公开(公告)号：US20210292927A1

公开(公告)日：2021-09-23

申请号：US16317998

申请日：2017-01-30

申请人： SUMITOMO METAL MINING CO., LTD.

发明人： Hiroshi TAKENOUCHI ,  Nobuyuki KAJI ,  Toshihiko NAGAKURA ,  Kenji TAKEDA ,  Satoshi ASANO

IPC分类号： C25C1/22 ,  C22B7/00 ,  C22B30/06 ,  C22B3/44

摘要： A method for refining bismuth is provided, which comprises recovering bismuth from a solution obtained after recovery of noble metals from a copper electrolytic slime.
The method comprises: 1) a neutralization step of adding alkali to an acid solution to adjust the pH to the range of 2.0 or more and 3.0 or less, and then performing solid-liquid separation to obtain a neutralized filtrate and a neutralized precipitate; 2) an alkaline leaching step of adding alkali to the neutralized precipitate obtained in the neutralization step to separate the resultant into an alkali leachate and an alkaline leaching residue; 3) a sulfuric acid leaching step of adding sulfuric acid to the alkaline leaching residue to separate the resultant into a sulfuric acid leachate and a sulfuric acid-leaching residue; 4) a cooling step of cooling the sulfuric acid leachate obtained in the sulfuric acid leaching step to obtain crystals of bismuth sulfate; 5) a bismuth oxidation step of adding alkali to the crystals of bismuth sulfate obtained in the cooling step to obtain bismuth oxide; and 6) an electrolysis step of adding an acid solution to the bismuth oxide obtained in the bismuth oxidation step for dissolution and then electrowinning the thus obtained solution to obtain metal bismuth.