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Steel’s recyclability: demonstrating the benefits of recycling steel to achieve a circular economy

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The International Journal of Life Cycle Assessment
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Purpose In a world where the population is expected to peak at around 9 billion people in the next 30 to 40 years, carefully managing our finite natural resources is becoming critical. We must abandon the outdated ‘take, make, consume and dispose’ mentality and move toward a circular economy model for optimal resource efficiency. Products must be designed for reuse and remanufacturing, which would reduce significant costs in terms of energy and natural resources. Methods To measure progress in achieving a circular economy, we need a life cycle approach that measures the social, economic and environmental impact of a product throughout its full life cycle—from raw material extraction to end-of-life (EoL) recycling or disposal. Life cycle thinking must become a key requirement for all manufacturing decisions, ensuring that the most appropriate material is chosen for the specific application, considering all aspects of a products’ life. The steel industry has been developing LCI data for 20 years. This is used to assess a product’s environmental performance from steel production to steel recycling at end-of-life. The steel industry has developed a methodology to show the benefits of using recycled steel to make new products. Using recycled materials also carries an embodied burden that should be considered when undertaking a full LCA. Results and discussion The recycling methodology is in accordance with ISO 14040/44:2006 and considers the environmental burden of using steel scrap and the benefit of scrap recycling from end-of-life products. It considers the recycling of scrap into new steel as closed material loop recycling, and thus, recycling steel scrap avoids the production of primary steel. The methodology developed shows that for every 1 kg of steel scrap that is recycled at the end of the products life, a saving of 1.5 kg CO2-e emissions, 13.4 MJ primary energy and 1.4 kg iron ore can be achieved. This equates to 73, 64 and 90 %, respectively, when compared to 100 % primary production. Conclusions Incorporating this recycling methodology into a full LCA demonstrates how the steel industry is an integral part of the circular economy model which promotes zero waste; a reduction in the amount of materials used and encourages the reuse and recycling of materials.
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LCA OF METALS AND METAL PRODUCTS: THEORY, METHOD AND PRACTICE
Steels recyclability: demonstrating the benefits of recycling steel
to achieve a circular economy
Clare Broadbent
1
Received: 25 May 2015 /Accepted: 25 February 2016 /Published online: 21 March 2016
#The Author(s) 2016. This article is published with open access at Springerlink.com
Abstract
Purpose In a world where the population is expected to peak
at around 9 billion people in the next 30 to 40 years, carefully
managing our finite natural resources is becoming critical. We
must abandon the outdated take, make, consume and dispose
mentality and move toward a circular economy model for
optimal resource efficiency. Products must be designed for
reuse and remanufacturing, which would reduce significant
costs in terms of energy and natural resources.
Methods To measure progress in achieving a circular econo-
my, we need a life cycle approach that measures the social,
economic and environmental impact of a product throughout
its full life cyclefrom raw material extraction to end-of-life
(EoL) recycling or disposal. Life cycle thinking must become
a key requirement for all manufacturing decisions, ensuring
that the most appropriate material is chosen for the specific
application, considering all aspects of a productslife. The
steel industry has been developing LCI data for 20 years.
This is used to assess a products environmental performance
from steel production to steel recycling at end-of-life. The
steel industry has developed a methodology to show the ben-
efits of using recycled steel to make new products. Using
recycled materials also carries an embodied burden that
should be considered when undertaking a full LCA.
Results and discussion The recycling methodology is in ac-
cordance with ISO 14040/44:2006 and considers the environ-
mental burden of using steel scrap and the benefit of scrap
recycling from end-of-life products. It considers the recycling
of scrap into new steel as closed material loop recycling, and
thus, recycling steel scrap avoids the production of primary
steel. The methodology developed shows that for every 1 kg
of steel scrap that is recycled at the end of the products life, a
saving of 1.5 kg CO
2
-e emissions, 13.4 MJ primary energy
and 1.4 kg iron ore can be achieved. This equates to 73, 64 and
90 %, respectively, when compared to 100 % primary
production.
Conclusions Incorporating this recycling methodology into a
full LCA demonstrates how the steel industry is an integral
part of the circular economy model which promotes zero
waste; a reduction in the amount of materials used and encour-
ages the reuse and recycling of materials.
