Resource recycling method for waste residues containing nickel, cobalt, iron and aluminum

Abstract

The invention discloses a resource recycling method for waste residues containing nickel, cobalt, iron and aluminum, which comprises the following steps: S1, adding water into the waste residues containing iron and aluminum, stirring to prepare slurry, adding concentrated sulfuric acid to control the pH value to be 1.5-2.0, carrying out nickel and cobalt ion acid leaching, and filtering to obtain sulfuric acid leachate and nickel, cobalt, iron and aluminum residues; s2, when the copper content in the sulfuric acid leaching solution is larger than 0.1 g / L, iron powder is added to replace copper ions in the sulfuric acid leaching solution into copper sponge, and a copper-removed solution is obtained through filtering; s3, adding an oxidizing agent to enable the ferrous ions to generate ferric ions; and S4, the low-copper-content sulfuric acid leaching solution or the copper removal solution serves as nickel and cobalt extraction pre-solution to be partially or completely conveyed to a nickel and cobalt extraction line, and water-phase raffinate and organic-phase extract liquor are obtained after extraction operation. According to the resource recycling method, the recycling efficiency of nickel, cobalt and other valuable metals is improved, the environmental risk of waste residue treatment is reduced, meanwhile, resource utilization of waste residues is achieved, and remarkable economic benefits and environmental benefits are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of resource recycling, and in particular to a method for recycling waste slag containing nickel, cobalt, iron and aluminum. Background Art

[0002] With the rapid development of electric vehicles and energy storage, the market demand for lithium batteries continues to grow, and the market size continues to expand. Among them, lithium batteries are most widely used in new energy vehicles. However, since the average service life of lithium batteries generally does not exceed 8 years, retired lithium batteries contain metals such as nickel, cobalt, manganese, lithium, and copper. If they are not recycled, it will not only cause a waste of resources, but also bring great pressure to the environment, which is not conducive to the development of the industrial chain and the resource utilization of waste. Therefore, the recycling of retired lithium batteries has become an urgent problem to be solved.

[0003] At present, the mainstream process of recycling retired lithium batteries is to discharge, disassemble, crush and sort the lithium batteries to obtain black powder, copper slag, aluminum slag, diaphragm, etc., then add acid and reducing agent to leach the black powder to obtain a solution containing nickel, cobalt, manganese, lithium, copper and aluminum and graphite slag, add iron powder to the solution to remove copper, obtain sponge copper and copper-removed liquid, add oxidant and alkaline reagent to the copper-removed liquid to remove iron and aluminum, and obtain iron-removed aluminum liquid and iron-aluminum slag. The iron-removed aluminum liquid is then extracted to recover nickel, cobalt, manganese and lithium metals. Among them, when adding alkaline reagents to remove iron and aluminum, a part of nickel, cobalt and manganese metals will be precipitated together, resulting in 1-3wt% nickel, cobalt and manganese in the iron-aluminum slag. Enterprises generally use dilute sulfuric acid to pulp and rinse the iron-aluminum slag, control a certain pH value, and dissolve the nickel, cobalt and manganese acid in the iron-aluminum slag into the liquid. However, in addition to nickel, cobalt and manganese ions, a large amount of aluminum ions will also be acid-dissolved in this pickling liquid. In addition to this pickling, alkaline reagents are generally added to precipitate iron and aluminum. In the process of removing iron and aluminum, iron-aluminum slag will be produced. This iron-aluminum slag still has more nickel and cobalt elements, and it needs to be pickled again. The nickel and cobalt concentration in this recycled aluminum removal liquid is low and cannot be used directly, or it can be used by adding alkaline reagents to precipitate nickel and cobalt as hydroxides. The iron-aluminum slag after pickling still has a high concentration of nickel and cobalt elements, so the iron-aluminum slag can only be reduced. Since the nickel and cobalt in the iron-aluminum slag after pickling exceeds the standard, the iron-aluminum slag produced by lithium battery recycling is generally treated as hazardous waste. This not only leads to the loss of valuable nickel, cobalt and manganese, but also the inability to utilize iron and aluminum, and the high cost of hazardous waste treatment. Therefore, it is necessary to develop iron and aluminum slag resource recovery technology to expand the recyclability rate of lithium-ion battery recycled materials and achieve pollution reduction and carbon reduction.

