Kawasaki Jukogyo Kabushiki Kaisha

Taiheiyo Cement Corporation

Other

Yoshihiro Mitsuda

Hiroshi Ueda

Mitsuaki Murata

Kanzaburo Sutoh

Fuminori Ando

Seisuke Sawamura

Akihiko Takayama

Ryuichi Okamura

Tsutomu Hirobe

A method of grinding cement clinkers and a cement clinker grinding apparatus having a vertical roller mill are provided. In the method, feed material is ground by a table and rollers. Next, substantially all the resultant ground material is taken out from an underside of the table and then converted to a separator for classifying the ground material by a bucket elevator. The resultant coarse powder provided by the separator is returned to a center of the table. In grinding, an pressing force of each of the rollers onto the table is selected so that a roller pressure per full sectional area of the roller ranges from 10 to 15 kg/cm,. Further, a circulation quantity of the coarse powder to be returned to the vertical roller mill is selected from 100 to 300% of the feed material charged into the center of the table. And the liquid of 0.5 to 3% of the feed material to be ground such as water alone or a mixture of water and diethylene glycol is sprayed on the only frictional grinding zone which is positioned outside a position where a relative speed between said table and each of said rollers is equal to zero, in the radial direction of said table. By spraying the liquid on the only frictional grinding zone, the materials are involved firmly between the table and the roller to form the layer of the ground materials, so that the vibration of the roller and table are restrained

Cement clinker grinding method using vertical roller mill and apparatus

The grinding efficiency can be improved by use of a vertical roller mill, while reducing the energy consumption and improving the product quality. The disclosed cement clinker grinding apparatus comprises a closed circuit for conveying the ground material from the vertical roller mill (21) to the external separator (28) by the bucket elevator (29), for classifying the conveyed material into coarse powder and fine powder, and further for returning the classified coarse powder into the vertical roller mill (21). That is, a part of the ground material conveyed by the bucket elevator (29) is divided by the distributing damper (32) and then directly returned to the vertical roller mill (21). Since the ground material are not conveyed by air flow conveyance (i.e., air sweep), it is possible to prevent an increase of power consumption of the suction fan (31). Further, since a part of the ground material is distributed by the distributing damper and then further ground again by the vertical roller mill, it is possible to obtain an optimum particle size distribution of the cement products, so that the cement quality can be improved.

Cement clinker grinding apparatus using vertical roller mill and its

A fluidized-bed classifier has a vessel defining a space divided into an upper fluidized-bed chamber and a lower gas chamber by a perforated dispersion plate having the shape of a funnel. Rising currents of a gas, such as air, are blown through the dispersion plate into the upper fluidized-bed chamber to produce a fluidized bed of a particulate material over the dispersion plate. The lower gas chamber is divided into a first gas chamber and a second gas chamber by a partition plate. The gas is supplied into the first air chamber so that rising gas currents of a velocity necessary for fluidizing coarse particles contained in the particulate material fed into the vessel are blown from the first air chamber through the dispersion plate into the fluidized-bed chamber. The gas is supplied into the second air chamber so that rising gas currents of a velocity lower than the velocity of the rising gas currents blown from the first air chamber into the fluidized-bed chamber are blown into the fluidized-bed chamber so that coarse particles contained in the particulate material are not fluidized and does not flow together with fine particles into a fine particle discharge chute.

Fluidized-bed classifier

Growing community of inventors

Kakogawa, Japan

Yoshihiro Mitsuda