Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide the method for separating and recovering nickel, cobalt, manganese and lithium from the ternary waste material, which has the advantages of simple process, environmental protection and high efficiency.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for separating and recovering nickel, cobalt, manganese and lithium in ternary waste comprises the following steps:
(1) preparation of lithium-containing solution: adding water into the ternary waste to prepare slurry, adding a phosphoric acid mixed solution to adjust the pH of the slurry to be less than 4 after the slurry is prepared, then adding a reducing agent to carry out reaction, adding an alkali reagent A to adjust the pH to 7.0-11.0 after the reaction is completed, and then separating to obtain a lithium-containing solution and filter residue A;
(2) preparing a nickel-cobalt-manganese refined solution: and (2) adding water into the filter residue A obtained in the step (1) to prepare slurry, adding ferric salt to perform double decomposition reaction after the slurry is prepared, adding an acid reagent to adjust the pH value of the system to 1.9-2.0 after the reaction is completed, aging and separating to obtain a nickel-cobalt-manganese crude solution and a filter residue B, continuously adding an alkali reagent B into the nickel-cobalt-manganese crude solution to adjust the pH value to 4.0-5.0 to perform precipitation, and separating to obtain a nickel-cobalt-manganese refined solution and a filter residue C.
Preferably, the liquid-solid ratio of the ternary waste to water in the step (1) is 1.5: 1-10: 1.
Preferably, the pulping in the step (1) can be carried out in a stirring mode, and the stirring is carried out at a stirring speed of 120-900 r/min for 0.5-2 h.
Preferably, the phosphoric acid mixed solution in the step (1) may be obtained by mixing phosphoric acid and at least one of sulfuric acid, hydrochloric acid, nitric acid, and the like.
Preferably, PO is contained in the phosphoric acid mixed solution 4 3- The molar concentration of the ions is 1-4 mol/L; h in the phosphoric acid mixed solution + The total molar concentration of the ions is 2-6 mol/L.
Preferably, the reducing agent in step (1) may include Na 2 S、Na 2 SO 3 、Na 2 S 2 O 3 、H 2 O 2 And the like.
Preferably, the adding amount of the phosphoric acid mixed solution in the step (1) is 1.0-1.05 times of the total reaction equivalent of the phosphate radical ions and the nickel-cobalt-manganese ions, and is calculated by taking hydrogen ions as 1.0-1.1 times of the reaction equivalent; the addition amount of the reducing agent is 1.0-2.0 times of the reaction equivalent.
Preferably, the reaction in the step (1) is carried out for 1-5 hours at the reaction temperature of 50-80 ℃ and the stirring speed of 120-900 r/min.
Preferably, the alkali agent A in step (1) may comprise NaOH, KOH, NH 4 At least one of OH, LiOH and the like.
Preferably, the separation in step (1) can be carried out by conventional procedures such as filtration and centrifugation.
Further, the lithium-containing solution obtained in the step (1) can be used for producing lithium salt, and the obtained filter residue A is mixed solid of nickel-cobalt-manganese phosphate, carbon powder, binder and the like.
Preferably, the liquid-solid ratio of the filter residue A to water in the pulping process in the step (2) is 1.5: 1-10: 1.
Preferably, the pulping in the step (2) is carried out by stirring, the stirring speed is 120-900 r/min, and the stirring time is 0.5-2 h.
Preferably, the ferric salt in step (2) may comprise FeCl 3 、Fe 2 (SO 4 ) 3 、Fe(NO 3 ) 3 And the like.
Preferably, the amount of the ferric iron salt added in the double decomposition reaction in the step (2) is 1.0-1.2 times of the reaction equivalent of the iron ions and the phosphate ions.
Preferably, the reaction temperature of the double decomposition reaction in the step (2) is 50-80 ℃, and the reaction time is 1-5 h.
Preferably, the double decomposition reaction process in the step (2) can be stirred at a stirring speed of 120-900 r/min.
Preferably, the acid reagent in step (2) may comprise HCl or H 2 SO 4 、HNO 3 And the like.
Preferably, the aging time in the step (2) is 0.5-2.0 h.
Preferably, the residue B in the step (2) can be washed with dilute acid, and the washing water obtained after washing the residue can be used for next pulping.
Preferably, the dilute acid may comprise at least one of dilute hydrochloric acid, dilute sulfuric acid, dilute nitric acid, and the like.
Preferably, in the slag washing process, the pH value of the system is controlled to be 2.0-4.0.
