Aqueous sulfuric acid solution containing lithium and method for producing the same

Abstract

The present invention relates to an aqueous sulfuric acid solution containing lithium and a method for producing the same, wherein the aqueous sulfuric acid solution of the present invention comprises the steps of: obtaining a valuable metal recovery composition containing a valuable metal alloy, a lithium compound, copper (Cu), and graphite from a waste battery; separating graphite from the valuable metal recovery composition; leaching the valuable metal, lithium compound, and copper (Cu) in the valuable metal recovery composition with sulfuric acid; recovering the valuable metal and copper (Cu) by solid-liquid separation in the aqueous sulfuric acid solution containing the leached lithium; and removing residual impurities from the aqueous sulfuric acid solution containing the leached lithium after the recovery steps.

Description

[Technical Field]

[0001] This invention relates to a sulfuric acid aqueous solution containing lithium obtained from waste batteries, as well as a method for producing the same, in relation to raw materials for battery manufacturing. [Background technology]

[0002] As demand for electric vehicles increases globally, the problem of disposing of waste batteries generated from these vehicles is emerging as a social issue. In the case of lithium secondary batteries, which are the main raw materials for these waste batteries, organic solvents, explosives, and heavy metals such as Ni, Co, Mn, and Fe are included. However, Ni, Co, Mn, and Li have significant rarity value as valuable metals, and the recovery and reuse process of lithium secondary batteries after they are discarded is emerging as an important research area.

[0003] Specifically, a lithium secondary battery mainly consists of copper and aluminum used as current collectors, Li, Ni, Co, and Mn-containing oxides that constitute the positive electrode material, and graphite used as the negative electrode material. It also includes a separator plate that separates the positive and negative electrode materials and an electrolyte injected into the separator plate. The solvent and salt used to constitute the electrolyte are mainly carbonate organic materials such as ethylene carbonate and propylene carbonate, for example, LiPF6 is used.

[0004] In order to utilize the aforementioned waste batteries, there is active development of waste battery recycling processes that involve crushing the waste batteries to produce intermediate materials such as waste battery crushed material or black powder, and then recovering valuable metals through subsequent processes.

[0005] The recovered valuable metals undergo a process of acid leaching to recover valuable metals such as Li, Ni, Co, and Mn from within the battery. This acid leaching process uses an acid such as sulfuric acid to change the valuable metals in the battery into an ionized state and remove impurities. The valuable metals such as Ni, Co, or Mn in the sulfuric acid from which the impurities have been removed are extracted in the form of sulfides through solvent extraction and crystallization processes.

[0006] After sulfuric acid leaching, the Li content in the sulfuric acid becomes approximately 6-10 g / L. However, after solvent extraction and crystallization of Ni, Co, Mn, etc., the Li remaining in the sulfuric acid is diluted to approximately 1-2 g / L. To utilize a low-concentration Li-containing sulfuric acid aqueous solution to produce a raw material for battery manufacturing, specifically lithium, a multi-stage impurity removal process and Li concentration process are required. The purity of Li2CO3 or LiOH for battery manufacturing must be 99.5% or higher. Obtaining a substance of this purity incurs high extraction costs and presents a problem of reduced Li recovery rates. Therefore, research is needed to find methods to solve these problems.

[0007] Furthermore, as a method for obtaining lithium, lithium-containing ores such as spodumene can be extracted by heat treatment at approximately 900°C or higher, followed by leaching in sulfuric acid to remove impurities. However, this method has the problem of generating a large amount of precipitate during impurity removal, resulting in excessive environmental treatment costs for landfilling the precipitate.

[0008] Furthermore, among lithium-containing materials, the lithium oxide (Li2O) or fluoride (LiF) forms present in the cathode material suffer from a problem where, when exposed to high temperatures, the Li(g) or LiF(g) vaporizes, causing the lithium to disappear, resulting in a reduced lithium recovery rate. [Overview of the project] [Problems that the invention aims to solve]

[0009] The problem to be solved by the present invention is to provide an aqueous sulfuric acid solution containing lithium that can be used as a raw material for manufacturing lithium secondary batteries and contains a high concentration of lithium.

[0010] Another technical problem to be solved by the present invention is to provide a method for manufacturing an aqueous sulfuric acid solution containing lithium that can be used as a raw material for manufacturing lithium secondary batteries and contains a high concentration of lithium.

Means for Solving the Problems

[0011] The aqueous sulfuric acid solution containing lithium according to one embodiment of the present invention is recovered from waste batteries and contains lithium (Li), aluminum (Al), nickel (Ni), cobalt (Co), manganese (Mn), and the balance of impurities, and can satisfy the following formula 1.

[0012] <Formula 1> 1.0 ≦ [Al] = 0.0297 × [Li] 2 +1.3205 × [Li] ± 5 ≦ 16.0

[0013] (In the above formula 1, [Li] and [Al] respectively represent the concentrations (g / L) of Li and Al in the aqueous sulfuric acid solution containing lithium.)

[0014] In one embodiment, the aqueous sulfuric acid solution can satisfy the following formula 2.

[0015] <Formula 2> 0.05 ≦ [Ni] = 0.1907 × [Li] 2 -0.2689 × [Li] ± 3 ≦ 16.0

[0016] (In the above formula 2, [Li] and [Ni] respectively represent the concentrations (g / L) of Li and Ni in the aqueous sulfuric acid solution containing lithium.)

[0017] In one embodiment, the aqueous sulfuric acid solution can satisfy the following formula 3.

[0018] <Expression 3> 0.05 ≤ [Co] = 0.0624 × [Li] 2 -0.1078 × [Li] ± 2 ≤ 14.0

[0019] (In formula 3 above, [Li] and [Co] represent the concentrations (g / L) of Li and Co in an aqueous sulfuric acid solution containing lithium, respectively.)

[0020] In one embodiment, an aqueous sulfuric acid solution can satisfy the following formula 4.

[0021] <Expression 4> 0.1 ≤ [Mn] = 0.0402 × [Li] 2 +0.117 × [Li] ± 1 ≤ 12.0

[0022] (In formula 4 above, [Li] and [Mn] represent the concentrations (g / L) of Li and Mn in an aqueous sulfuric acid solution containing lithium, respectively.)

[0023] Another embodiment of the present invention provides a method for producing a lithium-containing aqueous sulfuric acid solution, comprising the steps of: obtaining a valuable metal recovery composition containing a valuable metal alloy, a lithium compound, copper (Cu), and graphite from a waste battery; separating graphite from the valuable metal recovery composition; leaching the valuable metal, lithium compound, and copper (Cu) in the valuable metal recovery composition with sulfuric acid; recovering the valuable metal and copper (Cu) by solid-liquid separation in the leached lithium-containing aqueous sulfuric acid solution; and removing residual impurities from the leached lithium-containing aqueous sulfuric acid solution after the recovery step.

[0024] In one embodiment, at least a portion of the lithium compound may contain lithium disposed on a valuable metal alloy. In one embodiment, the step of obtaining a valuable metal recovery composition may include the steps of preparing a battery containing lithium (Li), crushing the battery, and heat-treating the crushed battery material in the range of 600 to 1,500°C.

[0025] In one embodiment, the step of heat-treating the crushed battery fragments in the range of 600 to 1,500°C may include lithium, with an oxygen concentration in the range of 0.1 to 2.0 vol%. In one embodiment, the step of separating graphite from the valuable metal recovery composition may be carried out by at least one of particle size separation, specific gravity separation, and flotation.

