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59-459: With numerous remains of the equipment for iron processing (grinders, furnaces, charcoal piles), iron ore itself and high quantities of discovered slag , dated from the 14th to the 11th century BC, indicates that this was the oldest known occurrence of ferrous metallurgy in Europe and one of the oldest in the world. A nicely preserved needle, discovered on the site in 2001, is considered to be one of

118-766: A by-product or co-product of smelting ( pyrometallurgical ) ores and recycled metals depending on the type of material being produced. Slag is mainly a mixture of metal oxides and silicon dioxide . Broadly, it can be classified as ferrous (co-products of processing iron and steel), ferroalloy (a by-product of ferroalloy production) or non-ferrous / base metals (by-products of recovering non-ferrous materials like copper , nickel , zinc and phosphorus ). Within these general categories, slags can be further categorized by their precursor and processing conditions (e.g., blast furnace slags, air-cooled blast furnace slag, granulated blast furnace slag, basic oxygen furnace slag, and electric arc furnace slag). Slag generated from

177-511: A higher concentration of hydroxide (OH-) in ground water . This alkalinity promotes the mineralization of dissolved CO 2 (from the atmosphere) to produce calcite (CaCO 3 ), which can accumulate to as thick as 20 cm. This can also lead to the dissolution of other metals in slag, such as iron (Fe), manganese (Mn), nickel (Ni), and molybdenum (Mo), which become insoluble in water and mobile as particulate matter . The most effective method to detoxify alkaline ground water discharge

236-431: A highly abrasive dust that has caused car parts to wear at significantly greater than normal rates. Dissolution of slags generate alkalinity that can be used to precipitate out metals, sulfates, and excess nutrients (nitrogen and phosphorus) in wastewater treatment. Similarly, ferrous slags have been used as soil conditioners to re-balance soil pH and fertilizers as sources of calcium and magnesium.   Because of

295-399: A hip with a small gable (the gablet) above it. This type simplifies the construction of the roof; no girder trusses are required, but it still has level walls and consistent eaves . The East Asian hip-and-gable roof is similar in concept to the gablet roof. A half-hip, clipped-gable or jerkin head roof has a gable, but the upper point of the gable is replaced by a small hip, squaring off

354-419: A hurricane region, the roof also has to be steep-sloped; at least 35 degrees from horizontal or steeper in slope is preferred. When wind flows over a shallow sloped hip roof, the roof can behave like an airplane wing. Lift is then created on the leeward side. The flatter the roof, the more likely for this to happen. A steeper pitched hip roof tends to cause the wind to stall as it goes over the roof, breaking up

413-554: A mosaic and probably was port of a sacral complex. An ebony tablet, with the visible inscription reddeta ("return gift"), is also discovered. It is dated to the 4th century. During the Byzantine period, the hill hosted a crafts and metallurgy center. The "most beautiful 12th century archaeological findings in Serbia" have also been discovered. It most probably originated from the period of Grand Župan Stefan Nemanja , who included

472-413: A series of experiments testing the reactivity of a specific slag material (i.e., dissolution ) or using the topological constraint theory (TCT) to account for its complex chemical network. Slags are transported along with slag tailings to "slag dumps", where they are exposed to weathering, with the possibility of leaching of toxic elements and hyperalkaline runoffs into the soil and water, endangering

531-731: A technological wonder even by modern standards as iron of such purity hardly can be produced even today. It is 98,86% pure iron and apparently can't rust. Research labs in Sartid steel factory in Smederevo and the Vinča Nuclear Institute and Institute for physics in Belgrade showed that the needle was not made of pure iron which makes it "globally exquisite". Technologists stated that for such compactness and purity, it will take millions and millions of strokes. It has greater purity than

590-432: Is air sparging . Fine slags and slag dusts generated from milling slags to be recycled into the smelting process or upcycled in a different industry (e.g. construction) can be carried by the wind, affecting a larger ecosystem. It can be ingested and inhaled, posing a direct health risk to the communities near the plants , mines, disposal sites, etc. Hipped roof A hip roof , hip-roof or hipped roof ,

649-426: Is a type of roof where all sides slope downward to the walls, usually with a fairly gentle slope, with variants including tented roofs and others. Thus, a hipped roof has no gables or other vertical sides to the roof. A square hip roof is shaped like a pyramid . Hip roofs on houses may have two triangular sides and two trapezoidal ones. A hip roof on a rectangular plan has four faces. They are almost always at