[0004] In the prior art, Chinese patent CN118754072A discloses a method for recycling iron-aluminum slag and a method for recycling waste lithium batteries with a full chain of carbon reduction. The method for recycling iron-aluminum slag is to wash the iron-aluminum slag, add acid and reducing agent to the washed slag for pulping, and then carry out acid leaching reaction to obtain a leachate; add sulfide to the leachate and adjust the pH to carry out nickel-cobalt-manganese removal reaction to obtain a nickel-cobalt-manganese removal solution; add an alkaline reagent to the nickel-cobalt-manganese removal solution for aluminum precipitation reaction to obtain an aluminum hydroxide product and an aluminum removal solution; first add a first phosphoric acid to the aluminum removal solution to remove calcium and magnesium, separate the solid and liquid after the reaction is completed, add a second phosphoric acid and an oxidant to the obtained impurity removal solution for a synthetic reaction, and obtain an iron phosphate product after the reaction is completed. This method uses a large amount of auxiliary materials such as acid, alkali, sulfide, reducing agent and oxidant, and the obtained nickel-cobalt-manganese is a sulfide, which cannot be directly used to extract and recover nickel-cobalt-manganese metal elements, and the operation process is complicated.

[0005] Chinese patent CN115180661A discloses a method for recovering nickel-cobalt-copper mixed sulfate from iron-aluminum slag. The method comprises the following steps: leaching iron-aluminum waste slag slurry with concentrated sulfuric acid, removing iron and aluminum with calcium carbonate slurry, obtaining iron-aluminum-calcium slag and aluminum removal liquid containing nickel-cobalt-copper mixed sulfate; adding sodium carbonate solution with a mass concentration of 20-30% to the aluminum removal liquid to generate nickel-cobalt-copper mixed carbonate; then dissolving the carbonate with sulfuric acid, and then removing aluminum for a second time with sodium carbonate solution. The method uses a large amount of auxiliary materials such as acid, alkali, and calcium carbonate, which will introduce calcium ions during the treatment process. The obtained nickel-cobalt-copper sulfate solution has a high concentration of calcium ions, which increases the cost of subsequent extraction and recovery of nickel-cobalt-copper. Calcium sulfate is introduced into the slag after the treatment, and the iron-aluminum slag cannot be reduced.

[0006] Therefore, it is necessary to develop a new method for resource recovery of nickel-cobalt-iron-aluminum slag to improve the resource recovery rate, reduce the risk of environmental pollution, reduce the treatment cost, and realize the resource recovery and harmless treatment of waste. Summary of the invention

[0007] In view of the above shortcomings of the prior art, the present invention provides a resource recovery method for nickel-cobalt-iron-aluminum waste slag to solve the technical problems of low metal recovery rate, high operating cost, serious environmental pollution and waste of resources in traditional recovery methods. Through the resource recovery method of the present invention, valuable metals such as nickel, cobalt, iron and aluminum are efficiently and economically recovered from nickel-cobalt-iron-aluminum waste slag, while reducing the impact on the environment, improving the recycling rate of resources, reducing the overall processing cost, and promoting the resource and harmless treatment of waste. The resource recovery method of the present invention can recover nickel-cobalt mixed sulfate from iron-aluminum waste slag, by adding sulfuric acid to the iron-aluminum slag for pulping and leaching, selectively extracting nickel and cobalt from iron and aluminum ions with an extractant, and stripping with sulfuric acid to obtain a nickel-cobalt sulfate solution, and simultaneously obtaining low-nickel-cobalt iron-removing aluminum slag, and the nickel and cobalt recovery rates are high, and the sorting and recovery process is safe and low in cost.

[0008] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0009] A method for recycling waste slag containing nickel, cobalt, iron and aluminum, comprising the following steps:

[0010] S1: Add water to a certain amount of iron-aluminum waste slag and stir to form a slurry, add sulfuric acid to the slurry to dissolve it, heat the reaction, control the pH value of the slurry to 1.5-2.0, so that the nickel and cobalt ions in the iron-aluminum waste slag are acid-leached, and filter to obtain sulfuric acid leaching liquid and iron-aluminum slag without nickel and cobalt; the present invention uses the principle that the pH value of acid dissolution of nickel hydroxide and cobalt hydroxide is higher than that of iron hydroxide and aluminum hydroxide, and under low acid conditions, nickel and cobalt in the waste slag are generated into metal ions, and iron and aluminum are kept as hydroxide precipitation as much as possible, and filtered to separate nickel and cobalt acid leaching liquid and iron-aluminum slag. The iron-aluminum slag is rinsed with clean water and further recovered with nickel and cobalt, which is a general solid waste.

