1. Introduction - Firenze University Press

penalty, but without separate capture and long transport distances the energy use should at least be
comparable to the capture step of CCGS, of the order of 2-5 GJ/ton CO2 (mainly heat).
In recent years, research into CO2 mineralisation has taken a giant leap forward as demonstrated by
the rate at which new process routes are suggested, patented and in several promising cases
developed to large-scale application [20]. Many of these processes do not require pure CO2, but can
be run with flue gases directly, such as the process routes suggested by Nottingham University [21],
Hunwick [22] and also the ÅA route, to be described below in more detail.
Fig 1. The location of the Meri-Pori power plant, indicated as , and ultramafic rock in Finland.
Also shown a photo of the nickel mine at Hitura and its location, and ultramafic rock findings in
southern Finland at Vammala and Suomusjärvi (circled).
3. Mineralisation of CO2
3.1 - General
Carbon dioxide mineralisation is the general term describing the sequestration of CO2 by reacting it
with Mg- or Ca-containing compounds, to produce stable carbonates. Magnesium in particular is
abundant in the earth’s crust, as silicates such as serpentinite and olivine. Calcium also has a
potential to store significant amounts of CO2, although calcium silicates are not as abundant as
magnesium silicates. In general, the exothermic reaction between magnesium or calcium silicates
and CO2 can be described by reaction 1.
(Mg,Ca)xSiyOx+2y+zH2z(s) + xCO2(g) x(Mg,Ca)CO3(s) + ySiO2(s) + zH2O(l/g) (1)
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