Method for removing iron and aluminum in ternary black powder leaching solution

Abstract

The invention relates to a method for removing iron and aluminum in ternary black powder leachate, which comprises the following steps: S1, first operation: adding an oxidizing agent and a precipitating agent into the ternary black powder leachate in a reaction tank, and carrying out chemical precipitation to obtain iron and aluminum removed liquid and first filter residue containing iron, aluminum, nickel, cobalt, manganese and lithium; s2, circularly removing iron and aluminum: S2.1, after the first operation, adding first filter residues into the ternary black powder leaching solution in the mixing and washing tank for mixing and washing to obtain a mixed and washed solution and second filter residues; s2.2, the mixed and washed liquid returns to the reaction tank, an oxidizing agent and a precipitating agent are added into the reaction tank, and after chemical precipitation, iron and aluminum removed liquid and first filter residues containing iron, aluminum, nickel, cobalt, manganese and lithium are obtained; and (S2.3) the step (S2.1) and the step (S2.2) are repeated. The nickel, cobalt, manganese and lithium in the first filter residues can be redissolved into the leaching solution under the low pH condition, and meanwhile, the nickel, cobalt, manganese and lithium in the first filter residues can be subjected to a replacement reaction with aluminum ions and iron ions in the ternary black powder leaching solution, so that the nickel, cobalt, manganese and lithium in the ternary black powder leaching solution are efficiently separated from iron and aluminum; and the loss rate of nickel, cobalt, manganese and lithium is effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery recycling, and particularly relates to a method for removing iron and aluminum in ternary black powder leaching solution. BACKGROUND

[0002] With the development of new energy automobile industry, ternary lithium ion power batteries have become one of the market mainstream choices due to their high energy density and large output power. After being retired, the batteries can be pretreated to obtain ternary black powder containing valuable metals such as nickel, cobalt, manganese and lithium. The ternary black powder is a mixed powder obtained after the waste ternary lithium ion battery is pretreated (such as discharging, disassembling, crushing, sorting and the like), and mainly contains valuable metal compounds such as nickel (Ni), cobalt (Co), manganese (Mn) and lithium (Li) in the positive and negative electrode materials of the waste battery, as well as graphite and binder in the negative electrode material, and has great recycling value.

[0003] In the prior art, metal recovery of ternary black powder is usually realized by three steps of acid leaching, impurity removal and separation, the core of which is to leach ternary black powder with sulfuric acid and a reducing agent, so that nickel, cobalt, manganese, lithium and the like are in the form of ions in the solution (i.e. ternary black powder leaching solution), and then each component is separated by chemical precipitation or extraction. While leaching nickel, cobalt, manganese and lithium, impurities such as iron, aluminum and copper will also enter the leaching solution, thereby bringing great difficulty to the subsequent separation process and affecting the purity and recovery rate of the product. Although the traditional yellow sodium jarosite method can remove iron and aluminum simultaneously, it needs to strictly control the pH value and temperature, the operating conditions are harsh, and the loss rate of nickel and cobalt is high. Generally, the impurity removal residue will be washed to elute the entrained nickel, cobalt, manganese and lithium, the washing water needs to be removed twice, the alkali consumption is high, and the process flow is complex.

[0004] CN117165772A discloses a method for recovering aluminum and iron from ternary black powder leaching solution, comprising the following steps: oxidation: adding an oxidizing agent to the ternary black powder leaching solution for reaction, the amount of the oxidizing agent being 1.0-5.0 times the theoretical amount of the oxidizing agent required for the oxidation of ferrous ions in the ternary black powder leaching solution; impurity removal and precipitation: further adding a solution containing phosphate ions to the ternary black powder leaching solution for reaction, the pH value of the reaction being maintained at 2.5-5; the ratio of the number of moles of the phosphate salt to the total number of moles of iron and aluminum in the ternary black powder leaching solution being 1-1.5:1, and after the reaction is completed, solid-liquid separation is performed to obtain a first residue containing aluminum and iron and a first filtrate containing nickel, cobalt, manganese and lithium; iron precipitation: the first residue is slurried and the pH value is adjusted to be greater than or equal to 11 to produce a precipitate, and solid-liquid separation is performed to obtain a second residue containing iron and a second filtrate containing aluminum; the second residue is calcined to obtain an iron red product; aluminum precipitation: an acid solution is added to the second filtrate to adjust the pH value to 3.0-10.0 to produce a precipitate, and solid-liquid separation is performed to obtain a third residue containing aluminum and a third filtrate containing phosphate ions, and the third residue is an aluminum phosphate product. However, the treatment process has problems of expensive auxiliary materials, low recycling rate of products and introduction of new impurities.