[0011] S2: Detect the copper content in the sulfuric acid leaching solution of step S1. When the copper content is less than or equal to 0.1 g / L, directly proceed to step S4; otherwise, when the copper content is greater than 0.1 g / L, first add iron powder to the sulfuric acid leaching solution to replace the copper ions in the sulfuric acid leaching solution with sponge copper to remove the copper, and filter to obtain a copper removal solution and sponge copper;

[0012] S3: adding an oxidant to the copper removal solution obtained in step S2 to convert the divalent iron ions into trivalent iron ions;

[0013] S4: The low-copper-content sulfuric acid leaching solution obtained in step S1 or the copper-removing solution treated in step S3 is partially or completely transported to the nickel-cobalt extraction line as a nickel-cobalt extraction pre-liquid, and an organic phase prepared by an extractant and a diluent and a saponifying agent are sequentially added to perform extraction operations. After sufficient mixing, the mixture is allowed to stand and separate into layers, and nickel-cobalt metal ions are extracted from the nickel-cobalt extraction pre-liquid into the organic phase to obtain an aqueous phase raffinate and an organic phase extract.

[0014] The resource recovery method of the nickel-cobalt iron-aluminum waste slag of the present invention, first, by controlling the pH value of the slurry to carry out acid leaching in the range of 1.5 to 2.0, the acid leaching process of nickel-cobalt ions is optimized, the high leaching rate of valuable metals is ensured, and the content of valuable metals in the iron-aluminum waste slag is reduced at the same time, which is beneficial to guarantee the resource recovery and utilization of each metal element in the follow-up. Secondly, when the copper content in the sulfuric acid leaching solution exceeds 0.1g / L, by adding iron powder to replace copper ions into sponge copper, not only copper is effectively recovered, but also because copper ions are difficult to strip, by removing copper ions, the purity of nickel-cobalt ions in the follow-up extraction process is advantageously improved. In addition, an oxidant is added to oxidize divalent iron ions into trivalent iron ions to reduce the extraction of divalent iron ions during the nickel-cobalt extraction operation. Through the extraction operation, nickel-cobalt metal ions are efficiently extracted from the nickel-cobalt extraction pre-liquid into the organic phase, and the obtained aqueous phase raffinate and organic phase extract are of high purity, which further guarantees the high recovery rate and high-purity reuse of subsequent metal elements.

[0015] As a preferred technical solution, in step S4, the remaining part of the nickel-cobalt extraction pre-liquid is stirred with another amount of iron-aluminum waste slag to form a slurry, sulfuric acid is added to heat the reaction to carry out the acid leaching operation of nickel-chromium ions, and the sulfuric acid leaching solution and the nickel-cobalt iron-aluminum slag are filtered to obtain the sulfuric acid leaching solution and the nickel-cobalt iron-aluminum slag; the sulfuric acid leaching solution is repeatedly subjected to the operations of steps S2, S3 and S4 to obtain a new aqueous phase raffinate and an organic phase extract. The preferred technical solution proposed in step S4 of the present invention achieves effective acid leaching of nickel-chromium ions by mixing the remaining part of the nickel-cobalt extraction pre-liquid with another amount of iron-aluminum waste slag to form a slurry, and adding sulfuric acid to heat the reaction, thereby increasing the concentration of nickel-cobalt ions in the sulfuric acid leaching solution. This method not only improves the recovery efficiency of nickel and cobalt, but also reduces the use of fresh water and chemical reagents by recycling the nickel-cobalt extraction pre-liquid, thereby reducing the cost of raw materials. At the same time, due to the increase in the nickel-cobalt concentration in the sulfuric acid leaching solution, the nickel-cobalt recovery rate of the subsequent extraction step is also increased, reducing the loss of valuable metals and improving the utilization efficiency of resources.

[0016] As a preferred technical solution, the resource recovery method also includes step S5-1: recycling the aqueous phase raffinate obtained in step S4 to the slurry of step S1; or first adding a precipitant to the aqueous phase raffinate to control the pH value to 3.0-3.5 to precipitate iron hydroxide, completing the recovery operation of iron in the iron-aluminum waste slag, and then continuing to add a precipitant to the filtrate after filtering to control the pH value to 4.0-4.5 to precipitate aluminum hydroxide, completing the recovery operation of aluminum in the iron-aluminum waste slag. The present invention further achieves efficient precipitation and recovery of iron and aluminum by precisely controlling the pH value, which not only improves the recovery rate of the two metals, but also allows the recovered iron hydroxide and aluminum hydroxide to be used as valuable by-products in other industrial processes, increasing the economic value of the by-products, reducing the generation of waste slag, and reducing waste treatment costs.

