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Hydrometallurgy
Hydrometallurgy is a technique within the field of extractive metallurgy, the obtaining of metals from their ores. Hydrometallurgy involve the use of aqueous solutions for the recovery of metals from ores, concentrates, and recycled or residual materials.Brent Hiskey "Metallurgy, Survey" in Kirk-Othmer Encyclopedia of Chemical Technology, 2000, Wiley-VCH, Weinheim. Processing techniques that complement hydrometallurgy are pyrometallurgy, vapour metallurgy, and molten salt electrometallurgy. Hydrometallurgy is typically divided into three general areas: *Leaching *Solution concentration and purification *Metal or metal compound recovery Leaching Leaching involves the use of aqueous solutions to extract metal from metal bearing materials which is brought into contact with a material containing a valuable metal. The first examples come from 11-12th centuries China where it was applied to extraction of copper and accounted for a significant share of total copper production. In the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extractive Metallurgy
Extractive metallurgy is a branch of metallurgical engineering wherein process and methods of extraction of metals from their natural mineral deposits are studied. The field is a materials science, covering all aspects of the types of ore, washing, concentration, separation, chemical processes and extraction of pure metal and their alloying to suit various applications, sometimes for direct use as a finished product, but more often in a form that requires further working to achieve the given properties to suit the applications. The field of ferrous and non-ferrous extractive metallurgy have specialties that are generically grouped into the categories of mineral processing, hydrometallurgy, pyrometallurgy, and electrometallurgy based on the process adopted to extract the metal. Several processes are used for extraction of same metal depending on occurrence and chemical requirements. Mineral processing Mineral processing begins with beneficiation, consisting of initially br ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lixiviant
A lixiviant is a chemical used in hydrometallurgy to extract particular elements from its ore. One of the most famous lixiviants is cyanide, which is used in extracting 90% of mined gold. The combination of cyanide and air converts gold particles into a soluble salt. Once separated from the bulk gangue, the solution is processed in a series of steps to give the metal. Etymology The origin is the word 'lixiviate', meaning to leach or to dissolve out, deriving from the Latin ''lixivium''.The New English Dictionary A lixiviant assists in rapid and complete leaching, for example during in situ leach In-situ leaching (ISL), also called in-situ recovery (ISR) or solution mining, is a mining process used to recover minerals such as copper and uranium through boreholes drilled into a deposit, ''in situ''. In situ leach works by artificially disso ...ing. The metal can be recovered from it in a concentrated form after leaching. Further reading * References Metallurgical process ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrowinning
Electrowinning, also called electroextraction, is the electrodeposition of metals from their ores that have been put in solution via a process commonly referred to as leaching. Electrorefining uses a similar process to remove impurities from a metal. Both processes use electroplating on a large scale and are important techniques for the economical and straightforward purification of non-ferrous metals. The resulting metals are said to be ''electrowon''. In electrowinning, an electrical current is passed from an inert anode (oxidation, made out of lead (Pb)) through a ''leach'' solution containing the dissolved metal ions so that the metal is recovered as it is deposited in an electroplating process onto the cathode (reduction, stainless steel, aluminium (Al), titanium (Ti)). In electrorefining, the anode consists of the impure metal (e.g., copper) to be refined. The impure metallic anode is oxidized and the metal dissolves into solution. The metal ions migrate through ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dicyanoaurate(I)-3D-balls
Potassium dicyanoaurate is an inorganic compound with formula K u(CN)2 It is a colorless to white solid that is soluble in water and slightly soluble in alcohol. The salt itself is often not isolated, but solutions of the dicyanoaurate ion ( u(CN)2sup>−) are generated on a large scale in the extraction of gold from its ores. Production In mining of gold from dilute sources, gold is selectively extracted by dissolution in aqueous solutions of cyanide, provided by dissolving sodium cyanide, potassium cyanide and/or calcium cyanide. The reaction for the dissolution of gold, the "Elsner Equation", is: :4 Au + 8 KCN + O2 + 2 H2O → 4 K u(CN)2+ 4 KOH In this process, oxygen is the oxidant. It can also be produced by reaction of gold(I) salts with excess potassium cyanide. :AuCl + 2 KCN → K u(CN)2 + KCl Structure : Potassium dicyanoaurate is a salt. The dicyanoaurate anion is linear according to X-ray crystallography. On the basis of infrared s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ion Exchange
Ion exchange is a reversible interchange of one kind of ion present in an insoluble solid with another of like charge present in a solution surrounding the solid with the reaction being used especially for softening or making water demineralised, the purification of chemicals and separation of substances. Ion exchange usually describes a process of purification of aqueous solutions using solid polymeric ion-exchange resin. More precisely, the term encompasses a large variety of processes where ions are exchanged between two electrolytes. Aside from its use to purify drinking water, the technique is widely applied for purification and separation of a variety of industrially and medicinally important chemicals. Although the term usually refers to applications of synthetic (man-made) resins, it can include many other materials such as soil. Typical ion exchangers are ion-exchange resins (functionalized porous or gel polymer), zeolites, montmorillonite, clay, and soil humus. Ion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cementation (metallurgy)