Keywords Circular economy .Cradle to grave .LCA .
Recycling .Steel
1 Introduction
1.1 The circular economy
Steel is everywhere in our lives and is at the heart of a sus-
tainable future. The steel industry is an integral part of the
global circular economy. The circular economy is a move
from linear business models, in which products are
manufactured from raw materials and then discarded at the
end of their useful lives, to circular business models where
intelligent design leads to products or their parts being
repaired, reused, returned and recycled (World Economic
Forum 2014). A circular economy aims to rebuild capital,
whether it is financial, manufacturing, human, social or natu-
ral. This approach enhances the flow of goods and services
(Ellen MacArthur Foundation 2014). The concept of the
Responsible editor: Andrea J. Russell-Vaccari
*Clare Broadbent
broadbent@worldsteel.org
1
World Steel Association, 120 rue Colonel Bourg,
1140 Brussels, Belgium
Int J Life Cycle Assess (2016) 21:16581665
DOI 10.1007/s11367-016-1081-1
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
circular economy drives optimal resource efficiency. It makes
sure that resources are efficiently allocated to products and
services in such a way as to maximise the economic well-
being of everyone. In addition, products need to be designed
to be durable, easy to repair and, ultimately, to be recycled.
The cost of reusing, repairing or remanufacturing products has
to be competitive to encourage these practices. Simply replac-
ing a product with a new one should no longer be the norm.
A circular economy ensures that value is maintained within
a product when it reaches the end of its useful life while at the
same time reducing or eliminating waste. This idea is funda-
mental to the triple-bottom-line concept of sustainability,
which focuses on the interplay between environmental, social
and economic factors. In a well-structured circular economy,
the steel industry has significant competitive advantages over
competing materials and these can be demonstrated through a
life cycle approach.
1.2 Life cycle assessment in the steel industry
The World Steel Association (worldsteel) has been developing
a database of life cycle inventories (LCI) of steel products for
more than 20 years together with an externally reviewed meth-
odology report. This LCI database of 15 steel products ac-
counts for the cradle to gate steel production, including raw
material mining and manufacturing, as well as accounting for
the benefits of recycling steel from products at the end of their
life. This database and methodology assist LCA practitioners
modelling steel products to carry out full cradle to grave life
cycle assessments. This report demonstrates what approaches
are currently available for including recycling in LCA and the
rationale for the approach that the steel industry has decided to
use based on the closed material loop recycling methodology.
A detailed account of the methodology is provided, which
demonstrates the environmental value of recycling steel from
products when they reach the end of their useful life.
2 Current practice for recycling methodologies
2.1 Existing recycling methodologies
The three main approaches to recycling which form the basis
for many discussions are the following:
Cut-off approach (1000)
The cut-off approach considers the impacts and/or
benefits of recycling that only occur within the product
system being studied. There is no crediting or assignment
of environmental impacts between different product sys-
tems, and metal scrap at the point of discard is considered
to have no upstream environmental impacts beyond re-
melting. This is also known as the recycled content
method because the benefits of metals recycling are only
taken into account on the input side (considered as being
free) and recycling at end-of-life is neglected regardless
of recycling rate. From a policy perspective, this method
leads to a focus on increasing the percentage of recycled
materials in the product. Figure 1shows how the cut-off
approach would be applied throughout the life cycle.
End-of-life approach (0100)
The end-of-life approach takes an overall approach to
recycling as it considers the assignment of environmental
impacts and credits between different product systems
across different life cycles and the environmental impact
of the product system is dependent on the recycling rate at
end-of-life. Where a material is recycled at end-of-life,
the product system is credited with an avoided burden
based on the reduced requirement for virgin material pro-
duction in the next life cycle. Equally, any recycled con-
tent adds the same burden to the product system, per
kilogram of steel scrap, in order to share the burden with
the previous life cycle. This method is also known as the
closed material loop method because recycling saves the
production of virgin material with the same properties.
