Industrial History of lime
A raw material with a long history
Nobody exactly knows when humans first discovered lime. We could well imagine that our ancestors used limestone rock to protect their fire place. The fire heated the rock and created by chance the first burnt lime. It may have started to rain, slaking the lime into Calcium hydroxide which reacts with the ashes and sand around the fire place. This could well have been the birth of the first ancient mortar. At some point someone must have recognised the context of limestone-fire-water and mortar. Lime foundations in eastern Turkey show that these skills have been applied since 14,000 years.
About 3000 years BC, the Egyptians built one of the limestone wonders of the world - the 137-meter high Cheops pyramid, consisting of about two million huge limestone blocks. At the same time, the first "professional" limekilns for the production of lime mortar get into operation in the land of Mesopotamia.
Lime is discovered as a soil stabiliser.
When the Chinese built their 2500 kilometres long wall to protect themselves against the barbarians, they stabilised the soil with lime. How could it otherwise bear the weight of this 16 meters high miracle work?
The Great Wall was built using various techniques, such as compacted clay, but also bricks with lime mortars. Whereas the clay parts weathered over time, the lime mortar that keeps the stones together stays almost undamaged today.
At several places in the Bible lime mortar and whitewash are described, which is a sign for the overall reputation of lime applications in those days.
The Egyptians tanned their skin with lime. Assyrians used it for glass production and glass colouring. Greeks and Romans used lime colours to create their splendid frescos. The Celts fertilised their fields regularly with lime. Even as a medicine lime was already known in antiquity.
- A large part of the over 500-miles “Via Appia” still exists in its original limestone paving.
The Roman Plinius mentions lime as one of the natural resources in a scientific work of 37 volumes, "Lard of the earth." During this time the women started a new fashion trend: they coloured their hair light red with unslaked lime.
The Romans introduced lime as a construction material. They developed the technology for burning lime to a standard that almost reached an industrial level. This technique has been spread throughout the Roman Empire - Roman type limekilns have been excavated in many regions.
Although the use of lime was already known before the Romans, the systematic and targeted use as building materials was introduced by these big builders. Thanks to professional Lime burners, the magister calcariarum, many soft lime stones containing names and portraits from Roman times survived.
- Old signs alchemists for lime
- Logo of the National Association of Dt. Lime
After the era of the Romans the migration period caused instability and changes everywhere. Much knowledge of the Greek and Romans sank into oblivion or were not tolerated in respect of the starting Christianisation. Despite of the progress of the sciences, there was hardly any technical innovation in the field of lime burning or in the extraction of raw materials.
Contrary to the Roman times, where lime was introduced as an important construction material, the farmers had become the main lime producers in this period. They used simple soil kilns. The monasteries had a large demand and often operated their own lime kilns or leased them together with the quarries.
With the introduction of black (gun) powder in the 15th century the quarrying technique changed. Wood in the form of faggots was used as fuel. Only later fuels such as charcoal, peat, lignite, pit coal and hard coal coke followed.
The development of the non-stopcontinous burning ovens took place at the end of the 18th and beginning of the 19th century and was initiated by the attempt to save fuel and to reduce energy losses.
During the industrial revolution a building boom of lime kilns started, as new industrial sectors needed more lime. This was the start of the present European lime industry.