Preferably, the alkali agent B in step (2) may comprise NaOH or NH 4 OH、Ni(OH) 2 、Mn(OH) 2 、Co(OH) 2 And the like.
Preferably, the separation in step (2) can be carried out by conventional procedures such as filtration and centrifugation.
Compared with the prior art, the invention has the following advantages and technical effects:
(1) according to the technical scheme, the mixed phosphoric acid solution is adopted to selectively leach lithium in the ternary waste, and meanwhile, the characteristic that the precipitation tendency of iron phosphate is far stronger than that of nickel phosphate, cobalt phosphate and manganese phosphate is utilized, so that the nickel-cobalt-manganese element and the nickel-cobalt-manganese phosphate are separated from the filter residue and converted into the nickel-cobalt-manganese solution through a one-step method, and high-valued operation is achieved. The method for separating and recovering nickel, cobalt, manganese and lithium provided by the invention has the advantages of simple process, low cost, high recovery rate of nickel, cobalt, manganese and lithium, low equipment requirement, low control precision requirement, small waste salt amount, solid state, no need of evaporation and drying treatment and the like.
(2) According to the technical scheme, an extraction reagent is not needed, impurities of a lithium-containing solution and a nickel-cobalt-manganese solution which are recycled due to the introduction of an organic phase are avoided, COD (chemical oxygen demand) wastewater and sodium sulfate waste salt which are generated due to the use of a large amount of the extraction reagent are avoided, and the environmental pollution is reduced.
Detailed Description
The present invention will be described in further detail with reference to the following detailed description and examples, but the embodiments of the present invention are not limited thereto. All the raw materials and reagents used in the present invention are commercially available raw materials and reagents, unless otherwise specified. In the examples, the components are used in g and mL in parts by mass.
Preparation of lithium-containing solution:
according to an embodiment of the invention, the ternary waste and water are pulped, leaching rates of elements in the ternary waste are increased along with the increase of the liquid-solid ratio, but the leaching rates are increased continuously after the liquid-solid ratio reaches a certain ratio, so that the leaching rates are not changed greatly, and therefore, in order to maintain a high leaching rate and save the use of reagents, the liquid-solid ratio of the ternary waste to the water is 1.5: 1-10: 1, and is preferably 4: 1-6: 1.
According to an embodiment of the invention, the ternary waste and water are uniformly mixed in a stirring manner in the pulping process of the ternary waste and water, wherein the stirring speed is 120-900 r/min, and the stirring time is 0.5-2 h. In order to better disperse the ternary waste in water, the slurry can be subjected to ultrasonic treatment and heating treatment, for example, the slurry is treated for 30-120 min at 50-60 ℃ under the condition of 500-1000W of ultrasonic power.
Further, the ternary waste material can be pretreated before pulping. The pretreatment may include the steps of: heating the ternary waste at 380-500 ℃ for 30-120 min. The binder is generally an organic high molecular compound, such as PDVF, which has stable structure and chemical properties and is insoluble in strong acid and strong base, so that an ash layer is easily formed in the process of carrying out acid leaching reaction on the ternary waste, and the leaching of valuable metals is not facilitated. The binder can be decomposed by adopting a high-temperature treatment mode, so that the nickel-cobalt-manganese-lithium active material is fully exposed, the dispersibility is improved, and the leaching rate is improved.
According to one embodiment of the invention, a phosphoric acid mixed solution is used in combination with a reductant to perform a selective leaching reaction on the ternary waste. The reducing agent may comprise Na 2 S、Na 2 SO 3 、Na 2 S 2 O 3 、H 2 O 2 And the like. The main active material in the ternary waste is LiNi 1-x-y Co x Mn y O 2 (x+y<1) Wherein the chemical valence of the transition metal elements Ni, Co and Mn is +2, +3 and +4, and Co is required to be added 3+ 、Mn 4+ Reduced to low valence and can be completely dissolved by acid. The phosphoric acid mixed solution is prepared by adding at least one of sulfuric acid, hydrochloric acid, nitric acid and the like into phosphoric acid. Among them, sulfuric acid, hydrochloric acid, nitric acid and the like are strong acids, and LiNi is easily converted 1-x- y Co x Mn y O 2 The Li, Ni, Co and Mn elements in the solution are leached into the solution in the form of metal ions, and simultaneously H is provided for a reaction system + And adjusting the pH of the reaction system<4; phosphoric acid mainly provides PO for reaction system 4 3+, And Ni 2+ 、Co 2+ 、Mn 2+ Phosphate precipitation is formed, and Li + And PO 4 3+ At pH<4 can not be precipitated under the condition of 4, exists in the solution in the form of ions, thereby realizing the selective leaching of the ternary waste material, and the elements of Ni, Co and MnAnd separating from Li element.
