Lime is an inorganic material composed primarily of calcium oxides and hydroxides . It is also the name for calcium oxide which occurs as a product of coal-seam fires and in altered limestone xenoliths in volcanic ejecta. The International Mineralogical Association recognizes lime as a mineral with the chemical formula of CaO. The word lime originates with its earliest use as building mortar and has the sense of sticking or adhering .
32-557: Dilala is a commune of the city of Kolwezi in the Democratic Republic of the Congo . This Democratic Republic of the Congo location article is a stub . You can help Misplaced Pages by expanding it . Kolwezi Kolwezi or Kolwesi is the capital city of Lualaba Province in the south of the Democratic Republic of the Congo , west of Likasi . It has an airport and a railway to Lubumbashi . Just outside of Kolwezi there
64-487: A lime kiln above 900 °C (1,650 °F) converts it into the highly caustic material burnt lime , unslaked lime or quicklime ( calcium oxide ) and, through subsequent addition of water, into the less caustic (but still strongly alkaline ) slaked lime or hydrated lime ( calcium hydroxide , Ca(OH) 2 ), the process of which is called slaking of lime . When the term is encountered in an agricultural context, it usually refers to agricultural lime , which today
96-474: A lime made from kankar which is a form of calcium carbonate. Selenitic lime, also known as Scotts' cement after Henry Young Darracott Scott , is a cement of grey chalk or similar lime, such as in the Lias Group , with about 5% added gypsum plaster (calcined gypsum ). Selenite is a type of gypsum, but selenitic cement may be made using any form of sulfate or sulfuric acid . Sulfate arrests slaking, causes
128-464: A limitation on its unhydrated oxide content." The term Type S originated in 1946 in ASTM C 207 Hydrated Lime for Masonry Purposes. Type S lime is almost always dolomitic lime, hydrated under heat and pressure in an autoclave, and used in mortar, render , stucco , and plaster . Type S lime is not considered reliable as a pure binder in mortar due to high burning temperatures during production. Kankar lime,
160-445: A source of hydroelectric power and a reservoir of water for the mining activities. Kolwezi and its cobalt mining economy was profiled in the May 24, 2021 edition of The New Yorker by writer Nicolas Niarchos. The acute financial and environmental impacts on the city and its economy were highlighted in the article. The rapid growth of the cobalt mining industry has caused a recent surge in
192-471: Is also known as rich, common, air, slaked, slack, pickling, hydrated, and high calcium lime. It consists primarily of calcium hydroxide which is derived by slaking quicklime (calcium oxide), and may contain up to 5% of other ingredients. Pure lime sets very slowly through contact with carbon dioxide in the air and moisture; it is not a hydraulic lime so it will not set under water. Pure lime is pure white and can be used for whitewash, plaster, and mortar. Pure lime
224-400: Is called the lime cycle . The conditions and compounds present during each step of the lime cycle have a strong influence of the end product, thus the complex and varied physical nature of lime products. An example is when slaked lime (calcium hydroxide) is mixed into a thick slurry with sand and water to form mortar for building purposes. When the masonry has been laid, the slaked lime in
256-479: Is done by composition as high calcium, argillaceous (clayey), silicious , conglomerate , magnesian , dolomite , and other limestones . Uncommon sources of lime include coral, sea shells, calcite and ankerite . Limestone is extracted from quarries or mines . Part of the extracted stone, selected according to its chemical composition and optical granulometry , is calcinated at about 900 °C (1,650 °F) in lime kilns to produce quicklime according to
288-502: Is located on the eastern edge of the city. Kolwezi has several medical clinics and hospitals along with dozens of primary and secondary schools. Is an upscale neighborhood located in the center of Kolwezi. The area is home to several foreign workers and a number of guest houses. Manika Stadium is located in the Dilala neighborhood. Kolwezi's Central Train Station is located on the eastern edge of
320-501: 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. 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 weeks. It is used for less expensive work and in mild climates. Moderately hydraulic lime contains 11-20% clay, slakes in one to two hours, and sets in approximately one week. It
352-670: Is named for the Dolomite Mountains in the Italian and Austrian Alps. In the United States the most commonly used masonry lime is Type S hydrated lime which is intended to be added to Portland cement to improve plasticity , water retention and other qualities. The S in type S stands for special which distinguishes it from Type N hydrated lime where the N stands for normal. The special attributes of Type S are its "...ability to develop high, early plasticity and higher water retentivity and by
