Slag-making agent and its application, recycling process of retired ternary lithium-ion batteries

Abstract

The present invention belongs to the technical field of resource recycling and utilization, and discloses a slag-forming agent and its application, and a recycling process for retired ternary lithium-ion batteries. The slag-forming agent is composed of a calcium compound, a magnesium compound and silicon dioxide. The recycling process for retired ternary lithium-ion batteries comprises the following steps: step S1, crushing retired ternary lithium-ion batteries to obtain powder; step S2, mixing the powder with the above-mentioned slag-forming agent to obtain a mixed material; step S3, smelting the mixed material in a smelting furnace to obtain a nickel-cobalt-manganese alloy and slag; step S4, leaching the slag with water, and the obtained leaching liquid is a lithium-containing solution. When the present invention reduces and smelts retired ternary lithium-ion battery powder, the metal recovery rate of nickel, cobalt and manganese is as high as more than 98%, and the recovery rate of lithium is as high as more than 95%; the separation of nickel, cobalt and manganese elements from calcium, magnesium, lithium and aluminum elements in retired ternary lithium-ion batteries is realized, and the recycling process is greatly shortened.

Description

Technical Field

[0001] The present invention belongs to the technical field of resource recycling, and in particular relates to the recovery of valuable metals in retired ternary lithium-ion batteries. Background Art

[0002] The rapid development of the new energy vehicle industry has led to an increase in the consumption of lithium-ion batteries, which has directly led to a serious shortage of energy metals such as cobalt, lithium, and nickel used in the production of battery materials. In the future, the output of retired lithium-ion batteries will increase exponentially. Recycling retired lithium-ion batteries can not only alleviate the current shortage of battery materials, but also solve the hazards caused by the accumulation of waste batteries.

[0003] After the discharge treatment of retired lithium-ion batteries, there are currently two main mainstream processes for the recovery of valuable metals in them: wet recovery and pyrometallurgical recovery. Wet recovery is to leach the positive active materials separated and enriched by pretreatment, so that the valuable metals in the materials are dissolved in the solution, and then the valuable metals in the materials are recovered by solvent extraction, chemical precipitation or electrolytic deposition. The wet recovery process brings serious wastewater treatment problems. The pyrometallurgical recovery process generally does not require screening and enrichment of battery materials. The graphite and organic binder components in them can be burned to provide heat for the reaction, and the process does not produce a large amount of acid and alkaline wastewater. The treatment of retired lithium-ion batteries through slag smelting process is also a direction that is currently being studied more. Slag smelting refers to the addition of slag-forming agents to make retired lithium-ion battery materials undergo physical or chemical transformation at high temperatures, and graphite acts as a reducing agent to reduce and smelt high-valent metal oxides, and finally obtain cobalt-based, iron-based and nickel-based alloys and slag products; metallic lithium forms oxides and enters the slag phase. At present, the slag-forming agents for recycling retired lithium-ion batteries are mainly SiO2-CaO-Al2O3 slag system. The slag system is used to reduce and smelt retired lithium-ion batteries. The smelting temperature is high, the recovery rate of valuable metals is low (the recovery rate of cobalt is less than 60%), and the subsequent recovery of lithium is more difficult. Summary of the invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a slag-forming agent and its application in recycling retired ternary lithium-ion batteries, and to provide a recycling process for retired ternary lithium-ion batteries.

[0005] To achieve the above objectives, the present invention provides the following specific technical solutions.

[0006] Firstly, the present invention provides a slag-forming agent, which is composed of a calcium compound, a magnesium compound and silicon dioxide.

[0007] Furthermore, preferably, the calcium compound is calcium sulfate and / or calcium carbonate.

[0008] Furthermore, preferably, the magnesium compound is magnesium sulfate and / or magnesium carbonate.

[0009] Furthermore, preferably, the ratio of the sum of the molar amounts of calcium and magnesium in the slag-forming agent to the molar amount of silicon is 0.5-4.

[0010] Secondly, the present invention provides the use of the above-mentioned slag-forming agent in the slag-forming and smelting process of retired ternary lithium-ion batteries.

