WO2024239538A1 - Coordinated recovery method for waste lithium ion battery material and high-grade nickel matte - Google Patents

Abstract

A coordinated recovery method for a waste lithium ion battery material and high-grade nickel matte, comprising the following steps: (1) mixing a waste lithium ion battery material with high-grade nickel matte, so as to obtain a mixture; (2) roasting the mixture, so as to obtain a co-roasted solid product; (3) leaching the solid product by means of deionized water, so as to obtain a lithium-containing water leachate and water leaching residues; (4) acid-dissolving the water leaching residues, so as to obtain an acidic leachate, and then precipitating and removing impurities from the leachate and performing extraction separation, so as to obtain metal sulfate; and (5) carrying out purification treatment on the lithium-containing water leachate, so as to obtain lithium carbonate. The present invention preferentially extracts lithium from retired lithium ion batteries, prepares nickel sulfate by means of atmospheric acid leaching of high-grade nickel matte, converts valuable metal in the lithium batteries into water-insoluble forms, and achieves a lithium leaching rate of over 92% and efficient separation of the valuable metal.

Description

A method for synergistically recovering waste lithium-ion battery materials and high-grade nickel matte Technical Field

The present invention belongs to the field of solid waste recycling and metallurgical technology, and in particular relates to a method for the coordinated recycling of waste lithium-ion battery materials and high-grade nickel matte.

Background Art

In recent years, with the promotion of electric vehicles in various countries around the world, the market demand for lithium-ion batteries has increased rapidly. Due to its excellent cycle performance, high conductivity, and high energy density, ternary positive electrode materials have become the first choice for positive electrode materials for electric vehicle power batteries. The rapid development of the power battery field has also led to high market demand for lithium carbonate and nickel sulfate. On the one hand, the price of battery-grade lithium carbonate has soared from 41,000 yuan/ton in 2019 to 600,000 yuan/ton in 2022; on the other hand, it is estimated that from 2020 to 2035, global demand for nickel sulfate will increase from 640,000 tons to 3.67 million tons, and the consumption share of new energy as the largest nickel sulfate consumption field will increase from 59% to 79%. However, my country's external dependence on lithium and nickel resources exceeds 70%. Therefore, the development of valuable metal recovery technology for retired lithium-ion batteries will help alleviate the shortage of lithium and nickel resources.

In order to give priority to lithium extraction from retired lithium-ion batteries, the combined treatment process of pyrometallurgy and hydrometallurgy is currently mainly used. Due to the large differences in the physical and chemical properties of different metal elements, it is difficult to efficiently recover lithium elements in powder waste by simple pyrometallurgy and hydrometallurgy. The combined pyrometallurgy and hydrometallurgy process first selectively converts the lithium in the powder waste into soluble lithium compounds, such as LiCl, Li ₂ CO ₃ , LiNO ₃ , Li ₂ SO ₄ , LiOH, etc., while other metals such as nickel, cobalt, and manganese form metal elements or oxides that are insoluble in water during the roasting process. For the leached residue after lithium extraction, inorganic acids and hydrogen peroxide are generally used to leach and recover the remaining metal elements. This method avoids the loss of lithium caused by traditional pyrometallurgical processes, and also greatly reduces the generation of wastewater and acidic waste compared to hydrometallurgical processes.

Nickel matte is an intermediate product of pyrometallurgical smelting of nickel ore. The traditional method of preparing nickel sulfate from nickel matte is staged pressurized acid leaching, but this process requires high equipment and high energy consumption, contains many types of impurity ions in the leaching solution, and has certain safety risks. The common process of dissolving nickel metal in sulfuric acid and preparing nickel sulfate by evaporation and crystallization has a complex nickel metal production process, resulting in excessively high costs for nickel sulfate. Therefore, it is necessary to develop a low-cost, easy-to-operate, and easily industrialized method for preparing nickel sulfate to achieve the rational use of nickel matte resources.

Chinese patent CN112111651B discloses a pyrometallurgical recovery process for recovering valuable metals from retired lithium-ion batteries by sulfation roasting using sulfate. The powder waste is mixed and roasted with sulfate to convert lithium into lithium sulfate, and then the lithium sulfate is transformed into lithium carbonate or lithium bicarbonate by alkali leaching with carbon dioxide, and lithium carbonate is obtained by evaporation. The leached residue is further leached with sulfuric acid. Although this method can selectively leach lithium elements, the sulfate used contains sodium or potassium ions, which are difficult to separate and affect the purity of lithium carbonate.

Chinese patent CN114574705A discloses a method for separating lithium and valuable metals from powder waste containing positive and negative electrodes of retired ternary lithium-ion batteries by sulfation roasting with concentrated sulfuric acid. The method mainly involves mixing the positive and negative electrode powders with a certain amount of sulfuric acid and deionized water, drying them, and then ball milling them. The mixture is roasted in an inert atmosphere to convert lithium into lithium sulfate, and a lithium-containing water leaching solution is obtained by water immersion. After impurity removal, the solution is used to prepare high-purity lithium carbonate. Although this method achieves preferential lithium extraction, concentrated sulfuric acid is used in the roasting and aging process. The amount of concentrated sulfuric acid used affects the extraction rate of lithium. The sulfuric acid and powder are easily mixed unevenly during the mixing process, and higher requirements are placed on the corrosion resistance of the device, which poses certain safety hazards.