From a policy perspective, this method encourages the
recycling of products at the end of their life. Figure 2
shows how this approach would be applied for each stage
of the life cycle; the impacts from the disposal of steel, if
any, are negligible. Note that the amount of scrap used in
the production of steel is typically lower than the amount
of scrap recycled at end-of-life in the primary production
route or for the secondary production route in the cases
where a large amount of direct reduced iron or hot metal
is used.
The 50:50 method
This method falls half way in between the cut-off
approach and end-of-life approach. For this reason, it
Fig. 1 Cut-off approach for a product system that uses virgin metal and
recycled metal inputs
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is seen as a compromise method, which credits both
recycled content and end-of-life recycling. This
method, although a compromise, can be a solution
for systems where it is not clear if it is beneficial to
provide incentives for recycled content or recycling
at end-of-life.
In addition, there are multiple frameworks that address the
incorporation of the benefits of recycling at the end of a prod-
ucts life. Some examples of such publications are the
following:
World Resources Institute/World Business Council for
Sustainable Development standards developed under the
GHG Protocol Initiative (The Greenhouse Gas Protocol
2004)
PAS 2050: Publicly Available Specification 2050:
Specification for the assessment of the life cycle green-
house gas emissions of goods and services (British
Standards Institute 2008)
EN 15804: Sustainability of construction works
(European Committee for Standardisation 2013)
ISO TS 14067: Carbon footprint of products (ISO TS
14067 2013)
ILCD: The European Commissions International
Reference Life Cycle Data System Handbook
(European Commission 2010)
The European Commissions Product Environmental
Footprint (European Commission 2013)
The Declaration by the Metals Industry on Recycling
Principles (Atherton et al. 2007) clearly defines the distinction
between the recycled content approach and the end-of-life
approach and why the latter is supported by the metals indus-
try. The end-of-life approach encourages the recycling of
products at the end of their life and therefore reduces waste
going to landfill and saves the use of natural resources in
creating new productsthese are both key to a circular
economy.
The European Commissions Product Environmental
Footprint standard is currently in the pilot phase, and one of
the aspects of this phase is to assess the methodology that has
been defined for the end-of-life of products. This is being
addressed by the different pilot projects including the metals
industries.
2.2 Steel recycling practice
In the manufacture of steel, the term primary production
generally refers to the manufacture of iron (hot metal) from
iron ore in a blast furnace (BF), which is subsequently proc-
essed in the basic oxygen furnace (BOF) to make steel.
Secondary productionrefers to the recyclingroute and is
typically the electric arc furnace (EAF) process, which con-
verts scrap into new steel by re-melting old steel. However,
primary steel production is not unique to the BOF route, and
similarly, secondary steel production is not unique to the EAF.
It is common practice to use 1030 % scrap as iron input in the
BOF route. Primary steel production also occurs in the EAF
route, when pre-reduced iron is used as a feedstock to the EAF
process. This is demonstrated in Fig. 3.
Steel is 100 % recyclable and scrap is converted to the same
(or higher or lower) grade steel depending upon the metallur-
gy and processing of the required product. Some recycled
products such as rebar require minimal processing, whilst
the higher value engineering steels require more metallurgical
and process controls to meet tighter specifications. The final
economic value of the product is not determined by recycled
content, and there are many examples of high value products
that contain large amounts of recycled steel. Some steel prod-
ucts are principally sourced via the primary route mainly be-
cause the steel specifications require low residual elements
and this can be achieved most cost-effectively using more
primary material. In most cases, scrap with a low amount of
residual elements commands a higher market price owing to
the ease of processing through the recycling routes.
The growing global demand for steel results in a con-
tinuing capacity to absorb steel scrap. There is not enough
scrap arising to manufacture all the steel required to sat-
isfy the market. This is not a consequence of deficiencies
in collecting scrap as the recovery rates of steel products
are high and the lifetime of products is often long.
Moving towards a circular economy, if more scrap be-
comes available, this could result in an increase in the
proportion of steel made in the EAF route. Continuing
improvements in the scrap processing plants and segrega-
tion of scrap types will improve efficiencies in the steel-
making process.
