Limestone Powder

A product of any coal fired combustion process is acidic gas. The common acidic gases are hydrogen chloride (HCl), nitrogen dioxide (NO₂), and sulphur dioxide (SO₂). If these acidic gases emitted to the atmosphere, they will damage the human respiratory system and cause harmful acid rain formation.

In order to deal with this pollution threat, flue gas desulphurization units (FGD) are installed in some power generation units to effectively remove this acidic gas. Green Island, using its expertise in mineral grinding, prepares a high quality limestone powder (CaCO₃) for the power plant to use when it cleans up its flue gas.

The SO₂ is converted into a sulphate salt called gypsum (CaSO₄) by a neutralization reaction with limestone. FGD Gypsum is a solid waste from power plants and which would otherwise be disposed to landfill and become the burden to the environment.

Green Island conducted extensive research on this by-product FGD gypsum and by upgrading its facility; GIC recycles this FGD gypsum as a cement production additive to replace natural gypsum (which is used to control the hydration rate of cement).