Chinese patent application CN114959252A discloses a method for producing nickel sulfate by oxidative roasting of high nickel matte. It oxidatively roasts high nickel matte to convert the metal elements therein into oxides. The roasted product is sequentially leached with sulfuric acid, removed from multiple stages, and concentrated and crystallized to obtain a nickel sulfate product. This method realizes the process technology of directly producing nickel sulfate from high nickel matte, so that nickel disulfide is roasted to form oxides, which can be better applied to wet processes of different systems. Although this method has strong properties, acidic tail gas and wastewater will be produced during the treatment process, resulting in a waste of resources, and improper treatment will also pose a risk of environmental pollution.

Chinese patent application CN114892001A discloses a method for preparing nickel sulfate by leaching high-grade nickel matte in three stages, which is divided into atmospheric pressure leaching, first oxygen pressure leaching with gradually increasing temperature and pressure, and second oxygen pressure leaching to achieve effective separation of nickel. This method converts sulfur into sulfate ions during oxygen pressure leaching without generating harmful gases, but the process has too many steps, which is not convenient for operation and cost reduction.

Summary of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology and provide a method for the coordinated recovery of waste lithium-ion battery materials and high-grade nickel matte.

In order to solve the above technical problems, the technical solution proposed by the present invention is:

A method for synergistically recovering waste lithium-ion battery materials and high-grade nickel matte comprises the following steps:

(1) mixing waste lithium-ion battery materials with high nickel matte to obtain a mixture;

(2) roasting the mixture obtained in step (1) to obtain a co-roasted solid product;

(3) leaching the solid product obtained in step (2) with deionized water to obtain a lithium-containing aqueous solution and aqueous leaching residue;

(4) acid dissolving the water-leached residue obtained in step (3) to obtain an acidic leaching solution; and the leaching solution is subjected to precipitation, impurity removal, extraction and separation to obtain metal sulfate;

(5) Purifying the lithium-containing aqueous solution obtained in step (3) to obtain lithium carbonate.

The present invention proposes a brand-new process method, which can realize the preferential extraction of lithium from retired lithium-ion batteries and the preparation of nickel sulfate by acid leaching of high-grade nickel matte at normal pressure, and the selective reaction of lithium to form lithium sulfate which is easily soluble in water through coordinated roasting, thereby converting the nickel, cobalt, manganese, aluminum, copper and other metals contained in the lithium battery into a form which is insoluble in water.

Preferably, the waste lithium-ion battery material in step (1) has a lithium content of 1 to 7 wt%.

Preferably, the waste lithium-ion battery material is a retired lithium-ion battery positive electrode material or a mixed powder of positive/negative electrode materials, and the retired lithium-ion battery positive electrode material or the positive/negative electrode material contains lithium and one or more of graphite, manganese, nickel, cobalt, copper, aluminum, phosphorus or fluorine.

Furthermore, the retired lithium-ion battery positive electrode material or positive/negative electrode material is one or more of lithium cobalt oxide, lithium manganese oxide, lithium nickel cobalt manganese oxide or lithium nickel cobalt aluminum oxide.

Preferably, the nickel matte in step (1) is nickel matte which is an intermediate product produced in the nickel metallurgical production process, and the nickel matte contains the main elements Ni, S and one or more of other metal elements such as Cu, Fe or Co.

Preferably, the high nickel matte in step (1) includes nickel sulfide as a main component and one or more of copper, cobalt or iron valuable metals, with a nickel content of 40 to 70 wt% and a sulfur content of 20 to 35 wt%.

Preferably, the molar ratio of Li in the waste lithium-ion battery material and S in the nickel matte in step (1) is 2:1 to 2:3.

Preferably, the calcination temperature in step (2) is 550-750° C., and the calcination time is 0.5-3 h.

Preferably, the mixture is laid with a thickness of 3 mm to 30 mm during the roasting process.

Preferably, the deionized water in step (3) is mixed with the solid product obtained by roasting at a solid-liquid ratio of 1:3 to 1:10 g/mL, the water immersion temperature is 20 to 90° C., and the leaching time is 0.5 to 3 h.

Preferably, the solution used for the acid leaching in step (4) is one or more of sulfuric acid, hydrochloric acid or nitric acid, the [H ⁺ ] concentration of the acid solution is greater than 0.1 mol/L, the water leaching residue is mixed with the acid leaching solution at a solid-liquid ratio of 1:5 to 1:20 g/mL, the acid leaching temperature is 20 to 90° C., and the leaching time is 0.5 to 3 h.

Furthermore, the metal sulfate is one or more of nickel sulfate, cobalt sulfate or manganese sulfate.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The present invention uses high-grade nickel matte to co-roast retired lithium-ion battery powder waste, which simply and efficiently achieves a lithium leaching rate of more than 92% and efficient separation of valuable metals, providing a guarantee for the subsequent preparation of high-purity lithium carbonate and battery-grade nickel/cobalt/manganese sulfate.

(2) The present invention uses high-grade nickel matte as an additive based on the fact that the metal elements in the retired lithium-ion battery powder waste are almost the same as the common impurity metals (cobalt, copper, iron, aluminum, etc.) in the high-grade nickel matte raw material. By controlling appropriate conditions, The nickel, cobalt, manganese and copper in the powder waste are converted into corresponding metal oxides or metals, and the nickel sulfide in the high-grade nickel matte forms nickel oxide after roasting, innovatively realizing the coupling of retired lithium-ion batteries and the atmospheric pressure acid leaching process of valuable metals in high-grade nickel matte.

