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metallurgy By:- Ayushi

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metallurgy Metallurgy is a domain of materials science that studies the physical and chemical behaviour of metallic elements, their inter-metallic compounds, and their mixtures, which are called alloys. It is also the technology of metals: the way in which science is applied to their practical use. Metallurgy is commonly used in the craft of metalworking.

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Extractive metallurgy is the practice of removing valuable metals from an ore and refining the extracted raw metals into a purer form. In order to convert a metal oxide or sulfide to a purer metal, the ore must be reduced physically, chemically, or electrolytically. Extractive metallurgists are interested in three primary streams: feed, concentrate (valuable metal oxide/sulfide), and tailings (waste). After mining, large pieces of the ore feed are broken through crushing and/or grinding in order to obtain particles small enough where each particle is either mostly valuable or mostly waste. Concentrating the particles of value in a form supporting separation enables the desired metal to be removed from waste products. Mining may not be necessary if the ore body and physical environment are conducive to leaching. Leaching dissolves minerals in an ore body and results in an enriched solution. The solution is collected and processed to extract valuable metals. Ore bodies often contain more than one valuable metal. Tailings of a previous process may be used as a feed in another process to extract a secondary product from the original ore. Additionally, a concentrate may contain more than one valuable metal. That concentrate would then be processed to separate the valuable metals into individual constituents. EXTRACTION

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“Iron is a transition metal which occurs in group 8th of the periodic table and has incompletely filled 3d” METALLURGY OF IRON

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Extraction of Iron and its metallurgy: Metallurgy of iron means extracting iron from its ore.The most important ore of iron is haematite (Fe2O3). High grade haematite ores have 60% iron and low grade have 20%.A blast furnace is a steel structure lined with refractory firebricks and is .. Uses of Sulphur, Selenium and Tellurium (i) Most of the sulphur produced is used for the manufacture of sulphuric acid and other industrially important sulphur compounds. (ii) Sulphur is used to prepare large number of medicines (Sulpha drugs) and can be used as ointment for curing skin diseases. (iii) It is also used in the manufacture .. Question: In metallurgy what do the terms gangue, flux, slag stand for? Give examples. Answer: The term 'Gangue' is used for all the earthly impurities associated with the ore of the metal. These need to be removed before the extraction step. Example: In iron ore, san..

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METALLURGY OF COPPER copper Cu In the 1st block-series of Transition Metals

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Metallurgy of gold

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Silver is usually recovered from silver ores by roasting the ore in a furnace to convert the sulfides to sulfates and then chemically precipitating metallic silver.Several metallurgical processes are used to extract silver from ores of other metals. In the amalgamation process, liquid mercury, which forms an amalgam with the silver, is added to the crushed ore.  After the amalgam is washed out of the ore the mercury is removed by distillation, leaving metallic silver.In lixiviation (separation) methods, the silver is dissolved in a solution of a salt, usually sodium cyanide, after which metallic silver is precipitated by bringing the solution in contact with metallic zinc or aluminium.For the Parkes process, which is used extensively in separating silver from copper and lead ores, the impure silver obtained in the metallurgical processes is usually refined by electrolytic methods or by cupellation, a process that involves removing impurities by vaporization or absorption. Metallurgy of silver

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Alkali Metals Group I of the Periodic Table is composed of highly reactive metals. They react vigorously with water to produce hydroxides and release hydrogen. Even in air they react quickly to cover their surfaces with oxides. In nature they are found in ionic compounds, but never in the pure state. Their chemical activity increases as you move downward through the periods from Li to Na to K, etc. Alkali metals tend to lose one electron and form ions with a single positive charge. They form ionic compounds (salts) in reaction with the halogens (alkali halides). Sodium and potassium ions form important constituents of body fluids (electrolytes). HIGHLY REACTIVE METALS

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Pure aluminium is a silvery-white metal with many desirable characteristics. It is light, nontoxic (as the metal), nonmagnetic and non sparking. Pure aluminium is soft and lacks strength, but alloys with small amounts of copper, magnesium, silicon, manganese, and other elements have very useful properties. ~Aluminium is the third most abundant element in the Earth's crust after oxygen and silicon metallurgy of aluminium

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Extraction of Aluminium Aluminum is extracted from its oxide ore "Bauxite". The extraction of aluminum involves the following steps. Purification of Bauxite Electrolysis of Alumina Refining Purification of Bauxite to Alumina Bauxite contains two main impurities Fe2O3 and SiO2. These impurities must be removed in order to get good quality aluminum. These impurities make the aluminum brittle and liable to corrosion. Depending upon the nature of impurity present in bauxite, any one of the following methods can be used for the purification of bauxite. Bayer's Process Bayer's process involves concentration and dehydration of bauxite to alumina (Al2O3). Treatment with NaOH Bauxite is treated with hot, concentrated NaOH solution. Aluminium oxide reacts with NaOH forming an aqueous solution of sodium aluminate. The impurities do not react. On filtration, impurities are separated from the sodium aluminate solution.

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Treatment with HCl The filtrate containing sodium aluminate is acidified with hydrochloric acid to form a precipitate of aluminium hydroxide.                                                    On filtration sodium chloride solution is obtained as a filtrate and is discarded. The pure aluminium hydroxide obtained as a gel is collected. Action of Heat on Al(OH) 3 The precipitate of Al(OH)3 is heated to a high temperature to obtain pure alumina.                                      Thus, pure alumina is obtained from bauxite.

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Hall's Process In this process, the pure alumina (Al2O3) obtained from Bayer's process is electrolytically reduced to aluminium.                                              An electrolytic cell used is called the Hall's cell. The Hall's cell is a steel tank lined inside with a layer of graphite which is made the cathode. The electrolyte consists of a mixture of fused (molten) alumina and cryolite. Cryolite is a flux and helps in lowering the melting point of alumina. A series of graphite rods dipped into the electrolyte serve as the anode. When electricity is passed through the cell, the molten alumina dissociates forming Al3+ and O2- ions,                               The Al3+ ions capture electrons of the cathode and get deposited at the bottom of the tank as molten aluminium. The O2- ions lose electrons to the anode and release oxygen gas. Some amoatoms with the graphite anode unt of carbon dioxide and carbon monoxide are also released, due to the reaction of oxygen

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Ionic Equations The molten aluminium thus collected is removed from an outlet at the bottom of the cell.

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