Provided herein is a method for preparing a nickel sulfate aqueous solution, comprising: (A-i) a reduction heat treatment process for thermally treating a first raw material containing nickel and lithium; (B) a first leaching process for leaching the heat-treated product produced by the reduction heat treatment process; (A-ii) a roasting process for thermally treating a second raw material containing nickel and sulfur; (C) a second leaching process for leaching the first leaching residue produced by the first leaching process and the calcine produced by the roasting process; (D) a neutralization process for neutralizing the second leached solution produced by the second leaching process; and (E) a solvent extraction process for refining nickel in the neutralized solution produced by the neutralization process.

Provided is a hydrometallurgical process for nickel oxide ore by high pressure acid leach that achieves a high iron oxidation ratio. The carbon grade in ore slurry and the flow rate are measured to determine the amount of carbon to be fed, and then, sulfuric acid is added. The blowing ratio of high pressure air and high pressure oxygen is adjusted so as to attain an oxygen purity of 21% to 60%. While the oxygen purity is maintained, an oxygen blowing amount per weight of carbon contained in the ore slurry and fed in the second step is adjusted to 200 to 600 Nm.sup.3, whereby ORP (Ag/AgCl basis) in the leaching treatment is controlled to 400 to 650 mV.

Provided is a method for recovering valuable metals that makes it possible to efficiently recover valuable metals at a high recovery rate. The present invention is a method for recovering the valuable metal from a raw material that contains the valuable metal. This method comprises: a preparation step for preparing a raw material; a melting step for introducing the raw material into a melting furnace and heating and melting the raw material to yield an alloy and a slag; and a slag separation step for separating the slag and recovering a valuable metal-containing alloy. The redox degree is adjusted in the melting step by introducing, as a reducing agent, scrap of a wound body, the wound body being an electrode assembly in which a positive electrode and a negative electrode are wound insulated from each other by a separator and carbon is used in the negative electrode.

The invention provides a targeted recycling method for waste battery, which comprises the following steps: the positive electrode strip of the waste battery is broken to obtain the broken product; In a carbon monoxide atmosphere, the broken product is pyrolyzed to obtain the pyrolysis product, and then the pyrolysis product is magnetically separated to obtain the magnetic separation product to achieve valuable metal recovery; The pyrolysis gas of the pyrolysis is passed into an alkaline solution to obtain a Li-rich solution and realize Li recovery. The method induces the directional transfer of solid oxygen in the waste cathode material through pyrolysis to form a coexistence environment of Co and Al.sub.2O.sub.3, effectively inhibits the high temperature alloying, and at the same time, the high temperature complex reaction of CO and the newborn Co particle is used to induce the targeted aggregation of cobalt nanoparticles against the concentration gradient of CO to form millimeter-sized particles, so as to realize magnetic separation and recovery. At the same time, the method of the invention can realize industrial application.

The present invention refers a method of recovering materials derived from nickel ore, involving a method of obtaining nickel ore concentrate and a processing method of said concentrate, whereby nickel ore can be processed in an efficient and ecological manner, and residues and materials currently untapped can be recovered from this nickel ore.

The present invention provides a method for recycling lithium batteries, including the following steps: Step 1, pretreating the lithium batteries, so as to obtain a mixture, the mixture includes positive electrodes of batteries, negative electrodes of batteries, and electrolyte; Step 2, performing oxygen-free pyrolysis on the mixture, at a pyrolysis temperature of 400-600 C.; Step 3, using a gas-solid filtration device to separate gas products from the pyrolysis, wherein anti-corrosion material(s) is (are) used to form filter element of the gas-solid filtration device; Step 4, taking out solid products from the pyrolysis, so as to recycle metal elements; the metal elements include but are not limited to one or more selected from the following: lithium, aluminum, copper, iron, nickel, cobalt, manganese.

A method and system of extracting iron oxide from ore is provided, which may include adding a chelating agent to an iron ore to form an iron ore and chelating agent solution, heating the solution to reflux in water, and filtering the solution to yield an extraction residue and a chelated iron solution. The chelated iron solution may be treated with a potassium hydroxide and water solution to yield iron hydroxide.

A process for using acid to leach metals from metal silicate, oxide, or oxide-hydroxide feedstock with subsequent alkalinization of the leach liquor, thereby bringing target metal ions into solution and separating the metals as hydroxides, oxides, or oxide-hydroxides. Electrodialysis is used to recycle acid and base in the process. Configurations of the electrochemical cell and means of combining cells in stacks and in series are provided that enable production of acid at high concentration allowing for decreased reactor volumes for leaching and precipitation and improved solid/liquid separation characteristics of the leached slurry.

Provided herein is a method for preparing a nickel sulfate aqueous solution, comprising: (A-i) a reduction heat treatment process for thermally treating a first raw material containing nickel and lithium; (B) a first leaching process for leaching the heat-treated product produced by the reduction heat treatment process; (A-ii) a roasting process for thermally treating a second raw material containing nickel and sulfur; (C) a second leaching process for leaching the first leaching residue produced by the first leaching process and the calcine produced by the roasting process; (D) a neutralization process for neutralizing the second leached solution produced by the second leaching process; and (E) a solvent extraction process for refining nickel in the neutralized solution produced by the neutralization process.

Provided are a method for removing aluminum which can effectively remove aluminum, and a method for recovering metals. A method for removing aluminum includes a leaching step of bringing a raw material obtained from lithium ion battery waste, the raw material having battery powder containing at least aluminum and nickel and/or cobalt, into contact with an acidic leaching solution to leach the battery powder to obtain a leached solution, wherein a molar ratio of fluorine to aluminum (F/Al molar ratio) of the raw material is 1.3 or more, and wherein, in the leaching step, the acidic leaching solution contains calcium and fluorine, aluminum is precipitated with calcium and fluorine, and the resulting precipitate is contained in a leached residue.