(3) The present invention converts lithium in the raw material into soluble matter under appropriate conditions by means of coordinated roasting, so as to preferentially extract lithium in the subsequent water leaching process; this technology can separate lithium from other metal elements, thereby making the subsequent acid leaching treatment more efficient.

(4) The process of the present invention has strong adaptability to raw materials and is suitable for the recovery of a variety of retired lithium-ion battery materials; the process is simple and easy to implement, and the loss of valuable metals during the recovery process is small, providing a reliable technical guarantee for the large-scale and efficient recovery of valuable metals in retired lithium-ion batteries.

(5) The advantages of the present invention are that it avoids the high temperature and high pressure acid leaching conditions required by the traditional process of preparing nickel sulfate from high-grade nickel matte, realizes the coupling of the recovery of nickel, cobalt and manganese in the leached slag after preferential lithium extraction and the recovery of nickel in high-grade nickel matte, and opens up a new and efficient process technology for preferential lithium extraction assisted by high-grade nickel matte and direct production of short-range efficient leaching, which is suitable for large-scale process production and has broad application value and development prospects.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

FIG1 is a process flow chart of comprehensive recovery of valuable metals from waste lithium-ion battery powder in an embodiment of the present invention.

DETAILED DESCRIPTION

In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

Embodiment 1:

A method for synergistically recovering waste lithium-ion battery materials and high-grade nickel matte, the process flow chart of which is shown in FIG1, comprises the following steps:

(1) 5g of retired lithium-ion battery powder waste (lithium content 3%) and 2.6g of high-grade nickel matte (sulfur content 26%) were mixed according to The mixture is mixed with a molar ratio of n(Li):n(S)=1:1, stirred thoroughly and evenly spread on an alumina crucible with a layer thickness of 10 mm. The alumina crucible is placed in a high-temperature furnace and calcined in an air atmosphere with an air flow rate of 600 mL/min, a reaction temperature of 600°C, and a reaction time of 120 min to obtain a solid product.

(2) The solid product obtained in step (1) is subjected to water leaching at a leaching temperature of 50° C., a leaching time of 0.5 h, and a solid-liquid ratio of 1:5 (g/mL) to obtain a lithium-containing water leaching solution and leached residue.

(3) The lithium-containing water extract obtained in step (2) is evaporated and concentrated, and the pH value of the water extract is adjusted to 11 with a 2 mol/L NaOH solution, and impurities are removed by precipitation to obtain impurity-removed residue and impurity-removed liquid.

(4) directly leaching the leached residue obtained in step (2) and the impurity-removed residue obtained in step (3) with a sulfuric acid solution, dissolving the filter residue to obtain an acidic leaching solution.

(5) Add the impurity-free solution obtained in step (3) to _a saturated _Na2CO3 solution ( _the molar amount of _Na2CO3 is about twice the molar amount of lithium element in the raw _material ) to precipitate _Li2CO3 , filter and obtain solid _Li2CO3 , wash _{the solid Li2CO3 with} hot water to remove residual sodium _ions , and obtain lithium carbonate with a purity greater than 99.5%.

(6) The nickel, cobalt and manganese-containing leaching solution obtained in step (4) is subjected to deep purification steps such as extraction and stripping to obtain battery-grade nickel sulfate/cobalt/manganese sulfate, which can be used for the preparation of ternary precursors.

According to calculation, the lithium leaching rate in this embodiment reaches 93.40%, and the leaching rates of nickel, cobalt and manganese in the acidic leaching solution reach 99.99%, 99.81% and 99.94% respectively.

Embodiment 2:

A method for synergistically recovering waste lithium-ion battery materials and high-grade nickel matte, the process flow chart of which is shown in FIG1, comprises the following steps:

(1) 5 g of retired lithium-ion battery powder waste (lithium content 5%) and 3.9 g of high nickel matte (sulfur content 26%) were mixed in a molar ratio of n(Li):n(S)=2:1.5, and the mixture was fully stirred and spread evenly in an alumina crucible with a layer thickness of 5 mm. The alumina crucible was placed in a high-temperature furnace and co-calcined in an air atmosphere with an air flow rate of 600 mL/min in the furnace, a reaction temperature of 650°C, and a reaction time of 180 min to obtain a solid product.

(2) The solid product obtained in step (1) is subjected to water leaching at a leaching temperature of 25° C., a leaching time of 1 h, and a solid-liquid ratio of 1:5 (g/mL) to obtain a lithium-containing water leaching solution and leached residue.

(3) The lithium-containing water extract obtained in step (2) is evaporated and concentrated, and the pH value of the water extract is adjusted to 11 with a 2 mol/L NaOH solution, and impurities are removed by precipitation to obtain impurity-removed residue and impurity-removed liquid.

(4) directly leaching the leached residue obtained in step (2) and the impurity-removed residue obtained in step (3) with a sulfuric acid solution, dissolving the filter residue to obtain an acidic leaching solution.

(5) Add the impurity-free solution obtained in step (3) to a saturated Na ₂ CO ₃ solution (the molar amount of Na ₂ CO ₃ is about twice the molar amount of lithium element in the raw material) to precipitate Li ₂ CO ₃ , filter to obtain solid Li ₂ CO ₃ , and wash the solid Li ₂ CO ₃ with hot water to remove The residual sodium ions are removed to obtain lithium carbonate with a purity greater than 99.5%.