[0026] In one embodiment, the step of leaching the valuable metal, lithium compound, and copper (Cu) in the valuable metal recovery composition with sulfuric acid allows the pH of the lithium-containing sulfuric acid aqueous solution to be controlled within the range of 0.2 to 4.0. In another embodiment, the step of leaching the valuable metal, lithium compound, and copper (Cu) in the valuable metal recovery composition with sulfuric acid allows the equivalent ratio of the sulfuric acid to be 0.5 to 4.0.

[0027] In one embodiment, the step of sulfuric acid leaching of valuable metals, lithium compounds, and copper (Cu) in the valuable metal recovery composition can be carried out in a temperature range of 10 to 150°C. In one embodiment, the step of sulfuric acid leaching of valuable metals, lithium compounds, and copper (Cu) in the valuable metal recovery composition can be carried out using an inert gas of 0.1 to 20.0 Nm³. 3 It can be supplied at a rate of / hr.

[0028] In one embodiment, the process may include a step of adding sodium hydroxide (NaOH) to remove impurities from the lithium-containing sulfuric acid aqueous solution between the steps of leaching the valuable metal, lithium compound, and copper (Cu) in the valuable metal recovery composition with sulfuric acid and recovering the valuable metal and copper (Cu) by solid-liquid separation in the sulfuric acid aqueous solution containing the leached lithium.

[0029] In one embodiment, the step of removing impurities from the sulfuric acid aqueous solution allows the pH of the sulfuric acid aqueous solution to be controlled between 3.0 and 8.0. In one embodiment, the steps of recovering the valuable metal and copper (Cu) by solid-liquid separation in the sulfuric acid aqueous solution containing leached lithium and the step of removing residual impurities from the sulfuric acid aqueous solution containing leached lithium after the recovery step may include a step of removing impurities by ion exchange.

[0030] In one embodiment, the step of removing residual impurities from the lithium-containing sulfuric acid aqueous solution after the recovery step can adjust the pH of the lithium-containing sulfuric acid aqueous solution to a range of 8.5 to 12.0. In one embodiment, the step of preparing the lithium (Li)-containing battery may include the step of freezing the battery. [Effects of the Invention]

[0031] According to one embodiment of the present invention, a sulfuric acid aqueous solution containing lithium can be used as a raw material for manufacturing lithium secondary batteries because it contains valuable metals in predetermined ratios, and provides a sulfuric acid aqueous solution containing a high concentration of lithium.

[0032] Another embodiment of the present invention provides a method for producing an aqueous sulfuric acid solution containing lithium by leaching a lithium-containing compound processed and recovered from a lithium-containing battery with sulfuric acid according to temperature and pH conditions, and removing impurities to produce an aqueous sulfuric acid solution as a high-purity lithium-containing raw material for the manufacture of lithium-containing batteries. [Brief explanation of the drawing]

[0033] [Figure 1] This graph shows the change in battery voltage according to the cooling temperature, according to one embodiment of the present invention. [Figure 2] This graph shows the relationship between battery weight, external cooling temperature, and cooling time according to one embodiment of the present invention. [Figure 3a]This photograph shows a fire that occurred when the material was crushed after freezing for a shorter time than the minimum cooling time specified in the comparative example of the present invention. [Figure 3b] This photograph shows a fire that occurred when the material was crushed after freezing for a shorter time than the minimum cooling time specified in the comparative example of the present invention. [Figure 3c] This is a photograph of an example in which no fire occurred when the material was crushed after being frozen for a longer time than the minimum cooling time according to the embodiment of the present invention. [Figure 3d] This is a photograph of an example in which no fire occurred when the material was crushed after being frozen for a longer time than the minimum cooling time according to the embodiment of the present invention. [Figure 4] This is a schematic diagram illustrating the production of a high-purity lithium-containing sulfuric acid aqueous solution according to one embodiment of the present invention. [Modes for carrying out the invention]

[0034] The terms first, second, third, etc., are used to describe various parts, components, regions, layers, and / or sections, but are not limited to these. These terms are used solely to distinguish one part, component, region, layer, or section from other parts, components, regions, layers, or sections. Accordingly, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section, without exceeding the scope of the present invention.

[0035] The technical terms used herein are for the sole purpose of referring to specific embodiments and are not intended to limit the invention. The singular form used herein also includes the plural form unless the text explicitly indicates the opposite. As used herein, “includes” embodies a particular characteristic, domain, integer, step, operation, element, and / or component, and does not exclude the presence or addition of other characteristics, domains, integers, steps, operations, elements, and / or components.

[0036] When one part is described as being "on top of" or "above" another part, it means that it is literally on top of or above the other part, or that the other part may be interposed between them. In contrast, when one part is described as being "directly above" another part, it means that the other part is not interposed between them.

[0037] Furthermore, unless otherwise specified, percentages in this specification refer to percentages by weight.

[0038] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as that generally understood by a person of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meaning consistent with the relevant technical literature and the present disclosure, and are not interpreted in their ideal or highly formal sense unless otherwise defined.

[0039] An aqueous sulfuric acid solution containing lithium according to one embodiment of the present invention has a high concentration of lithium and can be used as a raw material for producing lithium hydroxide, which is used in the manufacture of positive electrode active materials. Specifically, the aqueous sulfuric acid solution containing lithium can be recovered from waste batteries.

[0040] In one embodiment, a lithium-containing aqueous sulfuric acid solution may contain lithium (Li), aluminum (Al), nickel (Ni), cobalt (Co), manganese (Mn), and the remainder being impurities. The remainder being impurities may include, for example, at least one of Ni, Co, Mn, Cu, Ti, Zn, Pb, P, Ca, Mg, B, K, Na, Si, Zr, and Fe.

[0041] In one embodiment, an aqueous sulfuric acid solution containing lithium can satisfy the following formula 1.

[0042] <Expression 1> 1.0 ≤ [Al] = 0.0297 × [Li] 2 +1.3205 × [Li] ± 5 ≤ 16.0

[0043] (In Formula 1 above, [Li] and [Al] represent the concentrations (g / L) of Li and Al in an aqueous sulfuric acid solution containing lithium, respectively.)

[0044] Formula 1 can be a relational expression for the concentrations of Li and Al in an aqueous sulfuric acid solution containing lithium. Specifically, Formula 1 can satisfy the range of 1.0 to 16.0, and more specifically, 2.5 to 12.0. When Formula 1 is satisfied, it can be usefully applied to the production of LiOH used in the manufacture of high-nickel cathode active materials, and has the advantage of reducing material costs due to the high lithium concentration.

[0045] If Equation 1 falls outside the upper limit of the range mentioned above, lithium leaching is delayed, leading to a problem of reduced lithium recovery. If Equation 1 falls outside the lower limit of the range mentioned above, after leaching, Li co-precipitation occurs during hydroxide precipitation for Al removal, resulting in its disappearance.

[0046] In one embodiment, an aqueous sulfuric acid solution containing lithium can satisfy the following formula 2.

[0047] <Expression 2> 0.05≦[Ni]=0.1907×[Li] 2 -0.2689 × [Li] ± 3 ≤ 16.0

[0048] (In formula 2 above, [Li] and [Ni] represent the concentrations (g / L) of Li and Ni in an aqueous sulfuric acid solution containing lithium, respectively.)

