There are provided processes for treating red mud. For example, the processes can comprise leaching red mud with HCl so as to obtain a leachate comprising ions of a first metal (for example aluminum) and a solid, and separating said solid from said leachate. Several other metals can be extracted from the leachate (Fe, Ni, Co, Mg, rare earth elements, rare metals, etc.). Various other components can be extracted from solid such as TiO.sub.2, SiO.sub.2 etc.

Process of materials recovery from energy storage devices, wherein the process comprises cleaning, washing, deep discharging and then crushing the devices to recover floating non-magnetic materials and magnetic materials. Further the black mass is treated with baking process, water soaking process, gravity filtration process, leaching process, Cobalt salt recovery process, Manganese salt recovery process, Nickel salt recovery process, Sodium salt recovery process, Lithium salt recovery process and then selective absorption of respective ions using Ion-exchange resin and liquid-liquid extraction using organic solvent for beneficiation to recover pure Cobalt ions, Manganese ions, Nickel ions and Lithium ions. Further the process of the present invention facilitates in recovering all possible battery grade materials from used energy storage devices. The process of the present invention uses less water, energy, economical, safe, environment friendly without generating any hazardous gases while the process has very low carbon foot prints.

Process of materials recovery from energy storage devices, wherein the process comprises cleaning, washing, deep discharging and then crushing the devices to recover floating non-magnetic materials and magnetic materials. Further the black mass is treated with baking process, water soaking process, gravity filtration process, leaching process, Cobalt salt recovery process, Manganese salt recovery process, Nickel salt recovery process, Sodium salt recovery process, Lithium salt recovery process and then selective absorption of respective ions using Ion-exchange resin and liquid-liquid extraction using organic solvent for beneficiation to recover pure Cobalt ions, Manganese ions, Nickel ions and Lithium ions. Further the process of the present invention facilitates in recovering all possible battery grade materials from used energy storage devices. The process of the present invention uses less water, energy, economical, safe, environment friendly without generating any hazardous gases while the process has very low carbon foot prints.

A method for producing a mixed metal solution containing manganese ions and at least one of cobalt ions and nickel ions, the method including: an Al removal step of subjecting an acidic solution containing at least manganese ions and aluminum ions, and at least one of cobalt ions and nickel ions, to removal of the aluminum ions by extracting the aluminum ions into a solvent while leaving at least a part of the manganese ions in the acidic solution in an aqueous phase, the acidic solution being obtained by subjecting battery powder of lithium ion batteries to a leaching step; and a metal extraction step of bringing an extracted residual liquid obtained in the Al removal step to an equilibrium pH of 6.5 to 7.5 using a solvent containing a carboxylic acid-based extracting agent, extracting at least one of the manganese ions and at least one of the cobalt ions and the nickel ions into the solvent, and then back-extracting the manganese ions and at least one of the cobalt ions and nickel ions.

A method for producing a mixed metal solution containing manganese ions and at least one of cobalt ions and nickel ions, the method including: an Al removal step of subjecting an acidic solution containing at least manganese ions and aluminum ions, and at least one of cobalt ions and nickel ions, to removal of the aluminum ions by extracting the aluminum ions into a solvent while leaving at least a part of the manganese ions in the acidic solution in an aqueous phase, the acidic solution being obtained by subjecting battery powder of lithium ion batteries to a leaching step; and a metal extraction step of bringing an extracted residual liquid obtained in the Al removal step to an equilibrium pH of 6.5 to 7.5 using a solvent containing a carboxylic acid-based extracting agent, extracting at least one of the manganese ions and at least one of the cobalt ions and the nickel ions into the solvent, and then back-extracting the manganese ions and at least one of the cobalt ions and nickel ions.