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Hungarian Cement Concrete and Lime Association
Magyar Cement-, Beton- és Mészipari Szövetség

Lime

Construction and building material industry 
The role of limestone and lime in our everyday life

 

Different applications of lime:

reclamation, remediation, flue cleaning, water treatment, slag production, ore processing, pH neutralization, soil melioration, disinfection, soil stabilization, caustification

  • Applications:
  • Construction and building material industry
  • Steel industry
  • Aluminium industry
  • Paper industry
  • Chemical industry
  • Food industry
  • Environmental protection
  • Agriculture

 

Construction and building material industry
“A thousands of years of technology”

  • The hardening features of lime has been harnessed by man in order to create constructed environment since ancient times. An example that is familiar to everybody is the building of the pyramids, where the few millimetres of mortar between the 2-3 ton stone cubes were made of an exclusive mixture of lime and fine grain sand that – as we all know – still stands the test of time. Not until the Middle Ages were buildings of such heights erected again, and lime mortar was used again during the construction of medieval cathedrals to help them endure large weights over the centuries.
  • Today we use lime mainly in masonry and plastering, and during the production of sand lime bricks and other lime-based (Ytong) components.  It is also applicable during the construction of roads and other industrial facilities in order to stabilize the subsoil and improve the quality of asphalt.

 

Steel industry

  • Lime is used in several phases of steel production. First during ore processing as binder, then it is used to desulphurise, clean and adjust the pH of crude iron. (slag production)

 

Aluminium industry

  • Lime is an important agent during alum earth production. It is used mainly for the recovery of caustic soda, which is essential for the technology.

 

Paper industry

  • During the production of cellulose it fulfils a similar role to the one in alum earth production.
  • It determines the whiteness of paper and other characteristics during PPC production.

 

Chemical industry

  • The basic substance of paints and fillers.

 

Food industry

  • During sugar production it is used to clean contaminated sugar solution and to filter precipitated sludge.

 

Environmental production

  • Lime is used in every industry for different tasks related to environmental protection.
  • To decrease the concentration of harmful material emission (flue cleaning).
  • To soften, clean and adjust pH during water management.
  • To neutralize and disinfect contaminated areas during different reclamation and remediation works.


Agriculture

  • It is used to adjust the pH of acidic soils and also to improve soil structure.
  • It is effective for disinfection and fungus removal at fishponds, livestock farms, orchards and forestry sites.

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The role of limestone and lime in our everyday life

Calcium carbonate, or by its ordinary name, Limestone, is a well-known mineral. Its derivative, CaO (calcium oxide), cannot be found in nature.  Only few people know, however, how important is their role in several segments of life and what economic value they possess. Limestone and quicklime is utilized during the metallurgy of steel and non-ferrous metals and the production of concrete, mortar, bricks and asphalt. As a component, it plays an important role in glass, paint, carpet and paper manufacture. It also contributes to the stabilization of the soil during construction works or road building. Lime is also used in environmental protection during flue cleaning, wastewater treatment or the neutralization of solid or acidic refuse. Its widespread utilization also includes sugar manufacture, the treatment of acidic soils and several other fields of industry and agriculture.

A part of the mined stone, which is considered suitable based on its chemical characteristics and structure, is calcinated on 1000 degrees Celcius in different furnace types. Lime burning furnaces use a wide variety of fuels, such as natural gas, coal, oil, lignite and secondary fuels. The reaction is

CaCO3 + heat => CaO + CO2, and the output of this reaction is quicklime: CaO

The generated lumpy burnt lime, CaO, is classified based on customer demand, then subsequently grounded and stored.

One of the most popular transformation methods of quicklime is its combination with water, or hydration.

Depending on the amount of added water hydrated lime (Ca(OH)2) is generated in fine dust form (lime hydrate), slaked lime (lime plaster), or lime milk in different concentrations, which is completely liquid. The reaction is

CaO + H2O => Ca(OH)2 + heat.

If we add CO2 to the lime milk, we get limestone (CaCO3) again, however, its crystalline structure will differ significantly from the limestone found in nature. We call this product PPC. The reaction: CO2 + Ca(OH)2 => CaCO3 + H2O

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