[0005] CN112981112A discloses a method for preparing high-purity cobalt sulfate solution from waste ternary lithium battery positive electrode material, comprising the following preparation steps: S1: crushing and separating: crushing the waste ternary lithium battery, then performing magnetic attraction, grading and screening and cyclone settling to prepare battery powder; S2: primary sulfuric acid leaching: placing the battery powder in water and secondary leaching liquid to obtain a mixed liquid, then adding sulfuric acid to react and dissolve to obtain a dissolution liquid; S3: adding a reducing agent to the dissolution liquid, and after reaction, performing solid-liquid separation to obtain carbon powder residue and primary leaching liquid; S4: secondary sulfuric acid leaching: placing the carbon powder residue in water, adding sulfuric acid to react and dissolve to obtain a carbon powder residue dissolution liquid; S5: adding a reducing agent to the carbon powder residue dissolution liquid, and after reaction, performing solid-liquid separation to obtain secondary carbon powder residue and secondary leaching liquid; S6: removing aluminum and iron from the primary leaching liquid: adding sodium carbonate solution to the primary leaching liquid to perform iron and aluminum removal reaction, and after filtration, obtaining aluminum and iron residue and iron and aluminum removal liquid; S7: primary extraction: adding a metal extractant to the iron and aluminum removal liquid, and after extraction, separating to obtain cobalt-containing aqueous phase; S8: secondary extraction: adding a metal extractant to the cobalt-containing aqueous phase, and after extraction, separating to obtain cobalt-containing organic extraction phase; S9: stripping: placing the cobalt-containing organic extraction phase in a sulfuric acid solution, stripping the metal extractant after stripping, and preparing high-purity cobalt sulfate. The treatment process has problems of long process flow, uncontrollable impurity removal conditions and generation of organic wastewater.

[0006] Therefore, there is an urgent need to develop a new process for efficiently, greenly and low-costly recovering valuable metals from ternary black powder leaching liquid. SUMMARY

[0007] To solve the above technical problems, the present application provides a method for removing iron and aluminum from ternary black powder leaching liquid. In the first run, a first filter residue containing iron, aluminum, nickel, cobalt and manganese lithium is prepared by chemical precipitation. Then, the first filter residue containing iron, aluminum, nickel, cobalt and manganese lithium is mixed and washed with a ternary black powder leaching liquid with low pH. The nickel, cobalt and manganese lithium in the first filter residue can be redissolved into the leaching liquid under low pH conditions. Meanwhile, the nickel, cobalt and manganese lithium in the first filter residue containing iron, aluminum, nickel, cobalt and manganese lithium can react with aluminum ions and iron ions in the ternary black powder leaching liquid to form a displacement reaction. This effectively separates the nickel, cobalt and manganese lithium from the iron and aluminum in the ternary black powder leaching liquid, while effectively reducing the loss rate of the nickel, cobalt and manganese lithium.

[0008] To achieve this purpose, the present application adopts the following technical solutions:

[0009] In a first aspect, the present application provides a method for removing iron and aluminum from ternary black powder leaching liquid, which comprises:

[0010] S1: first run: adding an oxidizing agent and a precipitating agent to the ternary black powder leaching liquid in a reaction tank, and after chemical precipitation, separating to obtain a liquid after removing iron and aluminum and a first filter residue containing iron, aluminum, nickel, cobalt and manganese lithium;

[0011] S2 cycle for iron and aluminum removal:

[0012] S2.1: After the first run, add the first filter residue obtained in S1 to the ternary black powder leachate in the mixed washing tank for mixed washing, and separate the mixed washing liquid and the second filter residue.

[0013] S2.2: The mixed washing liquid obtained in S2.1 is returned to the reaction tank. An oxidant and a precipitant are added to the reaction tank. After chemical precipitation, the liquid after removing iron and aluminum and the first filter residue containing iron, aluminum, nickel, cobalt, manganese and lithium are separated.

[0014] S2.3: Repeat S2.1 and S2.2.

[0015] This invention first adds an oxidant and a precipitant to the ternary black powder leachate during the initial operation for chemical precipitation treatment. After separation, a first filter residue containing iron, aluminum, nickel, cobalt, manganese, and lithium is obtained. The first filter residue is alkaline, while the ternary black powder leachate is acidic. Utilizing the difference in their acidity and alkalinity, the ternary black powder leachate and the first filter residue are mixed and washed to reduce the amount of acid used. Simultaneously, the mixing and washing process also adjusts the pH of the ternary black powder leachate, further reducing the amount of alkali used. Furthermore, during the mixing and washing process, the acidic ternary black powder leachate effectively dissolves the iron, aluminum, nickel, cobalt, manganese, and lithium in the first filter residue. Valuable metal ions are removed to achieve the effect of recovering nickel, cobalt, manganese, and lithium. On the other hand, during the mixed washing process, aluminum and iron ions in the ternary black powder leachate can undergo a displacement reaction with nickel, cobalt, manganese, and lithium in the first filter residue containing iron, aluminum, nickel, cobalt, manganese, and lithium, thereby achieving the purpose of washing away and recovering valuable metals. Then, the mixed washing liquid is chemically precipitated again to obtain the first filter residue, which is then recycled to the mixed washing process. The mixed washing and chemical precipitation are repeated to ensure that the displacement reaction continues. The removal method of this invention can achieve resource recycling, generate no waste acid or alkali, has low auxiliary material prices, and the resulting product has high economic value.