With H 2 O 2 As an example of the reducing agent, the reaction equation is as follows:
6LiMeO 2 +18H + +4PO 4 3- +3H 2 O 2 →6Li + +2(Me) 3 (PO 4 ) 2 ↓+12H 2 O+3O 2 ↑
wherein Me is Ni, Co, Mn.
According to one embodiment of the invention, the addition amount of the reducing agent is 1.0-2.0 times of the reaction equivalent, and the sufficient addition amount of the reducing agent aims to thoroughly reduce high-valence Co and Mn into low-valence Co and Mn and improve the dissolution rate of Co and Mn; the adding amount of the phosphoric acid mixed solution is 1.0-1.05 times of the reaction equivalent of phosphate ions, the total adding amount of hydrogen ions is 1.0-1.1 times of the reaction equivalent, and the sufficient adding amount of the acid mainly aims at completely precipitating Ni, Co and Mn and improving the separation efficiency.
According to an embodiment of the present invention, after the reaction is completed, an alkaline reagent A is added to adjust the pH to 7.0-11.0, wherein the alkaline reagent B comprises NaOH, KOH, NH 4 At least one of OH, LiOH and the like, and the main purpose is to further completely precipitate nickel, cobalt and manganese phosphate and remove impurities from the system, and reduce impurities in the lithium-containing solution.
According to an embodiment of the invention, after the pH value of the alkali reagent A is adjusted to 7.0-11.0, a filtering operation is performed to obtain a lithium-containing solution and a filter residue A.
Preparing a nickel-cobalt-manganese refined solution:
according to an embodiment of the invention, filter residue A and water are pulped, the mass ratio of the filter residue A to the water in the pulping process is 1.5: 1-10: 1, pulping is carried out by stirring, the stirring speed is 120-900 r/min, and the stirring time is 0.5-2 h. The filter residue A is mixed solid of nickel cobalt manganese phosphate salt precipitate, carbon powder, binder and the like, and the pulping aims to fully disperse the nickel cobalt manganese phosphate salt precipitate in the solution and improve the reaction efficiency.
According to one embodiment of the present invention, the metathesis reaction is carried out after pulping by adding a ferric salt, which may include FeCl 3 、Fe 2 (SO 4 ) 3 、Fe(NO 3 ) 3 And the like. Using FePO 4 Much stronger precipitation tendency than Ni 3 (PO 4 ) 2 、Co 3 (PO 4 ) 2 、Mn 3 (PO 4 ) 2 The method is characterized in that Li, Ni and Co elements are replaced into ions from solid precipitates through double decomposition reaction and are dissolved in the solution, so that the Li, Ni and Co elements are separated from impurities such as carbon powder, a binder and the like, and a crude solution of nickel, cobalt and manganese and filter residue B are obtained.
The reaction equation for the metathesis reaction is as follows:
Me 3 (PO 4 ) 2 +2Fe 3+ +2H 2 O→FePO 4 ·2H 2 O↓+3Me 2+
wherein Me is Ni, Co or Mn.
According to an embodiment of the present invention, the amount of the trivalent iron salt added in the metathesis reaction is 1.0 to 1.2 times of the reaction equivalent. Adding a sufficient amount of a trivalent iron salt to effect Ni addition 3 (PO 4 ) 2 、Co 3 (PO 4 ) 2 、Mn 3 (PO 4 ) 2 The Ni, Co and Mn elements in the leaching solution are completely replaced, and the leaching efficiency is improved.
According to an embodiment of the present invention, after the double decomposition reaction is completed, an acid reagent is added to adjust the pH of the system to 1.9-2.0, and the system is aged for 0.5-2.0 h. The acid agent may include at least one of hydrochloric acid, sulfuric acid, nitric acid, and the like. During aging, FePO is reacted 4 ·2H 2 The small crystal grains of the O precipitate are gradually dissolved, the large crystal grains grow gradually, and the small crystal grains are adsorbed, occluded and occluded in FePO along with the dissolution of the small crystal grains 4 ·2H 2 Ni, Co and Mn ions in the O precipitation precipitate can be dissolved into the system again, thereby improving the recovery rate of Ni, Co and Mn and FePO 4 ·2H 2 Purity of O precipitated crystals.