SECTION 10
#1732863116143384-484: Is set on an arid plain in the south of the Democratic Republic of Congo . Upon its establishment in 1937 by the Union Minière du Haut-Katangahe, the company cleared the land of the acacias and miombo trees that once grew atop Kolwezi’s rich mineral deposits. They subsequently built a simple low-rise town across the area’s rolling hills, with wide streets and bungalows for Europeans, whose neighborhoods were segregated from
416-425: Is similar to hydraulic lime but has less soluble silica (usually minimum 6%) and aluminates , and will set under water but will never harden. Hydraulic lime is also called water lime . Hydraulic lime contains lime with silica or alumina and sets with exposure to water and can set under water. Natural hydraulic lime (NHL) is made from a limestone which naturally contains some clay . Artificial hydraulic lime
448-492: Is soluble in water containing carbonic acid , a natural, weak acid which is a solution of carbon dioxide in water and acid rain so it will slowly wash away, but this characteristic also produces autogenous or self-healing process where the dissolved lime can flow into cracks in the material and be redeposited, automatically repairing the crack. Semi-hydraulic lime, also called partially hydraulic and grey lime, sets initially with water and then continues to set with air. This lime
480-595: Is the static inverter plant of the HVDC Inga-Shaba . The population is approximately 573,000. Before the creation of Lualaba province in 2015 Kolwezi had two territories attached to it and the whole was known as the Kolwezi District . The settlement was created in 1938 to be the headquarters for the western mining group of the Union Minière du Haut Katanga . In 1971 it obtained city status and consisted of
512-632: Is used for better quality work and exterior walls in freezing climates. Eminently hydraulic lime contains 21-30% clay, slakes very slowly, and sets in approximately a day. It is used in harsh environments such as damp locations and near saltwater. Hydraulic lime is off-white in color. "The degree of hydraulicity of mortars will affect many characteristics. By selecting an appropriate ratio of clay to limestone mortars that carbonate or set hydraulically to varying extents can be designed for particular application requirements such as setting time, strength, colour, durability, frost resistance, workability, speed of set in
544-407: Is usually crushed limestone, not a product of a lime kiln. Otherwise it most commonly means slaked lime , as the more dangerous form is usually described more specifically as quicklime or burnt lime . In the lime industry, limestone is a general term for rocks that contain 80% or more of calcium or magnesium carbonate , including marble , chalk , oolite , and marl . Further classification
576-673: The cities of Lubumbashi and Dilolo . The city of Kolwezi has one of the main railway stations in Congo, from where mineral loads and passengers board every day. The station receives trains from the Benguela railway . The Kolwezi Airport serves Kolwezi and the surrounding area. The airport is located about 6 km (4 mi) south of Kolwezi. Lime (mineral) These materials are still used in large quantities as building and engineering materials (including limestone products, cement , concrete , and mortar ), as chemical feedstocks, for sugar refining , and other uses. Lime industries and
608-514: The city's population. Kolwezi has a monsoon-influenced humid subtropical climate ( Köppen climate classification Cwa ). The city has a dry-winter humid subtropical climate (Cwa, according to the Köppen climate classification), with warm rainy summers and pleasant, dry winters, with most rainfall occurring during summer and early autumn. Annual average rainfall is 45.8 inches. The city is crossed by Transafrican Highway 9 (TAH 9), which connects it to
640-566: The city. The government of Zaire asked Belgium , France, Morocco and the United States to restore order. The 2e REP , an elite paratroopers unit of the French Foreign Legion , were sent in to drive out the rebels and rescue any hostages. The Belgian army also deployed a force of some 750 Paracommando Regiment paratroopers and moved out just over 1,800 Europeans to other cities in the region. 700 Africans, including 250 rebels, 170 European hostages and 6 paratroopers died. Kolwezi
672-555: The communes of Dilala and Manika . In 1976 the territories of Lubudi and Mutshatsha , both previously part of Lualaba District , were attached to it to form the Kolwezi District (districts were called sub-regions at the time). In the 2015 repartitioning this was undone, the two territories and the city proper became separate parts of Lualaba province with the city as capital of the new province. On Saturday, 13 May 1978, ex- Katangese soldiers supported by Angola occupied
SECTION 20