[0011] Based on the same inventive concept, the present invention further provides a recycling process for retired ternary lithium-ion batteries, comprising the following steps:

[0012] Step S1, crushing retired ternary lithium-ion batteries to obtain powder;

[0013] Step S2, mixing the powder with the above-mentioned slag-forming agent to obtain a mixed material;

[0014] Step S3, smelting the mixed material in a smelting furnace to obtain a nickel-cobalt-manganese alloy and slag;

[0015] Step S4, leaching the slag with water, and the obtained leaching solution is a lithium-containing solution.

[0016] Furthermore, preferably, the amount of the slag-forming agent is 10-30% of the mass of the powder.

[0017] Furthermore, preferably, the smelting temperature is 1000-1600° C., and the smelting time is 0.5-4 h.

[0018] Furthermore, the method also includes the steps of treating the nickel-cobalt-manganese alloy: adding an inorganic acid and an oxidant to the nickel-cobalt-manganese alloy to perform oxidation leaching to obtain a leachate and a leaching residue; purifying the leachate to obtain a nickel-cobalt-manganese mixed salt solution; and using the nickel-cobalt-manganese mixed salt solution for a coprecipitation reaction of a precursor.

[0019] Preferably, the inorganic acid is at least one of sulfuric acid, nitric acid and hydrochloric acid; and the oxidant is hydrogen peroxide.

[0020] Preferably, the temperature of the oxidation leaching is 60-100° C., the pH value at the leaching endpoint is controlled to be 0.5-2.5, and the nickel concentration in the solution at the leaching endpoint is controlled to be 80-120 g / L.

[0021] Preferably, the leachate obtained by oxidation leaching of the nickel-cobalt-manganese alloy is further purified.

[0022] The purification method is: first adjust the pH value of the leaching solution to 2-4, then add sodium thiosulfate and / or sodium sulfide, react for 1-3 hours, separate the solid and liquid, adjust the pH value of the separated filtrate to 4-4.5, and separate the solid and liquid again to obtain the purified solution. The temperature during the purification process is 30-85°C.

[0023] Furthermore, preferably, carbonate is added to the lithium-containing solution to precipitate lithium.

[0024] Compared with the prior art, the present invention has the following obvious beneficial effects:

[0025] 1. When the slag-making agent of the present invention is used to reduce and smelt retired ternary lithium-ion battery powder, impurities such as aluminum, calcium, and magnesium enter the slag phase, and nickel, cobalt, and manganese form an alloy, thereby achieving the effect of separating nickel, cobalt, and manganese from impurity elements, with good separation effect and high nickel and cobalt recovery rate;

[0026] 2. Compared with the SiO2-CaO-Al2O3 slag system, the metal recovery rates of nickel, cobalt and manganese in the present invention are as high as over 98% and the recovery rate of lithium is as high as over 95% when reducing and smelting retired ternary lithium-ion battery powder;

[0027] 3. The present invention realizes the separation of nickel, cobalt, manganese and calcium, magnesium, lithium, aluminum and other elements in retired ternary lithium-ion batteries, greatly shortening the recycling process;

[0028] 4. The present invention has a large processing capacity for recycling retired ternary lithium-ion batteries and a small amount of wastewater, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a process flow chart for processing retired ternary lithium-ion batteries according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] 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.

[0031] 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.

[0032] 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.

[0033] The specific embodiment of the present invention adopts Figure 1 The technical scheme shown processes retired ternary lithium-ion batteries. The retired ternary lithium-ion batteries are crushed to obtain powder, which is mixed with a slag-making agent and smelted. After the smelting is completed, a nickel-cobalt-manganese alloy and slag are obtained; the nickel-cobalt-manganese alloy is leached by acid oxidation and then purified to obtain a nickel-cobalt-manganese mixed salt solution; the nickel-cobalt-manganese mixed salt solution is subjected to a co-precipitation reaction under the action of a precipitant and a complexing agent to obtain a nickel-cobalt-manganese ternary precursor; the slag is leached with water to obtain a lithium-containing solution; the lithium-containing solution can further precipitate lithium.

[0034] The slag-making agent of the present invention is used for smelting retired ternary lithium-ion batteries and consists of calcium compounds, magnesium compounds and silicon dioxide.