[0017] As a preferred technical solution, the resource recovery method further includes step S5-2: adding sulfuric acid to the organic phase extract obtained in step S4 to perform at least one stripping operation to obtain a stripping solution rich in nickel and cobalt sulfate. The present invention further adds sulfuric acid to perform a stripping operation on the organic phase extract to effectively extract a stripping solution rich in nickel and cobalt sulfate from the organic phase, which not only improves the recovery rate of nickel and cobalt, but also the stripping solution obtained can be directly used to produce nickel and cobalt sulfate, and further processed into high-purity nickel and cobalt products, thereby improving the purity of the products and realizing resource recycling.

[0018] As a preferred technical solution, the solid-liquid ratio of the slurry is 1:1-3, the reaction temperature is 50-90°C, and the reaction time is 1-5h.

[0019] As a preferred technical solution, the oxidant is at least one of hydrogen peroxide, sodium chlorate, sodium hypochlorite, and potassium chlorate.

[0020] As a preferred technical solution, the concentration of the extractant in the organic phase is 45-50%; and the extraction phase ratio (O / A) of the extraction operation is 1-2:1.

[0021] As a preferred technical solution, the extractant is a lipid extractant, and the preferred model is HBL 110 extractant. The extractant selected by the present invention can directly extract nickel, cobalt and copper in an acidic solution, and basically does not extract iron, aluminum, chromium, zinc, calcium and magnesium ions. The nickel content in the raffinate is less than 0.1 g / L, the nickel extraction rate is >90%, and the aluminum extraction rate is <5%.

[0022] As a preferred technical solution, the sulfuric acid concentration in the stripping operation is 50 to 75 g / L.

[0023] As a preferred technical solution, the precipitant is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate.

[0024] As a preferred technical solution, in the resource recovery method, the nickel and cobalt recovery rates of the iron and aluminum waste slag are not less than 99%, and the copper recovery rate is not less than 95%.

[0025] Beneficial effects of the present invention:

[0026] The resource recovery method of nickel-cobalt-iron-aluminum waste slag of the present invention has a simple process and is easy to operate. By innovatively integrating the steps of acid leaching, extraction, precipitation and stripping, it not only realizes the efficient recovery of valuable metals such as nickel, cobalt, copper, iron and aluminum from the waste slag, and obtains iron-aluminum slag, sponge copper, iron hydroxide, aluminum hydroxide and nickel-cobalt sulfate solution respectively, but also realizes the environmental friendliness and economy of the recovery process. The resource recovery method of the present invention not only enhances the recycling rate of resources, but also maintains the high purity of the recovered products, which helps to reduce pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a process flow chart of the present invention.

[0028] Figure 2 This is the pH isotherm of metal extraction using the HBL 110 extractant of the present invention. DETAILED DESCRIPTION

[0029] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0030] Example

[0031] like Figure 1 As shown, the resource recovery method of nickel-cobalt-iron-aluminum waste slag in this embodiment comprises the following steps:

[0032] Step S1: Add 200g of iron-aluminum waste slag generated during the recycling of waste nickel-cobalt-manganese ternary battery positive electrode materials into a 1000ml beaker (as a pulping acid leaching kettle), add 300ml of water, stir at a speed of 100 rpm to make a slurry, add 30g of sulfuric acid to the slurry for dissolution, heat to 50°C for reaction, react for 90min, detect the pH value of the slurry to be 1.5, so that the nickel and cobalt ions in the iron-aluminum waste slag are acid-leached, filter the reaction solution, and then rinse the filter residue with a small amount of clean water to obtain 480ml of 1# sulfuric acid leaching solution. The nickel content in the 1# sulfuric acid leaching solution was sampled and tested to be 2.87g / L, 1.69g / L for cobalt, 4.38g / L for copper, 13.6g / L for aluminum, and 0.16g / L for iron; after the filter residue was filtered with a filter press, 36g of 1# nickel-cobalt iron-aluminum slag was obtained. The raw material composition of the iron-aluminum waste slag is shown in Table 1. Table 1 Iron and aluminum waste slag composition test table element Ni Co Cu Al Fe <![CDATA[H2O]]> Content, wt% 0.72 0.43 1.12 5.40 0.24 65.5

[0033] The existence forms of Ni, Co, Cu, Fe and Al in the iron-aluminum waste slag include sulfates and hydroxides; the content of each element is measured by inductively coupled plasma (ICP-AES) and atomic flame absorption spectrometry (AAS).