[0049] Equation 2 can be a relational expression for the concentrations (g / L) of Li and Ni in the sulfuric acid aqueous solution. Specifically, Equation 2 can satisfy the range of 0.05 to 16.0, and more specifically, 0.3 to 7.5. When Equation 2 is satisfied, it can be usefully applied to the production of LiOH used in the manufacture of high-nickel cathode active materials, and has the advantage of reducing material costs due to the high lithium concentration.

[0050] When the formula 2 exceeds the upper limit value of the aforementioned range, there is a problem that the leaching of lithium is delayed and the lithium recovery rate is reduced. When the formula 2 is outside the lower limit value of the aforementioned range, there is a problem that Li is coprecipitated and disappears during the formation of hydroxide for removing Ni.

[0051] In one embodiment, the sulfuric acid aqueous solution containing lithium can satisfy the following formula 3.

[0052] <Formula 3> 0.05 ≤ [Co] = 0.0624 × [Li] 2 -0.1078 × [Li] ± 2 ≤ 14.0

[0053] (In the formula 3, [Li] and [Co] respectively represent the concentrations (g / L) of Li and Co in the sulfuric acid aqueous solution containing lithium)

[0054] The formula 3 can be a relational expression for the concentrations (g / L) of Li and Co in the sulfuric acid aqueous solution containing lithium. Specifically, the formula 2 can satisfy 0.05 to 14.0, more specifically 0.15 to 6.0. When the formula 3 is satisfied, it can be usefully applied to the production of LiOH utilized in the production of the high-nickel cathode active material, and there is an advantage that the cost of the substance can be reduced by the high lithium concentration.

[0055] When the formula 3 exceeds the upper limit value of the aforementioned range, there is a problem that the leaching of lithium is delayed and the lithium recovery rate is reduced. When the formula 3 is outside the lower limit value of the aforementioned range, there is a problem that Li is coprecipitated and disappears during the formation of hydroxide for removing Co.

[0056] In one embodiment, the sulfuric acid aqueous solution containing lithium can satisfy the following formula 4.

[0057] <Formula 4> 0.1 ≤ [Mn] = 0.0402 × [Li] 2 +0.117 × [Li] ± 1 ≤ 12.0

[0058] (In formula 4 above, [Li] and [Mn] represent the concentrations (g / L) of Li and Mn in an aqueous sulfuric acid solution containing lithium, respectively.)

[0059] Equation 4 can be a relational expression for the concentrations (g / L) of Li and Mn in the sulfuric acid aqueous solution. Specifically, Equation 4 can satisfy values ​​between 0.1 and 12.0, and more specifically, between 0.5 and 6.0. When Equation 4 is satisfied, it can be usefully applied to the production of LiOH used in the manufacture of high-nickel cathode active materials, and has the advantage of reducing material costs due to the high lithium concentration.

[0060] If equation 4 falls outside the upper limit of the range mentioned above, there is a problem that lithium leaching is delayed and the lithium recovery rate decreases. If equation 4 falls outside the lower limit of the range mentioned above, there is a problem that Li co-precipitates and disappears during hydroxide formation to remove Mn.

[0061] Thus, by ensuring that the lithium content in the lithium-containing sulfuric acid aqueous solution meets the aforementioned range, it becomes easier to increase the battery capacity, and the precursor of a positive electrode active material for lithium secondary batteries with excellent structural stability can be usefully applied.

[0062] A method for producing a lithium-containing aqueous sulfuric acid solution according to another embodiment of the present invention may include the steps of: obtaining a valuable metal recovery composition comprising a valuable metal alloy, a lithium compound, copper (Cu), and graphite from a waste battery; separating graphite from the valuable metal recovery composition; leaching the valuable metal, lithium compound, and copper (Cu) in the valuable metal recovery composition with sulfuric acid; recovering the valuable metal and copper (Cu) by solid-liquid separation in the leached lithium-containing aqueous sulfuric acid solution; and removing residual impurities from the leached lithium-containing aqueous sulfuric acid solution after the recovery step.

[0063] The step of obtaining a valuable metal recovery composition containing valuable metal alloys, lithium compounds, copper (Cu), and graphite from waste batteries may include the steps of preparing a lithium (Li)-containing battery, crushing the battery, and heat-treating the crushed battery material in the range of 600 to 1,500°C.

[0064] The step of preparing a lithium (Li)-containing battery may include waste materials from the manufacturing process of lithium-ion batteries, such as batteries that have reached the end of their lifespan, cathode materials such as scrap, jelly rolls, and slurry that constitute the waste battery, defective products generated during the manufacturing process, residues in the middle of the manufacturing process, and generated fragments.

[0065] In one embodiment, the step of preparing a lithium (Li) battery may include the step of freezing the battery. Specifically, by applying a certain pressure to the battery, the separator may be physically crushed, a high current may be formed due to a short circuit, and a spark may be generated. This spark may cause the electrolyte to ignite, potentially leading to a fire.

[0066] The step of freezing the battery suppresses the ignition of the liquid electrolyte contained within the battery by freezing it, and then the crushing process is carried out, so that no problems occur due to electrolyte ignition.

[0067] In one embodiment, the step of freezing the battery can be carried out by cooling in the range of -150°C to -60°C. If the temperature is outside the upper limit of the above temperature range, the voltage remaining inside the battery may not drop to 0V, a battery reaction due to a short circuit may occur, and the electrolyte will not be completely frozen, which is not appropriate.

[0068] If the temperature falls outside the lower limit of the aforementioned temperature range, the electrolyte will be sufficiently frozen, and the internal voltage of the battery will drop to 0V. In this case, even if a short circuit occurs where the positive and negative electrodes are in direct contact, no battery reaction will occur, the battery temperature will not increase, and gas generation and combustion of the electrolyte will not occur. Furthermore, because the electrolyte is frozen, the mobility of lithium ions is very low, which may significantly reduce the conductivity characteristics due to lithium ion movement. Also, since vaporization of the electrolyte does not occur, it may not generate flammable gases such as ethylene, propylene, and hydrogen.

[0069] In the step of freezing the battery, if the temperature exceeds the upper limit of the temperature range, the voltage remaining inside the battery may not drop to 0V, potentially causing a short circuit and battery reaction, and the electrolyte may not be completely frozen, which is unsuitable. If the temperature exceeds the lower limit of the temperature range, a large amount of energy must be invested for freezing, which is uneconomical.

[0070] In one embodiment, the step of freezing the battery can be carried out by cooling it in a temperature range of -60 to -20°C under a vacuum atmosphere of 100 torr or less. The step of freezing the battery can be carried out in the temperature range that suppresses the vaporization of the electrolyte. The vacuum atmosphere can be, for example, an inert gas, carbon dioxide, nitrogen, water, or a combination thereof.

[0071] By performing the process under a vacuum atmosphere with pressure below 100 torr, oxygen supply is suppressed, preventing the electrolyte from reacting with oxygen, thus preventing explosions, suppressing the vaporization of the electrolyte, and preventing the generation of flammable gases such as ethylene, propylene, and hydrogen.

[0072] In the step of freezing the battery, if the procedure is carried out in an air atmosphere or under a pressure exceeding 100 torr, there is a possibility that voltage may remain in the battery. Since the electrolyte is not frozen at a temperature range of -60 to -20°C, there is a problem that the electrolyte may vaporize and explode due to the sparks generated when a short circuit occurs due to the remaining voltage.

[0073] In one embodiment, the step of freezing the battery is a battery processing method that satisfies the following formula 7.

