Compositions: coating or plastic – Coating or plastic compositions – Inorganic settable ingredient containing
Patent
1996-04-23
1997-11-25
Marcheschi, Michael
Compositions: coating or plastic
Coating or plastic compositions
Inorganic settable ingredient containing
106743, 106750, 106756, 432 14, 432 58, 432106, C04B 745, C04B 747, F27B 702, F27B 1500
Patent
active
056907303
DESCRIPTION:
BRIEF SUMMARY
CROSS REFERENCE TO RELATED APPLICATION
This application is national stage application under 35 U.S.C. .sctn.371 of International Application No. PCT/JP95/01748, filed Sep. 1, 1995.
TECHNICAL FIELD
The present invention relates to a method of sintering cement clinkers by a single fluidized bed granulating and sintering furnace, and to a sintering apparatus for effecting this method.
BACKGROUND ART
Cement clinkers are manufactured by blending and crushing limestone, silica sand and so forth, preheating this raw material powder, granulating the preheated and partially calcined material powder, sintering the granules, and thereafter cooling them. Recently, cement clinkers are often manufactured by a sintering apparatus comprising two furnaces, i.e., a spouted bed granulating furnace or a fluidized bed granulating furnace and a fluidized bed sintering furnace (see, for example, JP-A-2-229745). This manufacturing apparatus of cement clinkers disclosed in JP-A-2-229745 further includes a primary cooling device and a secondary cooling device.
Also, there has been recently known a sintering apparatus of cement clinkers in which granulation and sintering are conducted by a single fluidized bed furnace (see, for example, JP-A-58-115047).
In the sintering apparatus of cement clinkers disclosed in JP-A-2-229745, raw material is granulated in a spouted bed granulating furnace, sintered in a fluidized bed sintering furnace, quenched in a primary fluidized bed cooling device, and cooled in a secondary fluidized bed cooling device while heat is recovered. This sintering apparatus comprises two furnaces, i.e., the spouted bed granulating furnace and the fluidized bed sintering furnace, so that sintering can be effected at high temperatures, thereby the manufacturing of cement clinkers of a high quality can be achieved. However, the apparatus involves a problem that the number of component devices is large, and that the operating cost of the apparatus is high. Consequently, there has been an increasing demand for the development of a sintering apparatus having a compact structure which can reduce the heat consumption and power consumption by a large degree.
In the sintering apparatus of cement clinkers disclosed in JP-A-58-115047, discharged air from a cooling device is introduced into a discharge chute in such a manner that a plurality of classifying zones of different flow velocities are formed in the discharge chute extending from the sintering furnace. However, since the air flow rate in each duct is determined by a differential pressure, it varies in accordance with the condition of granulated material dropping into the discharge chute, and therefore, it is difficult to regulate the flow velocity of the air at a predetermined level. Furthermore, once the granulated material drops into the chute, it does not disperse well in the chute, therefore the classifying effect in returning fine granules back to the fluidized bed is small.
Consequently, the particle size distribution of clinkers is broad, thereby causing the reduction of quality (sufficient sintering of fine granules cannot be expected). Also, the particle size distribution in the bed becomes broad, and accordingly, an unfavorable phenomenon called agglomeration tends to occur wherein granules stick to one another excessively. As a result, the sintering temperature can not be sufficiently raised, thus making it impossible to obtain cement clinkers of a high quality.
DISCLOSURE OF THE INVENTION
The present invention has been achieved in consideration of the above-described problems. The object of the invention is to provide a method and an apparatus for manufacturing cement clinkers with equipment of an extremely simple single-furnace structure which enables the sintering of cement clinkers of a high quality at low running costs.
In order to achieve the above object, according to the invention, a sintering method of cement clinkers, in which preheated cement raw material powder is granulated and sintered in a fluidized bed granulating and sintering furnac
REFERENCES:
patent: 5478234 (1995-12-01), Yokota et al.
patent: 5536167 (1996-07-01), Yokota et al.
Hashimoto Isao
Kanamori Shozo
Mukai Katsuji
Murao Mikio
Sato Nichitaka
Kawasaki Jukogyo Kabushiki Kaisha
Marcheschi Michael
Sumitomo Osaka Cement Co. Ltd.
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