[0034] According to the amount of each metal element in the 1# sulfuric acid leaching solution, divided by the amount of each metal element in the iron-aluminum waste slag, the primary sulfuric acid leaching rate of each metal primary color in the iron-aluminum waste slag was calculated respectively. The results are shown in Table 2. Table 2 Primary sulfuric acid leaching rate element Ni Co Cu Al Fe Leaching rate, % 95.7 94.3 93.9 60.4 27.4

[0035] Step S2: 400 ml of 1# sulfuric acid leaching solution is placed in a copper removal kettle, 1.84 g of iron powder (1.05 times the amount of copper) is added, and the mixture is stirred for 10 minutes. The copper content in the liquid is sampled and detected to be 0.02 g / L. Stirring is stopped, and the copper ions in the 1# sulfuric acid leaching solution are replaced with sponge copper to remove the copper. The 1# copper removal solution and sponge copper are obtained by filtration and separation.

[0036] Step S3: adding hydrogen peroxide to the 1# copper removal liquid obtained in step S2 for oxidation reaction to convert divalent ferrous ions into trivalent ferrous ions, starting stirring at a speed of 100 rpm, slowly adding 2.5 g of hydrogen peroxide, reacting for 15 min and stopping stirring, adjusting the pH value to between 2.0 and 2.5 with 10 wt % sodium hydroxide or 25 wt % sulfuric acid, under which low concentration of iron ions will not produce ferric hydroxide precipitation, and this liquid is 1# nickel-cobalt extraction pre-liquid, and the nickel content of the sampled test is 2.87 g / L, the cobalt content is 1.70 g / L, the copper content is 0.02 g / L, the aluminum content is 13.6 g / L, and the iron content is 4.76 g / L.

[0037] Step S4: First, prepare an extractant according to the nickel and cobalt content of the 1# nickel and cobalt extraction pre-liquid, take 250 ml of HBL 110 extractant (whose metal extraction performance is as follows Figure 2 As shown) into a 1000ml separatory funnel, add 250ml of sulfonated kerosene as a diluent, cover with a plug and oscillate for 5min to fully mix, compound to obtain an organic phase, then add 20ml of 10wt% sodium hydroxide as a saponifier, cover with a plug and oscillate for 20min to fully mix and react, this is 1# nickel-cobalt extractant. 100ml of 1# nickel-cobalt extraction pre-liquid obtained in step S3 is transported to the nickel-cobalt extraction line of a 250ml separatory funnel, 100ml of the 1# nickel-cobalt extractant is added for extraction operation, fully mixed, the plug is loosened, and the stratification is allowed to stand for 10min, and nickel-cobalt metal ions are extracted from the 1# nickel-cobalt extraction pre-liquid into the organic phase to obtain 1# aqueous phase raffinate and 1# organic phase extract. 95ml of aqueous phase is released from the stratified 250ml separatory funnel, and a portion of the aqueous phase is retained to block the organic phase. The nickel-cobalt-iron-aluminum concentration in the 1# aqueous phase raffinate is detected, and the extraction and separation effect is calculated once. The test results show that the nickel content in the raffinate of the 1# aqueous phase is 0.10g / L, the cobalt content is 0.87g / L, the copper content is 0.001g / L, the aluminum content is 13.1g / L, and the iron content is 4.65g / L. Assuming that the volume of the aqueous phase and the organic phase remains unchanged, the primary extraction rate of each metal element is calculated based on the concentration before extraction and the concentration after extraction, and the results are shown in Table 3. Table 3 Primary extraction rate element Ni Co Cu Al Fe Extraction rate, % 96.5 48.8 99.5 3.7 2.3