Fig. 2 End-of-life approach for a product system that uses both primary
and recycled steel inputs
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3 Worldsteels rationale for the chosen recycling
approach
The worldsteel LCI data collection methodology covers steel
production from cradle to gate and in addition takes account of
recycling of steel scrap in the following ways:
&Allocation for scrap inputs to the steelmaking process
&Allocation for steel scrap outputs from whole product sys-
tem (e.g. scrap arising from an end-of-life building or
vehicle)
Where systems have both scrap inputs and outputs, it is
necessary to apply consistent allocation procedures to both,
as is described in the worldsteel method.
This methodology is reviewed to conform to ISO
14044: 2006, which sets out allocation procedures for
reuse and recycling. Within this standard, a distinction
is made between open and closed loop recycling. Open
loop recycling is used to describe product systems where
material is recycled into a new different product or where
inherent material properties change. Closed loop
recycling applies to products that are recycled to produce
the same product type or where the inherent material
properties do not change. Where inherent material prop-
erties do not change, this is also known as closed mate-
rial loop recycling.
The vast majority of steel recycling involves re-melting
scrap to produce new steels with no change in the inherent
properties of the basic steel material, and therefore, steel
recycling can be regarded as closed loop. In this situation,
ISO 14044:2006 states that in such cases, the need for allo-
cation is avoided since the use of secondary material displaces
the use of virgin (primary) materials.Thisguidanceprovides
the basis for the closed material looprecycling methodology
employed by worldsteel, which is used to deal with scrap
inputs and outputs, and is recommended to be used for all
LCA studies containing steel.
The choice of recycling methodology can depend on not
only the goal and scope of the study but also the recycling
system for the material used in the product life cycle. In the
worldsteel methodology, the rationale for applying the closed
material loop method as default is that
1. Steel scrap has significant economic value, so scrap is
recovered, and it will be used for recycling. There is no
need to create a demand for recycled material as this is
already well established.
2. Steel is recycled in a closed material loop; the inherent
properties of the primary and secondary product are
equivalent, and thus, secondary material displaces prima-
ry production.
3. The magnitude of steel recycling is driven by end-of-life
recycling rates and an end-of-life approach captures the
impact of different recycling rates, regions and end-
product categories.
4. The demand for steel scrap exceeds the availability of the
scrap. This is magnified partly due to the long lifetime of
steel products. Designing products for easier end-of-life
disassembly and recycling will enable more steel scrap to
be recycled.
Using the closed material loop methodology, recovered
steel scrap for recycling is usually allocated a credit (or bene-
fit). When scrap is used in the manufacture of a new product,
there is an allocation (or debit) associated with the scrap input.
In this way, the benefit of net scrap arising or the debit of net
scrap input can be accounted. Based on guidance from ISO
14044:2006, this scrap is allocated a value associated with
avoided impacts such as an alternative source of equivalent
(virgin) ferrous metal.
In the case of steel, the best approximation for the virgin
product replaced by using scrap is the first recognisable steel
product, which is cast steel or steel slab. Secondary steel from
scrap (in the EAF route) avoids primary steel from the BOF
route. With this approach, the allocation for scrap needs to be
Fig. 3 Connection between
primary and secondary steel
production
Int J Life Cycle Assess (2016) 21:16581665 1661
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adjusted to take account of the scrap/steel yield associated
with secondary steel making.
The worldsteel methodology follows the end-of-life ap-
proach because it accounts for the full life cycle of a product,
from cradle to grave, the grave being the furnace into which
the steel scrap is recycled.
4 Worldsteel methodology for scrap recycling
The worldsteel methodology for the use of steel scrap in the
steelmaking process and the production of steel scrap at the
end-of-life of a product is described in detail in the following
sections.
4.1 Terminology required
A number of parameters relating to steel and recycling which
will be used in the following equations are as follows:
1. Recovery rate (RR): the fraction of steel recovered as
scrap during the lifetime of a steel product, including
scrap generated after manufacturing the steel product un-
der analysis. A value of 85 % has been used in Eq. 11.
2. Metallic yield (Y): the process yield (or efficiency) of the
EAF. It is the ratio of steel output to scrap input (i.e. >1-kg
scrap is required to produce 1-kg steel). This is calculated
using Eq. 4as 1.092 based on worldsteel data published in
2010.
