Managing Carbon in the Process Metallurgy of the Future

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Managing Carbon in the Process Metallurgy of the Future

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Managing Carbon in the Process Metallurgy of the Future
Joe Herbertson, Les Strezov
The Crucible Group Pty Ltd, PO Box 183, Mayfield, NSW, Australia

Keywords: Carbon, Climate change, Sustainability, Resource sector, Process metallurgy, Pyrolysis, Renewable energy

Abstract
In a sustainable future, the value of minerals and metals to
society will have to be delivered in ways that are in balance with
the ecology of the planet. A central challenge will be learning
how to operate mining and metallurgical processes in balanced
carbon cycles. At present the industry relies predominantly on
fossil fuels for sources of carbon to meet the needs for
electricity, heat, liquid fuels and reductants. This paper discusses
the challenges and principles for sustainable metals production.
The Crucible Group is developing technologies that address the
challenges and opportunities, which includes algae production
for liquid fuels and a carbon fuel cell for high efficiency
electricity generation. Particular attention is given here to the
Crucible’s pyrolysis technology, which is currently being
commercialised. The process outputs are biochar, which can be
a source of renewable carbon in metallurgy and a clean biogas
rich in hydrogen and carbon monoxide for process heat,
electricity generation or synthetic fuels production. The
presentation will provide an update on commercialisation
activities, especially projects being developed in Canada.

effect) and about 150 Gt in the ocean (increasing acidity). The
enhanced greenhouse effect is manifest in a global energy
imbalance of 0.75W/m2 [3] which is manifest mainly in
warming of the ocean and melting of ice. Global warming drives
climate change, and in general climate change accelerates
biodiversity loss and exacerbates eco-system degradation.
Climate change has serious social implications and will drive
social inequity.
VALUE

GDP - US$
per person

Carbon in the Context of Unsustainable
Dynamics in the Global Economy
Global society faces a fundamental challenge of enormous
proportions. The economy is out of balance with the ecology of
the planet, see Figure 1. This shows a general trend where
economic advancement comes at the price of greater impacts on
nature, as reflected in the ‘ecological footprint’ [1]. The
prevailing value paradigm is flawed in the sense that the more
the economy grows the greater is our impact on the natural
systems we depend on for vital goods and services, pleasure and
survival. We would need more earths to support the standard of
living currently enjoyed by developed economies, see Figure 2.
This highlights how the underlying trend over time is
unsustainable; in recent decades global society has moved into
‘ecological debt’.
The consequence of these trends is systematic degradation of
ecosystems, loss of biodiversity, deterioration of land and water
resources and widening inequity. Climate change is arguably the
most serious manifestation of this problem.
As process metallurgists we should look at this from the
perspective of the underlying mass and heat balances. Of course,
carbon per se is not the issue, but rather that our economic and
social activity has created a major imbalance in the global
carbon cycle, see Table 1 [2].
An estimated 350 Gt of fossil carbon has been extracted from
the lithosphere to fuel the economy and in the process put into
the biosphere. When one adds in the effect of net clearances of
terrestrial biomass, this has resulted is an accumulation of about
220 Gt of carbon in the atmosphere (increasing the greenhouse

Ecological
Footprint - ha
per person

IMPACT

Figure 1. Per capita GDP, expressed in US$, and ecological
footprint, expressed in hectares.

Figure 2. Aggregated global ecological footprint, expressed in
number of earths, as a function of time since 1960.
This cannot be solved as an ‘environmental’ problem, since it
goes to the very heart of how the economy operates and how
energy is used and generated. Under present circumstances,

2011 GUTHRIE SYMPOSIUM PROCEEDINGS - 84

where energy is delivered primarily through fossil fuels, every
1% of world GDP growth increases energy use by some 0.7%
and CO2 emissions by some 0.65%. This cannot be solved as an
‘environmental’ problem, since it goes to the very heart of how
the economy operates and how energy is used and generated.
Under present circumstances, where energy is delivered
primarily through fossil fuels, every 1% of world GDP growth
increases energy use by some 0.7% and CO2 emissions by some
0.65%.