#1732863116143704-633: The formation of magnesium sulfate salts." Magnesium sulfate salts may damage the mortar when they dry and recrystallize due to expansion of the crystals as they form, which is known as sulfate attack . Lime used in building materials is broadly classified as "pure", "hydraulic", and "poor" lime; can be natural or artificial ; and may be further identified by its magnesium content such as dolomitic or magnesium lime. Uses include lime mortar , lime plaster , lime render , lime-ash floors , tabby concrete , whitewash , silicate mineral paint , and limestone blocks which may be of many types . The qualities of
736-437: The magnesium compounds also slake to periclase which slake more slowly than calcium oxide and when hydrated produce several other compounds. Thus, these limes contain inclusions of portlandite , brucite , magnesite , and other magnesium hydroxycarbonate compounds. These magnesium compounds have very limited, contradictory research which questions whether they "...may be significantly reactive with acid rain, which could lead to
768-747: The many types of processed lime affect how they are used. The Romans used two types of lime mortar to make Roman concrete , which allowed them to revolutionize architecture, sometimes called the Concrete revolution . Lime has many complex qualities as a building product including workability which includes cohesion, adhesion, air content, water content, crystal shape, board-life, spreadability, and flowability; bond strength; comprehensive strength; setting time; sand-carrying capacity; hydraulicity; free lime content; vapor permeability; flexibility; and resistance to sulfates. These qualities are affected by many factors during each step of manufacturing and installation, including
800-420: The mortar slowly begins to react with carbon dioxide to form calcium carbonate (limestone) according to the reaction: The carbon dioxide that takes part in this reaction is principally available in the air or dissolved in rainwater so pure lime mortar will not recarbonate under water or inside a thick masonry wall. The lime cycle for dolomitic and magnesium lime is not well understood but more complex because
832-465: The neighborhood with train service to Likasi and Lubumbashi . Kolwezi is an important mining centre for copper and cobalt . There are also uranium , radium , oxide ores, and lime deposits. The Musonoi mine is a set of open-cut pits near Kolwezi from which copper and other metals have been extracted since the 1940s. The nearby Lake Nzilo was created by damming the Lualaba River to provide
864-476: The original ingredients of the source of lime; added ingredients before and during firing including inclusion of compounds from the fuel exhaust; firing temperature and duration; method of slaking including a hot mix (quicklime added to sand and water to make mortar), dry slaking and wet slaking; ratio of the mixture with aggregates and water; the sizes and types of aggregate; contaminants in the mixing water; workmanship; and rate of drying during curing. Pure lime
896-509: The poorly built ones where Congolese workers lived. The N39 highway runs through the center of town on a northwest-southeast axis. Large open pit cobalt mines are located to the west and north of the city center. Rond Point de L'Indépendance is the traditional center of the city with more formally laid out neighborhoods located to the west of the traffic circle. The center of the city contains administrative offices, dozens of guesthouses and hotels, banks and restaurants. Mutoshi Technical Institute
928-405: The presence of water, vapour permeability etc." Poor lime is also known as lean or meager lime. Poor lime sets and cures very slowly and has weak bonding. Poor lime is grey in color. Magnesium lime contains more than 5% magnesium oxide (BS 6100) or 5-35% magnesium carbonate (ASTM C 59-91). Dolomitic lime has a high magnesium content of 35-46% magnesium carbonate (ASTM C 59-91). Dolomitic lime
960-444: The quicklime to a form referred to as lime putty. Because lime has an adhesive property with bricks and stones, it is often used as a binding mortar in masonry works. It is also used in whitewashing as a wall-coat to allow the whitewash to adhere the wall. The process by which limestone (calcium carbonate) is converted to quicklime by heating, then to slaked lime by hydration, and naturally reverts to calcium carbonate by carbonation
992-409: The reaction: Before use, quicklime is hydrated , that is combined with water, called slaking, so hydrated lime is also known as slaked lime, and is produced according to the reaction: Dry slaking is slaking quicklime with just enough water to hydrate the quicklime, but to keep it as a powder; it is referred to as hydrated lime. In wet slaking , a slight excess of water is added to hydrate
Dilala - Misplaced Pages Continue
1024-549: The use of many of the resulting products date from prehistoric times in both the Old World and the New World. Lime is used extensively for wastewater treatment with ferrous sulfate . The rocks and minerals from which these materials are derived, typically limestone or chalk , are composed primarily of calcium carbonate . They may be cut, crushed, or pulverized and chemically altered. Burning ( calcination ) of calcium carbonate in
#142857