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 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 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 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.

The manufacture method disclosed herein includes: a preparation step of preparing a recovery object containing lithium and a first metal element; a chlorination heating step of heating the recovery object together with a metal chloride to produce LiCl; and a water dissolution step of immersing the recovery object after the chlorination heating step in water to dissolve LiCl in water to obtain a Li solution. In the manufacture method disclosed herein, a heating temperature in the chlorination heating step is 1000 C. or lower, and the metal chloride contains a second metal element that is more easily chlorinated than the first metal element in the recovered object and more hardly chlorinated than lithium in the chlorination heating step. Thereby, Li can be easily recovered from the recovery object at a low temperature of 1000 C. or lower.

A method for reducing waste by recovering transition metal of a lithium secondary battery of the present invention includes preparing a cathode active material from a cathode of the lithium secondary battery, producing a first leachate by treating the cathode active material with a first acidic solution containing a reducing agent in an amount smaller than an amount corresponding to a reaction equivalent of the cathode active material, and producing a second leachate by treating the remaining cathode active material, which excludes a fraction contained in the first leachate, with a second acidic solution containing a reducing agent. Accordingly, extraction rate of manganese and purity of cobalt may be improved.

The present disclosure relates to a method for lithium recovery by extraction-stripping separation and purification, including: (1) performing an extraction on a lithium-containing solution using an extraction system including a composite extractant at a pH in a range of 10-13 and separating to obtain a lithium-loaded organic phase; (2) subjecting the lithium-loaded organic phase obtained in step (1) to a gas-liquid-liquid three-phase stripping to obtain a lithium-loaded stripping solution; and (3) subjecting the stripping solution obtained in step (2) to a thermal treatment and separating to obtain a lithium product and a separated mother liquor.

This invention has an object to provide a method for producing a beryllium solution by dissolving beryllium oxide, the method being novel and having high energy efficiency. A production method (M10) for producing a beryllium solution includes a main heating step (S13) of dielectrically heating an acidic solution containing beryllium oxide to generate a beryllium solution.

A method comprising a) mixing and dissolving the solid hazardous heavy metal-containing composition with an acid solution; b) precipitating the heavy metal from the hazardous heavy metal acid compositions by; c) precipitating the heavy metal from the hazardous heavy metal acid composition with a heavy metal-precipitation agent; and d) separating out the heavy metal precipitate from the aqueous supernatant, whereby the heavy metal-precipitation agent comprises a diorgano-dithiophosphinic acid or the alkali metal or ammonia salts thereof. ##STR00001##

Improved methods for the removal of heavy metals, in particular cadmium, from an aqueous phosphoric acid containing composition, using an organothiophosphorous heavy metal precipitating agent to said composition, wherein the reaction between the heavy metals, in particular cadmium, and the organothiophosphorous precipitating agent is performed at a pH ranging between 1.6 and 2.0 measured after a 13-fold dilution by volume. Advantageously, an ionic polymer, particularly a cationic and/or an anionic poly(meth)acrylamide copolymer may be used to promote heavy metal precipitation and/or to facilitate the removal of the precipitates from the composition. More in particular, the phosphoric acid containing composition is obtained by the acid digestion of phosphate rock, preferably by nitric acid, sulfuric acid, or a combination thereof.

Improved methods for the removal of heavy metals, in particular cadmium, from an aqueous phosphoric acid containing composition, wherein an ionic polymeric flocculating agent is added to a phosphoric acid containing composition subsequent to the addition of an organothiophosphorous heavy metal precipitating agent to said composition, particularly under gentle mixing conditions, such as between 100 and 300 rpm. The flocculating agent promotes the formation of agglomerates of the heavy metal containing precipitate, thus facilitating their removal from the composition. More in particular, the phosphoric acid containing composition is obtained by the acid digestion of phosphate rock, preferably by nitric acid, sulfuric acid, or a combination thereof.

Improved methods for the removal of heavy metals, in particular cadmium, from an aqueous phosphoric acid containing composition, wherein an organothiophosphorous heavy metal precipitating agent and an ionic polymeric surfactant, particularly a cationic polyacrylamide copolymer surfactant, are both added to a phosphoric acid containing composition, particularly under vigorous mixing conditions, such as between 500 and 700 rpm. The ionic polymeric surfactant promotes the precipitation of the heavy metals. More in particular, the phosphoric acid containing composition is obtained by the acid digestion of phosphate rock, preferably by nitric acid, sulfuric acid, or a combination thereof.