making the most of your graphite - indmin

4th Graphite and Graphene Conf. page 1 © DORFNER Analysenzentrum und Anlagenplanungsgesellschaft mbH

Making the most of your graphite

by Dorfner ANZAPLAN GmbH, D-92242 Hirschau, Germany4th Graphite & Graphene Berlin, December 9th 2014


COPYRIGHT/DISCLAIMER

The graphics, tables, diagrams and other contents of this presentation are protected by copyright law. © Dorfner Analysenzentrum und Anlagenplanungsgesellschaft GmbH. All rights reserved. Neither this publication nor any part thereof may be copied, reprinted, sold, published or distributed without prior written permission. This presentation provides non-binding information only and we do not assume any liability for correctness, accuracy and completeness of the information provided. Dorfner Analysenzentrum und Anlagenplanungsgesellschaft GmbH makes every effort to provide timely and accurate information. Nevertheless, mistakes and confusions may occur. The information and statistical data herein have been obtained from sources we believe to be reliable. Nevertheless, such information has not been independently verified and we do not assume any liability. Any opinions or estimates herein reflect the judgment of Dorfner Analysenzentrum und Anlagenplanungsgesellschaft GmbH at the date of publication and are subject to changes at any time without notice. This applies especially to information reflecting estimations and technical standards since they are subject to changes over time. Dorfner Analysenzentrum und Anlagenplanungsgesellschaft GmbH does not intend, and does not assume any liability or obligation whatsoever, to update these forward-looking statements and/or estimations or to conform them to future events and developments.


Dorfner Group of Companies

Founded 1895 More than 100 years

experience in mineralsprocessing

Family owned Independent

Renowned in the Specialty Minerals Business


Dorfner Group of Companies

Day by day experience in mining and processing up to 1 Mio tons of industrial and specialty minerals every year

Mechanical, physical, thermal and chemical processing

Renowned in the Specialty Minerals Business


Dorfner ANZAPLAN

Founded in 1985 to become the most independent venture within the Dorfner Group.

The leading European Service Company in Specialty Minerals and Metals

CC


ANZAPLAN ServicesCombined Competencies

AnalyticsInternationally certified chemical and mineralogical analytics, ILAC accredited

Process EngineeringIndependent from any machinery manufacturer Anzaplan is committed to the best process design and innovative concepts in minerals processing.


Process Engineering

Anzaplan is globally active in the core areas of: Valuation of mineral

deposits, Process development, Pilot Scale Processing, Economic Assessment

and Feasibility studies, and Engineering.

Commitment to strategic minerals and metals

… within the mineral segments of:Quartz - Rare Earths – Graphite – Lithium Minerals – Nb/TaHPA - Clay Minerals - Fluorspar – Mica - Diatomite


Graphite Characteristics

Graphite Type Characteristics

Amorphous Amorphous is microcrystalline type of natural graphite, placed in seems with crystals not visible to the naked eye. Purity ranges 70 to 90%.

Flake Flake type is found as disseminated free flakes within a graphite deposit. Typical flake sizes range between 75 to 850 µm with grades ranging between 1 to 30%. Flotation produces concentrates typically +85%.

Vein Crystalline vein type consists of flake like to lumpy particlesup to large and jumbo sizes. Ore is typically in the range of 80 to +95%.


Flake Size and Purity MattersTypical flake sizes

Jumbo flakes +35 mesh >500 µm Large flakes 35 to 50 mesh 300 to 500 µm Medium flakes 50 to 80 mesh 150 to 300 µm Fine flakes -80 mesh <150 µm

The larger the flakes the higher the selling price at comparable purity. Higher purity sells at higher price at same flake size.

… therefore processing needs to balance purity with flake size recovery –at reasonablecost !


Graphite Processing

Ore Characterization

Chemical analysis of surface and drill core samples to determine ore grade.

Detailed mineralogical characterization of host rock and graphite ore samples to identify type of mineral impurities

Determination of primary flake size distribution

Graphite concentration

Quality but cost balanced design of tailored processes for optimum liberation of graphite flakes at maximum grade based on mineralogical and chemical results.

Specified particle size distribution and morphology

Pilot scale processing to provide concentrates for customer approval.

Advanced Purification

Chemical and/or thermal purification design to achieve 99,5 to +99,95%

Ensuring maximum performance in high end applications such as batteries and semicon-ductor manufacturing

Pilot scale processing for customer approval.


Graphite ProcessingStandard Processing

Standard processing is built on several flotation and regrinding steps.

Standard process needs standard ore.