[0016] Among them, the reaction equations of nickel, cobalt, manganese, and lithium with aluminum and iron ions in the first filter residue containing iron, aluminum, cobalt, manganese, and lithium are similar. Taking nickel as an example:

[0017] 2Al 3+ +3Ni(OH)2→2Al(OH)3+3Ni 2+

[0018] 2Fe 3+ +3Ni(OH)2→2Fe(OH)3+3Ni 2+

[0019] It should be noted that this invention is applicable to the treatment of ternary black powder leachate with different element contents in the prior art. Therefore, the content of nickel, cobalt, manganese, lithium, aluminum and iron in the ternary black powder leachate is not specifically limited.

[0020] As a preferred technical solution of the present invention, the volume ratio of the ternary black powder leachate in the reaction tank to the ternary black powder leachate in the mixing washing tank is 1:(0.8~1.2), for example, it can be 1:0.8, 1:0.9, 1:1, 1:1.1 or 1:1.2, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0021] Preferably, the pH value of the ternary black powder leachate is 1 to 2.5, for example, it can be 1, 1.2, 1.5, 2 or 2.5, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0022] As a preferred technical solution of the present invention, in step S1, when the oxidant is added, the solution potential is controlled to be 300~500mV, for example, it can be 300mV, 350mV, 400mV, 450mV or 500mV, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0023] In step S1 of this invention, the solution potential is controlled to be 300-500mV when the oxidant is added. The endpoint of the oxidant addition is controlled by controlling the potential. If the solution potential is lower than 300mV, the amount of oxidant added will be insufficient to oxidize the ferrous ions in the ternary black powder leachate. If the solution potential is higher than 500mV, the oxidant will be added too much, which will cause the cobalt in the ternary black powder leachate to be oxidized, resulting in the loss of cobalt during the impurity removal process.

[0024] Preferably, in step S1, the pH of the solution is controlled to be 4 to 6 when the precipitant is added. For example, it can be 4, 4.5, 5, 5.5 or 6, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0025] Preferably, the temperature of S1 is 50~90℃, for example, it can be 50℃, 60℃, 70℃, 80℃ or 90℃, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0026] In this invention, in step S1, the temperature and pH of the solution have a synergistic effect. To avoid the formation of colloids, the pH of the solution needs to be increased when the temperature decreases and decreased when the temperature increases.

[0027] Preferably, the reaction time of S1 is 2 to 4 hours, for example, it can be 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0028] As a preferred embodiment of the present invention, the oxidant includes hydrogen peroxide.

[0029] Preferably, the mass fraction of the hydrogen peroxide is 20-40%, for example, it can be 20%, 25%, 30%, 35% or 40%, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0030] As a preferred embodiment of the present invention, the precipitant comprises a sodium carbonate solution.

[0031] The present invention preferably uses sodium carbonate solution as a precipitant because sodium carbonate solution makes it easier to control the pH of the reaction process, avoids local over-alkaliness causing nickel, cobalt, manganese and lithium precipitation, and is inexpensive and readily available, and does not introduce other impurities.

[0032] Preferably, the mass fraction of the sodium carbonate solution is 25-30%, for example, it can be 25%, 26%, 27%, 28%, 29% or 30%, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0033] As a preferred technical solution of the present invention, in step S2.1, the mass ratio of the ternary black powder leachate and the first filter residue obtained in step S1 is (5~10):1, for example, it can be 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0034] Preferably, the temperature of the mixed washing is 70~90℃, for example, it can be 70℃, 75℃, 80℃, 85℃ or 90℃, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0035] Preferably, the mixing and washing time is 0.5 to 1.5 hours, for example, 0.5 hours, 0.7 hours, 1 hour, 1.3 hours or 1.5 hours, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0036] As a preferred technical solution of the present invention, in step S2.2, when the oxidant is added, the solution potential is controlled to be 300~500mV, for example, it can be 300mV, 350mV, 400mV, 450mV or 500mV, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0037] In step S2.2 of this invention, the solution potential is 300~500mV when the oxidant is added. The endpoint of the oxidant addition is controlled by controlling the potential. If the solution potential is lower than 300mV, the amount of oxidant added will be insufficient to oxidize the ferrous ions in the washing liquid. If the solution potential is higher than 500mV, the oxidant will be added too much, which will cause the cobalt in the washing liquid to be oxidized, resulting in the loss of cobalt during the impurity removal process.