(6) The nickel, cobalt and manganese-containing leaching solution obtained in step (3) is subjected to deep purification steps such as extraction and stripping to obtain battery-grade nickel sulfate/cobalt/manganese sulfate, which can be used for the preparation of ternary precursors.

According to calculation, the leaching rate of lithium in this embodiment reaches 92.63%, and the leaching rates of nickel, cobalt and manganese in the acidic leaching solution reach 99.86%, 98.11% and 98.26% respectively.

Embodiment 3:

A method for synergistically recovering waste lithium-ion battery materials and high-grade nickel matte, the process flow chart of which is shown in FIG1, comprises the following steps:

(1) 5 g of retired lithium-ion battery powder waste (lithium content 7%) and 3.7 g of high nickel matte (sulfur content 26%) were mixed in a molar ratio of n(Li):n(S)=2:1.2, and the mixture was fully stirred and spread evenly in an alumina crucible with a layer thickness of 5 mm. The alumina crucible was placed in a high-temperature furnace and co-calcined in an air atmosphere with an air flow rate of 600 mL/min in the furnace, a reaction temperature of 550°C, and a reaction time of 180 min to obtain a solid product.

(2) The solid product obtained in step (1) is subjected to water leaching, with a leaching temperature of 25° C., a leaching time of 0.5 h, and a solid-liquid ratio of 1:10 (g/mL) to obtain a lithium-containing water leaching solution and leached residue.

(3) The lithium-containing water extract obtained in step (2) is evaporated and concentrated, and the pH value of the water extract is adjusted to 11 with a 2 mol/L NaOH solution, and impurities are removed by precipitation to obtain impurity-removed residue and impurity-removed liquid.

(4) directly leaching the leached residue obtained in step (2) and the impurity-removed residue obtained in step (3) with a sulfuric acid solution, dissolving the filter residue to obtain an acidic leaching solution.

(5) Add the impurity-free solution obtained in step (3) to _a saturated _Na2CO3 solution ( _the molar amount of _Na2CO3 is about twice the molar amount of lithium element in the raw _material ) to precipitate _Li2CO3 , filter and obtain solid _Li2CO3 , wash _{the solid Li2CO3 with} hot water to remove residual sodium _ions , and obtain lithium carbonate with a purity greater than 99.5%.

(6) The nickel, cobalt and manganese-containing leaching solution obtained in step (3) is subjected to deep purification steps such as extraction and stripping to obtain battery-grade nickel sulfate/cobalt/manganese sulfate, which can be used for the preparation of ternary precursors.

According to calculation, the leaching rate of lithium in this embodiment reaches 93.28%, and the leaching rates of nickel, cobalt and manganese in the acidic leaching solution reach 98.28%, 98.23% and 98.69% respectively.

Embodiment 4:

A method for synergistically recovering waste lithium-ion battery materials and high-grade nickel matte, the process flow chart of which is shown in FIG1, comprises the following steps:

(1) 20 g of retired lithium-ion battery powder waste (lithium content 3%) and 7.9 g of high-grade nickel matte (sulfur content 26%) were mixed at a molar ratio of n(Li):n(S)=2:1.5, and the mixture was fully stirred and spread in an alumina crucible with a layer thickness of 20 mm. The alumina crucible was placed in a high-temperature furnace and calcined in an air atmosphere with an air flow rate of 600 mL/min. The reaction temperature was 650°C and the reaction time was 120 min to obtain a solid product.

(2) The solid product obtained in step (1) is subjected to water leaching at a leaching temperature of 50° C., a leaching time of 0.5 h, and a solid-liquid ratio of 1:5 (g/mL) to obtain a lithium-containing water leaching solution and leached residue.

(3) The lithium-containing water extract obtained in step (2) is evaporated and concentrated, and the pH value of the water extract is adjusted to 11 with a 2 mol/L NaOH solution, and impurities are removed by precipitation to obtain impurity-removed residue and impurity-removed liquid.

(4) directly leaching the leached residue obtained in step (2) and the impurity-removed residue obtained in step (3) with a sulfuric acid solution, dissolving the filter residue to obtain an acidic leaching solution.

(5) Add the impurity-free solution obtained in step (3) to _a saturated _Na2CO3 solution ( _the molar amount of _Na2CO3 is about twice the molar amount of lithium element in the raw _material ) to precipitate _Li2CO3 , filter and obtain solid _Li2CO3 , wash _{the solid Li2CO3 with} hot water to remove residual sodium _ions , and obtain lithium carbonate with a purity greater than 99.5%.

(6) The nickel, cobalt and manganese-containing leaching solution obtained in step (3) is subjected to deep purification steps such as extraction and stripping to obtain battery-grade nickel sulfate/cobalt/manganese sulfate, which can be used for the preparation of ternary precursors.

According to calculation, the leaching rate of lithium in this embodiment reaches 93.03%, and the leaching rates of nickel, cobalt and manganese in the acidic leaching solution reach 98.86%, 99.14% and 99.72% respectively.

