Zinc Sheet Environmental Profile - Life Cycle Assessment

Cradle-to-Gate System
Figure 2: Schematic illustration of the
boundaries of the gate‐to‐gate and the
cradle‐to‐gate systems of zinc sheet
production
Gate-to-Gate System
Upstream
Supplies
Zinc Sheet Production
at Site
Input/Output Balance of the
Production Site
For zinc sheet production processes, IZA collected primary
data from sites of its member companies using electronic
questionnaires. Secondary data about background processes
outside the operational control of IZA members (e.g. fuel and
electricity, auxiliary materials, transportation) were obtained
from the GaBi 4 life cycle database, literature and other industry
expertise. The LCI dataset came from five sites collectively
producing 255,000 tonnes per year of zinc sheet - representing
more than 50% of global zinc sheet production in 2006.
Study results
Table 1 shows selected results for the production of zinc sheet on
the basis of one 1m 2 zinc sheet/sheet thickness (0.7mm assumed)
produced. These results are based on averaged data.
The analysis of the zinc sheet production process undertaken for
the LCI study shows that the resulting environmental burden is
dominated by energy use during zinc sheet production at the
sites. (Note: This statement refers only to the direct process inputs
to produce the sheets.) This is also true for the LCI’s of most other
metals. The energy source/composition of the electricity grid mix
can significantly influence the associated environmental burdens.
To improve the related environmental burden, increased energy
efficiencies should be looked for where possible. A reduction in
the scrap rate at the different process steps, particularly during
rolling and slitting, would also help to reduce the environmental
effects by minimizing the gross amount of zinc alloy material
needed to produce a kilogram of zinc sheet.
Readers are encouraged to access the LCI results this profile
is based on to support studies analyzing the environmental
burdens of zinc sheet applications.
It is important to understand that the data set presented here
represents averaged information on the industrial process of zinc
sheet application.
Selected LCI Parameters of Zinc Sheet Inventory Results per m 2 Unit
Primary energy demand 266.5 MJ
Non-renewable energy resources 229.1 MJ
Renewable energy resources 37.6 MJ
Carbon dioxide 16.02 kg
Sulphur dioxide 0.05 kg
Selected LCIA Parameters Based on Impact Inventory Results per m 2 Unit
Methodology CML 2001
of Zinc Sheet
Global Warming Potential (GWP 100 years) 16.47 kg CO 2 Equiv.
Acidification Potential (AP) 0.12 kg SO 2 -Equiv.
Eutrophication Potential (EP) [kg Phosphate-Equiv.] 1.196E-02 kg Phosphate-Equiv.
Photochem. Ozone Creation Potential (POCP) 6.311E-03 kg Ethane-Equiv.
Ozone Layer Depletion Potential (ODP, steady state) 1.817E-06 kg R11-Equiv.
Table 1: Selected LCI parameters representing 1m 2 of zinc sheet production including the environmental burden of the consumed special high grade zinc
6 Zinc Sheet Environmental Profile
Life Cycle Assessment