Naturalflake

graphite

Hard host rock Soft host rock - graphite streak in sand

Natural graphite in clean technologies

Energy requirements of primary production

Martin Cermak1, Claire McCague, and Majid Bahrami2

Laboratory for Alternative Energy Conversion, School of Mechatronic Systems Engineering, Faculty of Applied Science, Simon Fraser University, Surrey, British Columbia, Canada

Conclusions

LAECLaboratory for

Alternative EnergyConversion

Martin Cermak, Claire McCague, and Majid Bahrami, "Graphite in clean technologies: the importance of availability of material production data," presented at Resources for Future Generations, Vancouver, B.C., Canada, 2018.

Graphite in clean technologies: The importance of availability of material production data

Lightweight heat sinks for cooling of electronics in cars, planes, chargers, power supplies, and electricity distribution systems

(smart grid)

Many technologies rely on parts with high thermal conductivity; aluminum and copper are typically used.

intercalationand

exfoliation

Natural graphite flakes Exfoliated flakes Natural graphite sheet

Compressionwithoutbinder

Corrosion resistant heat exchangers for flue gas heat and water

recovery, and geothermal energy

Heat sinks Heat exchangers Bipolar plates Air conditioningCost effective bipolar plates for fuel

cells in cars and energy storage systems

Parts for fast heat conduction in adsorption cooling systems

Why natural graphite sheet?

Ther

mal

con

duct

ivity

[Wm

-1K-1

]

Natural graphite

sheet

600

throughplane

Aluminum

inplane

Copper

high densitylow density

High thermal conductivity

Mat

eria

l cos

t [U

SD/d

m3 ]

Naturalgraphite

sheet

40

Aluminum Copper

Low material cost

low density - 0.7 high density - 2.7

43.5

4.8

Den

sity

[g/c

m3 ]

Natural graphite

sheet

2

Aluminum Copper

Low weight

4

6

8

10

Elec

tric

al c

ondu

ctiv

ity[S

m-1

]

Natural graphite

sheet

throughplane

Aluminum

inplane

Copper

high densitylow density

Electrical conductivity

101

103

105

107

high densitylow density

High density Low density

in-plane

through-plane

Simple manufacturing

Corrosion resistanceChallenges:

Low mechanical strengthComprehensive life cycle analyses (LCA) are needed to compare technologies and support long term planning

Electricity or fuels

LCA can answer prac�cal ques�ons such as: "Are electric vehicles cleaner than internal combus�on ones?" or "Is the carbon footprint of wind turbines higher than that of coal power plants?"

Energy

Natural resourcesEmissions

Electricity generation

A clean technology is truly clean only if the overall environmental footprint is low

Copper

Graphite oremining

Bayer process Al2O3

(Alumina)

Aluminum ingots

Bauxitemining

Benefication Purification Graphiteflakes

Naturalflake

graphite(Crushing, flotation, drying) (acid leaching, caustic roasting, ..)

Reported energy requirement [MJ/kg]

Copper

Graphite flakesGraphite flakesin host rock

Hall-HeroultProcessBauxite

Data source

Copper oresmining

Sulfides

Oxides

Pyrometallurgical processing

Hydrometallurgical processingCathodecopper

65.4 MJ/kg

9.0 MJ/kg

Energy requirement metric

Data sources are not consistent in the reported energy metricsElectricity generation may or may not be included - caution required to avoid mistakes in comparisons

(>99% fixed carbon)

50 100 150 200

Balomenos et al. (2011) [14]

Aluminum association (2013) [15]

Norgate et al. (2006) [16]

Int. Copper Association [17]

Alvarado et al. (2002) [18]

Gao et al (2018) [20]

Battery minerals [21]

Norgate et al. (2006) [16]

Total energy consumption [MJ/kg]

Primary energy demand [GJ/ton]

Gross energy requirement [MJ/kg]

Gross energy requirement [MJ/kg]

Primary energy demand [GJ/ton]

Specific energy consumption fuels [MJ/kg] specific energy consumption electricity [kWh/t]

Life cycle energy consumption [GJ/t]

"Energy required to produce 1 ton" [kWh/t]

HydroelectricCoal power

HydroPyro

EcoInvent [19] Diesel [MJ/kg], electricity [kWh/kg], heat [MJ/kg] 0.23 MJ/kg

Graphite studies: vary in the energy requirement metric, vary in the scope (e.g. only mining and benefication; purification omitted), are foused on graphite for anodes in Li-ion batteries, and show low reliability.