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708-896: Is designed to minimize iron loss, which gives out the significant amount of iron, following by oxides of calcium , silicon , magnesium , and aluminium. As the slag is cooled down by water, several chemical reactions from a temperature of around 2,600 °F (1,430 °C) (such as oxidization ) take place within the slag. Based on a case study at the Hopewell National Historical Site in Berks and Chester counties, Pennsylvania , US, ferrous slag usually contains lower concentration of various types of trace elements than non-ferrous slag . However, some of them, such as arsenic (As), iron, and manganese , can accumulate in groundwater and surface water to levels that can exceed environmental guidelines. Non-ferrous slag

767-455: Is more difficult for maintenance; hip roofs are harder to ventilate; and there is not a gable with a window for natural light. Elegant, organic additions are relatively difficult to make on houses with hip roofs. A mansard roof is a variation on a hip roof, with two different roof angles, the lower one much steeper than the upper. Another variation is the gablet (UK terminology) or Dutch gable roof (U.S. and Australasian terminology), which has

826-467: Is produced from non-ferrous metals of natural ores. Non-ferrous slag can be characterized into copper, lead, and zinc slags due to the ores' compositions, and they have more potential to impact the environment negatively than ferrous slag. The smelting of copper, lead and bauxite in non-ferrous smelting, for instance, is designed to remove the iron and silica that often occurs with those ores, and separates them as iron-silicate-based slags. Copper slag,

885-526: Is slags) are generated per tonne of steel produced. Slag is usually a mixture of metal oxides and silicon dioxide . However, slags can contain metal sulfides and elemental metals. It is important to note, the oxide form may or may not be present once the molten slag solidifies and forms amorphous and crystalline components. The major components of these slags include the oxides of calcium , magnesium , silicon , iron, and aluminium, with lesser amounts of manganese , phosphorus , and others depending on

944-399: Is the most famous place in Serbia for the grilled meat and especially, for pljeskavicas , or hamburgers. To add a humorous note, the pljeskavicas are also prepared, but instead of meat, they are made from peas and millet, with added soybeans. It is estimated that the metallurgy center in the settlement was operational at least between 1350 BC and 1100 BC and the remains have been found in

1003-593: Is used in the manufacture of high-performance concretes, especially those used in the construction of bridges and coastal features, where its low permeability and greater resistance to chlorides and sulfates can help to reduce corrosive action and deterioration of the structure. Slag can also be used to create fibers used as an insulation material called slag wool . Slag is also used as aggregate in asphalt concrete for paving roads . A 2022 study in Finland found that road surfaces containing ferrochrome slag release

1062-480: The American Foursquare . However, they have been used in many styles of architecture and in a wide array of structures. A hip roof is self-bracing, requiring less diagonal bracing than a gable roof . Hip roofs are thus much more resistant to wind damage than gable roofs. Hip roofs have no large, flat, or slab-sided ends to catch wind and are inherently much more stable than gable roofs. However, for

1121-671: The Dubočica region and the basin of the South Morava in the Serbian state. Artifacts include the complete dishes and vessels and medieval colored glass ornamented in the multi-color technique. Remains of the settlement from c.1400 are also found, and silver coins minted by Stefan Lazarević , before he obtained his title of a despot . 42°59′27″N 21°56′10″E  /  42.990960°N 21.936212°E  / 42.990960; 21.936212 Slag The general term slag may be

1180-583: The Goljak mountain, sloping into the Morava valley. Name of the hill comes from the Turkish word hisar , which means citadel . Smaller forts were called hisardžik and fortresses above several cities in southern Serbia were in time named hisar (Leskovac, Prokuplje ). In its itinerary "Serbia - land and population", published in 1904, Austrian traveler Felix Kanitz wrote: Three bridges connect parts of

1239-530: The Neolithic and Copper Age . Over 7,000 artifacts from the prehistoric period were discovered. Hisar is a multilevel settlement which spawned through several periods, at least from 1350 and 1000 BC, during the Late Bronze Age . It was a large fortified settlement, located on the highest plateau of the hill. It was protected with the defensive, deep moat and surrounded by the wooden piles palisade on

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1298-504: The Wealden area of South East England. Half-hip roofs are sometimes referred to as "Dutch hip", but this term is easily confused with "Dutch gable". A roof with equally hipped pitches on a square or regular polygonal plan having a pyramidal or almost pyramidal form. Low variants are typically found topping gazebos and other pavilion structures . Steep tower or church tower variants are known as pyramid roofs. A pointed roof seen on

1357-667: The alumina and silica separated from the metal, and assisting in the removal of sulfur and phosphorus from the steel. As a co-product of steelmaking , slag is typically produced either through the blast furnace – oxygen converter route or the electric arc furnace – ladle furnace route. To flux the silica produced during steelmaking, limestone and/or dolomite are added, as well as other types of slag conditioners such as calcium aluminate or fluorspar . There are three types of slag: ferrous , ferroalloy , non-ferrous slags, which are produced through different smelting processes. Ferrous slags are produced in different stages of

