Method for recovering scandium

Patent metadata

Field	Value
Publication number	US-2016047014-A1
Application number	US-201414437767-A
Country	US
Kind code	A1
Filing date	Apr 25, 2014
Priority date	May 10, 2013
Publication date	Feb 18, 2016
Grant date	—

Abstract

The present invention effectively recover high-grade scandium from nickel oxide ores. The present invention includes a leaching step (S 1 ) for charging nickel oxide ores and sulfuric acid into a pressurized vessel, a neutralizing step (S 2 ) for adding a neutralizing agent to the leachate to obtain a neutralized precipitate and a neutralized liquid, a sulfidizing step (S 3 ) for adding a sulfidizing agent to the neutralized liquid, an ion exchange step (S 4 ) for bringing the sulfidized solution into contact with a chelate resin, a solvent extraction step (S 6 ) for bringing a Sc eluent into contact with an extracting agent, a Sc precipitation Step (S 7 ) for adding a neutralizing agent or oxalic acid to a stripping solution, and a calcination step (S 8 ) for drying and calcining a precipitate to obtain scandium oxide.

First claim

1 . A method for recovering scandium, comprising:
the leaching step of obtaining a leachate and leach residue by solid-liquid separation under high temperature and high pressure after charging a nickel oxide ore containing scandium, aluminum and chromium into a pressure vessel with sulfuric acid, the neutralization step of obtaining neutralized sediment and a post-neutralization solution by adding a neutralizer to the leachate, the sulfuration step of by adding a sulfidizing agent to the post-neutralization solution, separating the liquid into nickel sulfide and a post-sulfuration solution, the ion exchange step of obtaining a scandium eluent by bringing the post-sulfuration solution into contact with a chelate resin to adsorb the scandium on the chelate resin, the solvent extraction step of obtaining a stripping solution by bringing the scandium eluent into contact with an extraction agent, the scandium precipitation step of obtaining precipitates by adding a neutralizer or oxalic acid to the stripping liquid, and the roasting step of obtaining scandium oxide by drying and roasting the precipitates: wherein the chelate resin is a resin having iminodiacetic acid as a functional group, and the ion exchange step comprises: the adsorption step of adsorbing the scandium on the chelate resin by bringing the post-sulfuration solution into contact with the chelate resin, the aluminum removal step of removing aluminum, which has been adsorbed on the chelate resin in the adsorption step, by bringing the chelate resin, which has adsorbed scandium in the adsorption step, into contact with 0.1 N or less sulfuric acid, the scandium elution step of obtaining the scandium eluent by bringing the chelate resin after the aluminum removal step into contact with from 0.3 N or more to less than 3 N sulfuric acid, and the chromium removal step of removing chromium, which has been adsorbed on the chelate resin in the adsorption step, by bringing the chelate resin after the scandium elution step into contact with 3 Nor more sulfuric acid.

2 . (canceled)

3 . The method for recovering scandium according to claim 1 ,
the leaching step of obtaining a leachate and leach residue by solid-liquid separation under high temperature and high pressure after charging a nickel oxide ore containing scandium, aluminum and chromium into a pressure vessel with sulfuric acid, the neutralization step of obtaining neutralized sediment and a post-neutralization solution by adding a neutralizer to the leachate, the sulfuration step of, by adding a sulfidizing agent to the post-neutralization solution, separating the liquid into nickel sulfide and a post-sulfuration solution, the ion exchange step of obtaining a scandium eluent by bringing the post-sulfuration solution into contact with a chelate resin to adsorb the scandium on the chelate resin, the solvent extraction step of obtaining a stripping solution by bringing the scandium eluent into contact with an extraction agent, the scandium precipitation step of obtaining precipitates by adding a neutralizer or oxalic acid to the stripping liquid, and the roasting step of obtaining scandium oxide by drying and roasting the precipitates; wherein the extraction agent is an organic solvent having trioctylphosphine oxide as a functional group, and the solvent extraction step comprises: the extraction step of, by mixing the scandium eluent and the extraction agent, separating the eluent into a post-extraction organic solvent which has extracted scandium, and raffinate, the scrubbing step of obtaining a post-washing organic solvent by mixing a hydrochloric acid solution with a concentration of from 2.0 mol/l or more to 9.0 mol/l or less, or a sulfuric acid solution with a concentration of from 3.5 mol/l or more to 9.0 mol/l or less with the post-extraction organic solvent to separate the impurities from the post-extraction organic solvent, and the stripping step of obtaining a stripping solution by mixing a starting solution for stripping containing a hydrochloric acid solution with a concentration of less than 2.0 mol/l or a sulfuric acid solution with a concentration of less than 3.5 mol/l with the post-washing organic solvent to back-extract scandium from the post-washing organic solvent.