Embodiment 5:

A method for synergistically recovering waste lithium-ion battery materials and high-grade nickel matte, the process flow chart of which is shown in FIG1, comprises the following steps:

(1) 5 g of retired lithium-ion battery powder waste (lithium content 5%) and 6.6 g of high nickel matte (sulfur content 26%) were mixed in a molar ratio of n(Li):n(S)=2:3, and the mixture was fully stirred and spread evenly in an alumina crucible with a material layer thickness of 10 mm. The alumina crucible was placed in a high-temperature furnace and co-calcined in an air atmosphere with an air flow rate of 600 mL/min in the furnace, a reaction temperature of 550°C, and a reaction time of 180 min to obtain a solid product.

(2) The solid product obtained in step (1) is subjected to water leaching at a leaching temperature of 25° C., a leaching time of 0.5 h, and a solid-liquid ratio of 1:5 (g/mL) to obtain a lithium-containing water leaching solution and leached residue.

(3) The lithium-containing water extract obtained in step (2) is evaporated and concentrated, and the pH value of the water extract is adjusted to 11 with a 2 mol/L NaOH solution, and impurities are removed by precipitation to obtain impurity-removed residue and impurity-removed liquid.

(4) directly leaching the leached residue obtained in step (2) and the impurity-removed residue obtained in step (3) with a sulfuric acid solution, dissolving the filter residue to obtain an acidic leaching solution.

(5) Add the impurity-free solution obtained in step (3) to _a saturated _Na2CO3 solution ( _the molar amount of _Na2CO3 is about twice the molar amount of lithium element in the raw _material ) to precipitate _Li2CO3 , filter and obtain solid _Li2CO3 , wash _{the solid Li2CO3 with} hot water to remove residual sodium _ions , and obtain lithium carbonate with a purity greater than 99.5%.

(6) The nickel, cobalt and manganese leaching solution obtained in step (3) is subjected to deep purification steps such as extraction and stripping to obtain a battery Grade nickel/cobalt/manganese sulfate; can be used for the preparation of ternary precursors.

According to calculation, the leaching rate of lithium in this embodiment reaches 92.80%, and the leaching rates of nickel, cobalt and manganese in the acidic leaching solution reach 99.59%, 98.30% and 98.63% respectively.

Embodiment 6:

A method for synergistically recovering waste lithium-ion battery materials and high-grade nickel matte, the process flow chart of which is shown in FIG1, comprises the following steps:

(1) 5 g of retired lithium-ion battery powder waste (lithium content 3%) and 1.6 g of high-grade nickel matte (sulfur content 26%) were mixed in a molar ratio of n(Li):n(S)=2:1.2, stirred thoroughly and spread evenly in an alumina crucible with a layer thickness of 5 mm. The alumina crucible was placed in a high-temperature furnace and calcined in an air atmosphere at an air flow rate of 600 mL/min, a reaction temperature of 700°C, and a reaction time of 180 min to obtain a solid product.

(2) The solid product obtained in step (1) is subjected to water leaching at a leaching temperature of 25° C., a leaching time of 2 h, and a solid-liquid ratio of 1:5 (g/mL) to obtain a lithium-containing water leaching solution and leached residue.

(3) The lithium-containing water extract obtained in step (2) is evaporated and concentrated, and the pH value of the water extract is adjusted to 11 with a 2 mol/L NaOH solution, and impurities are removed by precipitation to obtain impurity-removed residue and impurity-removed liquid.

(4) directly leaching the leached residue obtained in step (2) and the impurity-removed residue obtained in step (3) with a sulfuric acid solution, dissolving the filter residue to obtain an acidic leaching solution.

(5) Add the impurity-free solution obtained in step (3) to _a saturated _Na2CO3 solution ( _the molar amount of _Na2CO3 is about twice the molar amount of lithium element in the raw _material ) to precipitate _Li2CO3 , filter and obtain solid _Li2CO3 , wash _{the solid Li2CO3 with} hot water to remove residual sodium _ions , and obtain lithium carbonate with a purity greater than 99.5%.

(6) The nickel, cobalt and manganese-containing leaching solution obtained in step (3) is subjected to deep purification steps such as extraction and stripping to obtain battery-grade nickel sulfate/cobalt/manganese sulfate, which can be used for the preparation of ternary precursors.

According to calculation, the leaching rate of lithium in this embodiment reaches 94.80%, and the leaching rates of nickel, cobalt and manganese in the acidic leaching solution reach 99.59%, 98.00% and 98.63% respectively.

Comparative Example 1: Roasting time is too long

(1) 5 g of retired lithium-ion battery powder waste (lithium content 3%) and 2.0 g of high-grade nickel matte (sulfur content 26%) were mixed in a molar ratio of n(Li):n(S)=2:1.5, stirred thoroughly and spread evenly in an alumina crucible with a layer thickness of 5 mm. The alumina crucible was placed in a high-temperature furnace and calcined in an air atmosphere with an air flow rate of 500 mL/min in the furnace, a reaction temperature of 600°C, and a reaction time of 480 min to obtain a solid product.

(2) The solid product obtained in step (1) is subjected to water leaching at a leaching temperature of 60° C., a leaching time of 1 h, and a solid-liquid ratio of 1:10 (g/mL) to obtain a lithium-containing water leaching solution and leached residue containing impurity ions such as Ni and Mn.

(3) The lithium-containing aqueous solution obtained in step (2) was evaporated and concentrated, and the pH of the aqueous solution was adjusted with a 2 mol/L NaOH solution. To 11, after precipitation and impurity removal, impurity-removed residue and impurity-removed liquid are obtained.