[0038] Preferably, in step S2.2, when the precipitant is added, the pH value of the solution is controlled to be 4 to 6, for example, it can be 4, 4.5, 5, 5.5 or 6, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0039] Preferably, the temperature of S2.2 is 50~90℃, for example, it can be 50℃, 60℃, 70℃, 80℃ or 90℃, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0040] In this invention, in step S2.2, the temperature and pH of the solution have a synergistic effect. To avoid the formation of colloids, the pH of the solution needs to be increased when the temperature decreases and decreased when the temperature increases.

[0041] Preferably, the reaction time of S2.2 is 2 to 4 hours, for example, it can be 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0042] As a preferred technical solution of the present invention, the removal method further includes: washing the second filter residue with water to obtain a third filter residue containing iron and aluminum.

[0043] In this invention, since valuable metals are attached to the surface of the second filter residue, the valuable metals attached to the residue can be recovered by washing with water. At the same time, soluble salts can be washed away, reducing the metal loss rate. The wash water can be recycled. When the nickel ion content in the wash water is greater than 5g / L, the wash water can be used to prepare sodium carbonate alkaline solution or for acid leaching of ternary black powder.

[0044] Preferably, the removal method further includes: separating the liquid after iron and aluminum removal to obtain nickel-cobalt-manganese-lithium products.

[0045] It should be noted that the separation process in this invention is a commonly used separation method in the art, and those skilled in the art can choose according to their needs, without making specific limitations here.

[0046] As a preferred technical solution of the present invention, the liquid-solid ratio in the water washing process is (1~3):1, for example, it can be 1:1, 1.5:1, 2:1, 2.5:1 or 3:1, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0047] Preferably, the water washing temperature is 50~80℃, for example, it can be 50℃, 55℃, 60℃, 65℃, 70℃, 75℃ or 80℃, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0048] Preferably, the washing time is 0.5 to 1 hour, for example, it can be 0.5 hours, 0.6 hours, 0.7 hours, 0.8 hours, 0.9 hours or 1 hour, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0049] As a preferred technical solution of the present invention, the removal method includes:

[0050] S1 initial operation: An oxidant and a precipitant are added to the ternary black powder leachate in the reaction tank. After chemical precipitation at a temperature of 50~90℃ for 2~4 hours, the iron and aluminum removed liquid and the first filter residue containing iron, aluminum, nickel, cobalt, manganese and lithium are separated. When the oxidant is added, the solution potential is controlled at 300~500mV; when the precipitant is added, the pH value of the solution is controlled at 4~6.

[0051] S2 cycle for iron and aluminum removal:

[0052] S2.1: After the first run, add the first filter residue obtained in S1 to the ternary black powder leachate in the mixed washing tank and perform mixed washing at a temperature of 70~90℃ for 0.5~1.5h to separate the mixed washing liquid and the second filter residue.

[0053] S2.2: The mixed washing liquid obtained in S2.1 is returned to the reaction vessel. An oxidant and a precipitant are added to the reaction vessel. After chemical precipitation at a temperature of 50~90℃ for 2~4h, the liquid after removing iron and aluminum and the first filter residue containing iron, aluminum, nickel, cobalt, manganese and lithium are separated. When the oxidant is added, the solution potential is controlled at 300~500mV. When the precipitant is added, the pH value of the solution is controlled at 4~6.

[0054] S2.3: Repeat S2.1 and S2.2;

[0055] S2.4: The second filter residue obtained in S2.3 is subjected to water washing treatment with a liquid-solid ratio of (1~3):1, a temperature of 50~80℃, and a time of 0.5~1h to obtain a third filter residue containing iron and aluminum;

[0056] S2.5: The obtained liquid after removing iron and aluminum is separated to obtain nickel-cobalt-manganese-lithium products.

[0057] Compared with the prior art, the present invention has at least the following beneficial effects:

[0058] This invention combines chemical precipitation and metal replacement to efficiently separate and recover nickel, cobalt, manganese, and lithium from iron and aluminum in ternary black powder leachate. The process provided by this invention is simple, has a high recovery rate of valuable metals, and has the advantages of being green, low-carbon, environmentally friendly, and economically valuable, thus maximizing resource utilization. In addition, after stabilization, the removal rates of iron and aluminum are both >99.5%, and the loss rates of nickel, cobalt, manganese, and lithium are both <1%. Attached Figure Description

[0059] Figure 1 This is a process flow diagram of iron and aluminum removal from ternary black powder leachate provided in Embodiment 1 of the present invention. Detailed Implementation

[0060] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0061] Unless otherwise specified, the reagents or instruments used in the following examples and comparative examples are all commercially available products.