3. LCI for BOF steel production (X
BOF
): the LCI for steel
production from the BOF, which includes scrap. The val-
ue used in Eq. 8of 1.756 kg CO
2
is from the worldsteel
data published in 2010.
4. LCI for primary steel production (X
pr
): the theoretical LCI
for 100 % primary metal production, from the BOF route,
assuming 0 % scrap input.
5. LCI for secondary steel production (X
re
): the LCI for
100 % secondary metal production from scrap in the
EAF, assuming scrap= 100 %. The value used in Eq. 8
of 0.386 kg CO
2
is from the worldsteel data published in
2010.
6. The letter X in each of these terms refers to any LCI
parameter, e.g. natural gas, CO
2
, water and limestone.
7. Sis the amount of scrap used in the steelmaking process to
make a specific product. The value of 0.121 kg used in
Eq. 11 for hot rolled coil is from the worldsteel data pub-
lished in 2010.
4.2 The LCI of steel scrap
The methodology assumes the burdens of scrap input and the
credits for recycling the steel at the end of the life of a product
are equal, per kilogram, and that all scrap is treated equally. In
reality, there are numerous grades of steel products, and there-
fore, steel scrap grades and a combination of these scrap types
are used when making steel. It has not been feasible to calcu-
late an LCI for each scrap grade, but this could be addressed in
the future. As the use of scrap replaces the production of crude
steel, and not a finished steel product, it is appropriate to
assume a generic scrap grade for the purpose of these calcu-
lations. For coated or galvanised scrap grades, this will result
in an overestimation of the burden for the scrap input (the
yieldwillbelower)sowillgivemoreconservativeresults.
Collecting scrap at the end of the products life and
recycling it through the steel making process enables the sav-
ing of primary, virgin steel production.
This is commonly referred to as the integrated or BOF steel
making route, but in reality, some steel scrap is always re-
quired in the process as it acts as a coolant in order to maintain
the thermal balance in the process. Thus, there is no process
using 100 % virgin material (with 0 % scrap input), and this
theoretical value therefore needs to be calculated (see Sect.
6.3).
Furthermore, it is not the scrap itself that replaces this pri-
mary steel, as the scrap needs to be processed or recycled to
make new steel. The EAF process is an example of 100 %
scrap recycling, though some EAFs also use hot metal or
direct reduced iron (DRI) as an input to the process.
Finally, the EAF process is not 100 % efficient, i.e. it needs
more than 1 kg of scrap to make 1-kg steel.
The LCI associated with the scrap, ScrapLCI, is thus
equal to the credit associated with the avoided primary
production of steel (assuming 0 % scrap input), minus
the burden associated with the recycling of steel scrap to
make new steel, multiplied by the yield of this process
(see Fig. 4) to consider losses in the process (see
Sect. 4.1 for definitions):
ScrapLCI ¼XprXre

Yð1Þ
The letter Xin each of these terms refers to any LCI param-
eter, e.g. natural gas, CO
2
and water. The CO
2
for scrap would
be calculated as follows:
CO2Scrap ¼CO2pr CO2re

Yð2Þ
1 kg scrap
Y kg steel produced
Fig. 4 The yield of the EAF process
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Yis the process yield of the EAF (i.e. >1-kg scrap is re-
quired to produce 1-kg steel)
The values for X
re
and Yare known by the industry as these
values come from the steel producers. However, the theoreti-
cal value of X
pr
needs to be calculated.
4.3 Theoretical value of 100 % primary BOF steel, X
pr
The theoretical value of 100 % primary steel is calculated
based on the LCI of steel slab made by the primary, or BOF
route. As the steel slab contains a certain amount of scrap, this
needs to be removedfrom the LCI so that only virgin steel is
accounted for, see Fig. 5a.
The scrap input to the BOF process (m kg scrap per 1-kg
steel produced) that needs to be removed would be melted in
the EAF process producing mY kg steel, Ybeing the yield of
the steelmaking process. Therefore, the theoretical 100 % pri-
mary route, X
pr
, needs to produce 1-mY kg steel, see Fig. 5b.
In effect,
XBO F ¼1mYðÞXpr

þmY X re ð3Þ
where mis the scrap input to the BOF route (Scrap
BOF
)andY
is the inverse of the scrap input to the EAF, Scrap
re
,i.e.