(4) directly leaching the leached residue obtained in step (2) and the impurity-removed residue obtained in step (3) with a sulfuric acid solution, dissolving the filter residue to obtain an acidic leaching solution.

(5) Add the impurity-free solution obtained in step (3) to _a saturated _Na2CO3 solution ( _the molar amount of _Na2CO3 is about twice the molar amount of lithium element in the raw _material ) to precipitate _Li2CO3 , filter and obtain solid _Li2CO3 , wash _{the solid Li2CO3 with} hot water to remove residual sodium _ions , and obtain lithium carbonate with a purity greater than 99.5%.

(6) The nickel, cobalt and manganese-containing leaching solution obtained in step (3) is subjected to deep purification steps such as extraction and stripping to obtain battery-grade nickel sulfate/cobalt/manganese sulfate, which can be used for the preparation of ternary precursors.

After calculation, the leaching rates of lithium, nickel and manganese in the water leaching solution in this comparative example are 92.03%, 5.12% and 10.25%, respectively, and the leaching rates of nickel, cobalt and manganese in the acidic leaching solution are 93.89%, 99.66% and 88.54%, respectively.

In the coordinated roasting process of this comparative example, the roasting time is too long, and part of the Ni and Mn in the raw materials are converted into sulfates and enter the water leaching solution during the roasting process, affecting the separation effect of lithium. Therefore, the longer the reaction time, the less likely the entire process is to be well coupled, and the selective separation of Li, Ni, Co, and Mn cannot be achieved. At the same time, the ion composition in the water leaching solution is complicated, which increases the difficulty of removing impurities from the water leaching solution and reduces the recovery rate of each element.

Comparative Example 2: Excessive addition of high-grade nickel matte

(1) 5 g of retired lithium-ion battery powder waste (lithium content 3%) and 5.3 g of high nickel matte (sulfur content 26%) were mixed in a molar ratio of n(Li):n(S)=1:2, and the mixture was fully stirred and spread evenly in an alumina crucible with a layer thickness of 15 mm. The alumina crucible was placed in a high-temperature furnace and co-calcined in an air atmosphere with an air flow rate of 500 mL/min in the furnace, a reaction temperature of 600°C, and a reaction time of 120 min to obtain a solid product.

(2) The solid product obtained in step (1) is subjected to water leaching at a leaching temperature of 60° C., a leaching time of 1 h, and a solid-liquid ratio of 1:10 (g/mL) to obtain a lithium-containing water leaching solution and leaching residue containing impurity ions such as Ni, Co, and Mn.

(3) The lithium-containing water extract obtained in step (2) is evaporated and concentrated, and the pH value of the water extract is adjusted to 11 with a 2 mol/L NaOH solution, and impurities are removed by precipitation to obtain impurity-removed residue and impurity-removed liquid.

(4) directly leaching the leached residue obtained in step (2) and the impurity-removed residue obtained in step (3) with a sulfuric acid solution, dissolving the filter residue to obtain an acidic leaching solution.

(5) Add the impurity-free solution obtained in step (3) to _a saturated _Na2CO3 solution ( _the molar amount of _Na2CO3 is about twice the molar amount of lithium element in the raw _material ) to precipitate _Li2CO3 , filter and obtain solid _Li2CO3 , wash _{the solid Li2CO3 with} hot water to remove residual sodium _ions , and obtain lithium carbonate with a purity greater than 99.5%.

(6) The nickel, cobalt and manganese-containing leaching solution obtained in step (3) is subjected to deep purification steps such as extraction and stripping to obtain battery-grade nickel sulfate/cobalt/manganese sulfate, which can be used for the preparation of ternary precursors.

According to calculation, the leaching rates of lithium, nickel, cobalt and manganese in the water leaching solution in this comparative example are 95.90%, 13.93%, 15.29%, The leaching rates of nickel, cobalt and manganese in the acidic leaching solution were 85.53%, 84.61% and 77.86% respectively.

During the coordinated roasting process of this comparative example, due to the excessive addition of high-matte nickel, some Ni, Co, Mn, Al, and Cu in the raw materials were converted into sulfates and entered the water leaching solution during the roasting process, affecting the separation effect of lithium. Therefore, the excessive use of high-matte nickel makes it impossible to couple the entire process well, and it is impossible to achieve the selective separation of Li, Ni, Co, and Mn. At the same time, the ion composition in the water leaching solution is complicated, which increases the difficulty of removing impurities from the water leaching solution and reduces the recovery rate of each element.

Comparative Example 3: Calcination temperature is too low

(1) 5 g of retired lithium-ion battery powder waste (lithium content 3%) and 2.6 g of high nickel matte (sulfur content 26%) were mixed in a molar ratio of n(Li):n(S)=1:1, stirred thoroughly and spread evenly in an alumina crucible with a material layer thickness of 10 mm. The alumina crucible was placed in a high-temperature furnace and co-calcined in an air atmosphere with an air flow rate of 500 mL/min in the furnace, a reaction temperature of 400°C, and a reaction time of 180 min to obtain a solid product.

(2) The solid product obtained in step (1) is subjected to water leaching at a leaching temperature of 60° C., a leaching time of 1 h, and a solid-liquid ratio of 1:10 (g/mL) to obtain a lithium-containing water leaching solution and leached residue.

(3) The lithium-containing water extract obtained in step (2) is evaporated and concentrated, and the pH value of the water extract is adjusted to 11 with a 2 mol/L NaOH solution, and impurities are removed by precipitation to obtain impurity-removed residue and impurity-removed liquid.

