produced on the SEM can be

produced on the TEM with higher magnification

Electron diffraction patterns can be produced on the TEM.

Thanks to the mineral’s crystallographic properties

and dot-spacing, “fingerprint” identification can be achieved

for the material analyzed. From a health and safety perspective,

this helps us to indentify and manage any problematic

components.

Secondary electron image (left) and transmission electron image (right) of paper pitch taken on

the TEM.Back-scattered images can also be produced.

Indexed electron diffraction pattern of talc showing its unique symmetry

0.0

0.9

1.7

2.6

KCnt

3.4

4.3

1.00 2.00 3.4

720 µm

Mg

Si

010

ENERGY DISPERSIVE SPECTROSCOPY

(EDS)

Single-point ElementalAnalysis

Chemical analysis of individual particles on

either the SEM or the TEM.

Allows us to measure the chemical composition of a single particle or

a small area of a specimen. This provides a look at the chemistry in

addition to the morphology of a sample.

The defect was observed using SEM and backscattered electrons (BSE). To analyze what is below the surface crack, a microtome cross section is carried out.

crack

The microtome cross section shows the defect which is analyzed using EDS*.

Mg Si Ca

1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0

Mg

Si

Fe

Ca

1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0

Talc Mineral Particle

Calcium Carbonate Mineral Particle

011

Elemental Mapping

Scanning the area of interest for a specific element produces colored pixels upon detection. Several elemental maps can be superimposed onto each other as well as onto SEM images.

This allow us to profile the full elemental chemistry within a sample under analysis.

Elemental mapping showing the distribution of talc and calcium carbonate particles in paper

Mg Si Ca

100 µm

15 m

icro

ns

012

DIGITAL IMAGE PROCESSING

Spatial Measurement

Imaging that provides the ability to look at physical

dimensions of systems and structures in order to check for the position and

dispersion of our minerals within a product. A microporous polyethylene film containing calcium

carbonate as a porogen. This cross-section was produced by freeze-fracturing under liquid nitrogen. The thickness of the film determined after calibration of the

image is shown.

Elemental Distribution

Provides elemental map of a surface to

measure for dispersion. With false colors , we

are able to see how the minerals are arranged

within a particular application.

This image of superimposed elemental maps shows a high degree of talc liberation of the +200 mesh size

fraction of an Imerys Talc ore body. Area fractions calculated for each element were used to determine

the degree of liberation.

To further extract information from imaging techniques

Oxide Weight %

SiO2 1.27

Al2O3 0.1

Fe2O3 0.12

TiO2 ND

CaO 52.83

MgO 2.47

K2O ND

Na2O ND

P2O5 0.08

SO3 ND

SrO 0.04

Trace elements

ppm

Pb <10

Zn <10

Cu <10

Ba <20

As <20

Sn <10

Cr 40

Ni 23

Co <10

Sr <10

Mn 39

Total Weight Loss 9.0%

013

X-rayFluorescence (XRF)

BULKCHEMICAL ANALYSIS

The chemical analysis of powders is carried out using

X-Ray fluorescence technology. The secondary X-Rays give us the concentration of chemical

elements present.

This allows us to quantify the various chemical phases and

quantity within a system.

«<» preceding a value means that the content is below the detection limit of the measuring technique used.

014

Microcrystalline Talc

5

500

1000

1500

10 15 20 25 30 35 40

intensity (counts)

004 020

Typical XRD pattern for calcite

20-100

4900

4900

9900

14900

19900

24900

29900

25 30 35 40 45

°2 Theta

intensity (counts)

50

°2 Theta

Analysis of phases present (mineralogy)

in a bulk powder sample.

The X-rays pattern shows us which minerals are

present within a system. The positions of the peaks in an X-ray diffraction pattern are

determined by the lattice spacing of the crystallographic

planes from the phases contained in the sample.

Textural parameters such as degree of crystallinity can be

inferred from the patterns (see opposite).

Results from this test can be used to quantify mineral

makeup and in certain cases, orientation within a product.

Plate-perpendicular peaks, i.e. 020 are more significant than they are in platy talc due to the smaller, more random orientation of crystallites in this ore body (refer to page 6 for SEM image of this talc product).

X-RAY DIFFRACTION

015

THERMAL ANALYSISPhysical Properties and Particle Characterization

Moisture AnalysisAnalysis of moisture in minerals by weight loss after heating the sample at ~100°C. Generally reported as “weight percent” (wt. %).

Low Temperature AshAnalysis of weight loss when organics are burned off at < 500°C. This technique can be used to concentrate inorganic phases in an organic compound. Generally reported as “percent” (%).

Total weight loss (Loss on Ignition)Analysis of weight loss in the sample when structural H2O and/or CO2 is burned off at > 1000°C. This data can be used in conjunction with XRD analysis to provide quantitative mineralogy analysis. Generally reported as “percent” (%).

016

100 0

-0.2

-0.4

-0.6

-0.8

-1.0

-1.2

98

96

94

92

90

88

200 400 600 800 1000Temperature /°C

TG /%DTG /(96/min)

Talc 50.0%Chlorite 48.0%Dolomite 1.0%Moisture 0.2%Total weight loss at 1050°C 8.7%

Mass Change : -0.16%Moisture

Mass Change : -4.35 %Chlorite

Mass Change : -0.35 %Dolomite

Mass Change : -3.79 %Chlorite + Talc

[1]

exo[1]

|

|

|

Thermal Gravimetric Analysis (TGA)

Analysis of weight loss in a sample over a specific temperature range/heating rate. In mineral powders, weight loss corresponds to loss of CO2 from carbonate phases present and/or H2O from hydroxide phases present (such as talc or kaolin). Minerals lose these components at specific temperatures, therefore results can be used to quantify mineralogy.

