Provided is a method for recovering lithium, for recovering lithium from a lithium ion secondary battery, the method including: a thermal treatment step of thermally treating a lithium ion secondary battery having a residual voltage higher than or equal to 80% of a rated voltage, to obtain a thermally treated product; a pulverizing step of pulverizing the thermally treated product, to obtain a pulverized product; and a lithium recovering step of recovering lithium from the pulverized product.

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.

The purpose is to provide a method for recovering a valuable metal at low cost. The present invention is a method for recovering a valuable metal, the method comprising a step of preparing a burden material containing at least a valuable metal to obtain a raw material, a step of subjecting the raw material to an oxidation treatment and a reductive melting treatment to produce a reduced product containing an alloy and a slag, and a step of separating the slag from the reduced product to collect the alloy, in which the copper grade, which is a ratio of the mass of copper (Cu) to the total mass of nickel (Ni), cobalt (Co) and copper (Cu) contained in the alloy (i.e., a Cu/(Ni+Co+Cu) ratio), is adjusted to 0.250 or more.

The purpose is to provide a method for recovering a valuable metal at low cost. The present invention is a method for recovering a valuable metal, the method comprising a step of preparing a burden material containing at least a valuable metal to obtain a raw material, a step of subjecting the raw material to an oxidation treatment and a reductive melting treatment to produce a reduced product containing an alloy and a slag, and a step of separating the slag from the reduced product to collect the alloy, in which the copper grade, which is a ratio of the mass of copper (Cu) to the total mass of nickel (Ni), cobalt (Co) and copper (Cu) contained in the alloy (i.e., a Cu/(Ni+Co+Cu) ratio), is adjusted to 0.250 or more.

Proposed is a method for removing phosphorus from a phosphorus-containing substance which is applicable in an industrial scale so as to effectively reduce phosphorus contained in the phosphorus-containing substance. In this method, the phosphorus-containing substance used as a raw material for metal smelting or metal refining is reacted with a nitrogen-containing gas at a treatment temperature T (° C.) which is lower than a melting temperature (T.sub.m) of the substance, so that phosphorus is removed preferably in the form of phosphorus nitride (PN). In this regard, a nitrogen partial pressure and an oxygen partial pressure in the nitrogen-containing gas are preferably controlled, thereby reducing a load of dephosphorization process, for example.

Proposed is a method for removing phosphorus from a phosphorus-containing substance which is applicable in an industrial scale so as to effectively reduce phosphorus contained in the phosphorus-containing substance. In this method, the phosphorus-containing substance used as a raw material for metal smelting or metal refining is reacted with a nitrogen-containing gas at a treatment temperature T (° C.) which is lower than a melting temperature (T.sub.m) of the substance, so that phosphorus is removed preferably in the form of phosphorus nitride (PN). In this regard, a nitrogen partial pressure and an oxygen partial pressure in the nitrogen-containing gas are preferably controlled, thereby reducing a load of dephosphorization process, for example.

A method for recovering an active metal of a lithium secondary battery according to exemplary embodiments comprises preparing a preliminary cathode active material mixture including a lithium composite oxide and a binder, forming a cathode active material mixture by removing the binder from the preliminary cathode active material mixture through a heat treatment in a fluidized bed reactor, and recovering a lithium precursor from the cathode active material mixture. Accordingly, the active metal of the lithium secondary battery can be recovered with high purity and high efficiency.

A method for recovering an active metal of a lithium secondary battery according to exemplary embodiments comprises preparing a preliminary cathode active material mixture including a lithium composite oxide and a binder, forming a cathode active material mixture by removing the binder from the preliminary cathode active material mixture through a heat treatment in a fluidized bed reactor, and recovering a lithium precursor from the cathode active material mixture. Accordingly, the active metal of the lithium secondary battery can be recovered with high purity and high efficiency.

The invention provides a complete set of treatment system and method for deep utilization of dolomite resources. The system includes a primary calcination device, a carbon dioxide capture device, a digestion device, a carbonization separation device, a pyrolysis device and a secondary calculation device; the primary calcination device includes a dolomite calciner, a plurality of hoardings and an exhaust pipe, and an exhaust chamber is formed in a surrounding way between the hoardings, the top of the dolomite calciner and the outer wall of the blanking bin; the exhaust chamber is in communication with the carbon dioxide capture device through the exhaust pipe; the carbonization separation device includes a carbonization reaction tank whose gas inlet is in communication with the gas outlet of the carbon dioxide capture device; and the pyrolysis device includes a pyrolysis kettle and a vacuum pump which maintains a negative pressure state in the pyrolysis kettle.

The invention provides a complete set of treatment system and method for deep utilization of dolomite resources. The system includes a primary calcination device, a carbon dioxide capture device, a digestion device, a carbonization separation device, a pyrolysis device and a secondary calculation device; the primary calcination device includes a dolomite calciner, a plurality of hoardings and an exhaust pipe, and an exhaust chamber is formed in a surrounding way between the hoardings, the top of the dolomite calciner and the outer wall of the blanking bin; the exhaust chamber is in communication with the carbon dioxide capture device through the exhaust pipe; the carbonization separation device includes a carbonization reaction tank whose gas inlet is in communication with the gas outlet of the carbon dioxide capture device; and the pyrolysis device includes a pyrolysis kettle and a vacuum pump which maintains a negative pressure state in the pyrolysis kettle.