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30-458: Holeta came into existence with the construction of the Addis Ababa - Addis Alem road, and houses in the latter town were dismantled and brought to this new settlement. It became the new "country retreat" for Emperor Menelik II and Empress Taytu Betul According to Richard Pankhurst , when the couple were in residence, its population would mushroom from about 2,400 to as many as 15,000. It

60-411: A leather process called liming . The ion CaOH has been detected in the atmosphere of S-type stars . Limewater is a saturated aqueous solution of calcium hydroxide. Calcium hydroxide is sparsely soluble at room temperature in water (1.5 g/L at 25 °C ). "Pure" (i.e. less than or fully saturated) limewater is clear and colorless, with a slight earthy smell and an astringent/bitter taste. It

90-456: A process called sulfation , sulphur dioxide reacts with limewater: Limewater is used in a process known as lime softening to reduce water hardness. It is also used as a neutralizing agent in municipal waste water treatment. Calcium hydroxide adopts a polymeric structure, as do all metal hydroxides. The structure is identical to that of Mg(OH) 2 ( brucite structure ); i.e., the cadmium iodide motif. Strong hydrogen bonds exist between

120-580: A process known as nixtamalization . Nixtamalization makes the niacin nutritionally available and prevents pellagra . Traditionally lime water was used in Taiwan and China to preserve persimmon and to remove astringency . In chewing coca leaves , calcium hydroxide is usually chewed alongside to keep the alkaloid stimulants chemically available for absorption by the body. Similarly, Native Americans traditionally chewed tobacco leaves with calcium hydroxide derived from burnt mollusc shells to enhance

150-553: A total population of 7,516 of whom 3,482 were males and 4,034 were females. It is the largest settlement in Ejerie Aanaa . Ejerie is known for the Basilica Church of St Maryam. Its adjacent museum burned to the ground in 1997; however a new one has since opened. Ejerie was founded in 1900 by Menelik II as a new capital city ; Empress Taytu Betul picked the name. Although at one point he had 20,000 members of

180-720: Is a town in central Ethiopia . Located in the West Shewa Zone of the Oromia Region , west of Addis Ababa , this town has a latitude and longitude of 9°2′N 38°24′E  /  9.033°N 38.400°E  / 9.033; 38.400 with an elevation of about 2360 meters above sea level. Based on figures from the Central Statistical Agency in 2005, this town has an estimated total population of 13,423 of whom 6,420 were males and 7,003 were females. The 1994 census reported this town had

210-481: Is also used in tanning and making parchment . The lime is used as a dehairing agent based on its alkaline properties. Treating one's hair with limewater causes it to stiffen and bleach, with the added benefit of killing any lice or mites living there. Diodorus Siculus described the Celts as follows: "Their aspect is terrifying... They are very tall in stature, with rippling muscles under clear white skin. Their hair

240-406: Is as a flocculant , in water and sewage treatment . It forms a fluffy charged solid that aids in the removal of smaller particles from water, resulting in a clearer product. This application is enabled by the low cost and low toxicity of calcium hydroxide. It is also used in fresh-water treatment for raising the pH of the water so that pipes will not corrode where the base water is acidic, because it

270-414: Is basic in nature with a pH of 12.4. Limewater is named after limestone , not the lime fruit . Limewater may be prepared by mixing calcium hydroxide (Ca(OH) 2 ) with water and removing excess undissolved solute (e.g. by filtration). When excess calcium hydroxide is added (or when environmental conditions are altered, e.g. when its temperature is raised sufficiently), there results a milky solution due to

300-407: Is blond, but not only naturally so: they bleach it, to this day, artificially, washing it in lime and combing it back from their foreheads. They look like wood-demons, their hair thick and shaggy like a horse's mane. Some of them are clean-shaven, but others – especially those of high rank, shave their cheeks but leave a moustache that covers the whole mouth...". Calcium hydroxide is also applied in

330-464: Is cooked with nextli to become nixtamal , also known as hominy . Nixtamalization significantly increases the bioavailability of niacin (vitamin B3), and is also considered tastier and easier to digest. Nixtamal is often ground into a flour, known as masa , which is used to make tortillas and tamales. Limewater is used in the preparation of maize for corn tortillas and other culinary purposes using

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360-481: Is large enough that its solutions are basic according to the following dissolution reaction: The solubility is affected by the common-ion effect . Its solubility drastically decreases upon addition of hydroxide or calcium sources. When heated to 512 °C, the partial pressure of water in equilibrium with calcium hydroxide reaches 101   kPa (normal atmospheric pressure), which decomposes calcium hydroxide into calcium oxide and water: When carbon dioxide

390-561: Is passed through limewater, the solution takes on a milky appearance due to precipitation of insoluble calcium carbonate : If excess CO 2 is added: the following reaction takes place: The milkiness disappears since calcium bicarbonate is water-soluble. Calcium hydroxide reacts with aluminium . This reaction is the basis of aerated concrete . It does not corrode iron and steel , owing to passivation of their surface. Calcium hydroxide reacts with hydrochloric acid to give calcium hydroxychloride and then calcium chloride . In

420-518: Is self-regulating and does not raise the pH too much. Another large application is in the paper industry, where it is an intermediate in the reaction in the production of sodium hydroxide. This conversion is part of the causticizing step in the Kraft process for making pulp. In the causticizing operation, burned lime is added to green liquor , which is a solution primarily of sodium carbonate and sodium sulfate produced by dissolving smelt , which

450-483: Is the molten form of these chemicals from the recovery furnace. In orchard crops, calcium hydroxide is used as a fungicide. Applications of 'lime water' prevent the development of cankers caused by the fungal pathogen Neonectria galligena . The trees are sprayed when they are dormant in winter to prevent toxic burns from the highly reactive calcium hydroxide. This use is authorised in the European Union and

480-426: Is used as the colour solvent to apply on fresh plaster. Historically, it is known as the paint whitewash . Limewater is widely used by marine aquarists as a primary supplement of calcium and alkalinity for reef aquariums. Corals of order Scleractinia build their endoskeletons from aragonite (a polymorph of calcium carbonate). When used for this purpose, limewater is usually referred to as Kalkwasser . It

510-536: Is used in making naswar (also known as nass or niswar ), a type of dipping tobacco made from fresh tobacco leaves, calcium hydroxide ( chuna / choona or soon ), and wood ash. It is consumed most in the Pathan diaspora, Afghanistan , Pakistan , India and Bangladesh . Villagers also use calcium hydroxide to paint their mud houses in Afghanistan, Pakistan and India. In buon fresco painting, limewater

540-471: Is used in many applications, including food preparation, where it has been identified as E number E526 . Limewater , also called milk of lime , is the common name for a saturated solution of calcium hydroxide. Calcium hydroxide is modestly soluble in water, as seen for many dihydroxides. Its solubility increases from 0.66 g/L at 100 °C to 1.89 g/L at 0 °C. Its solubility product K sp of 5.02 × 10 at 25 °C, its dissociation in water

570-483: The Ethiopian Institute of Agricultural Research . Founded in 1963, this station is the national center for research to improve the yield of barley , highland oil crops, potatoes , and dairy products. The 2007 national census reported Holeta's population as 25,593, of whom 12,605 were men and 12,988 women. The majority of the inhabitants said they practised Ethiopian Orthodox Christianity , with 73% of

600-579: The Welega Oromo busy in constructing buildings in the new city, by 1903 he decided to keep the capital at Addis Ababa. However, it was used by the Emperor as his summer palace during the following years. The first paved road in Ethiopia was constructed between Ejerie and the capital, the work beginning in 1903, and reported in quite usable condition the next year. Around 1930, most of the wood for