(4) directly leaching the leached residue obtained in step (2) and the impurity-removed residue obtained in step (3) with a sulfuric acid solution, dissolving the filter residue to obtain an acidic leaching solution.

(5) Add the impurity-free solution obtained in step (3) to _a saturated _Na2CO3 solution ( _the molar amount of _Na2CO3 is about twice the molar amount of lithium element in the raw _material ) to precipitate _Li2CO3 , filter and obtain solid _Li2CO3 , wash _{the solid Li2CO3 with} hot water to remove residual sodium _ions , and obtain lithium carbonate with a purity greater than 99.5%.

(6) The nickel, cobalt and manganese-containing leaching solution obtained in step (3) is subjected to deep purification steps such as extraction and stripping to obtain battery-grade nickel sulfate/cobalt/manganese sulfate, which can be used for the preparation of ternary precursors.

According to calculation, the leaching rate of lithium in this comparative example is 63.82%, and the leaching rates of nickel, cobalt and manganese in the leaching solution containing nickel, cobalt and manganese are 99.19%, 98.93% and 99.67% respectively.

In this comparative example, the roasting temperature is low during the synergistic roasting process, and the synergistic roasting effect is weakened, so that the retired lithium-ion battery powder waste does not fully react with the high-grade nickel matte, resulting in a significant reduction in the leaching rate of Li during the water leaching process. The Li that is not leached by water will enter the sulfate solution containing Ni, Co, and Mn during the acid leaching process, reducing the recovery rate of Li. Therefore, the roasting temperature is low, the entire process cannot achieve good coupling, and it is difficult for the nickel element in the high-grade nickel matte to enter the solution through acid leaching under normal pressure conditions, reducing the recovery rate of each element.

Comparative Example 4: The thickness of the material layer is too large

(1) 30 g of retired lithium-ion battery powder waste (lithium content 3%) and 15.8 g of high-grade nickel matte (sulfur content 26%) were mixed at a molar ratio of n(Li):n(S)=1:1, stirred thoroughly and spread evenly in an alumina crucible with a layer thickness of 40 mm. The alumina crucible was placed in a high-temperature furnace and co-calcined in an air atmosphere with an air flow rate of 500 mL/min, a reaction temperature of 600° C., and a reaction time of 180 min to obtain a solid product.

(2) The solid product obtained in step (1) is subjected to water leaching at a leaching temperature of 60° C., a leaching time of 1 h, and a solid-liquid ratio of 1:10 (g/mL) to obtain a lithium-containing water leaching solution and leached residue.

(3) The lithium-containing water extract obtained in step (2) is evaporated and concentrated, and the pH value of the water extract is adjusted to 11 with a 2 mol/L NaOH solution, and impurities are removed by precipitation to obtain impurity-removed residue and impurity-removed liquid.

(4) directly leaching the leached residue obtained in step (2) and the impurity-removed residue obtained in step (3) with a sulfuric acid solution, dissolving the filter residue to obtain an acidic leaching solution.

(5) Add the impurity-free solution obtained in step (3) to _a saturated _Na2CO3 solution ( _the molar amount of _Na2CO3 is about twice the molar amount of lithium element in the raw _material ) to precipitate _Li2CO3 , filter and obtain solid _Li2CO3 , wash _{the solid Li2CO3 with} hot water to remove residual sodium _ions , and obtain lithium carbonate with a purity greater than 99.5%.

(6) The nickel, cobalt and manganese-containing leaching solution obtained in step (3) is subjected to deep purification steps such as extraction and stripping to obtain battery-grade nickel sulfate/cobalt/manganese sulfate, which can be used for the preparation of ternary precursors.

According to calculation, the leaching rate of lithium in this comparative example is 61.00%, and the leaching rates of nickel, cobalt and manganese in the leaching solution containing nickel, cobalt and manganese are 99.99%, 98.81% and 98.23% respectively.

In this comparative example, the material layer thickness is large during the synergistic roasting process, and the synergistic roasting effect is weakened, so that the retired lithium-ion battery powder waste and the high-grade nickel matte do not fully react, resulting in a significant reduction in the leaching rate of Li during the water leaching process. The Li that is not leached by water will enter the sulfate solution containing Ni, Co, and Mn during the acid leaching process, reducing the recovery rate of Li. Therefore, the material layer thickness is large, the entire process flow cannot achieve good coupling, and it is difficult for the nickel element in the high-grade nickel matte to enter the solution through acid leaching under normal pressure conditions, reducing the recovery rate of each element.

Comparative Example 5: No coordinated roasting process

(1) 5 g of retired lithium-ion battery powder waste (lithium content 3%) and 2.6 g of high-grade nickel matte (sulfur content 26%) were mixed at a molar ratio of n(Li):n(S)=1:1, and stirred thoroughly to obtain a solid mixture;

(2) The solid mixture obtained in step (1) is subjected to water leaching at a leaching temperature of 50° C., a leaching time of 0.5 h, and a solid-liquid ratio of 1:5 (g/mL) to obtain a lithium-containing water leaching solution and leached residue.

(3) The lithium-containing water extract obtained in step (2) is evaporated and concentrated, and the pH value of the water extract is adjusted to 11 with a 2 mol/L NaOH solution, and impurities are removed by precipitation to obtain impurity-removed residue and impurity-removed liquid.