According to an embodiment of the invention, the residue B is washed by dilute acid, and the washing water obtained after residue washing can be used for pulping the residue A next time. The dilute acid can be at least one of dilute sulfuric acid, dilute hydrochloric acid, dilute nitric acid and the like. The washing slagIn the process, the pH value of the system is controlled to be 2.0-4.0. Wherein the filter residue B is FePO 4 ·2H 2 Mixing solid of O precipitate and impurities such as carbon powder and binder, washing residue B with dilute strong acid to remove FePO in residue B 4 ·2H 2 Dissolving the O precipitate in washing water, reusing the O precipitate in pulping the filter residue A and water, and providing Fe for double decomposition reaction 3+ The reaction is carried out, so that the reagent is fully utilized, the reagent waste is reduced, and the cost is saved.
According to an embodiment of the present invention, the crude Ni-Co-Mn solution is precipitated by adding an alkali reagent to adjust the pH to 4.0-5.0. In the process of double decomposition reaction, in order to completely leach Ni, Co and Mn, excessive ferric salt is added, so that Fe also exists in the nickel-cobalt-manganese crude solution 3+ Thus adding an alkali agent to cause Fe 3+ Formation of Fe (OH) 3 (residue C) precipitation for impurity removal, since Fe (OH) 3 Much stronger precipitation tendency than Ni (OH) 2 、Co(OH) 2 、Mn(OH) 2 Therefore, under the condition that the pH value of the reaction system is 4.0-5.0, the added alkali reagent is preferentially mixed with Fe 3+ Formation of Fe (OH) 3 Precipitating, thereby obtaining the nickel-cobalt-manganese refined solution through filtering.
The following specific examples further illustrate the method for separating and recovering nickel, cobalt, manganese and lithium from the ternary waste material of the present invention, wherein the ternary waste material adopted in the examples comprises 7.2% of Li, 20.3% of Ni, 20.5% of Co and 19.0% of Mn.
Example 1: method for separating and recovering nickel, cobalt, manganese and lithium in ternary waste
(1) Preparation of lithium-containing solution: stirring the ternary waste and water to prepare slurry with a liquid-solid ratio of 6:1, stirring for 1h at a stirring speed of 600r/min to obtain slurry, adding a phosphoric acid mixed solution (phosphoric acid is mixed with sulfuric acid, the adding amount of phosphate ions is controlled to be 1.05 times of the total reaction equivalent of the phosphate ions and the nickel-cobalt-manganese ions, and the total adding amount of hydrogen ions is 1.1 times of the reaction equivalent) into the slurry to adjust the pH of the system<4, continuing to add H 2 O 2 (H 2 O 2 The adding amount is 1.5 times of the reaction equivalent), and the stirring speed is 600r/min at the reaction temperature of 65 DEG CAnd (3) reacting for 3 hours, adding LiOH to adjust the pH of the system to 9.0 after the reaction is finished, further precipitating and removing impurities, and filtering to obtain a lithium-containing solution and filter residue A.
(2) Preparing a nickel-cobalt-manganese refined solution: adding water into the filter residue A obtained in the step (1) for pulping, wherein the liquid-solid ratio is 6:1, stirring for 1h at the stirring speed of 600r/min to obtain slurry, and then adding Fe into the slurry 2 (SO 4 ) 3 (Fe 2 (SO 4 ) 3 The adding amount is 1.1 times of the reaction equivalent of iron ions and phosphate ions) to carry out double decomposition reaction, the reaction is carried out for 3 hours under the conditions that the reaction temperature is 65 ℃ and the stirring speed is 600r/min, and then H is added 2 SO 4 Adjusting the pH value of the system to 1.9, aging for 1h, filtering to obtain a nickel-cobalt-manganese crude solution and a filter residue B, and then adding Mn (OH) into the nickel-cobalt-manganese crude solution 2 Adjusting the pH value of the system to 4.5, precipitating and removing impurities, and filtering to obtain a nickel-cobalt-manganese refined solution and filter residue C;
(3) slag washing: and (3) washing the filter residue B obtained in the step (2) with dilute sulfuric acid with the pH value of 3.0, and using washing water obtained after washing the filter residue for next pulping of the filter residue A and water.
FIG. 1 is a flow chart of the process for separating and recovering nickel, cobalt, manganese and lithium as ternary wastes in example 1.
