CN115584393A - A method for selectively recovering lithium from waste lithium batteries and simultaneously preparing cobalt ferrite catalyst - Google Patents

Abstract

The invention discloses a method for selectively recovering lithium from a waste lithium battery and preparing a cobalt ferrite catalyst, which comprises the following steps: (1) Discharging, disassembling and classifying the waste lithium cobaltate battery to obtain a positive electrode material, and then performing high-temperature treatment to remove the adhesive; (2) Drying and screening lithium cobaltate positive electrode powder, uniformly mixing the lithium cobaltate positive electrode powder with copperas according to a certain mass ratio, and roasting for a certain time at a certain temperature; (3) Leaching the roasted product obtained in the first step by using deionized water to obtain a lithium sulfate leaching solution and a solution rich in CoFe ₂ O ₄ Leaching residue of (2); (3) Adding ammonia water into the leachate obtained in the second step to adjust the pH value, and filtering iron impurities; (4) Adding an ammonium carbonate solution into the filtrate obtained in the third step for carbonization, and filtering and drying the precipitate to obtain lithium carbonate; (5) Loading activity to the leaching residue obtained in the third stepAnd modifying the substance to obtain the SCR catalyst. The mixed roasting leaching process of the waste lithium cobaltate batteries and the copperas is adopted, the operation is simple, the production cost is low, the separation is easy, the waste lithium cobaltate batteries and the copperas are recycled, and the method has the characteristics of remarkable economic benefit and environmental friendliness.

Description

A method for selectively recovering lithium from waste lithium batteries and simultaneously preparing cobalt ferrite catalyst

technical field

The invention belongs to the field of resource utilization of solid waste, and mainly relates to a method for selectively recovering lithium from waste lithium batteries and simultaneously preparing a cobalt ferrite catalyst.

Background technique

Since the industrial revolution, the burning of fossil fuels has promoted the development of global industrialization, but it has caused serious energy and environmental problems. New energy technologies have attracted widespread attention because they can cope with world environmental problems and energy shortages. As one of the most important new energy carriers, lithium-ion batteries have been widely used in mobile electronic devices and electric vehicles due to their high energy density, good cycle performance and low memory effect. However, the long-term charging and discharging process of lithium-ion batteries leads to its short cycle life, and a large amount of waste lithium-ion batteries are generated every year. It is estimated that by 2030, the global quantity of used lithium-ion batteries is expected to reach 1.93 million tons, and the global lithium-ion battery recycling market is expected to reach 200 billion yuan. Waste lithium cobalt oxide batteries, as the earliest positive electrode materials, account for more than 20% of the world's waste lithium batteries. However, used lithium-ion batteries are classified as hazardous waste because toxic materials such as cobalt, nickel, and organic solvents will cause heavy metal pollution, spontaneous combustion, and explosion hazards. At the same time, used lithium-ion batteries are an important secondary resource that contains more valuable elements than natural resources such as minerals and brine. Therefore, recovering valuable metals from spent Li-ion batteries can effectively solve the problems of environmental pollution and resource scarcity.

Researchers have conducted extensive research on the resource utilization of valuable elements in waste lithium cobalt oxide batteries. Patent CN106868317A mixes the positive electrode material of lithium cobaltate battery with ferrous sulfate and puts it in the reactor, adds water to adjust the slurry, adds inorganic acid solution to the slurry for reaction, and then adds inorganic alkali to neutralize the remaining acid to adjust the pH value of the slurry Precipitate Fe ³⁺ to complete liquid-solid separation, in which the solid slag is a mixture of carbon powder and ferric hydroxide, and the leaching solution is a high-concentration cobalt and lithium solution. Patent CN113481368A reacts waste lithium cobaltate battery powder with high-concentration first sodium hydroxide solution, separates solid-liquid to obtain first filter residue and first filtrate, then reacts first filter residue with low-concentration second sodium hydroxide solution, Then the solid-liquid separation obtains the second filter residue and the second filtrate, and the first filtrate and the second filtrate are jointly used as the first leaching solution containing aluminum, and the second filter residue is used as the first leaching residue to react the first leaching residue with phosphoric acid for solid-liquid separation , to obtain a second leaching residue and a lithium-containing second leaching solution. The second leaching residue is reacted with a mixed solution of sulfuric acid and ascorbic acid, and the solid and liquid are separated to obtain a third leaching residue and a third leaching solution containing cobalt. The use of high and low alkalis reduces the consumption of aluminum-removing alkali and prevents the leaching of lithium cobaltate during the process of leaching aluminum, which is beneficial to obtain a higher recovery rate of cobalt and lithium. Patent CN114317977A pyrolyzes polyvinyl chloride and waste lithium cobaltate in a circulating inert gas atmosphere to obtain a co-pyrolysis product containing lithium and cobalt; then leaches the co-pyrolysis product with water and filters to obtain a leachate and a leachate, the leachate It is a leaching solution containing lithium salt, and the leaching product is a leaching product containing cobalt. In patent CN113943867A, the positive active material is placed in vitamin C and dilute nitric acid to react to obtain a mixed solution, and then the reacted mixed solution is filtered to obtain a leaching solution and residue containing valuable metal ions. However, the above method has the problems of expensive reducing agent or acid-base solution and complex process, which limits the recycling of waste lithium cobalt oxide batteries to a certain extent. Therefore, it is necessary to seek cheaper raw materials or simpler operating processes to meet the resource utilization of waste lithium cobalt oxide batteries.

