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heat a substance so that it oxidizes or reduces
the conversion of metals into their oxides as a result of heating to a high temperature

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…'を'焼いて生石灰にするか焼(かしょう)する / 焼いて生石灰になる / 生石灰
か焼(かしょう)(石灰を焼いて生石灰にすること)

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/11/14 13:28:35」(JST)

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Calcination (also referred to as calcining) is a thermal treatment process in absence of air or oxygen applied to ores and other solid materials to bring about a thermal decomposition, phase transition, or removal of a volatile fraction.^[1] The calcination process normally takes place at temperatures below the melting point of the product materials. Calcination is not the same process as roasting. In roasting, more complex gas–solid reactions take place between the furnace atmosphere and the solids.

Industrial processes

An oven for calcination of limestone

The process of calcination derives its name from the Latin calcinare (to burn lime)^[2] due to its most common application, the decomposition of calcium carbonate (limestone) to calcium oxide (lime) and carbon dioxide, in order to produce cement. The product of calcination is usually referred to in general as "calcine," regardless of the actual minerals undergoing thermal treatment. Calcination is carried out in furnaces or reactors (sometimes referred to as kilns or calciners) of various designs including shaft furnaces, rotary kilns, multiple hearth furnaces, and fluidized bed reactors.

Examples of calcination processes include the following:

decomposition of carbonate minerals, as in the calcination of limestone to drive off carbon dioxide;
decomposition of hydrated minerals, as in the calcination of bauxite and gypsum, to remove crystalline water as water vapor;
decomposition of volatile matter contained in raw petroleum coke;
heat treatment to effect phase transformations, as in conversion of anatase to rutile or devitrification of glass materials
removal of ammonium ions in the synthesis of zeolites.

Calcination reactions

Calcination reactions usually take place at or above the thermal decomposition temperature (for decomposition and volatilization reactions) or the transition temperature (for phase transitions). This temperature is usually defined as the temperature at which the standard Gibbs free energy for a particular calcination reaction is equal to zero. For example, in limestone calcination, a decomposition process, the chemical reaction is

CaCO₃ → CaO + CO₂(g)

The standard Gibbs free energy of reaction is approximated as ΔG°_r = 177,100 − 158 T (J/mol).^[3] The standard free energy of reaction is zero in this case when the temperature, T, is equal to 1121 K, or 848 °C.

Examples of chemical decomposition reactions common in calcination processes, and their respective thermal decomposition temperatures include:

CaCO₃ → CaO + CO₂; 848 °C

See also calcination equilibrium of calcium carbonate

Oxidation

In some cases, calcination of a metal results in oxidation of the metal. Jean Rey noted that lead and tin when calcinated gained weight, presumably as they were being oxidized.

Alchemy

In alchemy, calcination was believed to be one of the 12 vital processes required for the transformation of a substance.

Alchemists distinguished two kinds of calcination, actual and potential. Actual calcination is that brought about by actual fire, from wood, coals, or other fuel, raised to a certain temperature. Potential calcination is that brought about by potential fire, such as corrosive chemicals; for example, gold was calcined in a reverberatory furnace with mercury and sal ammoniac; silver with common salt and alkali salt; copper with salt and sulfur; iron with sal ammoniac and vinegar; tin with antimony; lead with sulfur; and mercury with aqua fortis.^[4]

There was also philosophical calcination, which was said to occur when horns, hooves, etc., were hung over boiling water, or other liquor, until they had lost their mucilage, and were easily reducible into powder.^[4]

References

^ IUPAC. "Calcination".
^ Mosby’s Medical, Nursing and Allied Health Dictionary, Fourth Edition, Mosby-Year Book Inc., 1994, p. 243
^ Gilchrist, J.D. (1989). Extraction Metallurgy (3rd ed.). Oxford: Pergamon Press. p. 145. ISBN 0-08-036612-0.
^ ^a ^b This article incorporates text from a publication now in the public domain: Chambers, Ephraim, ed. (1728). "Calcination". Cyclopædia, or an Universal Dictionary of Arts and Sciences (first ed.). James and John Knapton, et al.

English Journal

Human breast cancer bone metastasis in vitro and in vivo: a novel 3D model system for studies of tumour cell-bone cell interactions.

Holen I1, Nutter F1, Wilkinson JM2, Evans CA1, Avgoustou P1, Ottewell PD3.
Clinical & experimental metastasis.Clin Exp Metastasis.2015 Oct;32(7):689-702. doi: 10.1007/s10585-015-9737-y. Epub 2015 Aug 1.
Bone is established as the preferred site of breast cancer metastasis. However, the precise mechanisms responsible for this preference remain unidentified. In order to improve outcome for patients with advanced breast cancer and skeletal involvement, we need to better understand how this process is
PMID 26231669

Stable Hg isotope signatures in creek sediments impacted by a former Hg mine.

Smith RS, Wiederhold JG, Jew AD, Brown GE Jr, Bourdon B, Kretzschmar R.
Environmental science & technology.Environ Sci Technol.2015 Jan 20;49(2):767-76.
The goal of this study was to investigate the Hg stable isotope signatures of sediments in San Carlos Creek downstream of the former Hg mine New Idria, CA, USA and to relate the results to previously studied Hg isotope signatures of unroasted ore waste and calcine materials in the mining area. New I
PMID 25489982

Recovery of SO2 and MgO from By-Products of MgO Wet Flue Gas Desulfurization.

Yan L1, Lu X1, Wang Q1, Guo Q1.
Environmental engineering science.Environ Eng Sci.2014 Nov 1;31(11):621-630.
An industrial demonstration unit using natural gas as a heat source was built to calcine the by-products of MgO wet flue gas desulfurization from power plants; influencing factors on the SO2 content in calciner gas were comprehensively analyzed; and an advantageous recycling condition of MgO and SO2
PMID 25371652