Calcium metallurgy

Mantell, C.L. Hardy, C. (1945) Calcium Metallurgy and Technology. Reinhold, New York. 

Calcium Metallurgy Most calcium metal is obtained by the reduction of calcium oxide with aluminum. Calcium metal is used mainly in some alloys. For example, the addition of a small quantity of calcium to the lead used for the electrodes of lead storage batteries substantially reduces the decomposition of water into its elements during the recharging of the battery. Since gases are not produced during recharging, the battery can be sealed so it requires less maintenance. 

Alloys of calcium with siUcon ate used in ferrous metallurgy (qv) and ate generally produced in an electric furnace from CaO (or Si02, and a... 

Metallurgy. Calcium oxide reacts readily with acid anhydrides ... 

Sihcon carbide is comparatively stable. The only violent reaction occurs when SiC is heated with a mixture of potassium dichromate and lead chromate. Chemical reactions do, however, take place between sihcon carbide and a variety of compounds at relatively high temperatures. Sodium sihcate attacks SiC above 1300°C, and SiC reacts with calcium and magnesium oxides above 1000°C and with copper oxide at 800°C to form the metal sihcide. Sihcon carbide decomposes in fused alkahes such as potassium chromate or sodium chromate and in fused borax or cryohte, and reacts with carbon dioxide, hydrogen, ak, and steam. Sihcon carbide, resistant to chlorine below 700°C, reacts to form carbon and sihcon tetrachloride at high temperature. SiC dissociates in molten kon and the sihcon reacts with oxides present in the melt, a reaction of use in the metallurgy of kon and steel (qv). The dense, self-bonded type of SiC has good resistance to aluminum up to about 800°C, to bismuth and zinc at 600°C, and to tin up to 400°C a new sihcon nitride-bonded type exhibits improved resistance to cryohte. 

Calcinating a mineral removes its volatile components, such as water or carbon dioxide and leaves an usually crumbly solid residue. Calcinated secondary minerals such as limestone are the basic components of building cements, and in extractive metallurgy operations they facilitate the smelting of metals. Calcinating limestone (composed of calcium carbonate), for example, drives away carbon dioxide, leaving a solid, friable residue of quicklime (composed of calcium oxide) ... 

Calcium fluoride occurs in nature as the mineral fluorspar or fluorite. It is used as a flux in ferrous metallurgy to enhance the fluidity of the slag. An important application of this compound is in the manufacture of fluorine and hydrofluoric acid, starting materials for producing many fluoroorganics. It also is used in glass and ceramics. Pure crystals are used in lasers, optics, and electronics. Other applications are in high temperature, dry-film lubricants ... 

Johan Gottschalk Wallerius, 1709-1785. Swedish chemist, physician, mineralogist, and agriculturist. T, Bergman s predecessor as professor of chemistry, metallurgy, and pharmacy at Upsala. In his analyses of bone and other animal substances m 1760, he detected the calcium but not the phosphorus... 

Ferrosilicon - [CARBON - CARBON AND ARTIFICIALGRAPHITE - APPLICATIONS OF BAKED AND GRAPHITIZED CARBON] (Vol 4) - [SILICON AND SILICON ALLOYS - CHEMICAL AND METALLURGICAL] (Vol21) - [METALLURGY - EXTRACTIVE METALLURGY] (Vol 16) - [MINERALS RECOVERY AND PROCESSING] (Vol 16) - [SILICON COMPOUNDS-SILANES] (Vol 22) -as calcium carbide impurity [CARBIDES - CALCIUM CARBIDE] (Vol 4)... 

Cyanide. Potassium cyanide, [CAS 151-50-8], cyanide of potash, KCN, white solid, soluble, very poisonous, formed by reaction of calcium cyanamide and potassium chloride at high temperature. Used as a source of cyanide and for hydrocyanic acid, but usually replaced by the cheaper sodium cyanide. Also used in metallurgy, electroplating,... 

Linear alkylbenzenes are made from linear terminal olefins and benzene and are important precursors of biodegradable anionic surfactants (LAS, linear alkylbenzenesulfonates). The conventional catalyst is HF, first to be replaced by a fluorinated silica-alumina in the DETAL process. The DETAL process is safer than the HF process and also more cost-effective because no special metallurgy is required and no calcium fluoride waste stream exists.52 Zeolites such as Beta may come to the fore here because they display a higher selectivity to the desired 2-phenyl isomers.55... 

Calcium is utilized in the manufacture of special metals such as zirconium, thorium, uranium and the rare earths, as a refining agent in metallurgy (steel, copper, magnesium, tantalum, lead) and in the manufacture of calcium hydride (hydrogen source). 

Nishimura, T, and Robins, R. G., 1998, A re-evaluation ofthe solubility and stability regions of calcium arsenites and calcium arsenates in aqueous solution at 25°C Mineral Processing and Extractive Metallurgy Reviews, v. 18, p. 283-308. 

Derivation (1) Reduction of thorium dioxide with calcium (2) fused salt electrolysis of the double fluoride ThF4 KF. The product of both processes is thorium powder, fabricated into the metal by powder metallurgy techniques. Hot surface decomposition of the iodide produces crystal bar thorium. 

Calcium and its compounds are widely used commercially. The element is used as a reducing agent in the metallurgy of uranium, thorium, and other metals. It is also used as a scavenger to remove dissolved impurities such as oxygen, sulfur, and carbon in molten metals and to remove residual gases in vacuum tubes. It is a component of many alloys. 

Metallurgy. — Metallic, rubidium may be prepared in a variety of ways (1) electrolysis of the fused chloride, (2) heating RbOH with aluminium or mugnesinin, fH) heating Rb,t 0 with carhon or magnesium, (4) heating It Iff 1 wilh calcium, (5) heating the tartrate to white heat. 

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