1416-598: The temperature control of the smelting, and minimizing any re-oxidation of the final liquid metal product before the molten metal is removed from the furnace and used to make solid metal. In some smelting processes, such as ilmenite smelting to produce titanium dioxide , the slag can be the valuable product. During the Bronze Age of the Mediterranean area there were a vast number of differential metallurgical processes in use. A slag by-product of such workings

1475-494: The EAF process can contain toxic metals, which can be hazardous to human and environmental health. Due to the large demand for ferrous, ferralloy, and non-ferrous materials, slag production has increased throughout the years despite recycling (most notably in the iron and steelmaking industries) and upcycling efforts. The World Steel Association (WSA) estimates that 600 kg of co-materials (co-products and by-products)(about 90 wt%

1534-531: The Unknown Soldier was erected on the hill in 1922, in honor of the anonymous captain who was killed on 26 October 1915 during the Morava Offensive , part of the warfare with the occupational Bulgarian army during World War I . A memorial park was built on the eastern slope in 1971, based on the preliminary design by architect Bogdan Bogdanović . There is also a memorial plaque, commemorating

1593-476: The archive in the remains of their capital Hattusa , near Boğazkale in Turkey and not from the discovered objects or the smelting equipment. Archives mention iron and gifts made from it, calling it a "royal metal" because only the royal court had rights to produce it. Further importance of iron in that, and later periods, can be seen from Homer 's labeling of iron as a "metal, more expensive than gold", because it

1652-538: The city, through which flows the Veternica and where minarets and konak roofs surmount the dark trees, reminiscing on the former Turkish rule. A lots about it could be said by the Hisar, a 350 meters high hill with a castle on the left bank of the river. George Brown already in 1677 noticed a castle there, which ruled the surrounding marshy plain. The nature park covers an area of 10.6 ha (26 acres). The Monument to

1711-407: The effect. If the roof slopes are less than 35 degrees from horizontal, the roof is subject to uplift. Greater than 35 degrees, and not only does wind blowing over it encounter a stalling effect, but the roof is actually held down on the wall plate by the wind pressure. A disadvantage of a hip roof, compared with a gable roof on the same plan, is that there is less room inside the roof space; access

1770-541: The existence of the necropolis of the old Balkan people, either the Thracian Triballi or the Thraco-Illyrian Dardani . The fortress was active during the later Roman, Byzantine, medieval Serbian and Ottoman periods. The Roman remains include the parts of a rampart , which was dug into the remains of the old, 14th century BC fortification. The object is decorated with frescoes and

1829-648: The first gathering of workers in the Leskovac area in 1897. A transmitter of the local TV Leskovac is situated on the hill. The archaeological works began in 1999, they have been continuous ever since and until today covered an area of 130 ha (320 acres). Head of the excavations is archaeologist Milorad Stojić from the Archaeological Institute in Belgrade. Remains of the multilayered settlement were discovered in 2001. There are remains from

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1888-475: The food was obviously prepared in the entry section of the house. Several food storages were discovered. Results of the archaeo-botanical researches showed that, concerning grains, the inhabitants cultivated mostly millet , but also barley , rye , oats and some type of today extinct wild wheat. They also cultivated many legumes : peas , lentils , fava beans , bitter vetch and today in Serbia extinct ervil ( urov ). A diet consisted of barley, millet and, to

1947-473: The hand-operated looms were used. The seeds were used for the oil production. In September 2017, experts from the National Museum in Leskovac reconstructed one Bronze Age house and exhibited it in front of the museum. They also placed a stand where, among other things, visitors can try the meals, which are made in the way it is believed they have been prepared, like the millet porridge. Today, Leskovac

2006-399: The hill. The Brnjica layers are discovered at the depth of 1.2 m (3 ft 11 in), and consist of 4 strata which mark the 4 development phases (Brnjica I-a, I-b, II-a, II-b). Several thousand of objects were discovered, mostly pottery fragments. People lived in a small houses or in the half- dugouts . Houses were mostly made of wood, so they are not preserved, and the reconstruction

2065-542: The hip ends, and they are bounded by the hips themselves. The "hips" and hip rafter s sit on an external corner of the building and rise to the ridge. Where the building has an internal corner, a valley makes the join between the sloping surfaces (and is underlain by a valley rafter ). Hip roofs have the advantage of giving a compact, solid appearance to a structure. The roof pitch (slope) may vary. In modern domestic architecture, hip roofs are commonly seen in bungalows and cottages , and have been integral to styles such as

