Method for recovering scandium

Patent metadata

Field	Value
Publication number	US-2018087128-A1
Application number	US-201515557583-A
Country	US
Kind code	A1
Filing date	Dec 8, 2015
Priority date	Mar 24, 2015
Publication date	Mar 29, 2018
Grant date	—

Abstract

According to this method for recovering scandium, an acidic solution containing scandium is used and a scandium dissolution liquid after purification is obtained by a double sulfate precipitation step, and scandium is recovered from the obtained scandium dissolution liquid, as follows: [A] A precipitation step wherein sodium sulfate is added into the acidic solution containing scandium, so that a precipitate of a scandium double sulfate is obtained; [B] A neutralization step wherein pure water is added to the precipitate of a scandium double sulfate obtained in the precipitation step to dissolve the precipitate of a scandium double sulfate therein, and scandium hydroxide is obtained by adding a neutralizing agent into the obtained dissolution liquid; and [C] A re-dissolution step wherein an acid is added to the scandium hydroxide obtained in the neutralization step, so that a scandium dissolution after purification, in which the scandium hydroxide is dissolved, is obtained.

First claim

1 . A method for recovering scandium, comprising:
obtaining a scandium solution after purification from an acidic solution containing scandium by a double sulfates precipitation step including the following steps [A] to [C]; and subsequently recovering scandium from the scandium solution obtained: [A] a precipitation step of adding sodium sulfate to the acidic solution containing scandium to obtain a precipitate of double sulfates of scandium, [B] a neutralization step of adding pure water to the precipitate of double sulfates of scandium obtained in the precipitation step to dissolve the precipitate and adding a neutralizing agent to a resulting solution to obtain scandium hydroxide, and [C] a redissolution step of adding an acid to scandium hydroxide obtained in the neutralization step to obtain a scandium solution after purification having scandium hydroxide dissolved.

2 . The method for recovering scandium according to claim 1 , comprising an enrichment step of generating a precipitate of scandium from the acidic solution containing scandium and adding an acid to the precipitate to dissolve the precipitate, wherein
the acidic solution obtained in the enrichment step is subjected to a treatment in the double sulfates precipitation step.

3 . The method for recovering scandium according to claim 2 , wherein a neutralizing agent or oxalic acid is added to the acidic solution containing scandium to generate a precipitate of scandium and an acid is added to the precipitate to dissolve the precipitate in the enrichment step.

4 . The method for recovering scandium according to claim 2 , wherein the enrichment step comprises:
a first enrichment step of adding a neutralizing agent to the acidic solution containing scandium to generate a precipitate of scandium and adding an acid to the precipitate to dissolve the precipitate; and a second enrichment step of adding oxalic acid to the solution obtained in the first enrichment step to generate a precipitate of scandium oxalate and adding an acid to the precipitate to dissolve the precipitate.

5 . The method for recovering scandium according to claim 1 , comprising an oxalate-formation step of adding oxalic acid to the scandium solution after purification to obtain a crystal of scandium oxalate, wherein
the crystal of scandium oxalate obtained in the oxalate-formation step is subjected to a treatment in the roasting step.

6 . The method for recovering scandium according to claim 1 , wherein scandium hydroxide is obtained by adjusting a pH of the solution to a range of 8 to 9 by addition of a neutralizing agent in the neutralization step in the double sulfates precipitation step.

7 . The method for recovering scandium according to claim 1 , wherein the acidic solution containing scandium is a solution obtained through
a leaching step of leaching the nickel oxide ore with sulfuric acid under high temperature and high pressure to obtain a leachate, a neutralization step of adding a neutralizing agent to the leachate to obtain a neutralized precipitate containing impurities and a post-neutralization liquid, a sulfuration step of adding a sulfurizing agent to the post-neutralization liquid to obtain a nickel sulfide and a post-sulfuration liquid, and an ion exchange step of bringing the post-sulfuration liquid into contact with a chelating resin to allow scandium contained in the post-sulfuration liquid to be adsorbed by the chelating resin and thus to obtain a scandium eluate.

