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aluminium may allow production of high quality scrap based aluminium, be it with probably higher specific
emissions than those of current secondary production.
Conclusions
The results clearly indicate that, even with high emission factors for electricity, the factor 2 and even the factor
10 emission reductions are readily attainable in the steel sector, when CO2 removal is applied. In this case,
changes in the ratio between primary and scrap based production are not necessary; in some scenarios, some
primary production routes have even lower emissions than scrap based production routes. It is also important to
note that for the realisation of the factor 10 emission reduction, it is not necessary to call for processes that are
still in an experimental stage.
The reduction potential of primary aluminium production lags somewhat behind, but with a low emission factor
for electricity, a factor 8 reduction is possible, by a shift to the new bipolar electrode process. A moderate
increase of recycling would further decrease the emissions of aluminium production. If this would not be possible,
extra reductions in the steel sector could compensate.
The influence of external factors, especially that of the possibilities for CO2 removal, is strong, not only on the
total emissions reduction potential, but also on the choice of the production route. The choice for the best production
route requires extensive knowledge of the developments outside the base metal sector.
Because of this sensitivity of the results for developments outside the sector, and the fact that CO2 removal is
imperative for attainment of the factor 10 reduction in primary steel, it is advisable to investigate the possibilities
for increasing scrap based production. If a shift to secondary production is possible, the reduction potentials
for steel, and especially aluminium, further increase.
Two developments, mainly driven by forces outside the (primary and secondary) metal sector may further influence
the sector thoroughly, namely dematerialisation and the implementation of integral cycle management.
Both trends may substantially decrease the demand for primary produced (ferrous) materials and may also decrease
the related CO2 emissions.
Dematerialisation consists out of several phenomena, such as miniaturisation, substitution by light-weight materials,
resulting in a net decrease of the material intensity of the Gross Domestic Product. Especially the ferrous
metals production sector has already been affected by the dematerialisation trend. Therefore, the growth
rates in this sector have been lower than the GDP growth rates. A high dematerialisation trend in the future
may even stop the growth in the ferrous metals production sector, while it may favour the aluminium and plastic
production sectors.
Integral cycle management aims at the closing of material cycles in the society and the prevention of material
losses. This strategy consists out of society measures to increase the quality of materials derived from post consumption
waste and industry measures to increase the content of secondary materials in the production sectors.
Examples are design-to-dismantle and design-for-recycle practices in industry, standardisation of materials for
specific applications, separate collection and treatment of usable products, parts and other material streams. A
systematic approach can result in an optimal material cascade that saves more than 50% of the primary inputs
and decreases the energy requirements for materials with a similar percentage without compromising the quality
of materials and products [19].
List of abbreviations
ACEAF Alternating Current Electric Arc Furnace
BF150 air Blast Furnace, 150 kg/tonne coal injection
BF250 oxygen Blast Furnace, 250 kg/tonne coal injection
BOF Basic Oxygen Furnace
CCF Cyclone Converter Furnace
Cir Circofer