(4) directly leaching the leached residue obtained in step (2) and the impurity-removed residue obtained in step (3) with a sulfuric acid solution, dissolving the filter residue to obtain an acidic leaching solution.

(5) Add the impurity-free solution obtained in step (3) to a saturated Na ₂ CO ₃ solution (the molar amount of Na ₂ CO ₃ is about twice the molar amount of lithium element in the raw material) to precipitate Li ₂ CO ₃ , filter to obtain solid Li ₂ CO ₃ , and wash the solid Li ₂ CO ₃ with hot water to remove The residual sodium ions are removed to obtain lithium carbonate with a purity greater than 99.5%.

(6) The leaching solution obtained in step (3) is subjected to deep purification steps such as extraction and stripping to obtain battery-grade nickel/cobalt/manganese sulfate, which can be used for the preparation of ternary precursors. However, due to the presence of a large amount of lithium ions in the acid leaching solution, it is necessary to add an extra step to recover the lithium element, which reduces production efficiency and reduces the recovery rate of Li.

According to calculation, the lithium leaching rate in this embodiment is 0.05%, and the leaching rates of nickel, cobalt and manganese in the acidic leaching solution are 21.24%, 23.11% and 33.44% respectively.

This comparative example does not have a coordinated roasting process, resulting in no reaction between the retired lithium-ion battery powder waste and the high-grade nickel matte, so that Li is not leached during the water leaching process, but enters the sulfate solution containing Ni, Co, and Mn during the acid leaching process, reducing the recovery rate of Li. At the same time, the lack of a coordinated roasting process also prevents the nickel sulfide in the high-grade nickel matte from reacting, making it difficult to leach in normal pressure acid leaching, resulting in nickel loss. Therefore, the lack of a coordinated roasting process makes it impossible to effectively couple the entire process flow, and affects the acid leaching recovery rate of each element under normal pressure conditions.

Claims (10)

A method for synergistically recovering waste lithium-ion battery materials and high-grade nickel matte, characterized in that it comprises the following steps: (1) mixing waste lithium-ion battery materials with high nickel matte to obtain a mixture; (2) roasting the mixture obtained in step (1) to obtain a co-roasted solid product; (3) leaching the solid product obtained in step (2) with deionized water to obtain a lithium-containing aqueous solution and aqueous leaching residue; (4) acid dissolving the water-leached residue obtained in step (3) to obtain an acidic leaching solution; and the leaching solution is subjected to precipitation, impurity removal, extraction and separation to obtain metal sulfate; (5) Purifying the lithium-containing aqueous solution obtained in step (3) to obtain lithium carbonate. The method for collaboratively recovering waste lithium-ion battery materials and high-grade nickel matte as described in claim 1 is characterized in that the waste lithium-ion battery materials in step (1) have a lithium content of 1 to 7 wt%. The method for collaboratively recovering waste lithium-ion battery materials and high-grade nickel matte as described in claim 1 is characterized in that the waste lithium-ion battery materials are retired lithium-ion battery positive electrode materials or a mixed powder of positive/negative electrode materials, and the retired lithium-ion battery positive electrode materials or positive/negative electrode materials contain lithium and one or more of graphite, manganese, nickel, cobalt, copper, aluminum, phosphorus or fluorine. The method for collaboratively recovering waste lithium-ion battery materials and nickel matte as described in claim 1 is characterized in that the nickel matte in step (1) is an intermediate product produced in the nickel metallurgical production process, and the nickel matte contains the main elements Ni, S and one or more of other metal elements such as Cu, Fe or Co. The method for collaboratively recovering waste lithium-ion battery materials and nickel matte as described in claim 1 is characterized in that the nickel matte in step (1) includes nickel sulfide as a main component and one or more of copper, cobalt or iron valuable metals, with a nickel content of 40 to 70 wt% and a sulfur content of 20 to 35 wt%. The method for collaboratively recovering waste lithium-ion battery materials and nickel matte as described in claim 1 is characterized in that the molar ratio of Li in the waste lithium-ion battery materials and S in the nickel matte in step (1) is 2:1 to 2:3. The method for synergistically recovering waste lithium-ion battery materials and high-grade nickel matte as described in claim 1 is characterized in that the roasting temperature in step (2) is 550-750°C and the roasting time is 0.5-3h. The method for collaboratively recovering waste lithium-ion battery materials and high-grade nickel matte as described in claim 1 is characterized in that the thickness of the mixture laid during the roasting process is 3 mm to 30 mm. The method for collaboratively recovering waste lithium-ion battery materials and high-grade nickel matte as described in claim 1 is characterized in that the deionized water in step (3) is mixed with the solid product obtained by roasting at a solid-liquid ratio of 1:3 to 1:10 g/mL, the water immersion temperature is 20 to 90°C, and the leaching time is 0.5 to 3 hours. The method for collaboratively recovering waste lithium-ion battery materials and high-grade nickel matte as described in claim 1 is characterized in that the solution used for the acid leaching in step (4) is one or more of sulfuric acid, hydrochloric acid or nitric acid, the [H ⁺ ] concentration of the acid solution is greater than 0.1 mol/L, the water leaching residue and the acid leaching solution are mixed at a solid-liquid ratio of 1:5 to 1:20 g/mL, the acid leaching temperature is 20 to 90°C, and the leaching time is 0.5 to 3h.