A method for recovering valuable substance, for recovering it from lithium ion secondary battery includes: thermal treatment step of thermally treating lithium ion secondary battery to obtain thermally treated product; pulverizing/classifying step of classifying pulverized product obtained by pulverizing thermally treated product, to obtain coarse and fine-grained products both containing valuable substance; water leaching step of immersing fine-grained product in water, to obtain water-leached slurry; wet magnetic sorting step of subjecting water-leached slurry to wet magnetic sorting, to sort water-leached slurry into magnetically attractable materials and non-magnetically attractable material slurry; and acid leaching step of adding acidic solution to either or both of non-magnetically attractable material slurry recovered by wet magnetic sorting and non-magnetically attractable materials obtained by solid-liquid separation of non-magnetically attractable material slurry to leach non-magnetically attractable materials at pH lower than 4, followed by solid-liquid separation to obtain acid leaching liquid and acid leaching residue.

Provided is a treatment method whereby it becomes possible to recovery copper, nickel and cobalt, which are valuable metals, contained in a lithium ion battery waste and to separate copper, nickel and cobalt from one another effectively. A method for treating a lithium ion battery waste according to the present invention includes: an alloy production step S1 of introducing the lithium ion battery waste into a furnace and then melting the lithium ion battery waste by heating, thereby producing an alloy containing copper, nickel and cobalt; and an electrolytic purification step S2 of subjecting the alloy to such an electrolytic treatment that the alloy is charged as an anode into a sulfuric acid solution and then electricity is conducted between the anode and a cathode to electrodeposit copper contained in the alloy onto the cathode, thereby separating nickel and cobalt from each other.

A method for heat-treating battery waste containing lithium includes: allowing an atmospheric gas containing oxygen and at least one selected from the group consisting of nitrogen, carbon dioxide and water vapor to flow in a heat treatment furnace in which the battery waste is arranged, and heating the battery waste while adjusting an oxygen partial pressure in the furnace.

The present invention relates to a method for recovering a rare metal salt, the method including: an acid treatment step of obtaining a rare metal-containing acidic aqueous solution by bringing a material including a monovalent rare metal and a polyvalent rare metal into contact with an acidic aqueous solution; a separation step of obtaining permeated water including the monovalent rare metal and non-permeated water including the polyvalent rare metal from the rare metal-containing acidic aqueous solution by using a nanofiltration membrane satisfying the condition (1); and a concentration step of obtaining non-permeated water having a higher concentration of the monovalent rare metal and permeated water having a lower concentration of the monovalent rare metal than that of the permeated water in the separation step, by using a reverse osmosis membrane.

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.

Provided is a method for producing hematite for ironmaking, capable of using a conventional Ca-based neutralizing agent and a base rock-derived neutralizing agent other than the Ca-based neutralizing agent. The method is performed by a process of adding a mineral acid and an oxidizing agent to an ore containing iron and a valuable metal and then leaching the valuable metal under high temperature and pressure, and includes (1) a high-pressure acid leaching step, (2) a preliminary neutralization step, (3) a first solid-liquid separation step, (4) a neutralization step, (5) a second neutralization step, (6) a third solid-liquid separation step, (7) a step of adding part of the Fe-enriched slurry as a seed crystal in the neutralization step (4), and (8) a second solid-liquid separation step.

Provided is a method for producing hematite for ironmaking, capable of using a conventional Ca-based neutralizing agent and a base rock-derived neutralizing agent other than the Ca-based neutralizing agent. The method is performed by a process of adding a mineral acid and an oxidizing agent to an ore containing iron and a valuable metal and then leaching the valuable metal under high temperature and pressure, and includes (1) a high-pressure acid leaching step, (2) a preliminary neutralization step, (3) a first solid-liquid separation step, (4) a neutralization step, (5) a second neutralization step, (6) a third solid-liquid separation step, (7) a step of adding part of the Fe-enriched slurry as a seed crystal in the neutralization step (4), and (8) a second solid-liquid separation step.

Provided is a hydrometallurgical process of recovering Ni from nickel oxide ore using a high pressure acid leaching, in which abrasion of the facilities caused by an ore slurry is suppressed, the amount of a final neutralized residue is reduced, and impurity components are separated and recovered for recycling. The hydrometallurgical process includes, as steps of the high pressure acid leaching, at least one step selected from step (A): separating and recovering chromite particles in the ore slurry; step (B-1): through leaching step and a solid-liquid separation step, performing neutralization of a leachate obtained after the solid-liquid separation step using a Mg-based alkali such as Mg(OH).sub.2; and step (B-2): through leaching step and a solid-liquid separation step, performing neutralization of a leachate obtained after the solid-liquid separation step using a Mg-based alkali such as Mg(OH).sub.2, and then recovering hematite particles.

In the present invention, nickel is selectively extracted from an acidic solution that contains a high concentration of manganese. This valuable metal extraction agent is represented by the general formula. In the formula, R.sup.1 and R.sup.2 are alkyl groups that may be the same or different, R.sup.3 is a hydrogen atom or an alkyl group, and R.sup.4 is a hydrogen atom or any group, other than an amino group, bonded to an α carbon atom of an amino acid. The general formula preferably has a glycine unit, a histidine unit, a lysine unit, an aspartic acid unit or a n-methylglycine unit. When extracting nickel by using this extraction agent, it is preferable to adjust the pH of the acidic solution to 2.3 to 5.5 inclusive.

A method of treating rare earth metal-bearing permanent magnet scrap, waste or other material in a manner to recover the heavy rare earth metal content separately from the light rare earth metal content. The heavy rare earth metal content can be recovered either as a heavy rare earth metal-enriched iron based alloy or as a heavy rare earth metal based alloy.