[0035] In a specific embodiment, the calcium compound is calcium sulfate and / or calcium carbonate.

[0036] In a specific embodiment, the magnesium compound is magnesium sulfate and / or magnesium carbonate.

[0037] In a specific embodiment, the ratio of the sum of the molar amounts of calcium and magnesium in the slag-forming agent to the molar amount of silicon is 0.5-4, and more preferably 2-3.

[0038] In a specific embodiment, the amount of the slag-forming agent is 10-30% of the mass of the powder, and more preferably 15-20%.

[0039] In a specific implementation manner, the smelting temperature is 1000-1600° C., more preferably 1400-1500° C.; the smelting time is 0.5-4 h, more preferably 2-3 h.

[0040] In a specific embodiment, the acid used for acidic oxidation leaching of nickel-cobalt-manganese alloy is an inorganic acid, and the inorganic acid is at least one of sulfuric acid, nitric acid, and hydrochloric acid; and the oxidant is hydrogen peroxide.

[0041] In a specific embodiment, the temperature of the acidic oxidation leaching of the nickel-cobalt-manganese alloy is 60~100°C, and more preferably 90~98°C; the pH value of the leaching endpoint is controlled to be 0.5~2.5, and more preferably 1~2; the concentration of nickel in the solution at the leaching endpoint is controlled to be 80~120g / L, and more preferably 100~120g / L.

[0042] In a specific embodiment, the leachate obtained by oxidation leaching of the nickel-cobalt-manganese alloy is further purified. The specific purification method is: first adjust the pH value to 2-4, then add sodium thiosulfate and / or sodium sulfide, react for 1-3 hours, separate the solid and liquid, and then adjust the pH value of the separated solution to 4-4.5. The temperature during the purification process is 30-85°C, and preferably the temperature during the purification process is 60-80°C.

[0043] In a specific embodiment, carbonate is added to a lithium-containing solution to precipitate lithium to obtain lithium carbonate.

[0044] The technical concept of the present invention is further described below through specific embodiments.

[0045] In the following specific examples, the recovery rates of nickel, cobalt, manganese and lithium were calculated by the following method.

[0046] Recovery rate r (X, X is nickel, cobalt, manganese) = (volume of nickel-cobalt-manganese mixed salt solution × concentration of X) / (battery mass × content of X in the battery);

[0047] Recovery rate r(Li) = (volume of lithium-containing solution × lithium concentration) / (battery mass × lithium content in the battery).

[0048] Example 1

[0049] Slag-forming agent: 5g calcium sulfate, 5g magnesium sulfate and 5g silicon dioxide

[0050] The retired ternary lithium-ion batteries were crushed to obtain powder. The content of some metals in the powder is shown in Table 1.

[0051] Table 1

[0052]

[0053] (1) Smelting: 100 g of powder was mixed with slag-making agent (5 g of calcium sulfate, 5 g of magnesium sulfate and 5 g of silicon dioxide) by ball milling for 2 h at a ball milling speed of 300 r / min; then put into a smelting furnace, the smelting temperature was controlled at 1400 °C, and smelting was carried out for 2 h to produce nickel-cobalt-manganese alloy and slag.

[0054] The main components of nickel-cobalt-manganese alloy are shown in Table 2.

[0055] Table 2

[0056]

[0057] The main components of the slag are shown in Table 3.

[0058] Table 3

[0059]

[0060] (2) Nickel-cobalt-manganese alloy leaching:

[0061] 20 mL of 98% sulfuric acid, 70 mL of 35% nitric acid, and 30 mL of 30% hydrogen peroxide were added to the obtained nickel-cobalt-manganese alloy for acid oxidation leaching. The leaching temperature was 60°C, the pH value was controlled to be 1.5 at the leaching end point, and the total concentration of nickel, cobalt, and manganese was 120 g / L.

[0062] After the leaching is completed, the leaching solution and leaching residue are obtained by filtration.

[0063] The concentrations of some metal elements in the leaching solution are shown in Table 4.