Assessing the overall energy requirement of a technology requires the material production data

Interdisciplinary collabora�on between the resource extrac�on, material

processing, and technology development sectors is needed to perform reliable

LCA studies

Material produc�on data for natural graphite is limited and varies widely

Energy requirement is only one part of LCA; water requirement, waste

produc�on, emissions, and toxicity of effluents also have to be addressed

400

200

30

10

Data averaged from: [1]-[4]

Data averaged from: [1],[6]-[9],[10]-[13]

Data: [5]

[1] X. H. Wei, L. Liu, J. X. Zhang, J. L. Shi, and Q. G. Guo, “Mechanical, electrical, thermal performances and structure characteristics of flexible graphite sheets,” J. Mater. Sci., vol. 45, no. 9, pp. 2449–2455, 2010.[2] R. Liu, J. Chen, M. Tan, S. Song, Y. Chen, and D. Fu, “Anisotropic high thermal conductivity of flexible graphite sheets used for advanced thermal management materials,” ICMREE 2013 - Proc. 2013 Int. Conf. Mater. Renew. Energy Environ., vol. 1, pp. 107–111, 2013.[3] M. Bonnissel, L. Luo, and D. Tondeur, “Compacted exfoliated natural graphite as heat conduction medium,” Carbon N. Y., vol. 39, no. 14, pp. 2151–2161, 2001.[4] L. W. Wang, S. J. Metcalf, R. E. Critoph, R. Thorpe, and Z. Tamainot-Telto, “Thermal conductivity and permeability of consolidated expanded natural graphite treated with sulphuric acid,” Carbon N. Y., vol. 49, no. 14, pp. 4812–4819, 2011.[5] U.S. Geological Survey, Mineral Commodity Summaries 2017, vol. 1. 2017.[6] Mersen, “Papyex Flexible Graphite - technical guide.” 2012.[7] M. Polock, “GRAFOIL Flexible Graphite Engineering Design Manual 2nd edition.” 2002.[8] Graftech, “eGRAF SPREADERSHIELD Heat Spreaders - Technical data sheet 321.” 2016.[9] SGL Group, “SIGRAFLEX - Flexible graphite foils and sheets for heat treatment applications,” 2016. [Online]. Available: http://www.sglgroup.com/cms/_common/downloads/products/product-groups/gs/tds/expanded/SIGRAFLEX_TDS-TH_NH_THP_S_HP_UHP_Foil.01.pdf. [Accessed: 14-Dec-2017].[10] P.-H. Chen and D. D. L. Chung, “Thermal and electrical conduction in the compaction direction of exfoliated graphite and their relation to the structure,” Carbon N. Y., vol. 77, pp. 538–550, 2014.[11] X. Luo and D. D. L. Chung, “Electromagnetic interference shielding reaching 130 dE8 using flexible graphite,” Carbon N. Y., vol. 34, no. 10, pp. 1293–1294, 1996.[12] A. Celzard, J. F. Marêché, G. Furdin, and S. Puricelli, “Electrical conductivity of anisotropic expanded graphite-based monoliths,” J. Phys. D. Appl. Phys., vol. 33, pp. 3094–3101, 2000.[13] P. Qian, H. Zhang, J. Chen, Y. Wen, Q. Luo, Z. Liu, D. You, and B. Yi, “A novel electrode-bipolar plate assembly for vanadium redox flow battery applications,” J. Power Sources, vol. 175, no. 1, pp. 613–620, 2008.[14] E. Balomenos, D. Panias, and I. Paspaliaris, “Energy and exergy analysis of the primary aluminum production processes: A review on current and future sustainability,” Miner. Process. Extr. Metall. Rev., vol. 32, no. 2, pp. 69–89, 2011.[15] The Aluminum Association, “The Environmental Footprint of Semi- Finished Aluminum Products in North America,” 2013.[16] T. E. Norgate, S. Jahanshahi, and W. J. Rankin, “Assessing the environmental impact of metal production processes,” J. Clean. Prod., vol. 15, no. 8–9, pp. 838–848, 2007.[17] Internation Copper Association, “Copper Environmental Profile,” 2017.[18] S. Alvarado, P. Maldonado, A. Barrios, and I. Jaques, “Long term energy-related enviromental issues of copper production,” Energy, vol. 27, no. 2, pp. 183–196, 2002.[19] ecoinvent Association, “ecoinvent database.” [Online]. Available: https://v30.ecoquery.ecoinvent.org/Home/Index. [Accessed: 12-Sep-2017].[20] S. W. Gao, X. Z. Gong, Y. Liu, and Q. Q. Zhang, “Energy consumption and carbon emission analysis of natural graphite anode material for lithium batteries,” Mater. Sci. Forum, vol. 913, pp. 985–990, Feb. 2018.[21] “Battery minerals: A question of purity?,” Battery Minerals, pp. 41–45, Aug-2015.

Energy requirement during a life cycle

1mcermak@sfu.ca, 2mbahrami@sfu.ca (corresponding author)

20

50

References

Material production

Energy requirement

Conventional technologyIdeal clean technology

Resources-intensive "clean" technology

Illustrative demonstration of the importance of overall impact

Energy efficiency of the final product is not sufficientfor evaluating the environmental footprint of a technology!

Higher energy requirement despite improved efficiency of the product

Emissions Waste Emissions Waste

Manufacturing Final product Recycling

DisposalService

Aluminum Aluminum

(significant ash content)

Anisotropic and density dependent properties

Some applications such as batteries or fuel cells require high-purity graphite (up to 99.9995% fixed carbon content)Acid, caustic, or high temperature treatments are used to achieve high puritiesPurification is expected to be the major source of pollution in graphite production