[0074] [Formula 6] Minimum cooling time (Hr)=A×(W 0.33 )

[0075] (A = 4 × e(-0.02 × dT), W = Battery weight (kg), dT = |External cooling temperature - Target temperature|, || represents the absolute value)

[0076] In one embodiment, the step of freezing the battery may include a step of cooling the battery to -150°C to -20°C. In one embodiment, the step of preparing the battery may include a step of performing a forced discharge.

[0077] The step of crushing the battery may involve using a crusher to obtain crushed material. The crushing is a non-limiting example and may include crushing the waste battery by applying physical or mechanical force and crushing it into a fine powder. The crushing step can separate some of the larger impurities among the components contained in the waste battery, such as aluminum (Al), copper (Cu), iron (Fe), and plastic. The state in which the larger impurities have been separated is called black powder, and battery crushed material such as black powder can be produced through the crushing step.

[0078] In one embodiment, the battery fragments may include aluminum (Al), manganese (Mn), lithium (Li), copper (Cu), cobalt (Co), nickel (Ni), carbon (C), and residual impurities. In one embodiment, the black powder may contain 5-40 wt% nickel (Ni), 1-20 wt% cobalt (Co), 1-15 wt% manganese (Mn), 0.5-5 wt% lithium (Li), 10-70 wt% carbon (C), 0.0001-20 wt% aluminum (Al), and 0.0001-20 wt% copper (Cu), with the total amount of impurities such as iron (Fe) and phosphorus (P) being less than 10 wt%. The composition of the black powder can vary depending on the ratio of nickel, cobalt, and manganese, and the nickel, cobalt, and manganese can be adjusted by the cathode material oxides of the lithium secondary battery when the lithium secondary battery is crushed.

[0079] In one embodiment, the step of crushing the battery can be a crushing method utilizing at least one of shear, compression, and tensile forces. Specifically, the crushing step can be carried out by at least one of a hammer mill, a ball mill, and a stirring ball mill, for example. The hammer mill can perform at least one of the steps of disassembly, punching, and milling, and it is clear that various types of crushing or grinding equipment, such as industrial grinders, can be used for grinding, as a non-limiting example. In one embodiment, the particle size of the battery crushed material can be within 50 mm, specifically within 30 mm. If it is larger than the above range, there are uneconomical issues because more energy supply will be required in the heat treatment step described later.

[0080] The step of heat-treating the crushed battery material in the range of 600 to 1,500°C may be a step of dry heat treatment of the battery material. Specifically, the heat treatment step involves placing the crushed material into a heating furnace (Furnace) that can raise the temperature of the crushed material to a temperature above its melting point. The step of dry heat treatment of the crushed material (S200) may involve heat treatment conditions that carry out a high-temperature reduction reaction without going through a melting step.

[0081] In one embodiment, the heat treatment conditions can be in the range of 900 to 1,800°C. Specifically, the range can be 1,200 to 1,800°C, and more specifically, 1,300 to 1,700°C. If the temperature is outside the upper limit of the range, there is a problem of loss due to lithium vaporization, and if it is outside the lower limit of the range, there is a problem that the sintering and reduction of the alloying elements will not proceed. Within the temperature range, the carbon in the crushed material can be burned to a minimum, and the reduction reaction can be carried out in a state where carbon dioxide generation is almost zero.

[0082] In one embodiment, the step of dry heat treatment of the crushed material (S200) can be carried out in a gas atmosphere of at least one of an inert gas, carbon dioxide, carbon monoxide, and hydrocarbon gas. In the case of the inert gas, for example, at least one of argon and nitrogen can also be included. By carrying out the reduction reaction of the crushed material in the gas atmosphere, a valuable metal recovery alloy containing valuable metals as components can be effectively recovered.

[0083] In one embodiment, a portion of the gas atmosphere may contain impurities, including residual oxygen. If the oxygen content of the impurities is high, it can combine with the components of the crushed material during the reduction reaction to form carbon dioxide, which can then be gasified together with lithium, making recovery difficult.

[0084] In one embodiment, the average oxygen partial pressure in the dry heat treatment step can be in the range of 0.01 to 1 atm. Specifically, if the oxygen partial pressure is higher than the above value, there is a problem of lithium loss and large amounts of carbon dioxide generation in a localized high-on state. If the oxygen partial pressure is lower than the lower limit of the above range, there is a problem of reduced Li recovery rate due to inferior LiAlO2 formation.

[0085] Specifically, in the dry heat treatment step, the components in the crushed material, such as nickel, cobalt, manganese, and lithium-containing oxides, are alloyed to form a valuable metal recovery composition which may contain valuable metals and residual impurities. The valuable metal recovery composition may, for example, contain aluminum (Al), manganese (Mn), lithium (Li), copper (Cu), cobalt (Co), nickel (Ni), carbon (C), and residual impurities. Specifically, the valuable metal recovery composition may contain a valuable metal recovery alloy and a lithium compound. Specifically, the valuable metal recovery composition may contain a valuable metal alloy, a lithium compound, copper (Cu), and graphite.

[0086] The valuable metal recovery alloy may contain 45% by weight or more of valuable metals and the remainder being impurities, based on a total composition of 100% by weight of the valuable metal recovery alloy silver alloy. The valuable metal recovery alloy may contain at least one of the valuable metals such as nickel (Ni), cobalt (Co), manganese (Mn), lithium (Li), carbon (C), aluminum (Al), and copper (Cu), and the remainder being impurities. In this specification, valuable metals mean expensive metallic components contained in a battery, and can mean nickel, cobalt, manganese, aluminum, copper, and lithium. In one embodiment, the valuable metals may be 70% by weight or more.

[0087] In one embodiment, lithium (Li) can be included in the range of 0.01 to 5% by weight among the valuable metals. The advantage of maximizing the Li recovery rate during the Li smelting process is that the lithium content meets this range. If the lithium content falls outside the upper limit of the range, there is a problem of reduced Ni and Co recovery rates. If it falls outside the lower limit of the range, the Li recovery rate during the Li smelting process decreases, leading to increased process costs.

[0088] In one embodiment, the valuable metal recovery alloy may contain 0.02% by weight or more of copper (Cu). Specifically, the valuable metal recovery alloy may contain copper in the range of 0.1 to 15% by weight. If the copper content falls outside the upper limit of the range, there is a problem of increased process costs due to the increased amount of CuSO4 precipitated during leaching and solvent extraction. If the copper content falls outside the lower limit of the range, it becomes difficult to produce low-melting-point Ni-Co-Mn, leading to a problem of increased unreacted material.

[0089] In one embodiment, the copper can combine with nickel (Ni) among the valuable metals to form an alloy. In one embodiment, the nickel can be contained in a range of 5 to 40% by weight. If the nickel exceeds the upper limit of the range, there is a problem of reduced leaching rate due to the formation of nickel carbide (Ni3C), and if the nickel exceeds the lower limit of the range, there is a problem of reduced Ni recovery rate in leaching and solvent extraction.

[0090] In one embodiment, the valuable metal recovery alloy may contain 7% by weight or less of graphite. Specifically, the graphite content can be 1-6%, and more specifically, 2-5% by weight. By keeping the graphite content in the valuable metal recovery alloy within the aforementioned range, the leaching efficiency is improved due to the low graphite content during acid leaching, and CO2 generation can be reduced through the recovery of the graphite.

[0091] If the value falls outside the upper limit of the aforementioned range, the negative electrode material remains unreacted, alloying does not occur properly, and there is a problem that valuable metal oxides remain in the positive electrode material. If the value falls outside the lower limit of the aforementioned range, there is a problem that lithium may be lost due to high temperature.