Y¼1
Scrapre
ð4Þ
Therefore,
mY ¼ScrapBO F
Scrapre
ð5Þ
This would then give the following:
XBO F ¼1
ScrapBO F
Scrapre

Xpr

þScrapBO F
Scrapre

Xre ð6Þ
Rearranging this equation will enable the theoretical value
for 100 % primary steel to be calculated:
Xpr ¼
XBO F
ScrapBO F
Scrapre
Xre

1
ScrapBO F
Scrapre
ð7Þ
This value for X
pr
can now be included in the scrap LCI
equation and will therefore be applied to each of the inputsand
outputs of the LCI. The values that have been used are based
on the current worldsteel LCI data collection.
Xpr ¼
1:756
0:119
1:092 0:386

1
0:119
1:092
Xpr ¼1:92 kg CO2
ð8Þ
It should be noted that if an extrapolation was carried out in
order to determine the theoretical value for X
pr
with zero scrap
input, based on the values of X
BOF
and X
re
, the same values
would be reached for X
pr
of 1.92 kg CO
2
.Figure6plots the
global EAF steel value which is based solely on steel scrap,
together with the global BOF steel value which contains near-
ly 12 % scrap. Extrapolating this to a value of zero scrap input
gives this value of 1.92 kg CO
2
.
+
=
1 kg steel produced 1 – mY kg steel produced
XBOF
mkg scrap input XprXre
mY kg steel produced
-
=
1 kg steel produced
1 – mY kg steel produced
XBOF
mkg scrap input
XprXre
mY kg steel produced
a
b
Fig. 5 a Determination of the
theoretical value of 100 %
primary BOF steel, X
pr
.b
Theoretical value of 100 %
primary BOF steel, X
pr
Int J Life Cycle Assess (2016) 21:16581665 1663
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And for CO
2
, the equation would be as follows (i.e.
X=CO
2
):
ScrapLCI ¼XprXre

Y
ScrapLCI ¼1:920:386½
1
1:092
Scrap LCI ¼1:405kg CO2
ð9Þ
4.4 Summary of scrap LCI calculations
The methodology for determining the LCI for steel scrap, as
described in Sects. 6.2 and 6.3, is summarised in Fig. 7.The
figure uses CO
2
as an example and includes the scrap inputs to
the EAF and BOF processes to calculate the LCI for each
production route when including a burden for the scrap. As
the impact if the two routes can be equated when the burden
for scrap has been included, this means that the scrap LCI can
then be calculated.
4.5 Applying the scrap LCI burden and credit
The scrap LCI, defined in Eq. (1)asScrapLCI =(X
pr
X
re
)Y,is
applied to the steel product cradle to gate LCIs in order to
include the end-of-life phase. A credit is given for the amount
of steel scrap that will be recycled at the end-of-life of the
product, and this is referred to as RR. However, in doing this,
a burden needs to be applied to any scrap that is used in the
steelmaking process, referred to as S.
Thus, the LCI of a product, from cradle to gate including
end-of-life (LCI
including EoL
), can be calculated as
LCI includ ingE oL ¼XRRSðÞXprXre

Yð10Þ
0
0.5
1
1.5
0 0.5 1 1.5 2
CO2 emissions, kg
Scrap input kg
Glo ba l EAF s teel (Scra pre)
Extrapolation for 0% scrap input
Global B OF ste el
(Scra pBOF)
0
0.5
1
1.5
0 0.5 1 1.5 2
CO2 emissions, kg
Scrap input kg
Glo ba l EAF s teel (Scra pre)
Extrapolation for 0% scrap input
Global B OF ste el
(Scra pBOF)
Fig. 6 Extrapolation to show
CO
2
emissions for 0 % scrap
input
EAF BOF
Y kg scrap
Scrap:
ScrapBOF kg
Iron ore
Steel Slab
1.092kg 0.119kg
Measured
Measured
0.386kg 1.756kg
Measured Measured
Xre XBOF
balsgk1balsgk1
LCIre = Xre + Y*Scrap LCI
= 0.386 + 1. 092*Scrap LCI
LCIBOF = X BOF + ScrapBOF*Scrap LCI
= 1.756 + 0.119*Scrap LCI
Here, LCIre = LCIBOF
0.386 + 1.092*Scrap LCI = 1.756 + 0. 119*Scrap LCI
Scrap LCI = 1.41kg CO2
a
Fig. 7 Overview of scrap LCI
calculations
1664 Int J Life Cycle Assess (2016) 21:16581665
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where Xis the LCIof the product being studied and is cradle to
gate, i.e. including all upstream as well as steel production.
