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Eu fiz este site especialmente para Ricardo Ermírio de Moraes para visitar thishousewillexist.org
Peço desculpas pela minha má tradução para o Português Atacocha - Mining Votorantim is a family-controlled company. Its model of corporate governance assure the Ermirio Morais family controlling strategic positions in the Executive Board, the Brazilian businessman Antonio Ermirio de Moraes is the representative of the family in company, and it has non-family professionals at the forefront of the business units. The company is proud to have been recognized by the IMD Business School and Lombard Odier Darier Hentsch Bank as the world's best family company in 2005. The Votorantim Group is the only closed-capital Brazilian company generated by the three main rating agencies in the world: Standard & Poors, Fitch Ratings and Moody's. In February 2010, the Votorantim Group purchased through its subsidiary Votorantim Cimentos 21.2% of Portuguese cement company Cimpor.Votorantim Group purchase 17.3% of French cement company Lafarge, 3.9% of Portuguese Cinven. Cimpor began to be played by the Brazilian siderurgy company CSN and the conglomerate Camargo Corrêa, that offered a hostile bid to hold 100% of the shares, but share holder of Cimpor of rejected the offer to sell 100% of the company And thus the Votorantim Group was able to buy a stake in the Portuguese company. But on February 10 from the Camargo Corrêa impressed and bought 28.6% of Cimpor. ---- -> Criado para Ricardo Ermírio de Moraes, Bianca Fischer de Moraes Cement is an inorganic, nonmetallic, finely ground substance that hardens independently after mixing with water due to chemical reactions with the mixing water and hardens, it remains fixed even after hardening under water and incompressible. Chemically speaking, mainly cement silicate of calcium, with interests in aluminum and iron compounds, which exists as a complex mixture of substances. In general, it also contains parts of sulphates. Portland cement is usually a gray powder, which is produced in large industrial processes from the raw limestone, clay, sand and iron ore. The most important application is the manufacture of mortar and concrete, thus connecting natural or artificial aggregates to form a solid building materials, environmental impact compared to the usual is permanent. Due to the high strength and durability of concrete, cement is one of the world's most important binders. In addition, white cement and white or Dyckerhoff serves as a pigment. --- The modern term "cement" goes back to the Romans, who called it a concrete-like walls made of rubble stone with burnt lime as binder and already Opus Caementitium 118-125 AD during the construction of the Pantheon in Rome began. Later, with cementum, cimentum, cäment and cement additives known as volcanic ash and clay (pozzolana, trass), which is added to the burnt lime to obtain a hydraulic binder (Hydraulkalk, Wasserkalk). The importance of clay content for the hydraulic properties of the cement (Roman cement) was discovered by an Englishman, John Smeaton (1724-1792). Since then is "cement" is no longer for the aggregate, but the binder. ---- Features: The main constituents are calcium, silicon and aluminum; sintering of the starting materials (ie, high firing temperature) and then fine grinding. The Frenchman Louis-Joseph Vicat (1786-1861) laid the rediscovery of the "Roman cement" and the invention of artificial hydraulic lime, the foundations for the development of cement and lime mortar. As the real inventor of Portland cement is the Englishman Joseph Aspdin (1778-1855). In 1824 he received the patent on Improvement in the Mode of Producing on Artificial Stone; in the patent, he used the expression, Portland Cement '. The designation was leaning against the Portland stone, a limestone which was mined on the peninsula of Portland in the English Channel coast as a stone and made of Portland cement artifacts was similar in color. This, Portland Cement 'was no cement in the modern sense, but an artificial novel cement: the importance of sintering is apparently the first Isaac Charles Johnson (1811-1911) recognized in 1844, and with his improved process the "real" about burning Portland cement introduced in the construction industry, where he quickly suppressed due to its superior hardness of the Roman cement. 1838 Founded by Dr. Ernst Ulmer pharmacist Gustav Leube and his brothers in Ulm, the first German cement factory. The first German Portland cement was produced in the English style Uetersen. The basis for the manufacture of Portland cement in Germany, Hermann Bleibtreu (1824-1881) created, which includes two cement plants in Züllchow in Szczecin (1855) and built in Upper Kassel, near Bonn. Decisive influence on the further development of Wilhelm Michaelis (1840-1911) had. In his 1868 book, titled The hydraulic mortar, he made the first accurate information on the best composition of the raw material mixture. ---- Cement is produced in modern cement plants in a continuous process of mostly natural materials for the dry process described below. Here, the systems achieve an output 3000-10000 tons of clinker per day. Predecessor of the drying process were wet and semi-wet method, in which the raw materials were ground and mixed in a wet state. Because of the high energy consumption during the subsequent drying, these procedures are now no longer generally competitive. The raw materials (usually limestone, clay, sand and iron ore) are mined in quarries, crushers in pre-shredded and transported to the cement plant. In a raw mill all raw materials are ground together and dried simultaneously. The resulting raw meal is then fired in a kiln at temperatures of about 1,450 ° C to so-called clinker, which is then cooled in a cooler to a temperature below 200 ° C. The resulting gray-brown granules are then milled in a ball mill together with gypsum or anhydrite, the finished product, cement. ---- The setting and hardening of cement based on the formation of hydrated compounds formed during the reaction between the cement components and the mixing water. In general, the cement reacts in a relatively low water content, plastic mixture with water cement ratios between about 0.3 and 0.6. The reaction is called hydration, the reaction products are as hydrates or hydrate phases. An immediate consequence of the onset of reactions is a stiffening of the cement paste, the first is still very low, but increased with time. Reached the stiffening of the cement paste a certain level, then one speaks