BISMUTH PURIFICATION METHOD - SUMITOMO METAL MINING CO

Title:

BISMUTH PURIFICATION METHOD

Document Type and Number:

WIPO Patent Application WO/2018/138917

Kind Code:

A1

Abstract:

Provided is a bismuth purification method for recovering bismuth from a liquid obtained after recovering precious metals from copper electrolysis slime. The method comprises: 1) a neutralization step in which an alkali is added to an acidic solution to adjust the pH to a range of 2.0 to 3.0, and then solids and liquid are separated to obtain a neutralized filtrate and a neutralized precipitate; 2) an alkali leaching step in which an alkali is added to the neutralized precipitate obtained in the neutralization step to separate the same into an alkali leachate and an alkali leaching residue; 3) a sulfuric acid leaching step in which sulfuric acid is added to the alkali leaching residue to separate the same into a sulfuric acid leachate and a sulfuric acid leaching residue; 4) a cooling step for cooling the sulfuric acid leachate obtained in the sulfuric acid leaching step to obtain bismuth sulfate crystals; 5) a bismuth oxidation step characterized in that an alkali is added to the bismuth sulfate crystals obtained in the cooling step to obtain bismuth oxide; and 6) an electrolysis step in which an acid solution is added to the bismuth oxide obtained in the bismuth oxidation step to dissolve the same, and the solution obtained is electro-extracted to obtain metallic bismuth.

Inventors:

TAKENOUCHI HIROSHI (JP)
KAJI NOBUYUKI (JP)
NAGAKURA TOSHIHIKO (JP)
TAKEDA KENJI (JP)
ASANO SATOSHI (JP)

Application Number:

PCT/JP2017/003210

Publication Date:

August 02, 2018

Filing Date:

January 30, 2017

Export Citation:

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Assignee:

SUMITOMO METAL MINING CO (JP)

International Classes:

C22B30/06; C22B3/08; C22B3/44; C22B7/00; C25C1/22

Foreign References:

JP2012144754A	2012-08-02
JP2013155432A	2013-08-15
JPS4921210B1	1974-05-30
JP2010196140A	2010-09-09

Other References: