Calcium oxide lime

The choice of selected raw materials is very wide, but they must provide calcium oxide (lime), iron oxide [1309-37-1/, siHca, and aluminum oxide (alumina). Examples of the calcereous (calcium oxide) sources are calcium carbonate minerals (aragonite [14791-73-2] calcite [13397-26-7] limestone [1317-65-3] or mad), seasheUs, or shale. Examples of argillaceous (siHca and alumina) sources are clays, fly ash, mad, shale, and sand. The iron oxide commonly comes from iron ore, clays, or mill scale. Some raw matedals supply more than one ingredient, and the mixture of raw matedals is a function of their chemical composition, as deterrnined by cost and availabiHty. 

Calcium oxide (lime) Rotary kilns, vertical and shaft kilns, fluidized bed furnaces Particulate matter Cyclones plus secondary collectors (baghouse, ESP, wet scrubbers, granular bed filters, wet cyclones)... 

Alkali Ammonia Biocides Sodium hydroxide (caustic soda) Potassium hydroxide (caustic potash) Calcium oxide (lime) Calcium hydroxide Sodium, potassium and calcium carbonates Ammonia (q.v.)... 

Calcium Oxide (lime, Quicklime, Burnt Lime, Calx, Unslaked Lime, Fluxing Lime). CaO, mw 56.08, white or greyish-white lumps or powd, mp 2580°, bp 2850°, d 3.25-3.40g/cc. SI sol in w with formation of calcium hydroxide and evolution of large amts of heat sol in acids, and insol in ethanol. Coml prepn consists of heating calcium carbonate in kilns at 1000—1100° until all of the C02 is driven off. Lab prepn is by burning calcium carbonate or calcium oxalate at about 800° using a quartz crucible in an electric furnace... 

The production of steel begins when iron ore is fed into a blast furnace (Fig. 16.39). The furnace, which is approximately 40 m high, is continuously replenished from the top with a mixture of ore, coke, and limestone. Each kilogram of iron produced requires about 1.75 kg of ore, 0.75 kg of coke, and 0.25 kg of limestone. The limestone, which is primarily calcium carbonate, undergoes thermal decomposition to calcium oxide (lime) and carbon dioxide. The calcium oxide, which contains the Lewis base O2", helps to remove the acidic (nonmetal oxide) and amphoteric impurities from the ore ... 

Potassium hydroxide (caustic potash) Calcium oxide (lime)... 

Sulfur dioxide can be removed from power plant exhaust gas by a scrubber s tem. One common method involves the reaction of SO2 with calcium oxide (lime) to form calcium sulfite S02(g) + CaO( ) CaS03 ( ) Unfortunately, scrubber systems are expensive to operate, and the solid CaS03 is generated in large enough quantities to create significant disposal problems. 

Removing a product from a system at equilibrium also makes Q < and leads to the formation of additional products. This behavior is commonly used to advantage in chemical synthesis. For example, calcium oxide (lime), an important material in the construction industry, is made by heating calcium carbonate in a furnace to about 1100 K CaCOs ( ) CaO (s) + CO2 (g) = (pco2 = 10 at 1100 K... 

Many metal hydroxides are insoluble. For example, when MgO is made into a slurry, the white suspension is known as milk of magnesia. Calcium oxide (lime) is produced by heating limestone (calcium carbonate) at high temperature. 

Specifically, to react calcium oxide (lime) with water to form calcium... 

Hydroxides of reactive metals show no decomposition when they are heated. The hydroxides of moderately reactive metals do decompose to produce the metal oxide and water. This process is used to convert calcium hydroxide (slaked lime) into calcium oxide (lime). 

Some calcium oxide (lime) is added to remove these solid oxides as slag. The slag may be skimmed or poured off the surface. 

When calcium carbonate is heated strongly it thermally dissociates (breaks up reversibly) to form calcium oxide (lime) and carbon dioxide. 

Decomposition. A decomposition reaction can be considered to be the reverse of a combination reaction. In a decomposition reaction, one substance (the reactant) decomposes to form two or more products. For example, calcium carbonate (limestone) decomposes at high temperatures to calcium oxide (lime) and carbon dioxide. This reaction is used industrially to produce large quantities of lime. 

If calcium carbonate is heated, it decomposes into calcium oxide (lime) and carbon dioxide the reverse reaction is favored at sufficiently high pressures of carbon dioxide. The equilibrium can be studied experimentally, and it is found that at any given temperature the pressure of C02(g) is constant, independent of the amounts of CaC03(s) and CaO(s), as long as some of each is present (Fig. 14.3). The two pure solids do not appear in the mass action law, which reduces to the partial pressure of CO2. 

Calcium oxide (lime) Calcium hydroxide Softening, pH adjustment... 

Specifically, to react calcium oxide (lime) with water to form calcium hydroxide (slaked or hydrated lime), the reaction is CaO + H20 —> Ca(OH)2 + heat. The alternate spelling slake has the same meaning. 

As you saw in the last section, the calcium carbonate in limestone can be converted into calcium oxide (lime) and carbon dioxide. At normal temperatures, this reaction is so slow that most limestone formations remain unreacted for thousands of years. Why, then, does it take place rapidly at 1200 °C Similarly, why does the combustion of gasoline take place more quickly when the fuel air mixture in a cylinder of your car is compressed into a smaller volume by a moving piston How does your car s catalytic converter speed the conversion of NO( g ) into N2(j ) and 02 g) Now that we know more about the requirements for reaction, we can proceed to answer questions such as these. 

LIMAS (554-13-2) see lithium carbonate. LIME or LIME, BURNED or LIME, BURNT (1305-78-8) see calcium oxide. LIME CHLORIDE (7778-54-3) see calcium hypochlorite. 

Calcium Oxide. Lime burnt lime calx quicklime. GO mol wt 56.08. Ca 71.47%, O 28.53%. Properly stored line of commerce contains 90-95% free CaO. Commercial production from limestone W. L. Faith et al. Industrial Chemicals (John Wiley, New York, 3rd ed, 1965) pp 482-411. Ub prepn by ignition of CaCO, Ehrlich in Handbook si Preparative Inorganic Chemistry ml. 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) p 931. Review R, S. Boynton in Kirk -Othmer Encyclopedia of Chemical Ttthealogy voL 14 (Wiley-Interscience, New York, 3rd ed.. Iffl) pp 343-382. 

The chemical reactions below 1300°C are calcination, decomposition of clay minerals as well as the reaction of calcium carbonate (calcite) CaCOg or calcium oxide (lime) CaO with quartz and clay mineral decomposition products. Calcination of calcite, decomposition of clay minerals are endothermic reactions, while reaction of calcife or lime with quartz and clay mineral decomposition products are exothermic. Calcination of pure calcium carbonate is done according to the reaction ... 

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