[0038] Step S1-1: 200 ml of 1# nickel-cobalt extraction pre-liquid obtained in step S3 is transferred to a 1000 ml beaker, 200 g of the iron-aluminum waste slag generated in the process of recycling the positive electrode material of the waste nickel-cobalt-manganese ternary battery is added to the 1# nickel-cobalt extraction pre-liquid, and the stirring speed is 100 rpm to form a slurry, 28 g of sulfuric acid is added to the slurry for dissolution, the temperature is raised to 60°C for reaction, and the reaction time is 90 minutes. The pH value of the slurry is detected to be 1.6, so that the nickel-cobalt ions in the iron-aluminum waste slag are acid-leached, the reaction solution is filtered, and the filter residue is rinsed with a small amount of clean water to obtain 470 ml of 2# sulfuric acid leaching solution. The nickel content of the 2# sulfuric acid leachate was 4.04 g / L, the cobalt content was 2.32 g / L, the copper content was 3.96 g / L, the aluminum content was 18.89 g / L, and the iron content was 0.14 g / L; after the filter residue was filtered by a filter press, 45 g of 2# nickel-removing cobalt-iron-aluminum slag was obtained. The 2# sulfuric acid leachate was repeatedly subjected to steps S2, S3, and S4 to obtain 2# aqueous phase raffinate and 2# organic phase extract, and the specific operation steps are shown in S1-2, S1-3, and S1-4.

[0039] According to the amount of each element metal in the 2# sulfuric acid leaching solution minus the amount of each element metal brought in by the 1# nickel-cobalt extraction pre-liquid, and then divided by the amount of each element metal in the newly added iron-aluminum waste slag, the primary sulfuric acid leaching rate of each metal primary color in the iron-aluminum waste slag is calculated respectively. The results are shown in Table 4. Table 4 Primary sulfuric acid leaching rate element Ni Co Cu Al Fe Leaching rate, % 92.0 87.3 82.9 57.0 -

[0040] In Table 4, since the trivalent iron ions in the 1# nickel-cobalt extraction pre-liquid react with the hydroxide in the iron-aluminum waste slag to form iron hydroxide, the iron ions in the liquid are reduced. Therefore, the iron leaching rate in Table 4 does not need to be calculated.

[0041] Step S1-2: 400 ml of 2# sulfuric acid leaching solution is placed in a copper removal kettle, 1.06 times the amount of copper iron powder (1.68 g in total) is added, and the mixture is stirred for 10 minutes. The copper content in the liquid is sampled and detected to be 0.017 g / L. Stirring is stopped, and the copper ions in the 2# sulfuric acid leaching solution are replaced with sponge copper to remove the copper. The 2# copper removal solution and sponge copper are obtained by filtration and separation.

[0042] Step S1-3: adding hydrogen peroxide to the 2# copper removal liquid obtained in step S1-2 for oxidation reaction to convert divalent ferrous ions into trivalent ferrous ions, starting stirring at a speed of 100 rpm, slowly adding 2.2 g of hydrogen peroxide, reacting for 15 min and stopping stirring, adjusting the pH value to between 2.0 and 2.5 with 10 wt% sodium hydroxide or 25 wt% sulfuric acid, under which low concentration of iron ions will not produce iron hydroxide precipitation, and this liquid is 2# nickel-cobalt extraction pre-liquid, and the nickel content of the sampled test is 4.02 g / L, the cobalt content is 2.31 g / L, the copper content is 0.017 g / L, the aluminum content is 18.80 g / L, and the iron content is 4.32 g / L.

[0043] Step S1-4: first prepare an extractant according to the nickel-cobalt content of the 1# nickel-cobalt extraction pre-liquid, take 250ml of HBL 110 extractant into a 1000ml separatory funnel, add 250ml of sulfonated kerosene as a diluent, cover it and shake it for 5min to fully mix it, compound it to obtain an organic phase, then add 20ml of 10wt% sodium hydroxide as a saponifier, cover it and shake it for 20min to fully mix it, this is the 1# nickel-cobalt extractant. 100ml of the 2# nickel-cobalt extraction pre-liquid obtained in step S1-3 is transferred to the nickel-cobalt extraction line of the 250ml separatory funnel, add 100ml of the 1# nickel-cobalt extractant to perform extraction operation, fully mix it, loosen the stopper, stand for stratification for 10min, extract nickel-cobalt metal ions from the 2# nickel-cobalt extraction pre-liquid into the organic phase, and obtain 2# aqueous phase raffinate and 2# organic phase extract. Release 95 ml of the aqueous phase from the 250 ml separating funnel after stratification, and retain a portion of the aqueous phase to block the organic phase. Detect the nickel, cobalt, iron, and aluminum concentrations in the 2# aqueous phase raffinate, and calculate the primary extraction and separation effect. The test results show that in the 2# aqueous phase raffinate, the nickel content is 0.20 g / L, the cobalt content is 1.28 g / L, the copper content is 0.0006 g / L, the aluminum content is 18.13 g / L, and the iron content is 4.22 g / L. Assuming that the volumes of the aqueous phase and the organic phase remain unchanged, the primary extraction rates of each metal element are calculated based on the concentrations before and after extraction, and the results are shown in Table 5. Table 5 Primary extraction rate element Ni Co Cu Al Fe Extraction rate, % 95.0 44.6 96.5 3.6 2.3