THERMAL ANALYSIS

017

0 200 400 600 800 1000 1200

-0.10

-0.08

-0.06

-0.04

-0.02

-0.00

0.02

Tem

pera

ture

diff

eren

ce (

°C/m

g)

576°C

685°C823°C

912°C

-40

-30

-20

-10

0

10

20

30

40

65 90 115 140 165 190 215

Hea

t Flo

w E

ndo

up (m

W)

Temperature (Deg C)

Melting

Crystallization

Differential Thermal Analysis (DTA)

Analysis of the loss or gain of thermal energy corresponding to thermal reactions, i.e. exotherm or endotherm.

Reactions that do not involve weight loss can be detected by this method, i.e. conversion of quartz from α-quartz to β-quartz.

Differential Scanning Calorimetry (DSC)

Mg3OH3676 cm-1

Typical FTIR scan of carbonate

Ab

sorb

ance

wavenumber (cm-1)

018

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

5001000150020002500300035004000

CO32- n3

1440cm-1 CO32- n2

875cm-1

CO32- n4

712cm-1

Fourier Transmission

Characterization of organic and inorganic functional groups with computer evaluation of data, including spectral averaging, subtraction and computer spectral search matching. This allows us to identify unknown chemistries or mineralogies present.

FOURIER TRANSFORM INFRARED

SPECTROSCOPY(FTIR)

019

3100 3050 3000 2950 2900 2850 2800 2750

Talc with additive

Talc without additive

3500 3000 2500 2000 1500 1000

White impurity

Talc

Ethylene Propylene Diene Monomer

Diffuse Reflectance (DRIFTS)

IR Microspectroscopy by Attenuated Total Reflectance

(ATR)Functional group determination on samples using FTIR. This technique

is used for profiling the chemical nature of microscopic impurities.

DRIFTS is a surface-sensitive technique that enables the

identification of coatings and the analysis of surface treatment

chemicals.

The IR scan collected indicates that this impurity is EPDM and talc.

Understanding particle size is critical to designing mineral structures as it directly effects all the properties within any application.

1000

0

10

20

30

40

50

60

70

8090

100

Equivalent spherical diameter, microns

10.0 1.0 0.1

Cum

ulat

ive

mas

s (%

)

0

1

2

3

4

5

6

Particle Size (microns)

(%) V

olum

e C

hang

e

020

Laser Particle Size DistributionAnalysis of the particle size distribution based on laser light scattering of particles

as they pass through a measurement cell.

Sedigraph Particle Size DistributionAnalysis of the particle size

distribution based on particle settling (Stokes law) techniques.

Particle size distribution of a mineral. The d50 value for this product is 2µm

Physical Properties

PARTICLE CHARACTERIZATION

021

Hegman Gauge Analysis

Wet/Dry Sieve Analysis

Analysis of the top size or “fineness of grind” of a mineral powder dispersed in a liquid.

Analysis of particle size fractions by wet or dry sieves (including

Alpine Jet Sieve).

Loose Bulk DensityVolume occupied by a known sample mass without any compaction. Generally reported as pound per cubic foot (lb/ft3) or gram per cubic centimeter (g/cm3).

Tapped DensityVolume occupied by a known sample mass under standardized compaction conditions. Generally reported as pound per cubic foot (lb/ft3) or gram per cubic centimeter (g/cm3).

Powder RheometeryQuick and easy analysis of powder flow behaviors in industrial processing contexts.

Bulk powder handling is one the largest components of the industrial process. Imerys has a range of testing techniques to help understand and optimize powder behavior and performance in various industrial process such as bagging, transportation, silo discharge, and storage.

Bulk Powder HandlingSurface Area AnalysisSurface area is measured by quantifying the amount of nitrogen gas adsorbed onto the surface of the mineral particles from a known weight of sample. Generally reported as square meters per gram (m2/g). Surface area is important in predicting the behavior of minerals in numerous applications.

Oil AbsorptionAnalysis of the ability for mineral to absorb oil. Generally reported as grams of oil per 100 grams of mineral (g/100 g). This is important information when working on organic or resin based systems.

006

Physical Properties and Particle Characterization

COLOR AND BRIGHTNESS

ANALYSIS

Three axes define the “color space” for Hunter L, a and b values.

Tristimulus color matching functions

-a +a

L WHITE

BLACK

+b

2.0

1.5

1.0

0.5

400 500 600 700 Wavelength(nm)

-b

z(λ)

x(λ)

x(λ)

y(λ)

022

Brightness & Color

Analysis

Quantitative measurement of the color of mineral pigments. The brightness, whiteness, color and tinting strength is key property in many applications.

Imerys uses multiple testing methods to measure these optical characteristics.

023

APPLICATIONCAPABILITIES

Market Focused Analysis

Paints & CoatingsPlastics & PolymersEmulsions & LatexesAdhesives & Sealants Building & ConstructionFood & Beverages Paper & BoardAgricultureFilm & Packaging