Cement Production | Lime
Production | Iron and Steel
Carbon dioxide emissions arising from industrial processes are
substantial. If we ignore the carbon dioxide emissions associated
with industrial energy use, processes such as cement and lime production
have an additional carbon dioxide emission inherent to them.
The future trading of carbon credits and the likely increasing
financial cost of greenhouse gas emissions to individual companies
should help promote substantial cuts in incidental carbon dioxide
emissions from industry through improved efficiency and greenhouse
Carbon dioxide is produced in cement making as a result of the
production of a process ingredient called 'Clinker'. Clinker is
made when limestone is heated so as to produce lime, but substantial
amounts of carbon dioxide are also formed during this reaction.
The final amount of carbon dioxide produced varies depending the
type of cement being made. Globally, this source of carbon dioxide
is estimated to amount to 100 million tonnes of carbon emission
to the atmosphere each year.
Like cement production, the industrial lime production results
in carbon dioxide emission when limestone is heated up. As well
as straightforward 'quicklime' production, a second type of lime
called 'dolomitic' quick lime is also produced using a mixture of
limestone and magnesium carbonate. Quicklime production is thought
to result in about 800kg of carbon dioxide per tonne, while dolomitic
quicklime produces slightly more at about 900kg per tonne.
Iron and Steel
Much of the carbon dioxide arising from iron production comes directly
from the burning of coke or charcoal as fuel and reductant for the
blast furnace. Yet more carbon dioxide is produced when limestone
is added to the furnace to act as a flux. Steel production essentially
involves the reduction of the amount of carbon in the iron and this
refining process again produces some carbon dioxide.