Fujitsu Corporation

Nippon Light Metal Company, Ltd.

Nec Corporation

Nippon Telegraph and Telephone Corporation

Satoshi Takeda

Hiroshi Nakaide

Kaoru Sugita

Yoshihiro Taguchi

Yuji Ota

Hiroshi Sano

Atsuki Taniguchi

Toshiaki Hayashi

Kazuhiro Oda

Hiroshi Takeo

Yasushi Kobayashi

Masanori Kajiwara

Hiroshi Yamasaki

Michinobu Ohhata

Shinji Hiyama

Takao Moriya

Katsuhiko Nakamoto

Shinzi Hiyama

Masashi Ojiri

Norihisa Miura

Kensaburo Namba

Masashi Ohba

Ikuo Washiyama

Toshinari Kunieda

Provided is a method of recovering rare-earth elements by which rare-earth elements can be recovered efficiently from a bauxite residue serving as a raw material and containing the rare-earth elements. Specifically provided is a method of recovering rare-earth elements from a raw material, the raw material being a bauxite residue produced as a by-product in a Bayer process, the method including: using a bauxite residue having a specific surface area of 35 m/g or more; adding, to the raw material bauxite residue, a liquid leaching agent formed of an aqueous solution of at least one kind of mineral acid selected from sulfuric acid, hydrochloric acid, nitric acid, and sulfurous acid, thereby preparing a slurry having a liquid-solid ratio of 2 to 30 and a pH of 0.5 to 2.2; subjecting the slurry to leaching treatment of the rare-earth elements under a temperature condition of room temperature to 160&#xb0; C.; subjecting the slurry after the leaching treatment to solid-liquid separation, yielding a leachate; and separating and recovering the rare-earth elements from the leachate.

Method of recovering rare-earth elements

Provided is a method of recovering rare-earth elements, including causing rare-earth elements particularly including Nd and Dy to leach efficiently from a raw material for leaching which contains the rare-earth elements, and separating and recovering the rare-earth elements. The method of recovering rare-earth elements includes: a leaching step including performing leaching treatment of rare-earth elements in which an acidic slurry of a raw material for leaching which contains the rare-earth elements is held under a predetermined condition, and then subjecting the slurry obtained after the leaching treatment to solid-liquid separation, yielding a leachate containing the rare-earth elements; and a separation step of separating and recovering the rare-earth elements from the yielded leachate, in which: the raw material for leaching contains Ca as CaO at a ratio of 4 to 15 mass % and Ti as TiOat a ratio of 2 to 13 mass % in a solid component (S); an acid aqueous solution is an acid aqueous solution of hydrochloric acid and/or nitric acid; and the leaching treatment performed in the leaching step is digestion or maceration which is performed under the heating and pressurizing conditions of a temperature of 160 to 300&#xb0; C. and a pressure of 0.65 to 10 MPa, and the rare-earth elements are caused to leach together with Ca in the leaching step.

Rare earth element recovery method

A time switch control system having a cross-connect function is used for digital time-division. Multiplex communications permit desired channel settings and reduce power consumption. Identifying circuits identify which time-slot signals are to be retained by an input signal retaining memory, and output identification information to the retention memory, and to a retention memory controller. The retention memory controller stores therein the identification information from the identifying circuits, then reads out the identification information, and controls the input signal retaining memory in accordance with the contents of the identification information. Only the specified time-slot signals are stored and retained by the input signal retaining memory, thereby reducing power requirements. Exchange/output circuits exchange the time-slot signals stored in the input signal retaining memory in accordance with channel setting information, and output the exchanged signals.

Time-slot switching system identifying and storing only time-slot

At a CRC transmission side of a cross connect equipment, a CRC operation is applied to received channel data of each channel independently and sequentially in every sub frame having the same number of channels, series of which sub frames set up a main frame. The resultant CRC code of each channel obtained in a preceding sub frame is coupled to the received channel data of the corresponding channel to apply the same CRC operation to the thus received channel data, thereby the accumulated result of each channel is added in the last sub frame. At a CRC reception side, a cyclic CRC operation similar to that achieved at the CRC transmission side is applied to an outgoing channel data provided with the resultant CRC codes for each channel to obtain CRC results. During the cyclic CRC operation, a CRC error that once occurs is held during the main frame.

Channel data CRC systems for use with cross connect equipment

A synchronous control method in a plurality of channel units for synchronously transmitting each transmission signal in response to a synchronous control signal by a plurality of channel units comprising the process steps of providing a synchronous control circuit for outputting a synchronous control signal to each channel unit; and supplying the synchronous control signal from the synchronous control circuit corresponding to a high order channel unit to the self-channel unit and the synchronous control circuit corresponding to a low order channel unit in response to the synchronous signal in the transmission signal. By using this method, a synchronous control circuit having a single circuit constitution can respond to many combinations of arbitrary channels.

Synchronous control method in plurality of channel units and circuit

A digital signal transmission system includes a synchronization pattern detection circuit for detecting a synchronization pattern in response to a received transmitted digital signal, a pseudo synchronization detection circuit for detecting a pseudo synchronization pattern in the form of cyclic redundancy code in response to a received transmitted digital signal, and a synchronization protection circuit for counting the synchronization pattern detection signals produced when synchronization patterns are detected in response to a synchronization pattern detection signal from the synchronization pattern detection circuit. The synchronization protection circuit includes a main synchronization counter circuit and an auxiliary synchronization counter circuit. The count of protection steps for the confirmation of synchronization recovery of the auxiliary synchronization counter circuit in accordance with synchronization or asynchronization of the main synchronization counter circuit is variable.

Digital signal transmission system having frame synchronization operation

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Kawasaki, Japan

Satoshi Takeda