Green vitriol is a solid waste discharged during the production of titanium dioxide by the sulfuric acid method. For every ton of titanium dioxide produced, about 3.5 tons of vitriol will be produced. China's titanium dioxide production in 2021 is about 4.26 million tons, of which 91% is produced by the sulfuric acid process, resulting in nearly 12 million tons of vitriol. At present, the main use of green vitriol is to produce sulfuric acid through thermal decomposition, but this requires a large amount of energy consumption, and the production cost is higher than the existing sulfuric acid production. With the rapid development of the titanium dioxide industry, the resource utilization of green vitriol needs to be solved urgently.

Based on the above, the present invention uses titanium white solid waste greenite as an auxiliary agent, mixes it with the positive electrode material of the waste lithium cobaltate battery and roasts it, selectively extracts and separates the lithium element of the lithium cobaltate battery into the solution, and the leaching residue is cobalt ferrite , were prepared into lithium carbonate and iron-based SCR catalysts. The process adopts the mixed roasting and leaching process of lithium cobaltate and green vitriol, which is simple to operate, low in production cost, and easy to separate, and realizes the recycling of lithium cobaltate batteries and green vitriol. At the same time, there is very little iron leached in the solution, and the purification process is greatly improved. simplify. This process combines the characteristics of lithium cobaltate and green vitriol to make solid waste resource, which has the characteristics of significant economic benefits and environmental friendliness.

Contents of the invention

Aiming at the problems of resource utilization of waste lithium cobaltate batteries and solid waste treatment of titanium dioxide industry, the invention provides a method for selectively recovering lithium from waste lithium batteries and simultaneously preparing a cobalt ferrite catalyst.

The method for preparing lithium carbonate and SCR catalyst by using waste lithium cobalt oxide battery and green vitriol of the present invention uses waste and old lithium cobalt oxide battery and green vitriol as raw materials, and the process steps are as follows:

1. Dismantling, dismantling, crushing and screening of waste lithium cobalt oxide batteries and other pretreatment processes to obtain lithium cobalt oxide, the positive electrode material of lithium batteries;

2. Green vitriol decomposes lithium cobalt oxide, the positive electrode material

Evenly mix the lithium cobalt oxide positive electrode powder finely ground to below 2000 μm with green vitriol, and control the mass ratio of lithium cobalt oxide and green vitriol to 1:1-10; roast the mixture at 800-1000°C for 60-240 minutes to obtain a solid product;

3. Roasting product leaching

The solid product obtained in step 2 is leached with deionized water at 25-80°C, the leaching time is 30-240min, the liquid-solid mass ratio is 4-20:1, and the leached slurry is separated from solid-liquid to obtain lithium sulfate-containing Leachate and filter residue (the main component is cobalt ferrite);

3. Preparation of SCR catalyst

Add the filter residue obtained in step 3 into a salt solution (cerium nitrate, niobium nitrate, ammonium metavanadate, samarium nitrate), stir in a water bath at 80°C until it is completely evaporated to dryness, then place it in a blast drying oven at 100°C for 12 hours in vacuum to obtain SCR catalyst;

4. Preparation of lithium carbonate

Add ammonia water slowly to the filtrate obtained in step 3 to remove impurities, add an appropriate amount (the molar ratio of lithium sulfate to ammonium carbonate is 1:1 to 6) to the filtrate, and the concentration is 1 to 5mol/L ammonium carbonate solution, and collect the precipitate product and dried to obtain lithium carbonate product.