Example 2: method for separating and recovering nickel, cobalt, manganese and lithium in ternary waste
(1) Preparation of lithium-containing solution: stirring the ternary waste and water to prepare slurry with a liquid-solid ratio of 1.5:1, stirring for 0.5h at a stirring speed of 900r/min to obtain slurry, adding a phosphoric acid mixed solution (phosphoric acid is mixed with hydrochloric acid, the adding amount of phosphate ions is controlled to be 1.0 time of the total reaction equivalent of the phosphate ions and the nickel-cobalt-manganese ions, and the total adding amount of hydrogen ions is controlled to be 1.0 time of the reaction equivalent) into the slurry to adjust the pH of the system<4, continuing to add Na 2 S(Na 2 The adding amount of S is 1.0 time of the reaction equivalent), the reaction is carried out for 5 hours under the conditions that the reaction temperature is 80 ℃ and the stirring speed is 900r/min, NaOH is added after the reaction is finished to adjust the pH value of the system to be 11.0, the precipitation and the impurity removal are further carried out, and the lithium-containing solution and the filter residue A are obtained by filtering.
(2) Preparing a nickel-cobalt-manganese refined solution: adding water into the filter residue A obtained in the step (1) for pulping, wherein the liquid-solid ratio is 1.51, stirring for 0.5h at a stirring speed of 900r/min to obtain slurry, and adding FeCl into the slurry 3 (FeCl 3 The addition amount is 1.0 time of the reaction equivalent of iron ions and phosphate ions), carrying out double decomposition reaction, reacting for 5 hours at the reaction temperature of 80 ℃ and the stirring speed of 900r/min, then adding HCl to adjust the pH value of the system to be 2.0, aging for 2 hours, filtering to obtain a nickel-cobalt-manganese crude solution and a filter residue B, and then adding Co (OH) into the nickel-cobalt-manganese crude solution 2 And adjusting the pH value of the system to 4.0, precipitating, removing impurities, and filtering to obtain a nickel-cobalt-manganese refined solution and filter residue C.
Example 3: method for separating and recovering nickel, cobalt, manganese and lithium in ternary waste
(1) Preparation of lithium-containing solution: stirring the ternary waste and water to prepare slurry with a liquid-solid ratio of 10:1, stirring for 2 hours at a stirring speed of 120r/min to obtain slurry, adding a phosphoric acid mixed solution (phosphoric acid is mixed with nitric acid, the adding amount of phosphate ions is controlled to be 1.03 times of the total reaction equivalent of the phosphate ions and the nickel-cobalt-manganese ions, and the total adding amount of hydrogen ions is controlled to be 1.05 times of the reaction equivalent) into the slurry to adjust the pH of the system<4, continuing to add Na 2 SO 3 (Na 2 SO 3 The adding amount is 2.0 times of the reaction equivalent), the reaction is carried out for 1 hour under the conditions that the reaction temperature is 50 ℃ and the stirring speed is 120r/min, and NH is added after the reaction is finished 4 And (4) regulating the pH value of the system to be 7.0 by OH, further precipitating and removing impurities, and filtering to obtain a lithium-containing solution and filter residue A.
(2) Preparing a nickel-cobalt-manganese refined solution: adding water into the filter residue A obtained in the step (1) for pulping, wherein the liquid-solid ratio is 10:1, stirring for 2 hours at a stirring speed of 120r/min to obtain slurry, and then adding Fe (NO) into the slurry 3 ) 3 (Fe(NO 3 ) 3 The addition amount is 1.05 times of the reaction equivalent of iron ions and phosphate ions) to carry out double decomposition reaction, the reaction is carried out for 1 hour under the conditions that the reaction temperature is 50 ℃ and the stirring speed is 900r/min, and then HNO is added 3 Adjusting the pH value of the system to 1.9, aging for 0.5h, filtering to obtain a nickel-cobalt-manganese crude solution and a filter residue B, and then adding Ni (OH) into the nickel-cobalt-manganese crude solution 2 And adjusting the pH value of the system to 5.0, precipitating, removing impurities, and filtering to obtain a nickel-cobalt-manganese refined solution and filter residue C.
