Although the calcium carbonate is very little soluble in water, it is quite soluble if the water contains dissolved carbon dioxide, for in these solutions it forms bicarbonate when dissolving. It’s very demanded as construction material. The Iceland spar and the calcite are essentially pure carbonate forms, whilst the marble is impure and much more compact, reason why it can be polished. The natural carbonates are the most abundant calcium minerals. The pure calcium carbonate occurs in two crystalline forms: calcite, hexagonal shaped, which possesses birrefringent properties, and aragonite, rhombohedric. The acetylene is the base material of a great number of important chemicals for the organic industrial chemistry. Calcium carbide, CaC 2, is produces when heating up a mixture of lime and carbon at 3000✬ in an electric oven and it is an acetylate which produces acetylene by hydrolysis. The calcium silicate, CaSi, prepared in an electric oven from lime, silica and reducing carbonated agents, is useful as a steel-deoxidizing agent. The quick lime is an excellent absorbent for the carbon dioxide, because it produces carbonate, which is very insoluble. In the process of calcium hydroxide quenching, the volume of blown out lime expends to double the initial quantity of quick lime (CaO), fact that makes it useful to break down rocks or wood. The calcium oxide, Ca(OH) 2, has many applications in which the hydroxyl ion is necessary. The metallurgic industry extensively uses the oxide during the reduction of ferrous alloys. The oxide is used in high intensity light arcs (lime light) for its unusual spectral characteristics and as dehydrating industrial agent. The calcium oxide, CaO, is produced by thermal decomposition of carbonated minerals in furnaces, applying a continuous bed process. It is also used in making cements and mortar that are used in builldings. Calcium is an alloying used in the production of alluminium, beryllium, copper, lead and magnesium alloys. It is also used as a deoxidizer in the manufacture of many steels as a reducing agent in the preparation of metals as chromium, thorium, zirconium and uranium, and as separating material for gaseous mixtures of nitrogen and argon. The metal is used in aluminium alloys for bearings, as a helper in the bismuth removal form lead, as well as in controlling graphitic carbon in melted iron. The commercially produced metal reacts easily with water and acids and it produces hydrogen which contains remarkable amounts of ammonia and hydrocarbides as impurities. It burns in the air at a high temperature to produce nitride. In contact with air, calcium develops an oxide and nitride coating, which protects it from further corrosion. This is obtained by treatment of carbonated minerals with chlorhydric acid, or like a sub product of the carbonates Solvay process. In the industry, metallic calcium is separated from the melted calcium chloride by electrolysis. This can be avoided with the water softeners. It is less chemically reactive than alkaline metals and than the other alkaline-earth metals.Ĭalcium ions solved in water form deposits in pipes and boilers and when the water is hard, that is, when it contains too much calcium or magnesium. A well as beryllium and aluminium, and unlike the alkaline metals, it doesn’t cause skin-burns. The metal is trimorphic, harder than sodium, but softer than aluminium. The chemical element Calcium (Ca), atomic number 20, is the fifth element and the third most abundant metal in the earth’s crust. Separation and Concentration Purification RequestĬalcium - Ca Chemical properties of calcium - Health effects of calcium - Environmental effects of calcium.
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