In summary, the global economy has a deep sustainability
problem, manifest sharply in unbalanced carbon cycles and
climate change, and this is a fundamental challenge for the
minerals and metals sector to address.
In the context of this conference, the central question becomes:
how might carbon be managed sustainably in the process
metallurgy of the future?
Table 2. Australian minerals and metals companies amongst the
most exposed to carbon pricing.

Table 1.  Estimated global carbon balance, expressed in gigatonnes (Gt) of carbon.

One can see in Figure 3 [4], how the net carbon flux to the
atmosphere (red line) reflects the world economy; steady growth
since the industrial revolution, a faltering during the depression
and the second world war, unprecedented post war growth until
the oil shocks of the early 1970’s, followed by more growth.

Company

EBITDA per tonne
CO2

BlueScope Steel

$ 60

OneSteel

$ 122

Alumina

$ 147

Orica

$ 189

Boral

$ 217

Newcrest Mining

$ 278

BHP Billiton

$ 435

Leighton Holdings

$ 435

Rio Tinto

$ 526

Sustainability and the minerals and metals
resource sector
An effective approach to sustainable development needs to be
grounded in science and systems thinking [6]. An effective
systems approach is hierarchical, as shown in Table 3. This
provides a framework for high level consideration of energy and
climate change from a minerals and metals resource sector
perspective.
Table 3. A hierarchical approach to systems thinking

Figure 3. The amount of carbon entering the atmosphere from
fossil fuel burning, expressed in Gt, since the industrial
revolution (upper line blue) and the net flux after adjustment for
sources and sinks, such as the ocean (lower line red).

This general link between the economy and carbon emissions
becomes a business challenge at company level. In the current
paradigm, putting a price on carbon to promote low carbon
futures can threaten the profitability of companies, especially
those that are energy intensive.
Table 2 provides an Australian illustration [5]. Nine minerals
and metals sector companies are among the thirteen most
exposed companies to this challenge; ‘most exposed’ in this
context means lowest ratios of earnings (EBITDA) to CO2
emissions.

Level 1:
The System
Context

What is the system and how it
functions; signs of malfunction;
system boundaries; underlying science

Level 2:
Success
Principles

Principles for a fundamentally
sustainable outcome; the desired
future state

Level 3:
Strategies

Strategic guidelines for the transition;
technical platforms and process
principles

Level 4:
Actions

Initiatives, technologies, projects

Level 5:
Metrics

Analytical tools, reporting systems

2011 GUTHRIE SYMPOSIUM PROCEEDINGS - 85



Level 1: The System Context
Energy is a fundamental driver of the economy (and vice versa),
and an enabler for advances in the standard of living and of
civilised society generally. The enormous growth in economic
activity since the industrial revolution (and particularly post
war) has been fuelled by abundant, low cost energy sources,
mainly fossil fuels.
This is not sustainable under the combined pressures of climate
change and peak oil. Global warming and climate change is
modifying global eco-systems and puts civilised society at risk,
with many of the impacts to be borne disproportionately by the
poor.
Energy is a social and political issue; a force for liberation
and/or instability.
The minerals/metals resource sector is both an intensive user of
energy, especially liquid fuels, electricity, heat and reductants, a
major provider of energy resources to society, such as coal, and
a major provider of metals used in energy-related technologies.

Level 2: Success in Principle
In a sustainable future, mining, minerals processing and metals
processing operations will have the energy and energy security
necessary to fulfill their purpose and prosper through the
delivery of valued mineral, metal and energy products and
services to society.
From a systems and life cycle perspective, the material and
energy flows in which the resource sector participates will have
learnt how to function within balanced carbon cycles and
without systematic:






accumulation of greenhouse gases in the atmosphere
acidification of the ocean
deterioration of community health (air quality)
physical and chemical degradation of eco-systems
deterioration in the social and political fabric

Opportunities will be taken to address the negative legacy issues
of accumulated fossil fuel use. Moreover, the sector will create a
positive legacy through its contribution to new energy products
and services, new process technologies and new energy use
behaviours and systems that make efficient use of natural
resources and provide effective responses to climate change.
In a sustainable future, there will be social equity in the way the
benefits and value of energy are shared.
It is clear from these considerations of success, of the desired
future state, that current realties are a far cry from sustainable.