Example 4: method for separating and recovering nickel, cobalt, manganese and lithium in ternary waste
(1) Preparation of lithium-containing solution: pretreating ternary waste at 500 ℃ for 80min, stirring the ternary waste with water for pulping, wherein the liquid-solid ratio is 4:1, stirring the ternary waste at a stirring speed of 600r/min for 1h to obtain slurry, adding a phosphoric acid mixed solution (phosphoric acid is mixed with sulfuric acid, the adding amount of phosphate ions is controlled to be 1.05 times of the total reaction equivalent of the phosphate ions and the nickel-cobalt-manganese ions, and the total adding amount of hydrogen ions is controlled to be 1.1 times of the reaction equivalent) into the slurry to adjust the pH of the system<4, continuing to add H 2 O 2 (H 2 O 2 The adding amount is 1.5 times of the reaction equivalent), the reaction is carried out for 3 hours under the conditions that the reaction temperature is 65 ℃ and the stirring speed is 600r/min, KOH is added after the reaction is finished to adjust the pH value of the system to be 9.0, further precipitation and impurity removal are carried out, and the lithium-containing solution and the filter residue A are obtained by filtration.
(2) Preparing a nickel-cobalt-manganese refined solution: adding water into the filter residue A obtained in the step (1) for pulping, wherein the liquid-solid ratio is 6:1, stirring for 1h at the stirring speed of 600r/min to obtain slurry, and then adding Fe into the slurry 2 (SO 4 ) 3 (Fe 2 (SO 4 ) 3 The adding amount is 1.1 times of the reaction equivalent of iron ions and phosphate ions) to carry out double decomposition reaction, the reaction is carried out for 3 hours under the conditions that the reaction temperature is 65 ℃ and the stirring speed is 600r/min, and then H is added 2 SO 4 Adjusting the pH value of the system to 1.9, aging for 1h, filtering to obtain a nickel-cobalt-manganese crude solution and a filter residue B, and then adding NH into the nickel-cobalt-manganese crude solution 4 And (4) regulating the pH value of the system to be 4.5 by OH, precipitating, removing impurities, and filtering to obtain a nickel-cobalt-manganese refined solution and filter residue C.
Comparative example 1:
(1) preparation of lithium-containing solution: stirring the ternary waste and water to prepare slurry with a liquid-solid ratio of 6:1, stirring for 1h at a stirring speed of 600r/min to obtain slurry, adding a phosphoric acid mixed solution (phosphoric acid is mixed with sulfuric acid, the adding amount of phosphate ions is controlled to be 1.2 times of the total reaction equivalent of the phosphate ions and the nickel-cobalt-manganese ions, and the total adding amount of hydrogen ions is controlled to be 1.5 times of the reaction equivalent) into the slurry to adjust the pH of the system<4, continuing to add H 2 O 2 (H 2 O 2 The addition amount is reverse1.5 times of the equivalent), reacting for 3 hours at the reaction temperature of 65 ℃ and the stirring speed of 600r/min, adding LiOH to adjust the pH of the system to 9.0 after the reaction is finished, further precipitating and removing impurities, and filtering to obtain a lithium-containing solution and filter residue A.
(2) Preparing a nickel-cobalt-manganese refined solution: adding water into the filter residue A obtained in the step (1) for pulping, wherein the liquid-solid ratio is 6:1, stirring for 1h at the stirring speed of 600r/min to obtain slurry, and then adding Fe into the slurry 2 (SO 4 ) 3 (Fe 2 (SO 4 ) 3 The adding amount is 1.1 times of the reaction equivalent of iron ions and phosphate ions) to carry out double decomposition reaction, the reaction is carried out for 3 hours under the conditions that the reaction temperature is 65 ℃ and the stirring speed is 600r/min, and then H is added 2 SO 4 Adjusting the pH value of the system to 1.9, aging for 1h, filtering to obtain a nickel-cobalt-manganese crude solution and a filter residue B, and then adding Mn (OH) into the nickel-cobalt-manganese crude solution 2 And adjusting the pH value of the system to 4.5, precipitating, removing impurities, and filtering to obtain a nickel-cobalt-manganese refined solution and filter residue C.