[0062] The components of the ternary black powder leachate used in the following examples and comparative examples are shown in Table 1. The pH value of the leachate is 1.5.

[0063] Table 1

[0064]

[0065] Example 1

[0066] This embodiment provides a method for removing iron and aluminum from the leachate of ternary black powder. See [link to relevant documentation]. Figure 1 The removal method includes:

[0067] S1 initial operation: 30% hydrogen peroxide and 27% sodium carbonate solution were added to the ternary black powder leachate in the reaction tank. The solution potential was controlled at 400mV when adding hydrogen peroxide and the pH of the solution was controlled at 4.5 when adding sodium carbonate solution. After chemical precipitation at 80℃ for 3 hours, the iron and aluminum removed liquid and the first filter residue containing iron, aluminum, nickel, cobalt, manganese and lithium were separated.

[0068] The first filter residue containing iron, aluminum, nickel, cobalt, manganese, and lithium has the following mass percentages: iron 3.6 wt%, aluminum 17.5 wt%, nickel 10.1%, cobalt 1.82%, manganese 1.24 wt%, and lithium 2.41%. The liquid after removing iron and aluminum contains iron ions at a concentration of 0.0005 g / L and aluminum ions at a concentration of 0.0008 g / L.

[0069] S2 cycle for iron and aluminum removal:

[0070] S2.1: After the first run, the first filter residue obtained in S1 is added to the ternary black powder leachate in the mixing washing tank at a mass ratio of 8:1, and the mixture is washed at a temperature of 80℃ for 1 hour to separate the mixed washing liquid and the second filter residue; the volume ratio of the ternary black powder leachate in the reaction tank mentioned in S1 to the ternary black powder leachate in the mixing washing tank mentioned in S2.1 is 1:1;

[0071] S2.2: The mixed washing liquid obtained in S2.1 is returned to the reaction tank. 30% hydrogen peroxide and 27% sodium carbonate solution are added to the reaction tank. When adding hydrogen peroxide, the solution potential is controlled at 400mV. When adding sodium carbonate solution, the pH value of the solution is controlled at 4.5. After chemical precipitation at 80℃ for 3 hours, the liquid after removing iron and aluminum and the first filter residue containing iron, aluminum, nickel, cobalt, manganese, and lithium are separated.

[0072] S2.3: Repeat S2.1 and S2.2 until the cycle stabilizes; after stabilization, the second filter residue contains 3.4 wt% nickel, 0.6 wt% cobalt, 0.25 wt% manganese, and 0.14 wt% lithium; the liquid after iron and aluminum removal contains 0.0004 g / L of iron ions and 0.0008 g / L of aluminum ions.

[0073] S2.4: The second filter residue obtained in S2.3 after cyclic stabilization is subjected to water washing treatment with a liquid-to-solid ratio of 2:1, a temperature of 60℃, and a time of 0.5h to obtain a third filter residue containing iron and aluminum; wherein, in the third filter residue containing iron and aluminum, the mass percentage of nickel is 1.9wt%, the mass percentage of cobalt is 0.5wt%, the mass percentage of manganese is 0.14wt%, and the mass percentage of lithium is 0.08wt%.

[0074] S2.5: The obtained liquid after removing iron and aluminum is subjected to extraction and separation treatment to obtain nickel-cobalt-manganese-lithium products.

[0075] The criterion for judging the stability of the cycle is that the elemental content of each valuable metal in the mixed washing liquid is basically stable.

[0076] Example 2

[0077] This embodiment provides a method for removing iron and aluminum from ternary black powder leachate. The only difference from Embodiment 1 is that, except for adjusting the solution potential to 500mV in steps S1 and S2.2, the rest are the same as in Embodiment 1.

[0078] Example 3

[0079] This embodiment provides a method for removing iron and aluminum from ternary black powder leachate. The only difference from Embodiment 1 is that the solution potential in steps S1 and S2.2 is adjusted to 300mV, while the rest is the same as in Embodiment 1.

[0080] Example 4

[0081] This embodiment provides a method for removing iron and aluminum from ternary black powder leachate. The only difference from Embodiment 1 is that, except that the temperature in steps S1 and S2.2 is adjusted to 50°C and the pH value is adjusted to 6, the rest is the same as in Embodiment 1.

[0082] Example 5

[0083] This embodiment provides a method for removing iron and aluminum from ternary black powder leachate. The only difference from Embodiment 1 is that, except that the temperature in steps S1 and S2.2 is adjusted to 90°C and the pH value is adjusted to 4, the rest are the same as in Embodiment 1.