Level 3: Strategies for Sustainable Development
The strategic foundations of the journey to a sustainable future
will include:






An integrated approach to energy use, energy markets
and energy security and the wider links to water and
land use, eco-systems, community development,
material stewardship
Close monitoring of the science and politics of energy
and climate change, at an operational and a broader
societal level, based on the latest advances in science,
technology and practices
Partnerships with thought leaders and new technology
developers and open engagement with the community
and public

Persistent incremental and breakthrough advances in:
- Energy efficiency
- Use of renewable energy (solar, wind, bioenergy etc)
- Use of alternative energy resources (geothermal etc)
- Eco-efficiency including recycling and re-use of
metals, durability and performance of metal based
products, light-weighting and smart design
- Metals as ‘sustainability enablers’ in emerging
products and technologies
- Carbon capture and storage (geological, inorganic,
biological)
- Provision of new energy products and services
For companies, the essence of good strategy will be to turn the
challenges of sustainability and climate change into drivers of
innovation and to develop flexible technological platforms,
where improvements can be introduced step by step as they
become viable.
The successful companies will find economically attractive
pathways to a ‘carbon neutral’ future, with environmental
stewardship being a core component of their strategies for
business leadership.

Level 4: Technology Solutions
This is indeed a complex problem with social, ecological,
economic and political dimensions. But there is a core
technological challenge for the industry, which is to find carbon
neutral solutions to substitute for current uses of coal, diesel and
natural gas. These fossil fuels provide the industry with most of
the process heat, electricity, liquid fuels and reductants required
to mine minerals and produce metals.






Diesel is typically the largest source of greenhouse gas
emissions in mining operations, providing the liquid fuel
for mining equipment, trucks and trains. Diesel and fuel
oil can also be used to generate heat and electricity at
remote sites not connected to the grid.
Coal is typically the biggest source of greenhouse gas
emissions associated with the primary processing of ores
to metals. Coal is the main chemical reductant used in
the industry, providing carbon directly or as carbon
monoxide. It is also commonly the fuel source for the
power used in electricity based refining processes.
Natural gas is primarily used for process heat, but also
as a reductant. It is a source of hydrogen based
chemicals, for instance ammonium nitrate for
explosives. Natural gas is also used to generate power in
the industry.

One can see that the sector’s energy needs have significant
material and chemical features, especially the need for liquid
fuels and reductants. Thus the value of carbon for our industry
lies as much in its physical and chemical forms, as in its energy
content. As such, carbon cannot simply be substituted by solar,
wind, geothermal and other ‘carbon free’ energy forms. In this
regard, it can be argued that the industry has a strong strategic
interest in the emergence of bio-energy solutions, which are
‘carbon neutral’ not ‘carbon free’.
Fossil fuels were produced over millions of years from land and
aquatic biomass (vegetation and algae). Bio-energy draws on the
same biomass resources, but in balanced carbon cycles where
CO2 emissions contain carbon that was recently taken from the
atmosphere by photosynthesis, not from fossil stores.

2011 GUTHRIE SYMPOSIUM PROCEEDINGS - 86






‘Bio-diesel’ could be produced through the extraction of
the lipid fraction of algae or the oils contained in some
vegetation and crops. Alternatively, bio-diesel could be
synthesised from hydrogen and carbon dioxide
generated by biomass gasification or pyrolysis.
‘Bio-coal’ could be provided by the char fraction
produced through the pyrolysis of biomass
‘Bio-gas’ could be produced by anaerobic digestion of
biomass, for a methane rich gas. Alternatively
gasification and pyrolysis could produce a gas richer in
H2 and CO.