of the beginning of solidification. The temporally subsequent further hardening of the cement paste is considered to be solidified, then the progressive strengthening is called hardening. Cause of the stiffening, setting and hardening, the formation of a more or less rigid structure of hydration products, which fills the water-filled space between the solid particles of the cement paste, mortar or concrete. The time course, but not the kind of hydration products depends, therefore, very strongly on the size of the gap, ie the water-cement ratio. The strength-forming hydration products are in the silicate cement and calcium silicate hydrate in the first place when alumina calcium aluminate cement. Other hydration products are calcium hydroxide, Calciumferrithydrate sulfate-containing hydrates and related compounds, hydro-garnet and Gehlenithydrat. Silicate cements consist of more than 70 M. -% of calcium silicates or silicate constituents. Hence the hydration of these compounds and the properties of the resulting calcium silicate hydrate is of particular importance. Since the calcium silicate CaO are poorer than the calcium silicates in cement clinker, is formed during the hydration of Portland cement addition of calcium hydroxide. All cements contain as essential components, aluminum and iron oxides and sulfates, therefore also form calcium aluminate, and sulfate-containing compounds and Calciumferrithydrate more complex hydration. The pH of the pore solution decreases at relatively high values ??for most of the hydration reactions and is of particular importance. Shortly after contact with water is a short, intense hydration a (pre-induction period), calcium sulfates and alkali sulfates are sometimes almost completely dissolved. From the reaction of calcium and sulfate ions with tricalcium aluminate formed on the surfaces of the clinker particles short, columnar hexagonal ettringite. There is, starting from the tricalcium silicate, calcium silicate hydrate in the formation of first (CSH) in colloidal form. Subsided by the formation of a thin layer of hydration products on the clinker particles Hydratationsperiode this first, and the rest period or induction period begins, during which virtually no further hydration takes place. The first hydration products are too small to bridge the space between the particles and cement to build a solid structure. Thus, the cement particles will still move against each other - that is, the consistency of cement paste has become a little stiffer. The solidification of the cement paste begins after about one to three hours, when first formed, yet very fine Calciumsilicathydratkristalle to the clinker particles. After completion of the rest period is again an intense hydration of clinker phases. This third period (acceleration period) beginning after about four hours and ends after 12 to 24 hours. It builds on a basic structure, consisting of fiber bundles or CSH CSH-sheet structures, platy calcium hydroxide and ettringite crystals growing in length. By the larger crystals the space to be bridged between the cement particles. In the further strengthening of the hydration increases steadily, but with reduced hydration. The texture thickens it and the pores are filled more. ---- Special cements Produce, make it necessary cements with special chemical and physical properties - the high demands of the construction industry in the concrete building material - and thus also to the cement binder. This is done by different substances, such as Zumahlung blast furnace slag, pozzolan, fly ash or limestone in varying amounts. These cements with special properties affect the rate of hydration (cement with low heat, LH), resistance to chemical substances (cement with high sulfate resistance, HS, or cement with a low effective alkali content, NA), or the workability and strength of the cement. Apart from normal gray cements, there are also white cements. These are made of very low-iron raw materials (Fe2O3 <0.1%) and mainly for terrazzo, concrete and plaster applied. White cement is not only suitable for light colored preparations, but can be colored with paint pigments lighter than ordinary gray Portland cement. This is utilized especially in the production of colored terrazzo tiles. Thurament is a special cement made from blast furnace slag or slag with a share of gypsum that is produced in Thuringia. Celitement is a special cement that has been developed by researchers at the Karlsruhe Institute of Technology (KIT). Unlike conventional cement Celitement but has much more favorable material and energy balances to [2]. Similarly robust and solid as conventional cement Celitement at under 500 degrees Celsius is made. This would bring significant environmental and economic benefits [3]. The marketability of the product is forecast for 2014. Environmentally friendly spray or spray cement binders are rapidly solidifying, environmentally friendly binders that do not require the addition of setting accelerators in the manufacture of spray concrete and ensure the quick development of the shotcrete. The principle of the spray or spray cement binder consists essentially, is that it dispenses with the production of raw gypsum to the clinker to Zumahlung Abbindezeitverzögerung. The idea of ??such a binder in the manufacture of spray concrete had, in 1983 Robert Keller from Vils in Tyrol. He conducted comparative laboratory experiments with injection of cement and cement with one part accelerator by the other. In subsequent field trials, the binder was optimized and further developed. Also, research institutes have focused on accelerator-free spray or spray cement binders. These binders have been used in tunnel in Austria and Germany. Cement has been standardized very early. Currently, the cement composition is regulated in EN 197-1. The current standard is generally 28 different types of cement. 27 types of cement are distinguished by percentage weight of the constituent materials (cement, normal modes). The last type of cement (special cements) is only a description of provision which governs the designation of the cements used in the standard (because of their composition) can not be contained. The applications of various types of cement are also standardized. But here comes out of the EN 197-1 DIN 1164 are used. The DIN 1164 describes, for which environmental influences and installation situations (the standard used the term "exposure categories") which cements are required (eg blast furnace slag cements for underwater concrete). |
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