[0084] Example 6

[0085] This embodiment provides a method for removing iron and aluminum from ternary black powder leachate. The only difference from Embodiment 1 is that the concentration of sodium carbonate solution in steps S1 and S2.2 is adjusted to 30%, while the rest is the same as in Embodiment 1.

[0086] Example 7

[0087] This embodiment provides a method for removing iron and aluminum from ternary black powder leachate. The only difference from Embodiment 1 is that the concentration of sodium carbonate solution in steps S1 and S2.2 is adjusted to 25%, while the rest is the same as in Embodiment 1.

[0088] Comparative Example 1

[0089] This comparative example provides a method for removing iron and aluminum from a ternary black powder leachate. The only difference from Example 1 is that, except for adjusting the solution potential to 200mV in step S2.2, everything else is the same as in Example 1.

[0090] Comparative Example 2

[0091] This comparative example provides a method for removing iron and aluminum from a ternary black powder leachate. The only difference from Example 1 is that, except for adjusting the solution potential to 600mV in step S2.2, everything else is the same as in Example 1.

[0092] Comparative Example 3

[0093] This comparative example provides a method for removing iron and aluminum from a ternary black powder leachate. The only difference from Example 1 is that, except for adjusting the temperature to 25°C in step S2.2, the rest is the same as in Example 1.

[0094] Comparative Example 4

[0095] This comparative example provides a method for removing iron and aluminum from a ternary black powder leachate. The only difference from Example 1 is that the temperature in step S2.1, during the mixing and washing process, is adjusted to 25°C. All other aspects are the same as in Example 1.

[0096] Comparative Example 5

[0097] This comparative example provides a method for removing iron and aluminum from a ternary black powder leachate. The only difference from Example 1 is that, except for adjusting the pH value to 7 in step S1, the rest is the same as in Example 1.

[0098] Comparative Example 6

[0099] This comparative example provides a method for removing iron and aluminum from ternary black powder leachate. The only difference from Example 1 is that, except for the temperature adjustment to 25°C during the water washing process in step S2.4, everything else is the same as in Example 1.

[0100] Comparative Example 7

[0101] This comparative example provides a method for removing iron and aluminum from the ternary black powder leachate. The only difference from Example 1 is that, except for adjusting the concentration of the sodium carbonate solution in step S2.2 to 20%, everything else is the same as in Example 1.

[0102] In this comparative example, the sodium carbonate solution concentration was too low, resulting in excessive dilution of valuable metals in the ternary black powder leachate, which would be detrimental to the subsequent separation of nickel, cobalt, manganese, and lithium.

[0103] The elemental content of the nickel-cobalt-manganese-lithium products obtained after cyclic stabilization in Examples 1-7 and Comparative Examples 1-7 was tested using inductively coupled plasma atomic emission spectrometry (ICP-AES), and compared with the composition of the ternary black powder leachate. The impurity removal rates of aluminum and iron, as well as the loss rates of nickel, cobalt, manganese, and lithium, were calculated.

[0104] Taking aluminum as an example, the impurity removal rate (%) = (total aluminum content in the ternary black powder leachate - total aluminum content in the solution after iron and aluminum removal) / total aluminum content in the ternary black powder leachate × 100%;

[0105] Taking nickel as an example, the loss rate (%) = total nickel content in the third filter residue / total nickel content in the ternary black powder leachate × 100%, and the calculation results are shown in Table 2.

[0106] Table 2

[0107]

[0108] The test results show that:

[0109] (1) As can be seen from Examples 1 to 7, the present invention can efficiently separate and recover nickel, cobalt, manganese and lithium from iron and aluminum in the ternary black powder leachate by combining chemical precipitation and metal replacement. Meanwhile, in the present invention, the removal rate of iron and aluminum is >99.5%, and the loss rate of nickel, cobalt, manganese and lithium is <1%.

[0110] (2) As can be seen from Example 1 and Comparative Examples 1-2, in Example 1, the solution potential in step S2.2 is 400mV, and the removal rates of aluminum and iron are 99.96% and 99.98%, respectively, while the loss rates of nickel, cobalt, manganese, and lithium are 0.42%, 0.57%, 0.43%, and 0.6%, respectively; while in Comparative Example 1, the solution potential in step S2.2 is 200mV, and the removal rates of aluminum and iron are 78.96% and 73.54%, respectively, while the loss rates of nickel, cobalt, manganese, and lithium are 12.2%, 10.1%, 8.7%, and 8.9%, respectively; and in Comparative Example 2, the solution potential in step S2.2 is 600mV, and the removal rates of aluminum and iron are 99.96% and 99.98%, respectively. The losses of nickel, cobalt, manganese, and lithium were 9.82% and 99.91%, respectively, and the losses of nickel, cobalt, manganese, and lithium were 22.2%, 54.1%, 33.7%, and 12.1%, respectively. This indicates that the present invention can effectively control the amount of oxidant added by limiting the potential of the solution in step S2.2. When the potential is too low, the amount of oxidant added is too small, the ferrous iron is not fully oxidized, and the iron precipitation is insufficient. At the same time, the iron precipitation is reduced, and the aluminum adsorbed during the precipitation process is reduced, resulting in a decrease in the aluminum impurity removal rate. When the potential is too high, the amount of oxidant added is too large, and a large amount of cobalt is oxidized to trivalent, and manganese is oxidized to trivalent or tetravalent, resulting in co-precipitation of cobalt and manganese during the impurity removal process, which increases the loss of nickel and lithium through adsorption and entrainment mechanisms.