630-472: The murder of Hadush Araya on 14 February 1996, the academy was renamed for him. Hadush Araya was one of the military leaders of the Tigray People's Liberation Front . Like much of Ethiopia, the economy is mainly based on agriculture but industry is growing. Habesha Cement has announced that it is constructing a new cement plant within the city limits of Holeta. The town hosts a research station of

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660-734: The Art School in 1966 and then studied graphic arts in London; he has designed stamps, posters and insignia. Slaked lime Calcium hydroxide (traditionally called slaked lime ) is an inorganic compound with the chemical formula Ca ( OH ) 2 . It is a colorless crystal or white powder and is produced when quicklime ( calcium oxide ) is mixed with water . Annually, approximately 125 million tons of calcium hydroxide are produced worldwide. Calcium hydroxide has many names including hydrated lime , caustic lime , builders' lime , slaked lime , cal , and pickling lime . Calcium hydroxide

690-519: The United Kingdom under Basic Substance regulations. Calcium hydroxide is used in dentistry, primarily in the specialty of endodontics. Because of its low toxicity and the mildness of its basic properties, slaked lime is widely used in the food industry , In Nahuatl , the language of the Aztecs , the word for calcium hydroxide is nextli . In a process called nixtamalization , maize

720-573: The art work of the church of St. Maryam. Worku Mammo Dessalegn , born in Addis Alem in 1935, lost both hands in an accident while playing with a bomb at the age of twelve; he attended the Art School in 1960-1962, later studied in the USSR and then returned to the Art School in Addis Ababa as a teacher. A third is Tadesse Bedaso Begna , born in Ejerie in 1943, who attended a Baptist school, graduated from

750-633: The buildings and furniture in Addis Ababa was sawn from the forests near Addis Alem. During the Italian occupation , a factory for the production of slaked lime was established during the Italian time, and in its first year of production it turned out 30,000 hundredweights of the material. On 2 December 1940 the Arbegnoch , led by Admiqe Besha, attacked the Italian garrison. The Italians lost 72 men, and 2,007 rifles, cannons and hand grenades. On 3 April in

780-400: The effects. It has also been used by some indigenous South American tribes as an ingredient in yopo , a psychedelic snuff prepared from the beans of some Anadenanthera species. Calcium hydroxide is typically added to a bundle of areca nut and betel leaf called " paan " to keep the alkaloid stimulants chemically available to enter the bloodstream via sublingual absorption. It

810-545: The following year, the Italians sent a cavalry regiment 450 strong to recapture Ejerie; There it was defeated by the Arbegnoch superior numbers, leaving 42 men on the ground and 30 other injured including the regiment commander Vittorio Casardi. A number of notable artists are associated with this town. The church has some art work by Abebe Wolde Giorgis (1897-1967), who studied in France for 18 years, has contributed to

840-415: The layers. Calcium hydroxide is produced commercially by treating (slaking) quicklime with water: Alongside the production of quicklime from limestone by calcination , this is one of the oldest known chemical reactions; evidence of prehistoric production dates back to at least 7000 BCE. Calcium hydroxide is commonly used to prepare lime mortar . One significant application of calcium hydroxide

870-466: The population reporting they observed this belief, while 20.44% of the population were Protestant , and 5.43% were Muslim . According to the 1994 national census, the town's population was 16,785, of whom 8,040 were males and 8,745 females. It is the largest of three towns in the Walmara Aanaa . Ejere (town) Addis Alem ( Amharic : አዲስ ዓለም , New World ; also known as Ejerie )

900-735: Was the first place in Ethiopia to have a permanent water mill, built in 1909 on the Holetta River. Holeta is best known as the location of the Holeta Military Academy. Opened in January 1935, and staffed by five Swedish officers, the first class of 120 cadets did not complete their studies due to the Second Italo-Ethiopian War . It was reopened once Emperor Haile Selassie returned to Ethiopia, and celebrated its 25th anniversary 20–30 April 1960. After

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