Process for precipitating a carbonate or (oxy)hydroxide comprising nickel from an aqueous solution of a nickel salt wherein such process is carried out in a vessel comprising (A) a vessel body, (B) one or more elements that control the hydraulic flow of the slurry formed during the precipitation and that induce a loop-type circulation flow, and (C) a stirrer whose stirrer element is in the vessel but located separately from the element(s) (B).

A bimodal lithium transition metal oxide based powder mixture comprises a first and a second lithium transition metal oxide based powder. The first powder comprises particles of a material A comprising the elements Li, a transition metal based composition M and oxygen. The first powder has a particle size distribution characterized by a (D90D10)/D50<1.0. The second powder comprises a material B having single crystal particles, said particles having a general formula Li.sub.+bN.sub.bO.sub.2, wherein 0.03b0.10, and N=Ni.sub.xM.sub.yCo.sub.zE.sub.d, wherein 0.30x0.92, 0.05y0.40, 0.05z0.40 and 0d0.10, wherein M is one or both of Mn or Al, and E is a dopant different from M. The first powder has an average particle size D50 between 10 and 40 m. The second powder has a D50 between 2 and 4 m. The weight ratio of the second powder in the mixture is between 15 and 60 wt %.

A positive electrode for a lithium secondary battery includes a positive electrode current collector, a positive electrode active material layer, and a primer layer formed between the positive electrode current collector and the positive electrode active material layer. The primer layer includes lithium carbonate (Li.sub.2CO.sub.3) particles having two or more different particle diameters, a binder polymer, and a conductive material. The lithium secondary battery attains the overcharge cutoff voltage rapidly by virtue of the gas generated between the positive electrode current collector and the positive electrode active material layer, in an overcharged state. Thus, it is possible to ensure the safety of the lithium secondary battery.

A method according to an embodiment is for recovering a valuable metal from a waste electrode material of a lithium secondary battery by using lithium carbonate. An anode-cathode mixed electrode material that has been separated by draining, crushing, screening, and sorting a waste lithium secondary battery is preprocessed. A precipitation operation performed by adding lithium carbonate (Li2CO3) to a metal melt acquired by performing sulfuric acid dissolution using sulfuric acid. A valuable metal such as nickel, cobalt, manganese, aluminum, and copper is recovered as a residue in the form of a carbonate composite, and a lithium sulfate (Li2SO4) aqueous solution including lithium is recovered as a filtrate.

A method according to an embodiment is for recovering a valuable metal from a waste electrode material of a lithium secondary battery by using lithium carbonate. An anode-cathode mixed electrode material that has been separated by draining, crushing, screening, and sorting a waste lithium secondary battery is preprocessed. A precipitation operation performed by adding lithium carbonate (Li2CO3) to a metal melt acquired by performing sulfuric acid dissolution using sulfuric acid. A valuable metal such as nickel, cobalt, manganese, aluminum, and copper is recovered as a residue in the form of a carbonate composite, and a lithium sulfate (Li2SO4) aqueous solution including lithium is recovered as a filtrate.

The present disclosure provides a positive electrode additive and a preparation method thereof, a positive electrode plate and a lithium-ion secondary battery. The positive electrode additive comprises a modified lithium carbonate. The modified lithium carbonate comprises a lithium carbonate particle and a polymer coating. The polymer coating coats a surface of the lithium carbonate particle and comprises a polymer. The positive electrode additive of the present disclosure has low cost and simple preparation method, when the positive electrode additive is applied in lithium-ion secondary battery, it can significantly improve lithium-ion secondary battery safety performance without affecting electrical performance of the lithium-ion secondary battery.

A process for water removal and/or recycling of sodium sulphate and/or sodium dithionate containing liquors derived from processing a cobalt resource derived from components of lithium ion batteries comprising steps of deriving from the cobalt resource a solution containing cobalt sulphate and cobalt dithionate, precipitation of cobalt as cobaltous carbonate or cobaltous hydroxide followed by removal thereof from the liquor, crystallization of sodium sulphate and sodium dithionate and removal of the resulting crystals, followed by heating of the crystals to anhydrous sodium sulphate, sulphur dioxide and water and then separating the anhydrous sodium sulphate.

A process for water removal and/or recycling of sodium sulphate and/or sodium dithionate containing liquors derived from processing a cobalt resource derived from components of lithium ion batteries comprising steps of deriving from the cobalt resource a solution containing cobalt sulphate and cobalt dithionate, precipitation of cobalt as cobaltous carbonate or cobaltous hydroxide followed by removal thereof from the liquor, crystallization of sodium sulphate and sodium dithionate and removal of the resulting crystals, followed by heating of the crystals to anhydrous sodium sulphate, sulphur dioxide and water and then separating the anhydrous sodium sulphate.

A process for water removal and/or recycling of sodium sulfate and/or sodium dithionate containing liquors derived from processing cobalt resource material essentially free of lithium comprising the steps of precipitation of cobalt as cobaltous carbonate or cobaltous hydroxide followed by removal thereof from the liquor, crystallization of sodium sulfate and sodium dithionate and removal of the crystals, followed by heating of the crystals to anhydrous sodium sulfate, sulphur dioxide and water and then separating the anhydrous sodium sulfate.

A process for water removal and/or recycling of sodium sulfate and/or sodium dithionate containing liquors derived from processing cobalt resource material essentially free of lithium comprising the steps of precipitation of cobalt as cobaltous carbonate or cobaltous hydroxide followed by removal thereof from the liquor, crystallization of sodium sulfate and sodium dithionate and removal of the crystals, followed by heating of the crystals to anhydrous sodium sulfate, sulphur dioxide and water and then separating the anhydrous sodium sulfate.