[0092] In one embodiment, the valuable metal recovery alloy may contain aluminum (Al) in the range of 0.25 to 30% by weight. If the aluminum content falls outside the upper limit of the range, there is a problem of reduced Ni and Co recovery rates during the leaching and solvent extraction processes. If the aluminum content falls outside the lower limit of the range, LiAlO2 formation becomes difficult, resulting in a problem of reduced Li recovery rates.

[0093] The valuable metal content in the valuable metal recovery composition may be 45% by weight. Specifically, the valuable metal recovery composition may have nickel as its basic component, but may also contain substances such as cobalt, manganese, copper, aluminum, and lithium.

[0094] In one embodiment, the lithium content in the composition can be in the range of 0.1 to 10% by weight. Specifically, the lithium content in the composition can be in the range of 8 to 10% by weight.

[0095] The lithium content in the composition may include not only the lithium contained in the valuable metal recovery alloy but also the lithium content contained in the lithium compound. If the lithium content falls outside the upper limit of the range, there is a problem in which lithium is lost in the process in which oxygen burns carbon, which is not an oxygen-free reaction, making it impossible to recover lithium from the valuable metals in the battery. If the lithium content falls outside the lower limit of the range, there is a problem in which the recovery rate of valuable metals decreases.

[0096] The lithium compound is a valuable metal reaction product containing a lithium compound that includes one of LiAlO2, Li5AlO4, LiAl5O8, Li2CO3, LiF, Li3PO4, Li4P2O7, LiPO3, Li2SiO3, Li4SiO4, Li2Si2O5, LiFeO2, LiFe5O8, Li3Fe5O8, and Li5FeO4, and may contain lithium with a Li content of 4 to 35% based on 100% by weight of the total. In one embodiment, at least a portion of the lithium compound is placed on a valuable metal alloy. Specifically, at least a portion of the lithium compound can be bonded as a compound by the lithium and aluminum contained in the composition undergoing mutual physical or chemical bonding.

[0097] For example, when recovering valuable metals from a waste battery, the valuable metals in the waste battery exist in oxide form, and reduction by graphite in the negative electrode material occurs at the process temperature and oxygen atmosphere of the present invention, as described later. At this time, the copper current collector is molten and exists in a liquid state, and can play a role in agglomerating the reduced valuable metals. The aluminum of the current collector and other current collectors partially participate in the reduction reaction with the positive electrode material oxide, and the remainder reacts with lithium and can remain as lithium-aluminum oxide. Specifically, the valuable metal recovery composition may contain a lithium compound, and the lithium compound may be produced by the reduction reaction. For example, the lithium compound may be lithium-aluminate (2LiAlO2).

[0098] The aforementioned graphite may contain a degree of graphitization of 50% or more and be composed of graphite material accounting for 70% or more of the total weight.

[0099] In the step of separating graphite from the aforementioned valuable metal recovery composition, there is a possibility that powder containing a valuable metal alloy with sulfuric acid and nickel, which does not dissolve during sulfuric acid leaching, has hydrophobic characteristics, and may float and disappear between the graphite particles. To prevent this, a step of removing graphite from the valuable metal recovery composition in advance can be performed.

[0100] In one embodiment, the step of separating graphite from the valuable metal recovery composition can be carried out through at least one of particle size separation, specific gravity separation, and flotation.

[0101] The step of leaching the valuable metal, lithium compound, and copper (Cu) in the valuable metal recovery composition with sulfuric acid can be carried out when the pH of the lithium-containing sulfuric acid aqueous solution is 0.2 to 4.0, specifically 0.5 to 3.0, and more specifically 0.8 to 2.0. When the pH is within the above range, there is an excellent advantage in the selective leaching of the Li.

[0102] If the pH falls outside the upper limit of the aforementioned range, lithium leaching is delayed, leading to a problem of reduced lithium recovery. If the pH falls outside the lower limit of the aforementioned range, there is a problem of excessive leaching of valuable metals and copper.

[0103] The step of leaching the valuable metal, lithium compound, and copper (Cu) in the valuable metal recovery composition with sulfuric acid may involve an equivalent ratio of sulfuric acid of 0.5 to 4.0, specifically 0.8 to 3.5, and more specifically 1.0 to 3.0. When the sulfuric acid equivalent ratio satisfies the above range, the leaching rate of the valuable metal recovery alloy can be increased while minimizing the sulfuric acid content.

[0104] If the equivalent ratio of sulfuric acid falls outside the upper limit of the aforementioned range, there is a problem of excessive leaching of valuable metals and copper. If the equivalent ratio of sulfuric acid falls outside the lower limit of the aforementioned range, there is a problem of delayed lithium leaching and a decrease in lithium recovery rate.

[0105] The step of leaching the valuable metal recovery alloy with sulfuric acid can be performed at a temperature of 10 to 150°C, specifically 20 to 120°C, and more specifically 40 to 90°C. When the temperature is within this range, the boiling phenomenon is suppressed while the leaching efficiency is excellent.

[0106] If the operating temperature falls outside the upper limit of the aforementioned range, there is a problem of excessive leaching of valuable metals and copper. If the operating temperature falls outside the lower limit of the aforementioned range, there is a problem of delayed lithium leaching and a decrease in lithium recovery rate.

[0107] The step of leaching the aforementioned valuable metal recovery alloy, lithium compound, and Cu with sulfuric acid is performed using an inert gas of 0.1 to 20.0 Nm³. 3 / hr, specifically 1-15 Nm 3 / hr, more specifically 3-8 Nm 3 This can be carried out while supplying at a supply rate of / hr. The inert gas can be nitrogen, argon, helium, etc. When the oxygen is introduced within the supply rate range, the selective leaching rate of Li can be accelerated during the leaching process of the valuable metal recovery alloy.

[0108] If the supply rate of the gas exceeds the upper limit of the range described above, there is a problem of excessive leaching of valuable metals and copper. If the supply rate of the gas exceeds the lower limit of the range described above, there is a problem of delayed lithium leaching and a decrease in lithium recovery rate.

[0109] In the step of performing solid-liquid separation in a sulfuric acid aqueous solution containing leached lithium to recover the valuable metal and copper (Cu), the leached lithium-containing sulfuric acid aqueous solution can be separated as a liquid phase, and the valuable metal and copper (Cu) can be separated as a solid phase.

[0110] In one embodiment, the step of recovering the valuable metal and copper (Cu) by solid-liquid separation in a sulfuric acid aqueous solution containing leached lithium may include a magnetic separation step to separate the valuable metal and Cu after the solid-liquid separation. Further including a magnetic separation step after the solid-liquid separation step makes it easier to recover the copper.

[0111] In one embodiment, the process may include a step of adding sodium hydroxide (NaOH) to remove impurities from the lithium-containing sulfuric acid aqueous solution between the steps of leaching the valuable metal, lithium compound, and copper (Cu) in the valuable metal recovery composition with sulfuric acid and recovering the valuable metal and copper (Cu) by solid-liquid separation in the sulfuric acid aqueous solution containing the leached lithium.

[0112] In one embodiment, the step of removing impurities from the sulfuric acid aqueous solution can control the pH of the sulfuric acid aqueous solution to 3.0 to 8.0. Specifically, the pH can be 4.0 to 7.0. The step of removing impurities from the sulfuric acid aqueous solution can be a step to remove impurities from the sulfuric acid aqueous solution before the solid-liquid separation process to produce a sulfuric acid aqueous solution containing a high concentration of lithium. Specifically, the impurities can include, for example, at least one element from Ni, Co, Mn, Cu, Ti, Zn, Pb, P, Ca, Mg, B, K, Na, Si, and Fe.

