A variety of systems, methods and compositions are disclosed, including, in one method for recycling a spent alkaline battery comprising: dissolving insoluble metal ions in aqueous solution thereby producing pregnant leach solution; extracting zinc sulfate from aqueous solution thereby producing zinc sulfate product and raffinate solution comprising manganese sulfate and potassium sulfate; separating manganese hydroxide from raffinate solution thereby producing manganese sulfate product and aqueous potassium sulfate solution; crystallizing aqueous potassium sulfate solution to produce solid potassium sulfate product. A system for recycling spent alkaline battery comprising: first liquid-solid extraction unit capable of dissolving insoluble metal ions in aqueous solution thereby producing pregnant leach solution; liquid-liquid extraction unit capable of extracting zinc from pregnant leach solution; second liquid-solid extraction unit capable of precipitating manganese hydroxide from raffinate produced by liquid-liquid extraction unit; and third liquid-solid extraction unit capable of crystallizing aqueous potassium sulfate solution produced by second liquid-solid extraction unit.

A method for processing positive electrode active material waste of lithium ion secondary batteries, the waste containing cobalt, nickel, manganese and lithium, the method including: a carbon mixing step of mixing the positive electrode active material waste in the form of powder with carbon to obtain a mixture having a ratio of a mass of carbon to a total mass of the positive electrode active material waste and the carbon of from 10% to 30%; a roasting step of roasting the mixture at a temperature of from 600° C. to 800° C. to obtain roasted powder; a dissolution step including a first dissolution process of dissolving lithium in the roasted powder in water or a lithium-containing solution, and a second dissolution process of dissolving the lithium in a residue obtained in the first dissolution process in water; and an acid leaching step of leaching a residue obtained in the lithium dissolution step with an acid.

A method of manufacturing a cobalt-nickel-containing solution including: preparing a crude nickel hydroxide and/or a crude cobalt hydroxide as a starting material, the crude nickel or cobalt hydroxide containing cobalt and nickel and elements except the cobalt and nickel as impurities, the crude nickel hydroxide containing the nickel more than the cobalt, and the crude cobalt hydroxide containing the cobalt more than the nickel; a water-washing process for obtaining a post-water-washing crude hydroxide from the starting material; a leaching process for obtaining a post-leaching solution from the post-water-washing crude hydroxide; a neutralization process of subjecting the post-leaching solution to neutralization and solid-liquid-separation to remove the impurities as a post-neutralization residue containing one or more of iron, silicon, aluminum, and chromium, thereby obtaining a post-neutralization solution; and an extraction process of subjecting the post-neutralization solution to solvent extraction to obtain a post-extraction solution containing cobalt and nickel with the impurities reduced.

A method for recovering at least cobalt of valuable metals, cobalt and nickel, from an acidic solution obtained by subjecting waste containing positive electrode materials for lithium ion secondary batteries to a wet process, the acidic solution comprising cobalt ions, nickel ions and impurities, the method including: a first extraction step for Co recovery, the first extraction step being for extracting cobalt ions by solvent extraction from the acidic solution and stripping the cobalt ions; and a second extraction step for Co recovery, the second extraction step being for extracting cobalt ions by solvent extraction from a stripped solution obtained in the first extraction step for Co recovery and stripping the cobalt ions, wherein the first extraction step for Co recovery includes: a solvent extraction process for extracting cobalt ions in the acidic solution into a solvent; a scrubbing process for scrubbing the solvent that has extracted the cobalt ions; and a stripping process for stripping the cobalt ions in the solvent after the scrubbing into a solution.

In a method for recovering an active metal of a lithium secondary battery, a sulfuric acid solution is added to a lithium metal composite oxide so as to prepare a sulfated active material solution. A transition metal is extracted from the sulfated active material solution. A lithium precursor is recovered by adding a lithium extracting agent to the solution remaining after the transition metal has been extracted from the sulfated active material solution. In the method, the amount of impurities is reduced, and sulfuric acid and the neutralizing agent can be recycled so that a high-yield lithium precursor recovery is enabled.

A continuous solvent extract process is provided for concentrating rare earth elements from leachates generated from coal sources. The process involves solvent extraction which utilizes an organic extractant mixed into an organic solvent.

What is provided is a method for separating cobalt and nickel including: a crushing and sorting step of crushing and classifying the lithium ion secondary battery to obtain an electrode material containing at least cobalt, nickel, copper, and lithium; a leaching step of immersing the electrode material in a processing liquid containing sulfuric acid and hydrogen peroxide to obtain a leachate; a copper separation step of adding a hydrogen sulfide compound to the leachate with stirring and subsequently carrying out solid-liquid separation to obtain an eluate containing cobalt and nickel and a residue containing copper sulfide; and a cobalt/nickel separation step of adding an alkali metal hydroxide to the eluate to adjust a pH and subsequently, adding a hydrogen sulfide compound with stirring and carrying out solid-liquid separation to obtain a precipitate containing cobalt sulfide and nickel sulfide and a residual liquid containing lithium.

Provided are a selective recovery method of vanadium and cesium from a waste sulfuric acid vanadium catalyst by a hydrometallurgical method including water leaching, solid-liquid separation, vanadium solvent extraction, vanadium selective stripping, and cesium alum production, and a high-quality vanadium aqueous solution and cesium alum produced thereby.

Provided are a selective recovery method of vanadium and cesium from a waste sulfuric acid vanadium catalyst by a hydrometallurgical method including water leaching, solid-liquid separation, vanadium solvent extraction, vanadium selective stripping, and cesium alum production, and a high-quality vanadium aqueous solution and cesium alum produced thereby.

Provided are processes for extracting lithium and optionally nickel from a Nickel(II)/Lithium(I) (Ni.sup.2+/Li.sup.+) solution. The extraction is optionally performed in a series of steps with counterflow of aqueous and organic flows to thereby produce a lithium poor solution. The lithium poor solution may be treated so that remaining Ni in the lithium poor solution may be directly precipitated therefrom in the form of a Ni salt. Once complete, the process provides for recoverable nickel and/or lithium that may be recycled into batteries or sold for other uses.