4. Interaction with other sectors

Cement production may touch on other project areas, particularly where additional raw material components are used. For example, use is made of materials produced in lime works with inadequate lime content, other waste materials such as crystallised calcium carbonate from the chemical industry or ferrous residues from sulphuric acid production. Up to 5% gypsum per tonne of cement is required to control the rate of setting in the cement, and a major proportion of this gypsum requirement is now met in Europe by gypsum from flue gas desulphurisation plants. Up to 85% of fly ashes from power station dedusters and slags can also be added to the clinker to produce cement varieties with special properties.

Because of the high temperatures and comparatively long holding times of the materials in the relevant areas, cement kilns in particular are ideal for disposing of combustible waste. This possibility is increasingly important in countries where large quantities of vegetable waste with high potential energy, such as rice chaff, are produced in the region.

In the cement, lime and gypsum industry, secondary activities such as quarries, fuel stores, workshops etc. also exert environmental impact.

Table 2 - Environmental impacts of adjacent project areas - cement, lime and gypsum