The principal areas of application in environmental protection are the purification of exhaust gases and wastewater. For example, lime is used to bind sulphur oxide emissions.
Using lime in flue gas purification
Lime is used in a number of different processes to purify wastewater or flue gases. Depending on the process (dry/semi-dry/wet) and the plant requirements, either powdered hydrated lime, quicklime or limestone are used in flue-gas desulphurisation (FGD) plants to keep hazardous emission components such as SO2 (sulphur dioxide), HCL (hydrochloric acid) and HF (hydrogen fluoride) to a minimum.
FGD gypsum, a by-product of the purification process, is used in other areas such as the cement and building materials industries. This helps to conserve natural resources. Contaminants are bound, and the air is kept clean.
Using lime in wastewater purification
Lime helps us protect the environment. It is used to treat industrial residues such as wastewater and exhaust gases. Lime neutralises the wastewater in sewage treatment plants. Acidic wastewater containing hydrochloric acid, sulphuric acid or hydrofluoric acid, for example, is neutralised with milk of lime and can be fed back into the water cycle after cleaning.