A quite unusual attempt in specialties minerals disregarding potential benefits of ore specifics.


Standard circuitGraphite ProcessingFrom Standards to Specialties

In specialty minerals industry the ore should take the lead for defining the process.

Maximizing value by taking advantage of the ore´s benefits is achieved only by tailor made processing.

Tailored solutions base on detailed ore analyses and provide space for innovation and know how transfer from related industries.


Graphite processingDealing with challenges in mineral processing

2)

3) 4)

1) Intergrowth with gangue minerals

2) Graphite patch on surface

3) Graphite sprinkled on surface

4) Gangue mineral masked by graphite (overgrinding)

Liberation is key for downstream separation

1)


Challenges in mineral concentrationLiberation by conventional processing is limited

“Liberation is key for separation”

The finer the more liberated ... but sprinkling masking

may hamper concentration and fine grinding adds

processing costs and shifts flake size

distribution to less valued finer particles


Selective FragmentationImproved Liberation

Material in a dielectric liquid will be fragmented using high voltage pulses pulse rise time in ns, voltage up to 400 kV.

Graphite’s mechanical, electrical and anisotropic properties contrast strongly with surrounding rock matrix.

Electrical discharge forms plasma channels preferably along grain boundaries (high permittivity contrast).

Plasma channel expansion due to Ohmicheating generates strongest internal shockwaves liberating minerals with high mechanical contrast.


Graphite ProcessingFlowsheet Selective Fragmentation


Determined C contentafter SELFRAG indicatesC deportment into500 micron ranges

Selective FragmentationLiberation of coarse flakes

0

5

10

15

20

25

0 200 400 600 800 1000

C [

wt.

-%]

Grain size [µm]

Selective fragmentationConventional comminution


Flotation after Selective FragmentationFlotation results

High quality of graphiteconcentrate in earlyflotation stages in all fractions by leaving thecoarse flakes large.

0

10

20

30

40

50

60

70

80

90

100

C [

wt.

-%]

Flotation steps

start F1 F2

— 125 micron

— 300 micron— 800 micron


Graphite flakes are liberated selectively along crystal boundaries

Host rock (gangue minerals) is comminuted

Selective fragmentation offers improved liberation and separation of graphite flakes after a first crushing step.

Selective fragmentation will largely avoid problems associated with fine grinding as e.g. surface masking of silicates.

Selective FragmentationBenefits of selective fragmentation


SELFRAG Product Portfolio

Capacity Batch 100kg – 1tph 5‐10tph

Value proposition

PuritySelectivityBatch

PuritySelectivity

Continuous process

Coarse liberationEnergy saving

ApplicationsSample

preparationMining research

High purity glass recycling

Silicon crushingMining exploration

RecyclingMining

Lab system(batch)

Continuous systemLow‐throughput continuous systemSample production


Shaking tableShaking table - a viable addition

Exploits the principle of specific gravity difference of graphite and silicates, instead of just surface properties used by flotation.

In addition graphite flakes float on the surface.

Gangue particles (even if masked with graphite) can be separated.

Source: www.met-solvelabs.com


Graphite ProcessingFlowsheet Shaking Table


Chemical Purification of Graphite ConcentrateChemical purification needs to be tailored

Graphite concentrate > 90% is obtained bycomminution andflotation

Chemical purificationopens furtherpossibilities to achievehighest standards.

Two principal routes areavailable: caustic oracidic treatment followedby acid washing

Caustic baking at elevated temperature dissolves impurities such as feldspar, quartz and mica followed by acid washing.

Alternative HF leaching followed by sulfuric acid washing step depending on nature and ultimate level of purity by efficient removal of silicates.

Graphite after incineration

Graphite before incineration


Technical tests to prove transferability of laboratory results to pilot plant scale in the technical center

Processed samples are needed for downstream processdevelopment

Engineering parameters are picked up for upscalingequipment, throughput and chemicals consumption.

Customer approval and detailed feedback when samplesare presented.

Fixed pilot plant reduces flexibility during processdevelopment.

Pilot plant processingSized process approval of lab results


Advanced Refinement Caustic baking Acid leaching Thermal treatment Hot chlorination Filtration and washing,

neutralisation Dewatering and drying Water treatment and

recycling

Mineral Concentration Conventional comminution Autogenous grinding and

selective fragmentation Classification Sensor based sorting Gravimetric separation Magnetic separation Electrostatic separation Ultrasonic processing Flotation

From Standards to SpecialitiesPilot Plant Processing


ANZAPLAN ServicesProject Evaluation and Process Development

making the most of your graphite - indmin

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