Sumitomo Metal Mining Company, Ltd.

Hidemasa Nagai

Tatsuya Higaki

Hiroshi Kobayashi

Shin-ya Matsumoto

Yoshitomo Ozaki

Keiji Kudo

Shin-Ya Matsumoto

Itsumi Matsuoka

Satoshi Asano

Toshihiko Nagakura

Hirofumi Shoji

Hirofumi Shouji

Ryoma Yamaguma

A method for recovering scandium, by which scandium is able to be recovered from nickel oxide ore. The present invention comprises: a leaching step Sfor obtaining a leachate by leaching a nickel oxide ore containing scandium with use of sulfuric acid; a neutralization step by adding a neutralizing agent thereto; a sulfurization step by adding a sulfurizing agent to the post-neutralization solution; an ion exchange step by bringing the post-sulfurization solution into contact with a chelating resin; a dissolution step by obtaining a precipitate of scandium hydroxide by adding an alkali into the scandium eluent, and subsequently adding an acid solution to the scandium hydroxide; a solvent extraction step by bringing the scandium acid dissolution liquid into contact with a neutral extractant; and a scandium recovery step by adding oxalic acid to the extraction residue and subsequently roasting the salt of scandium oxalate.

Method for recovering scandium

The invention provides a method for recovering scandium from an acidic solution containing scandium. The method having [a] a precipitation step wherein sodium sulfate is added into the acidic solution containing scandium to obtain a precipitate of a scandium double sulfate; [b] a neutralization step wherein pure water is added to the precipitate of a scandium double sulfate to dissolve the precipitate of a scandium double sulfate therein, and scandium hydroxide is obtained by adding a neutralizing agent into the 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.

A method for recovering scandium is provided, which is capable of recovering highly-pure scandium from nickel oxide ore in a simple and efficient manner. The method for recovering scandium according to the present invention includes a scandium elution step Sof passing a solution containing scandium through an ion exchange resin to obtain an eluted liquid containing scandium from the ion exchange resin, a neutralization step Sof adding for neutralization a neutralizing agent to the eluted liquid, a solvent extraction step Sof solvent-extracting the neutralized eluted liquid using an amine-based extracting agent, and a scandium recovering step Sof obtaining a scandium precipitate from residual liquid separated by the solvent extraction, and then roasting the precipitate to obtain scandium oxide.

The method for recovering scandium pertaining to the present invention has: a first neutralization step for passing a solution containing scandium over an ion exchange resin, adding a neutralizing agent to the eluent eluted from the ion exchange resin and performing a neutralization treatment, and obtaining a primary neutralized sediment and a primary neutralized filtrate by solid-liquid separation; a second neutralization step for further adding a neutralizing agent to the primary neutralized filtrate and performing a neutralization treatment, and obtaining a secondary neutralized sediment and a secondary neutralized filtrate by solid-liquid separation; a hydroxide dissolution step for adding acid to the secondary neutralized sediment and obtaining a hydroxide solution; a solvent extraction step for subjecting the hydroxide solution to solvent extraction; and a scandium recovery step for recovering scandium oxide from a raffinate separated in the solvent extraction step.

The purpose of the present invention is to recover roughly purified scandium, which is purified to an extent acceptable for a technique for highly purifying scandium, efficiently and without any complicated operation from a neutralization sediment (drainage sediment) generated in neutralizing acid mine drainage which contains a sulfur component. This scandium recovery process includes a washing step (S) for washing a neutralization sediment (drainage sediment) and a dissolution step (S) for subjecting the washed sediment obtained in the washing step (S) to dissolution in an acid. It is preferable that the process further includes a re-dissolution step (S) for subjecting a dissolution residue which remains after the dissolution in the dissolution step (S) to dissolution with an acid. In the washing step (S), the neutralization sediment is washed with a washing liquid until the pH of the post-washing liquid generated in the washing step becomes 6 or higher.

Scandium recovery process

Provided is a method for recovering scandium with which scandium can be efficiently recovered as high purity scandium oxide from a scandium-containing solution containing impurities such as iron without causing problems such as increased cost and safety problems. According to the method for recovering scandium according to the present invention, the pH of a solution containing scandium and iron (scandium-containing solution) is adjusted within the range of not less than &#x2212;0.5 and less than 1, then scandium oxalate is obtained by adding the pH adjusted solution to an oxalic acid solution, and the scandium oxalate is roasted into scandium oxide.

Provided is a method for recovering scandium, with which it is possible to easily and efficiently recover high-purity scandium from nickel oxide ores. This method for recovering scandium involves passing a solution containing scandium through an ion exchange resin, then subjecting the eluant eluted from the ion exchange resin to solvent extraction and separating the extraction residual liquid and the extraction agent after extraction, then performing an oxalation process on the extraction residual liquid to obtain a scandium oxalate precipitate, and roasting the precipitate to obtain scandium oxide, wherein the method is characterized in that an amine-based extraction agent is used as the extraction agent for solvent extraction.

Method for recovering high-purity scandium

In order to recover high-quality scandium from nickel oxide ores efficiently, this method comprises: a step (S) for feeding Ni oxide ores and sulfuric acid into a pressure vessel, and subjecting the mixture to solid-liquid separation to form a leachate and a leach residue; a step (S) for adding a neutralizing agent to the leachate, and thus forming a neutralization sediment and a post-neutralization fluid; a step (S) for adding a sulfurizing agent to the post-neutralization fluid, and separating the obtained mixture into Ni sulfide and a post-sulfurization fluid; a step (S) for bringing the post-sulfurization fluid into contact with a chelating resin, making Sc adsorbed on the chelating resin, and forming an Sc eluent; a step (S) for bringing the Sc eluent into contact with an extracting agent, adding a back-extraction agent to the extract, and forming back-extracted matter; and a step (S) for roasting the back-extracted matter, and forming Sc oxide.

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Niihama, Japan

Hidemasa Nagai