Pyrolysis
Of the emerging bio-energy technologies, pyrolysis is
considered the most strategically important. Pyrolysis is thermal
decomposition of organic material without oxygen, where the
primary outputs are gas, oil/tar liquids and char. Pyrolysis is the
‘carbon neutral’ technology that in principle could best deliver a
flexible platform of gas, liquid and solid products to substitute
for fossil fuels.
Two criteria need to be satisfied for pyrolysis to emerge as an
effective source of bio-carbon substituting for coal, diesel and
natural gas based products.
Firstly, there will need to be a commitment to sustainable
biomass supply, with respect to biodiversity, nutrient cycles, soil
quality and water impacts. In general this will mean avoiding
mono-cultural plantations and making maximum use of wastes
and residues. Pyrolysis works on abundant lingo-cellulosic
(woody) material, making it intrinsically scalable. It does not
require the biomasss to have readily available oils or sugars and
thus reduces the ‘food versus fuel’ problems associated with
some energy crops.
Secondly, it will have to become economically attractive.
Currently available biomass pyrolysis technology is capital
intensive and energy inefficient with no significant commercial
deployment to date.

In the unique Crucible pyrolysis design, the fundamental
processes of water separation, tar cracking and gas scrubbing
occur within the reactor, which eliminates the capital costs of
biomass drying and gas treatment required in existing
technologies. Process heat is generated and recovered internal to
the process, leading to very high efficiency. Biomass containing
up to 50% moisture can be fed directly to the process. The
efficiency of the system is 95% or more, when defined as the
energy content of the gas and char products compared to the
energy content of the incoming biomass feed.
The oil/tar liquid fraction within the reactor is converted to a
biogas, which is sufficiently clean with respect to tars, sulphur
compounds and particulates to be used directly for electricity
generation and industrial heating. The gas could also provide
chemical precursors (eg. synthetic fuels and chemicals).
The biochar can be used to improve soils by enhancing
structure, water and nutrient retention and fertility. This
represents a value adding form of carbon capture and storage
that could be an adopted by resource companies as a part of their
rehabilitation practices. Alternatively the biochar could be used
by metal producing companies as a metallurgical reductant, for
instance in ironmaking.
The journey to commercialisation has taken four years.
Extensive mathematical modelling of the underlying
thermodynamics and the energy and material flows within the
process was initially used to develop a conceptual design for a
pyrolyser that could meet our high efficiency, low capital cost
objectives. A proof-of-concept apparatus was then used to
demonstrate all the core fundamental concepts of the
technology. This provided the foundations to design an
engineering prototype, to allow materials transport, operating
strategies, process control, temperature profile optimisation and
engineering design parameters to be confirmed. The prototype is
shown in Figure 4.

The Crucible Group
In the business ethos of The Crucible Group, sustainability is the
high level constraint and inspiration on all our consulting and
technology innovation activities. In response to the challenges of
climate change, the company is developing proprietary
technology in the areas of algae production, carbon fuel cell,
compact alloy processing and biomass pyrolysis.

New Pyrolysis Process
The Crucible Pyrolysis technology represents a new approach
for conversion of biomass, such as agricultural and industrial
residues, to a range of renewable energy and biochar products.
The technology creates a completely unique and patented [7]
thermo-chemical environment within the reactor, so that undried
feed materials can be fed directly to the process and very clean
gas is produced ready for direct use, for instance in electricity
generators. The technology also provides a strategic platform for
liquid fuels production through synthesis of H2 and CO, for
example by Fischer Tropsch reactions.
The design provides breakthrough performance with respect to
capital costs and process efficiency. The result is an
economically attractive pathway to industrial heat and power in
production systems that are ecologically sustainable.

Figure 4. The pyrolysis engineering prototype and development
team at the Crucible’s Research and Development Centre,
Newcastle, Australia.
Results with the engineering prototype demonstrated simple,
scalable design, process operability and efficiency, as well as the
production of a clean gas rich in H2 and CO. This provided the
confidence to move to commercialisation.
The Crucible Pyrolysis technology is built around a nominal one
tonne per hour commercial module, which can be operated
independently to cater for small applications or grouped together
to support higher production rates, with typical production rates

