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Glossary
Aggregate: material used in construction, including
sand, gravel and crushed stone.
Alternative fuels: products from full or partial
biogenic origin or from fossil fuel origin and not
classified as traditional fossil fuels, which are used as
a source of thermal energy.
Biomass: any organic (i.e. decomposing) matter
derived from plants or animals available on a
renewable basis, including wood and agricultural
crops, herbaceous and wood energy crops,
municipal organic wastes and manure.
Blended cement: Portland cement (PC) mixed with
other constituents as well as clinker.
Cement: a building material made by grinding
clinker together with various mineral components
such as gypsum, limestone, blast furnace slag, coal
fly ash and natural volcanic material. Cement acts
as a binding agent when mixed with sand, gravel or
crushed stone and water to make concrete. Although
cement qualities are defined by national standards,
there is no worldwide, harmonised definition or
standard for cement. In the World Business Council
for Sustainable Development (WBCSD) Cement
Sustainability Initiative (CSI) protocol and the
Getting the Numbers Right database, “cement”
includes all hydraulic binders that are delivered to
the final customer. That is, it includes all types of
PC, composite and blended cements, and ground
granulated slag and fly ash delivered to the concrete
mixers, but excludes clinker.
Cementitious product: total of all cements and
clinker produced by a cement company, excluding
the clinker purchased from another company and
used to make cement. The precise definition of
cementitious product in this context is according
to the WBCSD-CSI cement protocol (CSI, 2011).
Cement is the cementitious product when the net
balance of clinker sold and purchased is zero.
Clinker: an intermediate product in cement
manufacturing and the main substance in cement.
It is the result of calcination of limestone in the kiln
and subsequent reactions caused through burning.
Clinker to cement ratio: total clinker consumed
divided by the total amount of cement produced.
Comminution: a process in which solid materials are
reduced in size, by natural or industrial processes
including crushing and grinding, or a process in
which useful materials are freed from embedded
matrix materials. It is used to increase the surface
area of solids in industrial processes.
Concrete: material comprising cement, sand and
gravel or other fine and coarse aggregate.
Co-processing: the use of waste materials in
industrial processes (e.g. cement) as substitutes for
fossil fuels or raw materials.
Direct carbon dioxide (CO
2
) emissions: CO
2
emissions that are generated and released in the
cement production process.
Dry kiln: equipment that produces clinker without
using a water/limestone slurry mix as the feedstock.
Electricity intensity of cement: consumption
of electricity in cement production, including
electricity use in the production of the consumed
clinker in the kiln, divided by the cement and
substitute production.
Fly ash: exhaust-borne particulates generated and
captured at coal-fired power plants.
Gross direct CO
2
emissions: total direct CO
2
emissions from the cement production process
including CO
2
related to the combustion of wastes
based on fossil fuels but excluding those from
biogenic wastes (CSI, 2011).
Oxy-fuel: the combustion of fuels with oxygen
instead of air.
Petroleum coke: a carbon-based solid derived from
oil refineries.
Portland cement (PC): the most-common type of
cement, consisting of over 90% clinker and about
5% gypsum.
Pozzolana: a material that exhibits cementitious
properties when combined with calcium hydroxide.
Precalciner: a system that comes before the rotary
kiln in the cement manufacturing process where
most of the limestone calcination is accomplished,
thus making the process more energy efficient.
Process CO
2
emissions: CO
2
generated as a result of
chemical reactions from carbon contained in raw
materials.
Recarbonation: the chemical reaction in a natural
process by which carbon dioxide in
the ambient air
penetrates and reacts with hydration products.
Thermal energy intensity of clinker: total heat
consumption of kilns divided by the clinker
production.
Traditional fuels: fossil fuels defined by the guidelines
of the Intergovernmental Panel on Climate Change,
including mainly coal, petroleum coke, lignite, shale
petroleum products and natural gas.
Wet kiln: equipment that produces clinker using
water/limestone slurry as the feedstock.
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