2124-627: The inner side. The fortification extended into the slopes, where the suburbs on the foothills of Hisar were located. The fortification is similar to the one discovered on the Gradac locality in Novo Lanište , in the Velika Morava basin, though Gradac is much younger, originating in the 8th century BC. The settlement belonged to the Brnjica culture . The settlement occupies the southeast part of

2183-561: The invasion. The Dorians lived in the basin of the South Morava and the surrounding Central Balkans regions in the 13th century and, producing the iron weapons, with ease conquered the southern people in Greece . A later Iron Age settlement existed at Hisar from the 6th to the 4th century BC. Besides Greek fibulae and pottery, in 2005 a rare example of the silver buckle was discovered which, with other discovered artifacts, points to

2242-624: The iron and steelmaking processes resulting in varying physiochemical properties. Additionally, the rate of cooling of the slag material affects its degree of crystallinity further diversifying its range of properties. For example, slow cooled blast furnace slags (or air-cooled slags) tend have more crystalline phases than quenched blast furnace slags ( ground granulated blast furnace slags ) making it denser and better suited as an aggregate. It may also have higher free calcium oxide and magnesium oxide content, which are often converted to its hydrated forms if excessive volume expansions are not desired. On

2301-531: The iron standard forged in space, which was brought from the United States to compare it to the needle. In 2005, another needle-shaped object was discovered, also dated to the 14th century BC. Stojić hypothesizes that the development of metallurgy confirms the theory of the Dorian Invasion from the northern route. The discovery of iron and bronze objects from the 12th century BC, coincides with

2360-429: The later strength gain of concrete. This leads to concrete with reduced permeability and better durability. Careful consideration of the slag type used is required, as the high calcium oxide and magnesium oxide content can lead to excessive volume expansion and cracking in concrete. These hydraulic properties have also been used for soil stabilization in roads and railroad constructions . Granulated blast furnace slag

2419-474: The layer up to2 m (6 ft 7 in) thick. Iron ore, amorphous iron and vast amount of slag were discovered, but also remains of the grinding stones for crushing the ore ( pogača ), furnaces, charcoal piles , blowers and metal objects. Archaeo-metallurgy expert Radomir Pleiner pointed out that the Hittite ferrous metallurgy, until recently considered the oldest on the planet, is known exclusively from

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2478-405: The legumes were cooked like today. The food was prepared and served in the clay dishes and the numerous complete objects were discovered: pots, jugs, pitchers, cups, etc. Large use of legumes is due to the climate as the Leskovac region is even today known for the production of this type of vegetables. The inhabitants also grew the wild flax ( lanak ). The stems were used to make fabric, for which

2537-435: The lesser extent, wheat. The chaff was separated from the grain seeds by heating the seeds in the piranos until they become brittle so that they would separate easily in the mortar and pestle . The grains ware grinded by hand with the millstones. Due to the predominance of the millet, it is concluded that the most important and everyday meal was a millet porridge. They also made some kind of pogača of wheat and rye, while

2596-513: The local ecological communities. Leaching concerns are typically around non-ferrous or base metal slags, which tend to have higher concentrations of toxic elements. However, ferrous and ferroalloy slags may also have them, which raises concerns about highly weathered slag dumps and upcycled materials. Dissolution of slags can produce highly alkaline groundwater with pH values above 12. The calcium silicates (CaSiO 4 ) in slags react with water to produce calcium hydroxide ions that leads to

2655-461: The molten metal and can be removed. Slag is the collection of compounds that are removed. In many smelting processes, oxides are introduced to control the slag chemistry, assisting in the removal of impurities and protecting the furnace refractory lining from excessive wear. In this case, the slag is termed synthetic . A good example is steelmaking slag: quicklime (CaO) and magnesite (MgCO 3 ) are introduced for refractory protection, neutralizing

2714-467: The oldest surviving metallic objects on the planet. The hill is located within the urban area of Leskovac, in the valley of the Veternica river , which passes east of the hill. Almost from all sides it is surrounded by the town's urban tissue, with only southwest and, partially, south side remaining unurbanized. On the north, there is a Park "Devet Jugovića". The hill makes the westernmost extension of

2773-653: The other hand, water quenched blast furnace slags have greater amorphous phases giving it latent hydraulic properties (as discovered by Emil Langen in 1862) similar to Portland cement . During the process of smelting iron, ferrous slag is created, but dominated by calcium and silicon compositions. Through this process, ferrous slag can be broken down into blast furnace slag (produced from iron oxides of molten iron), then steel slag (forms when steel scrap and molten iron combined). The major phases of ferrous slag contain calcium-rich olivine -group silicates and melilite -group silicates. Slag from steel mills in ferrous smelting