[0064] Table 4

[0065]

[0066] Treatment of leachate: First, adjust the pH value of the leachate to 2.5-3 with a sodium carbonate solution at a concentration of 200 g / L, then add sodium thiosulfate (4 times the amount of copper metal), react at 60-80 ° C for 2 hours, and then filter press, then adjust the pH value of the filtrate to 4.5 with a sodium carbonate solution at a concentration of 200 g / L, react at 80 ° C for 2 hours, and then filter press. The filtrate after filtration can be used to synthesize the ternary precursor.

[0067] (3) Slag treatment: The slag is repeatedly leached with water, with a leaching liquid-solid ratio of 1:3. After leaching until the lithium concentration reaches 15 g / L, filter to obtain a filtrate and a filter residue; add sodium carbonate to the filtrate to precipitate lithium to obtain lithium carbonate.

[0068] According to calculations, the recovery rates of nickel, cobalt and manganese are 98.5%, 98.2% and 98.3% respectively, and the recovery rate of lithium is 96%.

[0069] Example 2

[0070] Slag forming agent: 10g magnesium sulfate and 5g silicon dioxide

[0071] The retired ternary lithium-ion batteries were crushed to obtain powder. The contents of some metals in the powder are shown in Table 5.

[0072] Table 5

[0073]

[0074] (1) Smelting: 100 g of powder was mixed with a slag-forming agent (10 g of magnesium sulfate and 5 g of silicon dioxide) by ball milling for 2 h at a ball milling speed of 300 r / min; then put into a smelting furnace, the smelting temperature was controlled at 1500 °C, and smelting was carried out for 2 h to produce a nickel-cobalt-manganese alloy and slag.

[0075] The main components of nickel-cobalt-manganese alloy are shown in Table 6.

[0076] Table 6

[0077]

[0078] The main components of the slag are shown in Table 7.

[0079] Table 7

[0080]

[0081] (3) Nickel-cobalt-manganese alloy leaching:

[0082] 20 mL of 98% sulfuric acid and 80 mL of 30% hydrogen peroxide were added to the obtained nickel-cobalt-manganese alloy for acid oxidation leaching. The leaching temperature was 60° C. The pH value was controlled to be 1.5 at the leaching end point. The total concentration of nickel, cobalt and manganese was 110 g / L.

[0083] After the leaching is completed, the leaching solution and leaching residue are obtained by filtration.

[0084] The concentrations of some metal elements in the leachate are shown in Table 8.

[0085] Table 8

[0086]

[0087] Treatment of leachate: First, add 200g / L sodium hydroxide solution to the leachate to adjust the pH to 3.2. Then add sodium sulfide (4 times the amount of copper metal), react at 60-80℃ for 2h and filter press, then adjust the pH of the filtrate to 4.5 with 200g / L sodium hydroxide solution, react at 80℃ for 2h and filter press. The filtrate after filter press can be used to synthesize the ternary precursor.

[0088] (3) Slag treatment: The slag is repeatedly leached with water, with a leaching liquid-solid ratio of 1:3. After leaching until the lithium concentration reaches 16 g / L, the slag is filtered to obtain a filtrate and a filter residue; sodium carbonate is added to the filtrate to precipitate lithium to obtain lithium carbonate.

[0089] After calculation, the recovery rates of nickel, cobalt and manganese are 98.2%, 98.0% and 98.3% respectively, and the recovery rate of lithium is 96.20%.

[0090] Example 3

[0091] Slag-forming agent: 10g calcium sulfate, 5g magnesium sulfate and 5g silicon dioxide

[0092] The retired ternary lithium-ion batteries were crushed to obtain powder. The contents of some metals in the powder are shown in Table 9.

[0093] Table 9

[0094]

[0095] (1) Smelting: 100 g of powder was mixed with a slag-making agent (10 g of calcium sulfate, 5 g of magnesium sulfate and 5 g of silicon dioxide) by ball milling for 2 h at a ball milling speed of 300 r / min; then put into a smelting furnace, the smelting temperature was controlled at 1600 °C, and smelting was carried out for 1.5 h to produce a nickel-cobalt-manganese alloy and slag.

[0096] The main components of nickel-cobalt-manganese alloy are shown in Table 10.

[0097] Table 10

[0098]

[0099] The main components of the slag are shown in Table 11.

