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Limestone, metamorphosed by heat and pressure produces marble, which has been used for many statues, buildings and stone tabletops. [104] On the island of Malta , a variety of limestone called Globigerina limestone was, for a long time, the only building material available, and is still very frequently used on all types of buildings and sculptures.
The early use of simple rotary kilns had the advantages that a much wider range of limestone size could be used, from fines upwards, and undesirable elements such as sulfur can be removed. On the other hand, fuel consumption was relatively high because of poor heat exchange compared with shaft kilns, leading to excessive heat loss in exhaust gases.
Artificial hydraulic lime is made by adding forms of silica or alumina such as clay to the limestone during firing, or by adding a pozzolana to pure lime. [13] Hydraulic limes are classified by their strength: feebly, moderately and eminently hydraulic lime. Feebly hydraulic lime contains 5-10% clay, slakes in minutes, and sets in about three ...
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Calcination is thermal treatment of a solid chemical compound (e.g. mixed carbonate ores) whereby the compound is raised to high temperature without melting under restricted supply of ambient oxygen (i.e. gaseous O 2 fraction of air), generally for the purpose of removing impurities or volatile substances and/or to incur thermal decomposition.
(Limestone ties up [further explanation needed] sulphur. Manganese may also be added to tie up [ clarification needed ] sulphur.) [ 54 ] : 123–125 [ 55 ] [ 56 ] [ 47 ] : 122–123 Coke iron was initially only used for foundry work, making pots and other cast iron goods.
Limestone-plastered wall discovered in Pompei. Lime plaster is a type of plaster composed of sand, water, and lime, usually non-hydraulic hydrated lime (also known as slaked lime, high calcium lime or air lime). Ancient lime plaster often contained horse hair for reinforcement and pozzolan additives to reduce the working time.
These kilns were built up the side of a slope, such that a fire could be lit at the bottom and the heat would rise up into the kiln. Traditional kilns include: Dragon kiln of south China: thin and long, climbing up a hillside. This type spread to the rest of East Asia giving the Japanese anagama kiln, arriving via Korea in the 5th century. This ...