The term (RR S) is also known as the net scrap that is gen-
erated from the product system. When this value is negative
that implies that there is more scrap consumed to make the
steel than is recycled from the product at the end-of-life.
In order to calculate the LCI of a steel product, including
end-of-life recycling, an example for CO
2
emissions is shown
in Fig. 8and Eq. (11), for global hot rolled coil, using an end-
of-life recycling rate of 85 %. This gives a net scrap value of
0.85 0.121 = 0.729 kg.
The value of scrap, (X
pr
X
re
)Y, has been calculated above,
and the CO
2
emissions and scrap content of hot rolled coil are
provided from the global average data published in February
2010. New data will be available at the end of 2015.
LCI includingE oL ¼1:8890:850:121ðÞ*1:405
LCI includingE oL ¼0:86kgCO2ð11Þ
CO
2
is used in this example as it is one of the most com-
monly used LCI flows. The same calculation method applies
to all inputs and outputs of the LCI.
5Conclusions
The steel industry is an integral part of the circular economy
model, and steel has fundamental advantages as a material in
achieving this goal. The promotion of zero waste, reducing the
amount of resources and energy used, making products that
are easier to reuse or remanufacture, and finally being able to
recycle steel from all parts of a products life make steel an
essential material for the future. The methodology described
here addresses the recycling aspect of the circular economy as
well as the zero waste aspect. By demonstrating the benefits of
recycling steel, it is evident that this practise should be encour-
aged and enabled through improved design of products, so
that once they have been reused or remanufactured, the steel
parts can easily enter into the recycling stream, reducing the
need for primary raw materials.
However, due to the long life of steel products, the amount
of steel in stock is a limiting factor in terms of what is available
for recycling. Therefore, it is necessary to continue with pri-
mary steel production in order to meet the demands for steel.
In addition, as more scrap is being used, attention must be paid
to the proper sorting of the scrap to ensure that the higher
quality steel grades can be achieved.
The steel industry is currently looking into product-related
indicators, and this can incorporate indicators that address the
circularity of steel in product applications. An indicator
reflecting the benefits of recycling steel at the end of its life
would show the contribution of using recyclable materials to
achieve a circular economy.
There is scope for the steel industry to engage with its
customers to improve the yield during the manufacturing pro-
cesses as well as to design products which are easier to reuse,
remanufacture and recycle. Scrap collection facilities should
be improved to continue to increase the amount of scrap that is
being recovered. Ongoing efforts to improve the environmen-
tal performance of steel production are also the key. This will
all contribute to the goal of achieving a circular economy.
Open Access This article is distributed under the terms of the Creative
Commons Attribution 4.0 International License (http://
creativecommons.org/licenses/by/4.0/), which permits unrestricted use,
distribution, and reproduction in any medium, provided you give appro-
priate credit to the original author(s) and the source, provide a link to the
Creative Commons license, and indicate if changes were made.
References
Atherton J et al (2007) Declaration by the metals industry on recycling
principles. Int J Life Cycle Assess 12(1):5960
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Steel scrap from system for recycling = 0.85 kg
1kg Hot Rolled Coil
Iron ore 0.121 kg scrap
Steel producon
Product manufacture,
use, maintenance and
final disposal
Fig. 8 Example cradle to grave system
Int J Life Cycle Assess (2016) 21:16581665 1665
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PAS 2050”Specification for the measurement of the embodied greenhouse gas emissions of products and services” on Carbon footprinting. And: BSI British Standards (with DEFRA and Carbon Trust Guide to PAS 2050 - How to assess the carbon footprint of goods and services
  • Standards Bsi British
  • Institute