[0100] Table 11

[0101]

[0102] (4) Nickel-cobalt-manganese alloy leaching:

[0103] 20 mL of 98% sulfuric acid and 100 mL of 35% nitric acid were added to the obtained nickel-cobalt-manganese alloy for acid oxidation leaching. The leaching temperature was 98° C. The pH value was controlled to be 1.5 at the leaching end point. The total concentration of nickel, cobalt and manganese was 105 g / L.

[0104] After the leaching is completed, the leaching solution and leaching residue are obtained by filtration.

[0105] The concentrations of some metal elements in the leachate are shown in Table 12.

[0106] Table 12

[0107]

[0108] Treatment of the leachate: first use a saturated sodium carbonate solution to adjust the pH value of the leachate to 3, then add sodium thiosulfate (4 times the amount of copper metal), react at 60-80°C for 2 hours and filter press, then use a saturated sodium carbonate solution to adjust the pH of the filtrate to 4.5, react at 80°C for 2 hours and filter press. The filtrate after filtration can be used to synthesize the ternary precursor.

[0109] (3) Slag treatment: The slag is repeatedly leached with water, with a leaching liquid-solid ratio of 1:3. After leaching until the lithium concentration reaches 18 g / L, filter to obtain a filtrate and a filter residue; add sodium carbonate to the filtrate to precipitate lithium to obtain lithium carbonate.

[0110] After calculation, the recovery rates of nickel, cobalt and manganese are 98.7%, 98.35% and 98.65% respectively, and the recovery rate of lithium is 96.24%.

[0111] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. The application of slag-making agent in the slag-making and smelting process of retired ternary lithium-ion batteries is characterized in that: The slag-forming agent is composed of a calcium compound, a magnesium compound and silicon dioxide; the calcium compound is calcium sulfate and / or calcium carbonate; the magnesium compound is magnesium sulfate and / or magnesium carbonate; and the ratio of the sum of the molar amounts of calcium and magnesium in the slag-forming agent to the molar amount of silicon is 0.5-4.

2. A recycling process for retired ternary lithium-ion batteries, characterized in that: The following steps are involved: Step S1, crushing retired ternary lithium-ion batteries to obtain powder; Step S2, mixing the powder with a slag-forming agent to obtain a mixed material; the slag-forming agent is composed of a calcium compound, a magnesium compound and silicon dioxide; the calcium compound is calcium sulfate and / or calcium carbonate; the magnesium compound is magnesium sulfate and / or magnesium carbonate; the ratio of the sum of the molar amounts of calcium and magnesium in the slag-forming agent to the molar amount of silicon is 0.5-4; Step S3, smelting the mixed material in a smelting furnace to obtain a nickel-cobalt-manganese alloy and slag; Step S4, leaching the slag with water, and the obtained leaching solution is a lithium-containing solution.

3. The recycling process of retired ternary lithium-ion batteries according to claim 2, characterized in that: The dosage of the slag-forming agent is 10-30% of the powder mass.

4. The recycling process of retired ternary lithium-ion batteries according to claim 2, characterized in that: The smelting temperature is 1000-1600° C. and the smelting time is 0.5-4 hours.

5. The recycling process of retired ternary lithium-ion batteries according to claim 2, characterized in that: The method also includes the steps of treating the nickel-cobalt-manganese alloy: adding an inorganic acid and an oxidant to the nickel-cobalt-manganese alloy to perform oxidation leaching to obtain a leachate and a leaching residue; purifying the leachate to obtain a nickel-cobalt-manganese mixed salt solution; and using the nickel-cobalt-manganese mixed salt solution for a coprecipitation reaction of a precursor.

6. The recycling process of retired ternary lithium-ion batteries according to claim 5, characterized in that: The temperature of the oxidation leaching is 60-100°C, the pH value of the leaching endpoint is controlled to be 0.5-2.5, and the total concentration of nickel, cobalt and manganese in the solution at the leaching endpoint is controlled to be 80-120 g / L; the purification method of the leachate is: first adjust the pH value of the leachate to 2-4, then add sodium thiosulfate and / or sodium sulfide, react for 1-3 hours, separate the solid and liquid, and then adjust the pH value of the separated solution to 4-4.5, and the temperature during the purification process is 30-85°C.

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