[0111] (3) As can be seen from Example 1 and Comparative Example 3, the temperature of step S2.2 in Example 1 is 80°C, and the removal rates of aluminum and iron are 99.96% and 99.98%, respectively, while the loss rates of nickel, cobalt, manganese and lithium are 0.42%, 0.57%, 0.43% and 0.6%, respectively; while the temperature of step S2.2 in Comparative Example 3 is 25°C, and the removal rates of aluminum and iron are 45.87% and 52.49%, respectively, while the loss rates of nickel, cobalt, manganese and lithium are 41.2%, 43.5%, 50.2% and 49.9%, respectively. This shows that if the temperature in step S2.2 is too low, iron and aluminum will form a large amount of colloid, which is not only difficult to filter, but will also carry a large amount of nickel, cobalt, manganese and lithium.

[0112] (4) As can be seen from Example 1 and Comparative Example 4, the temperature of the mixed washing in step S2.1 of Example 1 is 80°C, and the removal rates of aluminum and iron are 99.96% and 99.98%, respectively, while the loss rates of nickel, cobalt, manganese and lithium are 0.42%, 0.57%, 0.43% and 0.6%, respectively. In contrast, the temperature of the mixed washing in step S2.1 of Comparative Example 4 is 25°C, and the removal rates of aluminum and iron are 99.49% and 99.76%, respectively, while the loss rates of nickel, cobalt, manganese and lithium are 28.7%, 35.6%, 24.3% and 21.7%, respectively. This indicates that the low temperature during the mixed washing process results in low nickel, cobalt, manganese and lithium elution rates, leading to excessively high nickel, cobalt and manganese loss rates.

[0113] (5) As can be seen from Example 1 and Comparative Example 5, the pH value in step S1 of Example 1 is 4.5, and the removal rates of aluminum and iron are 99.96% and 99.98%, respectively, while the loss rates of nickel, cobalt, manganese and lithium are 0.42%, 0.57%, 0.43% and 0.6%, respectively; while the pH value in step S1 of Comparative Example 5 is 7, and the removal rates of aluminum and iron are 99.94% and 99.87%, respectively, while the loss rates of nickel, cobalt, manganese and lithium are 35.6%, 22.9%, 22.8% and 22.1%, respectively. This shows that if the pH value in step S1 is too high, it will lead to excessive precipitation of nickel, cobalt, manganese and lithium, resulting in low efficiency of subsequent mixing and washing and excessive loss of nickel, cobalt and manganese.

[0114] (6) As can be seen from Example 1 and Comparative Example 6, the temperature of the water washing process in step S2.4 of Example 1 is 60°C, and the removal rates of aluminum and iron are 99.96% and 99.98%, respectively, while the loss rates of nickel, cobalt, manganese and lithium are 0.42%, 0.57%, 0.43% and 0.6%, respectively; while the temperature of the water washing process in step S2.4 of Comparative Example 6 is 25°C, and the removal rates of aluminum and iron are 99.84% and 99.92%, respectively, while the loss rates of nickel, cobalt, manganese and lithium are 19.8%, 15.7%, 16.2% and 15.9%, respectively. This shows that the water washing temperature is too low, making it difficult to wash away the soluble salts of nickel, cobalt, manganese and lithium entrained by the second filter residue, resulting in an excessively high loss rate of nickel, cobalt, manganese and lithium.

[0115] In summary, this invention combines chemical precipitation and metal replacement to efficiently separate and recover nickel, cobalt, manganese, and lithium from iron and aluminum in ternary black powder leachate. The process provided by this invention is simple and solves the problems of high loss rate of valuable metals, low impurity removal rate, low recycling rate of by-products, and long process in the acid leaching process of existing technologies. It completes the impurity removal process with the advantages of high impurity removal rate, low loss rate, short process, and low cost, and realizes the recycling of by-products, which meets the dual goals of resource recycling and environmental protection. At the same time, in this invention, the impurity removal rate of iron and aluminum is >99.5%, and the loss rate of nickel, cobalt, manganese, and lithium is <1%.