Comparative example 2:
(1) preparation of lithium-containing solution: stirring the ternary waste and water for pulping with the liquid-solid ratio of 6:1, stirring for 1h at the stirring speed of 600r/min to obtain slurry, adding a phosphoric acid mixed solution (phosphoric acid is mixed with sulfuric acid, the adding amount of phosphate ions is controlled to be 0.9 time of the total reaction equivalent of the phosphate ions and the nickel-cobalt-manganese ions, and the total adding amount of hydrogen ions is controlled to be 0.9 time of the reaction equivalent) into the slurry to adjust the pH of the system<4, continuing to add H 2 O 2 (H 2 O 2 The adding amount is 1.5 times of the reaction equivalent), the reaction is carried out for 3 hours under the conditions that the reaction temperature is 65 ℃ and the stirring speed is 600r/min, after the reaction is finished, LiOH is added to adjust the pH value of the system to be 9.0, the precipitation and the impurity removal are further carried out, and the lithium-containing solution and the filter residue A are obtained by filtration.
(2) Preparing a nickel-cobalt-manganese refined solution: adding water into the filter residue A obtained in the step (1) for pulping, wherein the liquid-solid ratio is 6:1, stirring for 1h at the stirring speed of 600r/min to obtain slurry, and then adding Fe into the slurry 2 (SO 4 ) 3 (Fe 2 (SO 4 ) 3 The addition amount is 1.1 times of the reaction equivalent of the iron ions and the phosphate ions) to carry out double decomposition reactionReacting at 65 deg.C under stirring speed of 600r/min for 3H, and adding H 2 SO 4 Adjusting the pH value of the system to 1.9, aging for 1h, filtering to obtain a nickel-cobalt-manganese crude solution and a filter residue B, and then adding Mn (OH) into the nickel-cobalt-manganese crude solution 2 And adjusting the pH value of the system to 4.5, precipitating, removing impurities, and filtering to obtain a nickel-cobalt-manganese refined solution and filter residue C.
Comparative example 3:
(1) preparation of lithium-containing solution: stirring the ternary waste and water to prepare slurry with a liquid-solid ratio of 6:1, stirring for 1h at a stirring speed of 600r/min to obtain slurry, adding a phosphoric acid mixed solution (phosphoric acid is mixed with sulfuric acid, the adding amount of phosphate ions is controlled to be 1.05 times of the total reaction equivalent of the phosphate ions and the nickel-cobalt-manganese ions, and the total adding amount of hydrogen ions is 1.1 times of the reaction equivalent) into the slurry to adjust the pH of the system<4, continuing to add H 2 O 2 (H 2 O 2 The adding amount is 3.0 times of the reaction equivalent), the reaction is carried out for 3 hours under the conditions that the reaction temperature is 65 ℃ and the stirring speed is 600r/min, after the reaction is finished, LiOH is added to adjust the pH value of the system to be 9.0, the precipitation and the impurity removal are further carried out, and the lithium-containing solution and the filter residue A are obtained by filtration.
(2) Preparing a nickel-cobalt-manganese refined solution: adding water into the filter residue A obtained in the step (1) for pulping, wherein the liquid-solid ratio is 6:1, stirring for 1h at the stirring speed of 600r/min to obtain slurry, and then adding Fe into the slurry 2 (SO 4 ) 3 (Fe 2 (SO 4 ) 3 The adding amount is 1.1 times of the reaction equivalent of iron ions and phosphate ions) to carry out double decomposition reaction, the reaction is carried out for 3 hours under the conditions that the reaction temperature is 65 ℃ and the stirring speed is 600r/min, and then H is added 2 SO 4 Adjusting the pH value of the system to 1.9, aging for 1h, filtering to obtain a nickel-cobalt-manganese crude solution and a filter residue B, and then adding Mn (OH) into the nickel-cobalt-manganese crude solution 2 And adjusting the pH value of the system to 4.5, precipitating, removing impurities, and filtering to obtain a nickel-cobalt-manganese refined solution and filter residue C.
Comparative example 4:
(1) preparation of lithium-containing solution: stirring the ternary waste and water to prepare slurry with a liquid-solid ratio of 6:1, stirring for 1h at a stirring speed of 600r/min to obtain slurry, and then adding a phosphoric acid solution into the slurryAdjusting the pH of the system<4, continuing to add H 2 O 2 (H 2 O 2 The adding amount is 1.5 times of the reaction equivalent), the reaction is carried out for 3 hours under the conditions that the reaction temperature is 65 ℃ and the stirring speed is 600r/min, after the reaction is finished, LiOH is added to adjust the pH value of the system to be 9.0, the precipitation and the impurity removal are further carried out, and the lithium-containing solution and the filter residue A are obtained by filtration.