[0044] Step 5-1: Take 90ml of the 1# aqueous phase raffinate obtained in step S4 and 90ml of the 2# raffinate obtained in step S1-4 and put them into a 500ml beaker, stir and heat to 60°C, slowly drip 20wt% sodium carbonate solution, control the pH of the reaction to 3.0-3.5 so that the trivalent iron ions generate iron hydroxide precipitation, filter, and rinse the filter residue with a small amount of water to obtain 4g of 1# iron slag; combine the water washing liquid and the filtrate to obtain 200ml of 1# iron removal liquid. At this time, sample and detect the nickel, cobalt, copper, iron, and aluminum metal contents of 1# iron slag, as shown in Table 6. Take 200ml of 1# iron removal liquid and put it into a 500ml beaker, stir and heat to 60°C, slowly drip 20wt% sodium carbonate solution, control the pH of the reaction to 4.0-4.5 so that the aluminum ions generate aluminum hydroxide precipitation, filter, and rinse the filter residue with a small amount of water to obtain 12g of 1# aluminum hydroxide slag; combine the water washing liquid and the filtrate to obtain 230ml of 1# aluminum removal liquid. At this time, samples were taken to test the nickel, cobalt, copper, iron and aluminum metal contents of 1# aluminum hydroxide slag, as shown in Table 6.

[0045] Take 35g of 1# nickel-cobalt-iron-aluminum slag obtained in step S1 and 44g of 2# nickel-cobalt-iron-aluminum slag obtained in step S1-1 into a 500ml beaker, add 200ml of sulfuric acid solution with a pH of 2 for rinsing, stir at a speed of 100 rpm, heat to 50°C, react for 45min, then filter, and rinse the residue with clean water to obtain 1# slag washing water; the 1# slag washing water can be recycled to the slurry prepared with iron and aluminum waste residue in the acid leaching process. The residue is the rinsed iron and aluminum slag, recorded as 3# iron and aluminum slag, a total of 75g; at this time, sample and detect the nickel, cobalt, copper, iron, and aluminum metal contents of 3# iron and aluminum slag, as shown in Table 6.

[0046] Step 5-2: Mix the 1# organic phase extract obtained in step S4 and the 2# organic phase extract obtained in step S1-4, put them into a 250ml separatory funnel, drain the excess aqueous phase, add 50ml of 50g / L sulfuric acid for a stripping operation, cover and vibrate for 10min to mix them thoroughly, loosen the stopper, let stand for 10min, separate the extracted organic phase and the aqueous phase, and obtain 48ml of 1# stripping solution rich in nickel and cobalt sulfate; then add 50ml of 50g / L sulfuric acid for a second stripping operation to obtain 50ml of 2# stripping solution rich in nickel and cobalt sulfate. At this time, sample and detect the nickel, cobalt, copper, iron, and aluminum metal contents in the 1# stripping solution and the 2# stripping solution, as shown in Table 6. Table 6 Summary of test data

[0047] According to step S1 and step S1-1, a total of 400 g of iron-aluminum waste slag is added, and the nickel, cobalt and copper contents of 4 g of 1# iron slag, 12 g of 1# aluminum hydroxide slag and 75 g of 3# iron-aluminum slag after treatment are calculated. The nickel, cobalt and copper in the liquid produced in the intermediate process can also be recovered later. The recovery rates of nickel, cobalt and copper metal elements in the iron-aluminum waste slag are calculated respectively: nickel is 99.4%, cobalt is 99.0% and copper is 95.6%.