[0116] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for removing iron and aluminum from a ternary black powder leachate, characterized in that, The removal method includes: S1 First Run: Oxidizing agent and precipitant are added to the ternary black powder leachate in the reaction tank. After chemical precipitation, the liquid after removing iron and aluminum and the first filter residue containing iron, aluminum, nickel, cobalt, manganese and lithium are separated. S2 cycle for iron and aluminum removal: S2.1: After the first run, add the first filter residue obtained in S1 to the ternary black powder leachate in the mixed washing tank for mixed washing, and separate the mixed washing liquid and the second filter residue. S2.2: The mixed washing liquid obtained in S2.1 is returned to the reaction tank. An oxidant and a precipitant are added to the reaction tank. After chemical precipitation, the liquid after removing iron and aluminum and the first filter residue containing iron, aluminum, nickel, cobalt, manganese and lithium are separated. S2.3: Repeat S2.1 and S2.

2.

2. The removal method according to claim 1, characterized in that, The volume ratio of the ternary black powder leachate in the reaction tank to the ternary black powder leachate in the mixing and washing tank is 1:(0.8~1.2); Preferably, the pH value of the ternary black powder leachate is 1~2.

5.

3. The removal method according to claim 1 or 2, characterized in that, In step S1, the solution potential is controlled to be 300~500mV when the oxidant is added; Preferably, in step S1, the pH of the solution is controlled to be 4-6 when the precipitant is added; Preferably, the temperature of S1 is 50~90℃; Preferably, the reaction time of S1 is 2-4 hours.

4. The removal method according to any one of claims 1-3, characterized in that, The oxidant includes hydrogen peroxide; Preferably, the hydrogen peroxide has a mass fraction of 20-40%.

5. The removal method according to any one of claims 1-4, characterized in that, The precipitant includes a sodium carbonate solution; Preferably, the sodium carbonate solution has a mass fraction of 25-30%.

6. The removal method according to any one of claims 1-5, characterized in that, In S2.1, the mass ratio of the ternary black powder leachate and the first filter residue obtained in S1 during the mixed washing is (5~10):1; Preferably, the temperature for the mixed washing is 70~90℃; Preferably, the washing time is 0.5 to 1.5 hours.

7. The removal method according to any one of claims 1-6, characterized in that, In step S2.2, the solution potential is controlled to be 300~500mV when the oxidant is added; Preferably, in step S2.2, the pH of the solution is controlled to be 4-6 when the precipitant is added; Preferably, the temperature of step S2.2 is 50~90℃; Preferably, the reaction time of S2.2 is 2 to 4 hours.

8. The removal method according to any one of claims 1-7, characterized in that, The removal method further includes: washing the second filter residue with water to obtain a third filter residue containing iron and aluminum; Preferably, the removal method further includes: separating the liquid after iron and aluminum removal to obtain nickel-cobalt-manganese-lithium products.

9. The removal method according to claim 8, characterized in that, The liquid-to-solid ratio during the water washing process is (1~3):1; Preferably, the temperature of the water wash is 50~80℃; Preferably, the washing time is 0.5 to 1 hour.

10. The removal method according to any one of claims 1-9, characterized in that, The removal method includes: S1 initial operation: An oxidant and a precipitant are added to the ternary black powder leachate in the reaction tank. After chemical precipitation at a temperature of 50~90℃ for 2~4 hours, the iron and aluminum removed liquid and the first filter residue containing iron, aluminum, nickel, cobalt, manganese and lithium are separated. When the oxidant is added, the solution potential is controlled at 300~500mV; when the precipitant is added, the pH value of the solution is controlled at 4~6. S2 cycle for iron and aluminum removal: S2.1: After the first run, add the first filter residue obtained in S1 to the ternary black powder leachate in the mixed washing tank and perform mixed washing at a temperature of 70~90℃ for 0.5~1.5h to separate the mixed washing liquid and the second filter residue. S2.2: The mixed washing liquid obtained in S2.1 is returned to the reaction vessel. An oxidant and a precipitant are added to the reaction vessel. After chemical precipitation at a temperature of 50~90℃ for 2~4h, the liquid after removing iron and aluminum and the first filter residue containing iron, aluminum, nickel, cobalt, manganese and lithium are separated. When the oxidant is added, the solution potential is controlled at 300~500mV. When the precipitant is added, the pH value of the solution is controlled at 4~6. S2.3: Repeat S2.1 and S2.2; S2.4: The second filter residue obtained in S2.3 is subjected to water washing treatment with a liquid-solid ratio of (1~3):1, a temperature of 50~80℃, and a time of 0.5~1h to obtain a third filter residue containing iron and aluminum; S2.5: The obtained liquid after removing iron and aluminum is separated to obtain nickel-cobalt-manganese-lithium products.

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