Flue Gas Purification
Lime is essential to lowering emission values when purifying flue gases. Quicklime and lime products are used to bind gases from combustion processes – such as sulphur dioxide, hydrogen chloride and hydrogen and make them suitable for recycling. Special lime mixtures can absorb mercury and dioxins / furans. Every year, millions of tonnes of lime products are used just for these applications, mainly for flue gas desulphurisation in power plants, waste incineration plants and industrial plants.
Drinking water is almost always purified with lime before it flows from our taps.The addition of lime binds corrosive carbonic acid and, depending on its original hardness, makes the water harder or softer in order to prevent the formation of boiler scale and corrosion in the piping. Lime is also responsible for adjusting the pH value. Last but not least, lime is used to remove naturally occurring heavy metals from our drinking water.
Process Water Treatment
Milk of lime is also used for the purification of industrial water that returns to the water circulation, such as process water for power plants, paper mill and steel plants.
Neutralisation of effluent in sewage treatment plants
Lime neutralises the effluent in sewage plant by adjusting the acid capacity and pH value to stabilise the biological sewage treatment process. Process water from industry can be purified with lime or milk of lime and returned to the water circulation. The quality of rivers and lakes as a habitat for micro-organisms can also be improved with a lime-based buffer against acids and alkalis.
Remediation of contaminated sites
The remediation of contaminated sites is a special application of lime. Lime products can be used to neutralise acids, bind heavy metals and support the degradation of pollutants.
Treatment of effluent and sludge
Milk of lime neutralises acid effluent and removes heavy metals in treatment plants for industrial effluent so the process water can be returned to the water circulation. Users include a whole variety of industries, such as the silicic acid and silicone industry, as well as producers of printed circuit boards.
In hundreds of municipal sewage treatment plants, lime not only serves to dewater and minimise the volume of sludge produced. Through its hygienic action, it also produces a valuable and safe fertiliser of secondary raw material.
Biological sewage treatment processes can be stabilised and efficiently controlled by creating an adequate acid capacity or loading the activated sludge with hydrated high-calcium lime. At the same time, the quality of rivers and lakes as a habitat for micro-organisms is improved with a lime-based buffer against acids and alkalis.