(2) Preparing a nickel-cobalt-manganese refined solution: adding water into the filter residue A obtained in the step (1) for pulping, wherein the liquid-solid ratio is 6:1, stirring for 1h at the stirring speed of 600r/min to obtain slurry, and then adding Fe into the slurry 2 (SO 4 ) 3 (Fe 2 (SO 4 ) 3 The adding amount is 1.1 times of the reaction equivalent of iron ions and phosphate ions) to carry out double decomposition reaction, the reaction is carried out for 3 hours under the conditions that the reaction temperature is 65 ℃ and the stirring speed is 600r/min, and then H is added 2 SO 4 Adjusting the pH value of the system to 1.9, aging for 1h, filtering to obtain a nickel-cobalt-manganese crude solution and a filter residue B, and then adding Mn (OH) into the nickel-cobalt-manganese crude solution 2 And adjusting the pH value of the system to 4.5, precipitating, removing impurities, and filtering to obtain a nickel-cobalt-manganese refined solution and filter residue C.
The lithium-containing solutions obtained in example 1, comparative example 2, and comparative example 3 and the residue a were subjected to content analysis of Li element, and the results are shown in table 1.
TABLE 1 Li content in Li-containing solution and residue A
|
Example 1 (%)
|
Comparative example 1 (%)
|
Comparative example 2 (%)
|
Comparative example 3 (%)
|
Lithium-containing solution
|
21.4651
|
18.7736
|
17.2975
|
21.8142
|
Residue A
|
0.0147
|
0.2971
|
0.3882
|
0.0129 |
As can be seen from the data in Table 1, the phosphoric acid mixed solution of comparative example 1 was added in an excessive amount and PO was excessively added in comparison with example 1 4 3+ With Li + In the subsequent process of adjusting the pH value to 7.0-11.0 and removing impurities, PO is converted from an acidic condition to an alkaline condition 4 3+ With Li + Generation of Li 3 PO 4 Precipitating to reduce the content of Li in the lithium-containing solution and increase the content of Li in the filter residue A; ② compared with the embodiment 1, the phosphoric acid mixed solution of the comparative example 2 has insufficient addition amount, the Li element leaching amount in the ternary waste is reduced, thereby leading to the reduction of Li content in the Li-containing solution and the increase of Li content in the filter residue A, furthermore, because PO is adopted 4 3+ Insufficient, Ni, Co and Mn ions leached by acid are not completely precipitated, and the impurity content of Ni, Co and Mn in the lithium-containing solution is increased; ③ compared with the example 1, the reducing agent with the reaction equivalent of 3.0 times is added in the comparative example 3, but the Li content in the Li-containing solution is not increased significantly, furthermore, if the adding amount of the reducing agent is insufficient, the high-valence Co and Mn in the ternary waste material can not be reduced to low-valence completely, because the high-valence Co and Mn can not be leached by acid, the recovery rate of Co and Mn can be reduced, therefore, in order to save resources and ensure the recovery rate of Co and Mn, the reduction is controlled in the technical proposal of the inventionThe addition amount of the agent is 1.0-2.0 times of the reaction equivalent.
The lithium-containing solution and the nickel-cobalt-manganese refined solution prepared in examples 1 to 4 were subjected to Ni, Co, Mn, and Li content measurement, and the recovery rates of Ni, Co, Mn, and Li in the ternary wastes were calculated, and the results are shown in table 2.
TABLE 2 recovery of Ni, Co, Mn, Li from ternary wastes
As can be seen from the data in Table 2, in comparative example 4, the ternary waste is leached by using the single phosphoric acid, and the phosphoric acid is inorganic weak acid and has poor leaching effect on transition metals such as Ni, Co, Mn and the like, so that the leaching rate of Ni, Co, Mn and Li in the ternary waste is improved by using the phosphoric acid mixed strong acid as the leaching solution, and the leached Ni, Co and Mn ions can be mixed with PO 4 3- The formation of the nickel cobalt manganese phosphate precipitate is the premise of one-step separation and recovery of the nickel cobalt manganese solution in the technical scheme, thereby improving the recovery rate of Ni, Co and Mn.
As can be seen from the data of examples 1 to 4 in table 2, the recovery rates of Ni, Co, Mn, and Li in the technical scheme are high, the separation and recovery of nickel, cobalt, manganese, and lithium in the ternary waste can be well completed, and the technical problems of high cost and large environmental pollution caused by the separation and recovery by using an extraction agent in the prior art are solved.
The above embodiments are the best mode for carrying out the present invention, but the embodiments of the present invention are not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be regarded as equivalent substitutions and are included in the scope of the present invention.