[0113] The step of removing residual impurities from the lithium-containing sulfuric acid aqueous solution that has undergone the recovery step can remove residual impurities in the lithium-containing sulfuric acid aqueous solution recovered by solid-liquid separation, such as elements like Mg or Ca.

[0114] In one embodiment, the step of removing residual impurities from the lithium-containing sulfuric acid aqueous solution that has undergone the recovery step can adjust the pH of the lithium-containing sulfuric acid aqueous solution to a range of 8.5 to 12.0. Specifically, the pH is 9.0 to 11.0. By satisfying the aforementioned pH range, residual impurities such as Ca and Mg in the lithium sulfate can be easily removed, and a lithium-containing sulfuric acid aqueous solution with a high lithium concentration can be provided.

[0115] In one embodiment, the steps of recovering the valuable metal and copper (Cu) by solid-liquid separation in a sulfuric acid aqueous solution containing the leached lithium, and removing residual impurities from the sulfuric acid aqueous solution containing the leached lithium after the recovery step, may include a step of removing impurities by ion exchange.

[0116] The step of removing impurities by the ion exchange method may be the step of removing elements such as Zr, T, B, or F that remain in small amounts in the lithium-containing sulfuric acid aqueous solution recovered by solid-liquid separation. [Examples]

[0117] The following describes embodiments of the present invention in detail. However, these are presented as examples only and do not limit the present invention, which is defined solely by the scope of the claims described below.

[0118] <Example of experiment> Manufacturing of compositions for recovering valuable metals

[0119] <Battery internal temperature according to minimum freezing time> The battery pack used in the example was crushed using the same crusher as in the example, without being frozen. During the crushing process, flames were generated due to a short circuit, as shown in Figures 3a and 3b. The battery used at this time was a 622NCM battery.

[0120] Thus, through the examples and comparative examples, it can be confirmed that including a step of freezing the battery pack containing the battery before crushing the battery prevents short circuits and flames from occurring during the battery crushing step, resulting in excellent stability.

[0121] Figure 1 shows the change in battery voltage according to the cooling temperature in one embodiment of the present invention.

[0122] Referring to Figure 1, when measuring the battery voltage while freezing the battery at -80°C, the battery pack shows almost the same voltage up to a high temperature of approximately 40°C, room temperature, and -60°C, confirming that the battery characteristics are not lost. Subsequently, when the temperature decreases from -60°C to -70°C, the voltage drops sharply, and below -70°C, the voltage becomes 0. Thus, it was confirmed that no short circuit occurs when freezing the battery at -60 to -150°C.

[0123] Figure 2 is a graph showing the relationship between battery weight, external cooling temperature, and cooling time according to one embodiment of the present invention.

[0124] Referring to Figure 2, it can be confirmed that the battery processing method according to one embodiment of the present invention allows for the derivation of a minimum cooling time for cooling the battery in the step of freezing the battery. Specifically, it can be confirmed that the minimum cooling time is related to the battery weight, the external cooling temperature, and the target temperature.

[0125] More specifically, the external cooling temperature and minimum cooling time are shown when the target temperature is set to -70°C and the battery weights are 2.5 kg (A), 10 kg (B), 20 kg (C), and 50 kg (D), respectively. When cooling the battery, the electrolyte in the battery begins to cool after a predetermined time, and it is possible to confirm that the voltage drops to 0. This confirms that a minimum maintenance time is required to sufficiently cool the inside of the battery, specifically the electrolyte, when cooling the battery.

[0126] Specifically, considering the specific heat of the battery itself in the heat transfer situation for cooling, which involves removing heat to the outside, it is possible to confirm the battery weight and the time required for cooling. Thus, in this invention, the minimum time required for cooling can be determined by using the external cooling temperature for freezing, the target temperature, and the battery weight.

[0127] Table 1 below lists the minimum cooling times based on battery weight and external cooling temperature.

[0128] [Table 1]

[0129] As can be seen from Table 1, the smaller the battery weight, the shorter the minimum cooling time for the battery to be cooled. Furthermore, when the battery is cooled using the value of Equation 2, which is derived from the relationship between battery weight, external cooling temperature, and target temperature, as the minimum cooling time, it can be confirmed that the battery, specifically the electrolyte of the battery, is cooled. In addition, if the battery is cooled for a time longer than the value of Equation 2, a fire will not occur during the subsequent battery crushing process.

[0130] Figures 3a and 3b are photographs showing a fire that occurred when the material was crushed after freezing for a shorter time than the minimum cooling time according to the comparative example of the present invention, while Figures 3c and 3d are photographs showing an example in which no fire occurred when the material was crushed after freezing for a longer time than the minimum cooling time according to the embodiment of the present invention.

[0131] Referring to Figures 3a and 3b, an experiment was conducted to determine the fire-causing conditions of crushed materials when the battery was frozen for a shorter time than the minimum required cooling time. In the experiment, with a battery weight of 25 kg, an external cooling temperature of -95°C, and a target freezing temperature of -70°C, the value of Equation 2 below was 7 hours, and the experiment was conducted for a shorter time of 5 hours.

[0132] <Expression 2> Minimum cooling time = A × (W) 0.33 )

[0133] (In the above formula 2, A = 4 × e (-0.02×dT) W = Battery weight (kg), dT = |External cooling temperature - Target temperature|, || represents the absolute value)

[0134] Referring to Figures 3c and 3d, the experiment showed the fire-causing conditions of crushed materials when frozen for a period exceeding the minimum freezing time required for battery cooling. In this experiment, the same battery weight, external cooling temperature, and minimum freezing time as in Figures 3a and 3b were used, but with a minimum freezing time of 7 hours or more.

[0135] Table 2 below compares the fire occurrence conditions of the examples and comparative examples corresponding to 3a to 3d, with the same battery weight, external cooling temperature, and minimum freezing time. The fire occurrence conditions were judged as "O" if a fire was observed after battery crushing, and "X" otherwise.

[0136] [Table 2]

[0137] As can be seen in Table 2 above, when the battery is cooled for a value smaller than the value in Equation 2, which corresponds to the minimum cooling time, the electrolyte is not cooled, and a fire occurs after the battery is crushed. Thus, when the value in Equation 2 is used as the minimum cooling time for cooling the battery, it can be confirmed that the crushed material can be used stably without a fire occurring after the battery is crushed.

[0138] <Battery shredder calcination heat treatment> The step of heat-treating the crushed battery material involved dry heat treatment at a temperature range of 700 to 1,350°C with an oxygen content of 5 vol% or less. Specifically, the heat treatment in this experiment was performed dry at a temperature range of 900 to 1,200°C, specifically around 1,100°C, with an oxygen content of approximately 3 vol% or less to obtain a composition for recovering valuable metals.

[0139] At this time, the size of the battery fragments is 10-20 mm along the longest axis of the width, length, and height, with a graphite content of 5% or more, and an impurity content of less than 5% of plastic or iron fragments such as Al covers and PCB substrates in the fragments.

[0140] The valuable metal recovery compositions produced through the aforementioned heat treatment step include a valuable metal alloy, a lithium compound, copper, and graphite, each having a core containing a valuable metal and a shell containing a lithium compound placed on the core.

[0141] <Separated from a composition for recovering valuable metals> The valuable metal recovery composition obtained through a high-temperature reduction process was separated into magnetic and non-magnetic materials using a magnetic separator with a magnetic field strength of 3000 gauss.

