Limepit

A limepit is either a place where

quicklime (calcium oxide, CaO) is produced, an essential component in waterproofing and in wall plastering

Primitive limepits

The production of lime in the

Lachish area, several lime kilns were excavated by a team on behalf of the IAA, and which kilns were partially hewn in the bedrock and partially built of fieldstones, and last used at some point between the mid-15th century and the mid-17th century CE.^[6]

In Bedouin-Arab culture in Palestine, the limepit was dug to a depth of about 2.5 metres (8.2 ft) and about 3 metres (9.8 ft) in diameter. By all appearances, the pit was made after the same basic principle used in a "

shaft kiln. After cooling, wood ashes that had accumulated were then separated from the burnt blocks of limestone. The limestone blocks were then crushed, afterwards slaked (the process of adding water and constantly turning the lime to create a chemical reaction, whereby the burnt lime, or what is known also as calcium oxide,^[7] is changed into calcium hydroxide), and mixed with an aggregate

to form an adhesive paste (plaster) used in construction and for daubing buildings.

When properly burnt, limestone loses its

depilatory

.

Basic design

Many limepits were sunken in the ground at a depth of between 2.5 and 5 meters and 3 to 4.5 meters in diameter, in a circular fashion, and some were built with a

Bedouins in the Negev

, during the late 19th and early 20th-century:

Lime is derived from chalk [sic] by burning. The Bedouins used it in plastering their cisterns. Burning chalk stone was performed in simple kilns in close proximity to where the chalk was found. Lime kilns were made by digging a round hole, three metres wide, two and a half metres deep. After the hole was dug, the chalk and fuel for a fire would be brought to it. Stones of chalk (limestone) would be arranged in a circular dome in the pit. The burning process would last three to six days, without letup. After the burning was finished, the kiln would be left to cool for four to six days. The lime would then be taken out. The large lime blocks along the edge of the pit were considered of the highest quality, while the small pieces towards the center of the pit were considered grade B. One camel load, or cantur (qentar / quntar = 100 ratels, or 250-300 kilograms), of lime would fetch 40 grush on the Jerusalem market in the early 1880s.^[11]

In

Ottoman period, throughout the Levant.^[5] Modern kilns for burning lime first appeared in Palestine during the British Mandate.^[11]

Chemical changes

The lime stones selected were those that had the least amount of impurities within them. Limepits were almost always built near the supply of limestone, and a sufficient pile of wood kindling was heaped in great store before the actual burning process began, a supply that was to last between 3 and 7 days of continual burning, both, by night and day. In the southern Mediterranean regions, one of the favorite wood sources was thorny burnet (

Sarcopoterium spinosum).^[13]^[14] The fire was attended by men with long staves and pitchforks who pushed the burning material into the pit. Initially, a cloud of smoke billowed from the pit. After several days of burning, when the uppermost stone in the fire pit began to glow a fiery red, it signaled that the burning process of the lime was finished, and that the process of carbon dioxide emissions from the limestone has been completed, and that the lime was now ready for marketing as lime or powder.^[13] After being allowed to cool, the burnt limestone was extracted from the pit when it was light and brittle. During the burning process, the limestone loses about 50% of its original anatomical weight.^[13]

The lime becomes ready for use only after water has been added.

Gallery

Limepit in the Jewish National Fund Forest, near Nes Harim
Ancient limepit in Jerusalem
Lime kiln in Judaea, in the Angels Forest, Shahariyya, near Kiryat Gat
Lime pit in Judaea, the Angels Forest

References

^ Mizrachi, Yonatan (2008): Photo - p. 3
^ Zilberbod, Irina (2006): Photo - p. 3; English - Final Report; Image
^ Be'eri, Ron (2012): Photo - p. 12; English - Final Report; Image
^ Eliyahu-Behar, A., et al. (2017), p. 15
^ ^a ^b Eliyahu-Behar, A., et al. (2017), p. 28
^ Fraiberg, Alexander (2013): Photo - p. 7
^ Slaking is a strongly exothermic reaction in which quicklime absorbs hydrogen and oxygen from water to produce lime — a fine-grained white powder (Eliyahu-Behar, A., et al. 2017).
^ ^a ^b Young, Clyde; Engel, Bernard (1943), p. 250
^ Eliyahu-Behar, A., et al. (2017), p. 29
^ Cohen, Amnon (1989), p. 81
^ ^a ^b Abu-Rabiʻa, ʻAref (2001), p. 46
^ Dalman (2013), vol. 2, pp. 384, 565
^ ^a ^b ^c Spanier, Y. & Sasson, A. (2001), p. 7 (Preface)
^ Dalman (2013), vol. 2, p. 384