kalkverk

Kalkverk, or lime works, are facilities where limestone is transformed into lime through calcination. The term covers the kilns, ovens, and associated processing equipment used to produce quicklime and, in many cases, hydrated lime for construction, agriculture, and industry.

The basic process begins with mining and crushing limestone. The material is fed into a kiln, where fuel provides the heat. At temperatures around 900–1000°C, calcium carbonate decomposes into quicklime (CaO) and carbon dioxide. The produced lime can be removed from the kiln and used directly as quicklime or combined with water to form hydrated lime (Ca(OH)2). Some lime works also produce lime putty or hydraulic lime by adding pozzolanic materials.

There are several kiln designs. Traditional beehive or mound kilns are small, intermittent units typical of centuries past. Shaft kilns and modern rotary kilns allow continuous operation and greater output. Regenerative and other energy-efficient designs reduce fuel use and emissions. In many countries, beehive kilns are preserved as historical monuments.

Lime production has a long history. Quicklime was essential in medieval and early modern construction for mortars and plasters, while agricultural lime improves soil pH. In Sweden and other Nordic countries, many old kalkverk were established along quarries and waterways; many have become industrial heritage sites, museums, or tourist attractions.

Environmental considerations include CO2 emissions and dust. Modern plants use emission controls, dust collection, and energy-efficient burners. Today, lime is still produced commercially in many regions, with applications in construction, farming, water treatment, and chemical industries.