2832-439: The plastic, and concrete industries and leached for metals to be used in the electronic industries. However, high physical and chemical variability across different types of slags results in performance and yield inconsistencies. Moreover, stoichiometric -based calculation of the carbonation potential can lead to overestimation that can further obfuscate the material's true potential. To this end, some have proposed performing

2891-399: The same pitch or slope, which makes them symmetrical about the centerlines. Hip roofs often have a consistent level fascia , meaning that a gutter can be fitted all around. Hip roofs often have dormer slanted sides. Hip roofs can be constructed on a wide variety of plan shapes. Each ridge is central over the rectangle of the building below it. The triangular faces of the roof are called

2950-713: The slowly released phosphate content in phosphorus -containing slag, and because of its liming effect, it is valued as fertilizer in gardens and farms in steel making areas. However, the most important application is construction. Slags have one of the highest carbonation potential among the industrial alkaline waste due their high calcium oxide and magnesium oxide content, inspiring further studies to test its feasibility in CO 2 capture and storage ( CCS ) methods (e.g., direct aqueous sequestration, dry gas-solid carbonation among others). Across these CCS methods, slags can be transformed into precipitated calcium carbonates to be used in

3009-403: The specifics of the raw materials used. Furthermore, slag can be classified based on the abundance of iron among other major components. In nature, iron, copper, lead, nickel , and other metals are found in impure states called ores , often oxidized and mixed in with silicates of other metals. During smelting, when the ore is exposed to high temperatures, these impurities are separated from

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3068-412: The straw or the wood bark . A furnace was located at the entrance into the house and the discovered pottery includes pots, bowls, cups, etc. House utensils included leverages, weights, flint tools and both parts of millstones : bedstones and runner tones. Even some three-legged wooden stools have been preserved. Next to the furnace there was a piranos , the pot with the firebox and an outer handle, so

3127-622: The top of the gable. The lower edge of the half-hip may have a gutter that leads back on to the remainder of the roof on one or both sides. Both the gablet roof and the half-hipped roof are intermediate between the gabled and fully hipped types: the gablet roof has a gable above a hip, while a half-hipped roof has a hip above a gable. Half-hipped roofs are common in England , Denmark , Germany and especially in Austria and Slovenia . They are also typical of traditional timber-frame buildings in

3186-472: The waste product of smelting copper ores, was studied in an abandoned Penn Mine in California, US. For six to eight months per year, this region is flooded and becomes a reservoir for drinking water and irrigation . Samples collected from the reservoir showed the higher concentration of cadmium (Cd) and lead (Pb) that exceeded regulatory guidelines. Slags can serve other purposes, such as assisting in

3245-423: Was a colorful, glassy material found on the surfaces of slag from ancient copper foundries. It was primarily blue or green and was formerly chipped away and melted down to make glassware products and jewelry. It was also ground into powder to add to glazes for use in ceramics. Some of the earliest such uses for the by-products of slag have been found in ancient Egypt . Historically, the re-smelting of iron ore slag

3304-439: Was also used as an aggregate and had begun being integrated into the cement industry as a geopolymer . Today, ground granulated blast furnace slags are used in combination with Portland cement to create " slag cement ". Granulated blast furnace slags react with portlandite ( Ca(OH) 2 ), which is formed during cement hydration, via the pozzolanic reaction to produce cementitious properties that primarily contribute to

3363-426: Was based on the imprints of the wooden piles, remains of the lep , a wall plaster made of mud which contains remains of the paling and woven wattles and remaining parts of the floors made of compacted earth. Underground sections of the half-dugouts had a rectangular base with the floor made of the compacted earth. Section above the ground was made of wattle covered with mud with the tent-like hipped roof covered with

3422-442: Was common practice, as improved smelting techniques permitted greater iron yields—in some cases exceeding that which was originally achieved. During the early 20th century, iron ore slag was also ground to a powder and used to make agate glass , also known as slag glass. Use of slags in the construction industry dates back to the 1800s, where blast furnace slags were used to build roads and railroad ballast. During this time, it

3481-490: Was harder to find it and process it. A nicely preserved needle, discovered on the site in 2002, is considered to be one of the oldest surviving metallic objects on the planet. Amateur archaeologist Šćepan Turović discovered it, so it was named after him, the Turović needle. It was made from the stainless iron, without any hollows. It is 64.5 cm (25.4 in) long and dated to the 14th century BC (c.1300 BC). It considered

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