_The above method utilizes the ferrous iron in the vitriol and the SO2 produced by thermal decomposition to continue reducing and sulfating the lithium cobaltate positive electrode material, so that lithium and cobalt are converted into corresponding sulfates. The thermal stability of cobalt sulfate is worse than that of lithium sulfate, and it will be decomposed into oxides above 800 degrees, so as to realize the selective extraction of lithium, and cobalt oxide is further combined with iron oxide produced by the decomposition of green vitriol to form cobalt ferrite.

8LiCoO ₂ +12FeSO ₄ ·7H ₂ O+O ₂ (g)＝6Fe ₂ O ₃ +4Li ₂ SO ₄ +84H ₂ O(g)+8CoSO ₄ (1)

8CoSO ₄ +8Fe ₂ O ₃ ＝8CoFe ₂ O ₄ +8SO ₂ (g)+4O ₂ (g) (2)

Compared with the prior art, the present invention has the following advantages: (1) the process uses industrial solid waste as a raw material, realizing waste resource utilization; (2) the process has mild reaction conditions; (3) the process uses solid waste green vitriol , a wide range of sources, both reducing environmental pollution and saving production costs; (4) the present invention is simple in process, easy to operate, low in production cost, and has industrial application prospects.

Description of drawings

Fig. 1 is a process flow diagram of the present invention

detailed description

The present invention will be described in detail below in conjunction with the examples, but the protection scope of the present invention is not limited to the following examples.

Each element composition (mass percentage) of the positive electrode material after the pretreatment of waste lithium batteries in the following examples is 54.38% CO, 6.76% Li, 0.1% Al, 0.05% Ni, and the XRD analysis results show that the main phase in the positive electrode powder is Lithium Cobalt Oxide.

Embodiment one

(1) Discharge, disassemble and classify the waste lithium cobalt oxide battery to obtain the positive electrode material, and then perform high-temperature treatment to remove the binder;

(2) Mix the lithium cobaltate positive electrode powder finely ground to below 200 μm with green vitriol evenly, and the mass ratio of lithium cobaltate and green vitriol is 1:1; roast the mixture at 800°C for 60 minutes to obtain a solid product;

(3) The solid product obtained in step 2 was magnetically stirred with deionized water at 25° C., leached for 180 min, the liquid-solid mass ratio was 4:1, and solid-liquid separation was performed to obtain lithium sulfate-containing leachate and filter residue;

(4) Add the filter residue obtained in step 3 into the cerium nitrate solution, stir in a water bath at 80°C until it is completely evaporated to dryness, and then place it in a blast drying oven at 100°C for vacuum drying for 12 hours to obtain an SCR catalyst;

(5) Add ammoniacal liquor slowly in the filtrate that step 3 obtains, filter and remove aluminum and iron ion, add appropriate amount (the mol ratio of manganese sulfate and ammonium carbonate is 1:1) to filtrate, concentration is the ammonium carbonate solution of 5mol/L , the precipitated product was collected and dried to obtain a lithium carbonate product.

Embodiment two

(1) Discharge, disassemble and classify the waste lithium cobalt oxide battery to obtain the positive electrode material, and then perform high-temperature treatment to remove the binder;

(2) Mix the lithium cobaltate positive electrode powder finely ground to below 200 μm with green vitriol evenly, and the mass ratio of lithium cobaltate and green vitriol is 1:4; roast the mixture at 900°C for 120min to obtain a solid product;

(3) The solid product obtained in step 2 was magnetically stirred with deionized water at 55° C., leached for 60 minutes, the liquid-solid mass ratio was 8:1, and separated from solid-liquid to obtain lithium sulfate-containing leachate and filter residue;

(4) Add the filter residue obtained in step 3 into the niobium nitrate solution, stir in a water bath at 80°C until it is completely evaporated to dryness, and then place it in a blast drying oven at 100°C for vacuum drying for 12 hours to obtain an SCR catalyst;

(5) Add ammoniacal liquor slowly in the filtrate that step 3 obtains, filter and remove aluminum and iron ion, add appropriate (the mol ratio of manganese sulfate and ammonium carbonate is 1:2) to filtrate, concentration is the ammonium carbonate solution of 6mol/L , the precipitated product was collected and dried to obtain a lithium carbonate product.