8 . The method for recovering scandium according to claim 2 , comprising an oxalate-formation step of adding oxalic acid to the scandium solution after purification to obtain a crystal of scandium oxalate, wherein
the crystal of scandium oxalate obtained in the oxalate-formation step is subjected to a treatment in the roasting step.

9 . The method for recovering scandium according to claim 3 , comprising an oxalate-formation step of adding oxalic acid to the scandium solution after purification to obtain a crystal of scandium oxalate, wherein
the crystal of scandium oxalate obtained in the oxalate-formation step is subjected to a treatment in the roasting step.

10 . The method for recovering scandium according to claim 4 , comprising an oxalate-formation step of adding oxalic acid to the scandium solution after purification to obtain a crystal of scandium oxalate, wherein
the crystal of scandium oxalate obtained in the oxalate-formation step is subjected to a treatment in the roasting step.

11 . The method for recovering scandium according to claim 2 , wherein scandium hydroxide is obtained by adjusting a pH of the solution to a range of 8 to 9 by addition of a neutralizing agent in the neutralization step in the double sulfates precipitation step.

12 . The method for recovering scandium according to claim 3 , wherein scandium hydroxide is obtained by adjusting a pH of the solution to a range of 8 to 9 by addition of a neutralizing agent in the neutralization step in the double sulfates precipitation step.

13 . The method for recovering scandium according to claim 4 , wherein scandium hydroxide is obtained by adjusting a pH of the solution to a range of 8 to 9 by addition of a neutralizing agent in the neutralization step in the double sulfates precipitation step.

14 . The method for recovering scandium according to claim 5 , wherein scandium hydroxide is obtained by adjusting a pH of the solution to a range of 8 to 9 by addition of a neutralizing agent in the neutralization step in the double sulfates precipitation step.

15 . The method for recovering scandium according to claim 8 , wherein scandium hydroxide is obtained by adjusting a pH of the solution to a range of 8 to 9 by addition of a neutralizing agent in the neutralization step in the double sulfates precipitation step.

16 . The method for recovering scandium according to claim 2 , wherein the acidic solution containing scandium is a solution obtained through
a leaching step of leaching the nickel oxide ore with sulfuric acid under high temperature and high pressure to obtain a leachate, a neutralization step of adding a neutralizing agent to the leachate to obtain a neutralized precipitate containing impurities and a post-neutralization liquid, a sulfuration step of adding a sulfurizing agent to the post-neutralization liquid to obtain a nickel sulfide and a post-sulfuration liquid, and an ion exchange step of bringing the post-sulfuration liquid into contact with a chelating resin to allow scandium contained in the post-sulfuration liquid to be adsorbed by the chelating resin and thus to obtain a scandium eluate.

17 . The method for recovering scandium according to claim 3 , wherein the acidic solution containing scandium is a solution obtained through
a leaching step of leaching the nickel oxide ore with sulfuric acid under high temperature and high pressure to obtain a leachate, a neutralization step of adding a neutralizing agent to the leachate to obtain a neutralized precipitate containing impurities and a post-neutralization liquid, a sulfuration step of adding a sulfurizing agent to the post-neutralization liquid to obtain a nickel sulfide and a post-sulfuration liquid, and an ion exchange step of bringing the post-sulfuration liquid into contact with a chelating resin to allow scandium contained in the post-sulfuration liquid to be adsorbed by the chelating resin and thus to obtain a scandium eluate.

18 . The method for recovering scandium according to claim 4 , wherein the acidic solution containing scandium is a solution obtain

Assignees

• Sumitomo Metal Mining Co

Inventors

• Nagai Hidemasa
• Kudo Keiji
• Matsumoto Shin-Ya
• Kobayashi Hiroshi
• Asano Satoshi

Classifications

• C22B59/00

  Obtaining rare earth metals · CPC title

• C22B3/42 Primary

  by ion-exchange extraction · CPC title

• C22B3/08

  Sulfuric acid {, other sulfurated acids or salts thereof} · CPC title

• C22B3/44

  by chemical processes (treatment or purification of solutions by liquid-liquid extraction C22B3/26, by ion-exchange extraction C22B3/42) · CPC title

• C01F17/13

  by using ion exchange resins, e.g. chelate resins · CPC title