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Page 1: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Mineralogy of fine particles in slurry from

multispectral imaging

Sophie LEROYG. Dislaire, P. Barnabé, E. Pirard

Eric Pirard
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Page 2: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

Predictive Mineralogy

Process Control

Exploration

Remote Sensing

Reserve Estimation

University of Liège (BE)• Georesources & Geo-Imaging Research Group

© CSIRO

Quantitative Microscopy

On Line Vision

Core Scanning

3D particle size & shape

Page 3: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

2D Particle Imaging

• Range 50µm -> 5mm+

• 104 particles/min

o Mechanical dispersion• Vibration (tray)• Acceleration (conveyor)

o Suction • Laminar air flow

• Free flowing powders

Page 4: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

2D Particle Imaging

• Range 500nm - 150µm+

• 105 particles / min

• Vacuum dispersion• For dry powders

• Flow cell• For wet powders

suspensionsemulsions,…

• Non free flowing powders

Page 5: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

2D Particle Imaging

• Estimation of chromite content in UG2 slurrieso Modified flow cell

• Identification of chromite grains (opaque)• Real time estimation of chromite content and liberation

• Size and Mineralogy

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[chromite] from AA[c

hrom

ite] f

rom

IMAG

E

Page 6: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

Reflectance of particles

• Existing spectral databaseso Specular reflectance of ore-forming minerals

• QDFIII 400nm-700nm (Criddle & Stanley, 1993)• Extended to 1000nm (Brea et al., 2010)

• Mineralogy & Particle Size

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15,00

20,00

25,00

30,00

35,00

40,00

45,00

50,00

55,00

400 500 600 700 800 900 1000

Wavelength (nm)

Ref

lect

ance

(%

)

PO (CR286_012)

PO (CR286_014)

PO (CR286_020)

CUB - (CR286_019)

CUB - (CR286_019)

CP (CR286_001)

CP (CR286_007)

Page 7: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

Reflectance of particles

• Existing spectral databaseso Diffuse reflectance of rock forming minerals

• Speclab USGS, Grove et al. (1992)

• Mineralogy & Particle Size

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< 45 µm

< 125 µm

< 500 µm

Chalcopyrite

Pyrite

Specular (QDFIII)

Page 8: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

Imaging System

• Best of both worldso Diascopic imaging for opaques

• White LED illuminationo Episcopic imaging

• Selected LEDs Eight wavelength

• Dichroic mirrors• Dark field objective

• Multispectral Set Up

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LED

455

LED

405

LED

530

LED 735

LED 590

LED 850

LED

940

Dichroic mirrors and their shift limits

Incident Light main trajectory

Reflected light

605

567 505 425

638

805

900

LED 617

Camera

Darkfield lense

Plain Mirror

Sample Cell

LED

BL

Page 9: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

Imaging System

• Gangue Silicates vs Sulphides

• Diascopic Imaging

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Page 10: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

Imaging System

• Oxides vs Sulphides

• Episcopic Darkfield RGB Imaging

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Page 11: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

Imaging System

• Chromite vs Pyriteo Photonfocus MV1 D1312ie

• 1312x1082 (binning)• 3,1 µm/pixel• 400 ms

• Episcopic Darkfield Spectral Imaging

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Backlit imageF0=405 nm

F1=455 nm F3=590 nm

F4=617 nm

F2=530 nm

F5=735 nm F6=950 nm

Page 12: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

Mineralogical Mapping

• Darkfield imagingo Reflectance angles

• Maximum reflectance depends on particle shape and λ

• Calibration and discrimination

Limit angle

peak peak

Cu wire Ø=100 µm

Page 13: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

Mineralogical Mapping

• Darkfield imagingo Pyrite vs. Copper

• Percentile P80 of intensity distribution within particle Combination of > P80 per wavelength

• Discrimination

Pixels voted > P80 for every λ

Pyrite Ø=52 µm

Mask

P80

Cu wire Ø=100 µm

P80

P99

Raw spectrumRaw spectrum

Page 14: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

Test on Sulphide Slurries

• LYSC: Pyrite-rich (> 91%) • LYSB: Mixed sulphides (Py+Cp+…)

• Particle sizing vs. 405nm/617nm band ratio

• Discrimination

Pyrite-rich (LYSC )Mixed sulphides (LYSB)

Page 15: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

Test on Sulphide Slurries

• LYSC: Pyrite-rich (> 91%) • LYSB: Mixed sulphides (Py+Cp+…)

• Particle sizing vs. 455nm/617nm band ratio

• Discrimination

Pyrite-rich (LYSC )Mixed sulphides (LYSB)

Py

Cp

Page 16: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

Test on Sulphide Slurries

• LYSC: Pyrite-rich (> 91%) • LYSB: Mixed sulphides (Py+Cp+…)

• Particle sizing vs. 405nm/617nm band ratio

• Discrimination

Pyrite-rich (LYSC )Mixed sulphides (LYSB)

Grey sulphide(sphalerite, galena, arsenopyrite,…) (tbc)

Yellow sulphides mix(pyrite,chalcopyrite,…)

Page 17: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

Conclusions

• Improved flow cell imaging systemo Combined dia- and episcopic imagingo Particle size, shape + mineralogy, (liberation)

• Multispectral imagingo Simple and flexibleo Tunable to dedicated minerals

• Image processing o Spectra of brightest pixels (> P80) to limit size and shape influence

• Mineralogyo Band-ratio discrimination

• Online mineralogy

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Page 18: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

Perspectives

• Mineralogical Analysiso Needs further calibrationo Cross-validation with chemistry and XRD

• Discrimination limitso Gangue

• Carbonates vs. Silicateso Sulphides

• Cp, Py, Ga, Sp, Po,…o Oxides

• Hem vs. Goe; Ilm vs. Lcx vs. Rut; …• Sample Preparation

o Dilution needed for dirty and dense pulps

• Multimodal imagingo Add other imaging modules (i.e. SWIR, Raman,…)

• Online mineralogy

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Page 19: Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement Predictive Mineralogy Process Control Exploration Remote Sensing Reserve Estimation

Université de Liège - GeMMe - Génie Minéral, Matériaux & Environnement

Thank You• See you in Liège in 2015

www.em-georesources.eu

Liège, Belgium


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