4 . The method for recovering scandium according to claim 1 ,
wherein a neutralizer is added to the scandium eluent to adjust the pH to a range of from 2 or more to 4 or less, a reducing agent is then added thereto to adjust the oxidation-reduction potential of the scandium eluent to a range of from more than 200 mV to 300 mV or less as electric potential using a silver-silver chloride electrode as a reference electrode, the pH is then adjusted to a range of from 1 or more to 2.5 or less by adding sulfuric acid to obtain a post-pH adjustment solution of the scandium eluent, and the ion exchange step is carried out again using this post-pH adjustment solution.

5 . The A method for recovering scandium comprising,
the leaching step of obtaining a leachate and leach residue by solid-liquid separation under high temperature and high pressure after charging a nickel oxide ore containing scandium, aluminum and chromium into a pressure vessel with sulfuric acid, the neutralization step of obtaining neutralized sediment and a post-neutralization solution by adding a neutralizer to the leachate, the suffixation step of by adding a sulfidizing agent to the post-neutralization solution separating the liquid into nickel sulfide and a post-sulfuration solution, the ion exchange step of obtaining a scandium eluent by bringing the post-sulfuration solution into contact with a chelate resin to adsorb the scandium on the chelate resin, the solvent extraction step of obtaining a stripping solution by bringing the scandium eluent into contact with an extraction agent, the scandium precipitation step of obtaining precipitates by adding a neutralizer or oxalic acid to the shipping liquid, and the roasting step of obtaining scandium oxide by drying and roasting the precipitates; and further comprising: the oxalation step of oxalating the scandium contained in the scandium eluent obtained in the ion exchange step, wherein the oxalation step comprises: adjusting the pH to a range of from 8 or more to 9 or less by adding a neutralizer to the scandium eluent, obtaining a redissolved liquid by adding hydrochloric acid to the sediment obtained by this adjustment, then obtaining scandium oxalate crystals by adding oxalic acid to the redissolved liquid, and then dissolving the crystals in sulfuric acid and/or hydrochloric acid, wherein after the oxalation step, the crystal-dissolved solution is used for the solvent extraction step.

6 . The method for recovering scandium according to claims 1 , wherein the scandium precipitation step is a step of adding oxalic acid to the stripping solution.

7 . The method for recovering scandium according to claim 1 , wherein the scandium precipitation step is a step of, by adding a neutralizer to the stripping solution, adjusting the pH to a range of from 8 or more to 9 or less.

8 . The method for recovering scandium according to claim 3 ,
wherein a neutralizer is added to the scandium eluent to adjust the pH to a range of from 2 or more to 4 or less, a reducing agent is then added thereto to adjust the oxidation-reduction potential of the scandium eluent to a range of from more than 200 mV to 300 mV or less as electric potential using a silver-silver chloride electrode as a reference electrode, the pH is then adjusted to a range of from 1 or more to 2.5 or less by adding sulfuric acid to obtain a post-pH adjustment solution of the scandium eluent, and the ion exchange step is carried out again using this post-pH

Assignees

• Sumitomo Metal Mining Co

Inventors

• Ozaki Yoshitomo
• Nagakura Toshihiko

Classifications

• C22B23/043

  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

• C22B59/00 Primary

  Obtaining rare earth metals · CPC title

• C22B3/42

  by ion-exchange extraction · CPC title

• C22B3/08

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