Cementation is a type of precipitation, a heterogeneous process in which ions are reduced to zero valence at a solid metallic interface. The process is often used to refine leach solutions. Cementation of copper is a common example. Copper ions in solution, often from an ore leaching process, are precipitated out of solution in the presence of solid iron. The iron oxidizes, and the copper ions are reduced through the transfer of electrons. The reaction is spontaneous because copper is higher on the galvanic series than iron. : Cu2+(aq) + Fe(s) → Cu(s) + Fe2+(aq) This was a historically useful process for the production of copper, where the precipitated solid copper metal was recovered as flakes or powder on the surface of scrap iron. Cementation is used industrially to recover a variety of heavy metals including cadmium Cadmium is a chemical element with the Symbol (chemistry), symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeolite
Zeolites are microporous, crystalline aluminosilicate materials commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ･y where is either a metal ion or H+. These positive ions can be exchanged for others in a contacting electrolyte solution. exchanged zeolites are particularly useful as solid acid catalysts. The term ''zeolite'' was originally coined in 1756 by Swedish mineralogist Axel Fredrik Cronstedt, who observed that rapidly heating a material, believed to have been stilbite, produced large amounts of steam from water that had been adsorbed by the material. Based on this, he called the material ''zeolite'', from the Greek , meaning "to boil" and , meaning "stone". Zeolites occur naturally but are also produced industrially on a large scale. , 253 unique zeolite frameworks have been identified, and over 40 naturally occurring zeolite frameworks are known. Every new zeolite structure tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chelate
Chelation is a type of bonding of ions and molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central metal atom. These ligands are called chelants, chelators, chelating agents, or sequestering agents. They are usually organic compounds, but this is not a necessity, as in the case of zinc and its use as a maintenance therapy to prevent the absorption of copper in people with Wilson's disease. Chelation is useful in applications such as providing nutritional supplements, in chelation therapy to remove toxic metals from the body, as contrast agents in MRI scanning, in manufacturing using homogeneous catalysts, in chemical water treatment to assist in the removal of metals, and in fertilizers. Chelate effect The chelate effect is the greater affinity of chelating ligands for a metal ion than that of similar nonchelating (monodentate) ligands for the same metal. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solvent Extraction
A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for polar molecules and the most common solvent used by living things; all the ions and proteins in a cell are dissolved in water within the cell. The quantity of solute that can dissolve in a specific volume of solvent varies with temperature. Major uses of solvents are in paints, paint removers, inks, and dry cleaning. Specific uses for organic solvents are in dry cleaning (e.g. tetrachloroethylene); as paint thinners (toluene, turpentine); as nail polish removers and solvents of glue (acetone, methyl acetate, ethyl acetate); in spot removers (hexane, petrol ether); in detergents ( citrus terpenes); and in perfumes (ethanol). Solvents find various applications in chemical, pharmaceutical, oil, and gas industries, including in chemical s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raffinate
In chemical separation terminology, the raffinate (from French ''raffiner'', to refine) is a product which has had a component or components removed. The product having the removed materials is referred to as the extract. For example, in solvent extraction, the raffinate is the liquid stream which remains after solutes from the original liquid are removed through contact with an immiscible liquid. In metallurgy, raffinating refers to a process in which impurities are removed from liquid material. In pressure swing adsorption the raffinate refers to the gas which is not adsorbed during the high pressure stage. The species which is desorbed from the adsorbent at low pressure may be called the "extract" product. Types Raffinate-1 or C4R1 In naphtha cracking process, C4R1 refers to C4 residual obtained after separation of 1,3-butadiene from C4 raffinate stream and which, mainly consists of isobutylene 40~50 wt% and ''cis''- or ''trans''-2-butene 30~35 wt%. Normally C4R1 is a side pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diluent
A diluent (also referred to as a filler, dilutant or thinner) is a diluting agent. Certain fluids are too viscous to be pumped easily or too dense to flow from one particular point to the other. This can be problematic, because it might not be economically feasible to transport such fluids in this state. To ease this restricted movement, diluents are added. This decreases the viscosity of the fluids, thereby also decreasing the pumping/transportation costs. One industrial application is the transport of crude oil via pipelines. Heavy crude oil/bitumen are fluids with high viscosity, especially at low temperatures. The addition of a diluent enables the diluted fluid (dilbit in the case of bitumen) to meet pipeline specifications in order for it to be efficiently transported. Typical diluent in this case is naphtha or condensate. Types of diluents more familiar to the general public include paint thinner and nail polish thinner, both of which improve the consistency and appl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extract
An extract is a substance made by extracting a part of a raw material, often by using a solvent such as ethanol, oil or water. Extracts may be sold as tinctures, absolutes or in powder form. The aromatic principles of many spices, nuts, herbs, fruits, etc., and some flowers, are marketed as extracts, among the best known of true extracts being almond, cinnamon, cloves, ginger, lemon, nutmeg, orange, peppermint, pistachio, rose, spearmint, vanilla, violet, rum, and wintergreen. Extraction techniques Most natural essences are obtained by extracting the essential oil from the feedstock, such as blossoms, fruit, and roots, or from intact plants through multiple techniques and methods: * Expression ( juicing, pressing) involves physical extraction material from feedstock, used when the oil is plentiful and easily obtained from materials such as citrus peels, olives, and grapes. * Absorption ( steeping, decoction). Extraction is done by soaking material ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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