2011 GUTHRIE SYMPOSIUM PROCEEDINGS - 87

in the range 10,000 to 100,000 tonnes per annum depending on
biomass availability. Typical inputs and outputs per one tonne
of biomass feed (on a dry weight basis) are summarised in Table
4 for two operating configurations: standard biochar mode and
high gas yield mode.
In Australia, the first commercial unit has been ordered for the
WA wheat belt, where straw will be converted into electricity
for the grid and biochar for soil conditioning. A commercial
scale demonstration facility has also been set up at Vales Point,
NSW, to process timber industry residues, such as shavings, saw
dust and bark. The first projects in the Australian wood
processing sector have been identified. We are also working
with the steel industry to develop bio-carbon injectants for the
blast furnace and EAF.
International deployment of the technology will commence with
projects in Canada. The initial focus is British Columbia where
opportunities have already been identified for:




conversion of woody green waste to municipal heat
and electricity
processing of forest and timber mill residues to
industrial heat, power and metallurgical carbon
facilities designed especially for use by remote
communities not connected to the grid.

Table 4. Input and output data for a commercial module based
on one tonne per hour production on a dry weight basis.
Input/Output 

Standard Biochar 
Mode 

Feedstock 
Energy Content 
Energy for 
Process Heat 

High Gas 
Mode 

Acknowledgement
The authors are most pleased to be able to contribute to the
Guthrie Honorary Symposium. We have a long relationship of
collaboration and friendship, dating back the 1980’s when Dr
Herbertson first worked as a post doctoral researcher with
Professor Guthrie at McGill University.

References
1.

20 GJ 
2.
1 GJ 

1.5 GJ 

350 kg  

100 kg  

(10 GJ) 

(2.5 GJ) 

Biogas 
Generation 

9 GJ 

16 GJ 

Electricity 
Option 

1 MWh 

1.8 MWh 

Biochar     
Output 

well illustrated by one of the early business opportunities in
British Columbia.
The BC forest and timber industry has been hit by the problem
of pine beetle infested timbers, extending over millions of
hectares, which is creating a stranded biomass resource. There is
enthusiasm for using the Crucible’s pyrolysis technology to
create value from the infected timbers before it is lost, as well as
creating energy from forest and timber mill residues on a
permanent basis. This represents an opportunity for indigenous
employment and business development, as the problem effects
First Nations land and forest holdings. It is also an opportunity
for regional development, especially the BC timber industry. An
in-principle agreement has been reached with the Tl'azt'en
Nation for the first pyrolyser to be built at Tache near Fort St.
James, with commissioning within a year from now. Samples of
the infected timbers are to be tested at the Crucible’s R&D
Centre in Australia shortly to provide the design parameters for
the plant.

3.

4.
The Crucible is working in partnership with BC based Poncho
Wilcox Energy [8] to develop these opportunities. The first
commercial unit is expected to be in operation around the end of
2011.

5.

6.

Sustainabilty Innovation in Practice
All of the Crucible’s technology innovation is in response to
sustainability challenges. The Crucible Pyrolysis Process
provides a cost effective platform for renewable energy, carbon
capture and storage in soils, regenerative land practices, waste
minimisation and value capture from degraded resources. This is

7.
8.

For information on the ecological footprint methodology
and results, see the work of Professor Mathis
Wackernagel; www.footprintnetwork.org.
Information on carbon balance has been derived from data
in the IPCC Fourth Assessment Report, Working Group 1,
Climate Change 2007, The Physical Science; 1994 data
taken from Fig.7.3, p515.
See the work of Professor James Hansen, NASA and
Columbia University (www.columbia.edu/~jeh1/) ,
‘Storms of my grandchildren’, Bloomsbury, 2009; latest
estimate: J. Hansen, M. Sato, P. Kharecha, K. von
Schuckmann, 2011: Earth's energy imbalance and
implications, draft paper.
www.globalwarmingart.com/wiki/Carbon_Dioxide_Galler
y.
Table derived from data published by the Carbon
Disclosure Project: www.cdproject.net; this is the largest
global data base on the emissions of companies.
The Crucible’s approach to sustainable development
builds on the framework of the Natural Step:
www.naturalstep.org.
Crucible Pyrolysis Patent: Processing of Organic
Materials, PCT/AU2009/000455.
Poncho Wilcox Energy: www.pw-energy.com.

2011 GUTHRIE SYMPOSIUM PROCEEDINGS - 88

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