Abstract: A method for reducing waste by recovering transition metal of a lithium secondary battery of the present invention includes preparing a cathode active material from a cathode of the lithium secondary battery, producing a first leachate by treating the cathode active material with a first acidic solution containing a reducing agent in an amount smaller than an amount corresponding to a reaction equivalent of the cathode active material, and producing a second leachate by treating the remaining cathode active material, which excludes a fraction contained in the first leachate, with a second acidic solution containing a reducing agent. Accordingly, extraction rate of manganese and purity of cobalt may be improved.

Abstract: 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.

Abstract: A method of recovering a cathode active material precursor according to an embodiment of the present invention includes preparing a cathode active material mixture including a lithium composite oxide, separating lithium from the cathode active material mixture to form a preliminary transition metal precursor, acid-treating the preliminary transition metal precursor to form a complex transition metal salt solution, and adding an acidic extractant to the complex transition metal salt solution and then adding a basic compound to recover a transition metal precursor, and thus the extraction rate of transition metals can be improved.

Abstract: Provided is a method for separating normal paraffin and isoparaffin from raffinates of a benzene, toluene, and xylene (BTX) reforming process including C5 to C8 light naphtha, the method including: a liquid hydrogenation process for removing olefin by feeding raffinates in which hydrogen is dissolved into a reactor filled with a hydrogenation catalyst.

Abstract: Provided is a method for separating normal paraffin and isoparaffin from raffinates of a benzene, toluene, and xylene (BTX) reforming process including C5 to C8 light naphtha, the method including: a liquid hydrogenation process for removing olefin by feeding raffinates in which hydrogen is dissolved into a reactor filled with a hydrogenation catalyst.