[0142] Subsequently, the non-magnetic materials separated by magnetic separation were subjected to flotation separation using the Denver Sub_A flotation separator with a mineral solution concentration of 30%, an impeller rotation speed of 500 rpm, kerosene at 0.1 ml / 100 g, and MIBC at 0.1 ml / 100 g. Through this flotation separation, the lighter graphite powder floated to the top of the separator, and this was separated to recover the graphite.

[0143] After the aforementioned flotation separation process, graphite was separated as suspended solids, and the lithium-containing substance was separated and recovered as a precipitate.

[0144] Subsequently, the coarse magnetic material was ground using an Attrition Mill, a vertical stirring mill, at 500 rpm, an impeller tip speed of 2.8 m / sec, a grinding time of 60 minutes, and a solid content of 30% by weight. It was confirmed that the reaction product, consisting of a core containing valuable metals and a shell containing a lithium-containing compound placed on the core, was separated into the core and the shell through the grinding process. To further separate the alloy core containing valuable metals and the lithium compound from the resulting material after the grinding process, a 3000 gauss magnetic separator was used to separate the magnetic material from the non-magnetic material.

[0145] Subsequently, particle size separation was performed using a 75 μm mesh to recover the coarse particles of the NCM alloy and the fine particles of the Li oxide.

[0146] Valuable metal-containing alloys, lithium compounds, and Cu were obtained through the aforementioned magnetic separation, flotation separation, and particle size sorting methods.

[0147] <Selective lithium leaching step> Valuable metal-containing alloys, lithium compounds, and Cu were obtained through a high-temperature heat treatment process, and lithium (Li) was selectively leached from the valuable metal-containing alloys, lithium compounds, and Cu through sulfuric acid leaching. The leaching of lithium can be explained by the following reaction equation.

[0148] [Reaction Equation 1] Ni(s) + H2SO 4(aq) =NiSO 4(aq) +H 2(g) , △G o m = -46.3 (kJ / mol)

[0149] [Reaction Equation 2] Co(s) + H2SO 4(aq) =CoSO 4(aq) +H 2(g) , △G o m = -54.7 (kJ / mol)

[0150] [Reaction Equation 3] Li2O(s) + H2SO 4(aq) =Li2SO 4(aq) +H2O (aq) , △G o m = -260.5 (kJ / mol)

[0151] [Reaction Equation 4] Cu(s) + H2SO 4(aq) =CuSO 4(aq) +H 2(g) , △G o m = 69.5 (kJ / mol)

[0152] According to reaction equations 1 and 2, the Gibbs-free energy (Gibbs-free energy) for leaching Ni and Co into sulfuric acid is -46 to -53 kJ / mol, which is about 20% lower than the Gibbs-free energy of -260.5 kJ / mol for leaching lithium oxide into sulfuric acid, confirming that the leaching reaction is not accelerated. In the case of Cu, the Gibbs-free energy is 69.5 kJ / mol, which is higher than that of Ni, Co, and Li, confirming that leaching in sulfuric acid is not easy.

[0153] Lithium-containing alloys and lithium compounds, obtained through high-temperature heat treatment, were selectively subjected to lithium leaching for 120 minutes at a pH range of 0.4 to 2.0, a temperature of 50°C, and a sulfuric acid equivalent ratio of 0.8 to 2.0 M. The experiment was conducted to achieve a lithium concentration of 6 g / L, assuming a 100% lithium leaching rate in the sulfuric acid solution.

[0154] Tables 3 to 5 below show the lithium leaching results over time when the sulfuric acid equivalent ratios were 1.0 M, 1.2 M, and 1.6 M, respectively. Specifically, Table 3 below shows the selective Li leaching results (g / L) over time (sulfuric acid equivalent ratio = 1.0 M, temperature = 50°C), Table 4 below shows the selective Li leaching results (g / L) over time (sulfuric acid equivalent ratio = 1.2 M, temperature = 50°C), and Table 5 below shows the selective Li leaching results (g / L) over time (sulfuric acid equivalent ratio = 1.6 M, temperature = 50°C).

[0155] [Table 3]

[0156] [Table 4]

[0157] [Table 5]

[0158] Tables 3 to 5 show that when lithium is leached at a temperature of 50°C within 120 minutes, a lithium leaching rate of 94-99% or more can be ensured depending on the sulfuric acid equivalent ratio. Simultaneously, it was confirmed that the leaching concentrations of Ni, Co, and Mn can be controlled to 5 g / L or less, and the leaching concentration of Cu to 1 g / L or less.

[0159] <Removal of impurities from lithium-containing sulfuric acid solution> The lithium-containing sulfuric acid aqueous solution, which has undergone the lithium leaching process described above, contains impurities of Ni, Co, Mn, Cu, Ti, Zn, Pb, P, Ca, Mg, B, K, Na, Si, and Fe. An impurity removal process was performed to remove the impurities from the sulfuric acid aqueous solution.

[0160] To remove impurities from the aforementioned sulfuric acid aqueous solution, sodium hydroxide (NaOH) was added to the lithium-containing sulfuric acid aqueous solution obtained through a sulfuric acid leaching process of the lithium-containing sulfuric acid aqueous solution, based on the following reaction equations 5 and 6, to adjust the pH of the lithium-containing sulfuric acid aqueous solution to 3.0-8.0. By adjusting the sulfuric acid aqueous solution within the aforementioned pH range, residual Ni, Co, Mn, Cu, Ti, Zn, Pb, P, Ca, Mg, B, K, Na, Si, and Fe impurities in the sulfuric acid aqueous solution were removed.

[0161] [Reaction Equation 5] Me2(SO4) 3(aq) +6NaOH=2Me(OH)3(s)+3Na2SO 4(aq) +H2SO 4(aq)

[0162] (Me=Fe, Al, Ti)

[0163] [Reaction Equation 6] MeSO4 4(aq) +2NaOH=Me(OH)2(s)+Na2SO 4(aq) +H2SO 4(aq)

[0164] (Me=Ni, Co, Mn, Cu, Zn, Pb)

[0165] <Solid-liquid separation> Solid-liquid separation was performed to separate the precipitated substance in the sulfuric acid aqueous solution from which the aforementioned impurities had been removed. Through solid-liquid separation, the precipitated material in the sulfuric acid aqueous solution was separated, and a high-purity lithium-containing sulfuric acid aqueous solution was separated separately.

[0166] <Removal of additional impurities> Subsequently, impurities such as Zr, T, B, and F remaining in small amounts in the solid-liquid separated sulfuric acid solution were removed by ion exchange. Then, to further remove impurities such as Ca and Mg remaining in the sulfuric acid solution, the pH of the sulfuric acid solution was adjusted to 8.5-12.0 to produce a high-purity Ni-containing sulfuric acid solution.

[0167] Table 6 below shows the concentrations of the lithium-containing sulfuric acid aqueous solution after the lithium leaching step and the impurity removal step.

[0168] [Table 6]

[0169] As can be seen in Table 6 above, the lithium-containing sulfuric acid aqueous solution of the present invention has a high lithium concentration and a low impurity concentration, confirming that a high-purity sulfuric acid aqueous solution that can be used as a raw material for lithium secondary batteries, specifically for manufacturing cathode materials, was produced.

[0170] Table 7 below compares the concentrations of the lithium-containing sulfuric acid aqueous solution of the present invention, the sulfuric acid aqueous solution extracted from spodumene, and the lithium-containing sulfuric acid aqueous solution of a prototype commonly used in the manufacture of cathode materials.

