The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Jan. 05, 2016

Filed:

Dec. 07, 2012
Applicant:

Nippon Light Metal Company, Ltd., Tokyo, JP;

Inventors:

Kaoru Sugita, Shizuoka, JP;

Yasushi Kobayashi, Shizuoka, JP;

Yoshihiro Taguchi, Shizuoka, JP;

Satoshi Takeda, Shizuoka, JP;

Yuji Ota, Shizuoka, JP;

Masashi Ojiri, Shizuoka, JP;

Kazuhiro Oda, Shizuoka, JP;

Hiroshi Sano, Shizuoka, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C22B 59/00 (2006.01); B09B 3/00 (2006.01); C01F 17/00 (2006.01); C22B 3/26 (2006.01); C22B 3/04 (2006.01); C22B 3/20 (2006.01); C22B 3/44 (2006.01); C22B 7/00 (2006.01);
U.S. Cl.
CPC ...
C22B 59/00 (2013.01); B09B 3/00 (2013.01); C01F 17/00 (2013.01); C22B 3/0005 (2013.01); C22B 3/04 (2013.01); C22B 3/20 (2013.01); C22B 3/44 (2013.01); C22B 7/00 (2013.01); C22B 7/007 (2013.01); Y02W 30/54 (2015.05);
Abstract

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° 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.


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