Embodiment Three

(1) Discharge, disassemble and classify the waste lithium cobalt oxide battery to obtain the positive electrode material, and then perform high-temperature treatment to remove the binder;

(2) Mix the lithium cobaltate positive electrode powder finely ground to less than 200 μm with green vitriol evenly, and the mass ratio of lithium cobaltate and green vitriol is 1:1; roast the mixture at 1000° C. for 120 min to obtain a solid product;

(3) The solid product obtained in step 2 was magnetically stirred with deionized water at 70° C., leached for 240 min, the liquid-solid mass ratio was 10:1, and separated from solid-liquid to obtain lithium sulfate-containing leachate and filter residue;

(4) Add the filter residue obtained in step 3 into the vanadium nitrate solution, stir in a water bath at 80°C until it is completely evaporated to dryness, and then place it in a blast drying oven at 100°C for vacuum drying for 12 hours to obtain an SCR catalyst;

(5) Add ammoniacal liquor slowly in the filtrate that step 3 obtains, filter and remove aluminum and iron ion, add appropriate amount (the mol ratio of manganese sulfate and ammonium carbonate is 1:4) to filtrate, concentration is the ammonium carbonate solution of 4mol/L , the precipitated product was collected and dried to obtain a lithium carbonate product.

Embodiment Four

(1) Discharge, disassemble and classify the waste lithium cobalt oxide battery to obtain the positive electrode material, and then perform high-temperature treatment to remove the binder;

(2) Mix the positive electrode material lithium cobalt oxide finely ground to below 200 μm with green vitriol evenly, and the mass ratio of lithium cobaltate and green vitriol is 1:1; roast the mixture at 1000°C for 240min to obtain a solid product;

(3) The solid product obtained in step 2 was magnetically stirred with deionized water at 80° C., leached for 240 minutes, and the liquid-solid mass ratio was 20:1. After solid-liquid separation, the leachate containing lithium sulfate and cobalt ferrite were obtained. filter residue;

(4) Add the filter residue obtained in step 3 into the cerium nitrate solution, stir in a water bath at 80°C until it is completely evaporated to dryness, and then place it in a blast drying oven at 100°C for vacuum drying for 12 hours to obtain an SCR catalyst;

(5) In the filtrate that step 3 obtains, add and slowly add ammoniacal liquor, filter and remove aluminum and iron ion, add appropriate (the mol ratio of manganese sulfate and ammonium carbonate is 1:6) to filtrate, concentration is the ammonium carbonate solution of 1mol/L , the precipitated product was collected and dried to obtain a lithium carbonate product.

Claims (6)

1. A method for selectively recovering lithium from waste lithium batteries and simultaneously preparing a cobalt ferrite catalyst is characterized by comprising the following steps:

step 1: discharging, disassembling and classifying the waste lithium cobaltate battery to obtain a positive electrode material, and then performing high-temperature treatment to remove the adhesive;

step 2: uniformly mixing lithium cobaltate positive electrode powder which is finely ground to be less than 200 mu m with copperas according to a certain mass ratio, and roasting for a certain time at 800-1000 ℃ to obtain a solid product;

and step 3: magnetically stirring the solid product obtained in the step 2 with deionized water at a certain temperature for a certain time, and performing suction filtration on the leachate to realize solid-liquid separation to obtain leachate containing lithium sulfate and filter residue containing cobalt ferrite;

and 4, step 4: modifying the cobalt ferrite filter residue obtained in the step 3 by adopting an impregnation method to load an active component to obtain an SCR catalyst;

and 5: and 3, adjusting the pH value of the leachate obtained in the step 3 by using ammonia water, filtering iron ions, adding ammonium carbonate into the filtrate, collecting a precipitate product and drying to obtain a lithium carbonate product.

2. The method for selectively recycling lithium and simultaneously preparing a cobalt ferrite catalyst by using waste lithium batteries as claimed in claim 1, wherein the mass ratio of the lithium cobaltate to the copperas in the step 2 is 1:1-10.

3. The method for selectively recovering lithium and simultaneously preparing a cobalt ferrite catalyst by using waste lithium batteries as claimed in claim 1, wherein the calcination time in step 2 is 60-240 min.

4. The method for selectively recovering lithium and simultaneously preparing the cobalt ferrite catalyst by using the waste lithium batteries as claimed in claim 1, wherein the solid product in the step 3 has a water leaching temperature of 25-80 ℃, a leaching time of 30-250 min and a liquid-solid mass ratio of 2-20.

5. The method for selectively recovering lithium and simultaneously preparing a cobalt ferrite catalyst by using the waste lithium batteries as claimed in claim 1, wherein the active components in the step 4 comprise one or more of Ce, nb, V and Sm.

6. The method for selectively recovering lithium from waste lithium batteries and simultaneously preparing a cobalt ferrite catalyst according to claim 1, wherein the pH value of the solution obtained in the step 5 after adding ammonia water is 4-8, the solution temperature is 25-100 ℃, the concentration of ammonium carbonate is 1-5 mol/L, the molar ratio of lithium cobaltate to ammonium carbonate is 1:1-6, and the reaction time is 30-180 min.

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