[0171] [Table 7]

[0172] Referring to Table 7 above, it can be confirmed that, as in the present invention, the lithium-containing sulfuric acid aqueous solution recovered from waste batteries satisfies formulas 1 to 4, which are characteristic of the present invention. On the other hand, it was confirmed that the sulfuric acid aqueous solution extracted from spodumene via a leaching process and the generally recovered Black Mass test product did not satisfy formulas 1 to 4, which are characteristic of the present invention. Furthermore, the lithium-containing sulfuric acid aqueous solution recovered from waste batteries in the present invention has a higher lithium content relative to the aluminum content compared to the spodumene extract of the comparative example, and has the advantage of generating less aluminum hydroxide during solid-liquid separation, which is advantageous for solid-liquid separation. It can be confirmed that the lithium content of the lithium-containing sulfuric acid aqueous solution recovered from waste batteries in the present invention is higher than that of the Black Mass of the comparative example. In addition, the lithium content is higher relative to the Ni, Co, and Mn content in the sulfuric acid aqueous solution, which has the advantage of reducing the loss of Ni, Co, and Mn during impurity removal by NaOH addition, compared to Black Mass which has a high Ni, Co, and Mn content.

[0173] Although preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto. Various modifications and improvements made by those skilled in the art, utilizing the basic concepts defined in the following claims, also fall within the scope of the present invention.

Claims

1. A step of obtaining a valuable metal recovery composition from waste batteries, comprising valuable metal alloys, lithium compounds, copper (Cu), and graphite; A step of separating graphite from the aforementioned valuable metal recovery composition; A step of sulfuric acid leaching of valuable metals, lithium compounds, and copper (Cu) in the valuable metal recovery composition; A step of recovering the valuable metal and copper (Cu) by solid-liquid separation in a sulfuric acid aqueous solution containing leached lithium; and A method for producing a lithium-containing sulfuric acid aqueous solution, comprising the step of removing residual impurities from the lithium-containing sulfuric acid aqueous solution that has undergone a recovery step.

2. A method for producing an aqueous sulfuric acid solution containing lithium according to claim 1, wherein at least a portion of the lithium compound is disposed on a valuable metal alloy.

3. The step of obtaining the aforementioned valuable metal recovery composition is: Steps to prepare a battery containing lithium (Li); Step of crushing the battery; A method for producing an aqueous sulfuric acid solution containing lithium according to claim 1, comprising the step of heat-treating crushed battery fragments in the range of 600 to 1,500°C.

4. The method for producing an aqueous sulfuric acid solution containing lithium according to claim 3, wherein the step of heat-treating the crushed battery material in the range of 600 to 1,500°C is performed in the range of an oxygen concentration of 0.1 to 2.0 vol%.

5. The method for producing an aqueous sulfuric acid solution containing lithium according to claim 3, wherein the step of separating graphite from the valuable metal recovery composition is performed by at least one of particle size separation, specific gravity separation, and flotation separation.

6. The method for producing a lithium-containing sulfuric acid aqueous solution according to claim 1, wherein the step of leaching the valuable metal, lithium compound, and copper (Cu) in the valuable metal recovery composition with sulfuric acid is to control the pH of the lithium-containing sulfuric acid aqueous solution to a range of 0.2 to 4.

0.

7. The method for producing an aqueous sulfuric acid solution containing lithium according to claim 1, wherein the step of leaching the valuable metal, lithium compound, and copper (Cu) in the valuable metal recovery composition with sulfuric acid is wherein the equivalent ratio of the sulfuric acid is 0.5 to 4.

0.

8. The method for producing an aqueous sulfuric acid solution containing lithium according to claim 1, wherein the step of leaching the valuable metal, lithium compound, and copper (Cu) in the valuable metal recovery composition with sulfuric acid is performed in a temperature range of 10 to 150°C.

9. The step of leaching the valuable metals, lithium compounds, and copper (Cu) in the valuable metal recovery composition with sulfuric acid is performed using an inert gas at a rate of 0.1 to 20.0 Nm. ３ A method for producing an aqueous sulfuric acid solution containing lithium according to claim 1, supplied at a supply rate of / hr.

10. A method for producing a lithium-containing sulfuric acid aqueous solution according to claim 1, comprising the steps of leaching a valuable metal, a lithium compound, and copper (Cu) in the valuable metal recovery composition with sulfuric acid, and recovering the valuable metal and copper (Cu) by solid-liquid separation in the sulfuric acid aqueous solution containing the leached lithium, with the step of adding sodium hydroxide (NaOH) to remove impurities from the lithium-containing sulfuric acid aqueous solution.

11. The method for producing a lithium-containing aqueous sulfuric acid solution according to claim 10, wherein the step of removing impurities from the aqueous sulfuric acid solution is to control the pH of the aqueous sulfuric acid solution to 3.0 to 8.

0.

12. A method for producing a lithium-containing sulfuric acid aqueous solution according to claim 1, comprising the steps of recovering the valuable metal and copper (Cu) by solid-liquid separation in the sulfuric acid aqueous solution containing the leached lithium, and removing residual impurities from the sulfuric acid aqueous solution containing the leached lithium after the recovery step, wherein the step of removing impurities is further comprising the step of removing impurities by ion exchange.

13. The method for producing a lithium-containing sulfuric acid aqueous solution according to claim 1, wherein the step of removing residual impurities from the lithium-containing sulfuric acid aqueous solution leached out after the recovery step is to adjust the pH of the lithium-containing sulfuric acid aqueous solution to a range of 8.5 to 12.

0.

14. The method for producing an aqueous sulfuric acid solution containing lithium according to claim 3, wherein the step of preparing the battery containing lithium (Li) includes the step of freezing the battery.

15. These were recovered from discarded batteries. It contains lithium (Li), aluminum (Al), nickel (Ni), cobalt (Co), manganese (Mn), and the remainder of impurities. A sulfuric acid aqueous solution containing lithium that satisfies the following formula 1. <Formula 1> 1.0≦[Al]=0.0297×[Li] ２ +1.3205×[Li]±5≦16.0 (In formula 1 above, [Li] and [Al] represent the concentrations (g / L) of Li and Al in an aqueous sulfuric acid solution containing lithium, respectively.)

16. An aqueous sulfuric acid solution containing lithium according to claim 15, satisfying the following formula 2. <Formula 2> 0.05 ≦ [Ni] = 0.1907 × [Li] ２ -0.2689×[Li]±3≦16.0 (In formula 2 above, [Li] and [Ni] represent the concentrations (g / L) of Li and Ni in an aqueous sulfuric acid solution containing lithium, respectively.)

17. An aqueous sulfuric acid solution containing lithium according to claim 15, satisfying the following formula 3. <Formula 3> 0.05≦[Co]=0.0624×[Li] ２ -0.1078×[Li]±2≦14.0 (In formula 3 above, [Li] and [Co] represent the concentrations (g / L) of Li and Co in an aqueous sulfuric acid solution containing lithium, respectively.)

18. An aqueous sulfuric acid solution containing lithium according to claim 15, satisfying the following formula 4. <Formula 4> 0.1≦[Mn]=0.0402×[Li] ２ +0.117×[Li]±1≦12.0 (In formula 4 above, [Li] and [Mn] represent the concentrations (g / L) of Li and Mn in an aqueous sulfuric acid solution containing lithium, respectively.)

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