[0048] The present invention uses the iron-aluminum waste slag generated in the process of recycling the positive electrode material of waste nickel-cobalt-manganese ternary batteries as raw materials, uses sulfuric acid to leach nickel, cobalt and copper metal ions in the waste slag, and uses the property that the dissolution pH value of nickel hydroxide, cobalt hydroxide and copper hydroxide is higher than that of aluminum hydroxide, iron hydroxide and the like, controls the addition speed and amount of sulfuric acid, selectively leaches nickel, cobalt and copper in the iron-aluminum waste slag, and converts the original hazardous waste iron-aluminum slag into environmentally friendly iron-aluminum slag; iron powder is added to the mixed solution of nickel sulfate, cobalt sulfate and copper sulfate obtained by leaching, so that copper is recovered in the form of sponge copper, and an oxidant and sodium hydroxide and sulfuric acid are added to the remaining nickel sulfate, cobalt and iron-aluminum solution to adjust the solution pH value to 2.0-2.5, and uses the characteristics of HBL110 extractant having a higher extraction rate for nickel and cobalt ions in an acidic solution, while having a lower extraction rate for iron, aluminum, calcium and magnesium ions, to extract nickel and cobalt ions into an organic phase under a high aluminum and iron system, and the raffinate is a high aluminum and iron solution with low nickel and cobalt. Sulfuric acid is used for back extraction to obtain a nickel sulfate and cobalt mixed solution. Sodium carbonate solution is added to a liquid containing low nickel and cobalt and high iron and aluminum to precipitate iron and aluminum into iron hydroxide and aluminum hydroxide step by step. The liquid after iron and aluminum removal can be recycled to the sulfuric acid leaching process of iron and aluminum slag. The present invention processes the original nickel-cobalt iron and aluminum waste slag, not only recovers the high-priced nickel, cobalt and copper metals that are harmful to the environment, but also recovers and utilizes two commodities, iron hydroxide and aluminum hydroxide. The method is simple and easy to operate, low in cost, and while achieving economic benefits, it eliminates environmental pollution factors and has good social benefits.

[0049] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention, and these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A method for recycling nickel-cobalt-iron-aluminum waste slag, characterized in that: The resource recovery method comprises the following steps: S1: adding water to a certain amount of iron-aluminum waste slag and stirring to form a slurry, adding sulfuric acid to the slurry to dissolve it, raising the temperature to react, controlling the pH value of the slurry to 1.5-2.0, leaching the nickel and cobalt ions in the iron-aluminum waste slag with acid, and filtering to obtain a sulfuric acid leaching solution and nickel-cobalt-free iron-aluminum slag; S2: Detect the copper content in the sulfuric acid leaching solution of step S1. When the copper content is less than or equal to 0.1 g / L, directly proceed to step S4; otherwise, when the copper content is greater than 0.1 g / L, first add iron powder to the sulfuric acid leaching solution to replace the copper ions in the sulfuric acid leaching solution with sponge copper to remove the copper, and filter to obtain a copper removal solution and sponge copper; S3: adding an oxidant to the copper removal solution obtained in step S2 to convert the divalent iron ions into trivalent iron ions; S4: The low-copper-content sulfuric acid leaching solution obtained in step S1 or the copper-removing solution treated in step S3 is partially or completely transported to the nickel-cobalt extraction line as a nickel-cobalt extraction pre-liquid, and an organic phase prepared by an extractant and a diluent and a saponifying agent are sequentially added to perform extraction operations. After sufficient mixing, the mixture is allowed to stand and separate into layers, and nickel-cobalt metal ions are extracted from the nickel-cobalt extraction pre-liquid into the organic phase to obtain an aqueous phase raffinate and an organic phase extract.

2. The method for recycling nickel-cobalt-iron-aluminum waste slag as claimed in claim 1, characterized in that: In step S4, the remaining part of the nickel-cobalt extraction pre-liquid is stirred with another amount of iron-aluminum waste slag to form a slurry, sulfuric acid is added to heat the reaction to carry out acid leaching of nickel and chromium ions, and the sulfuric acid leaching solution and nickel-cobalt-removed iron-aluminum slag are obtained by filtration; the sulfuric acid leaching solution is repeatedly subjected to the operations of steps S2, S3 and S4 to obtain a new aqueous phase raffinate and an organic phase extract.

3. The method for recycling nickel-cobalt-iron-aluminum waste slag as claimed in claim 1 or 2, characterized in that: The resource recovery method also includes step S5-1: recycling the aqueous phase raffinate obtained in step S4 to the slurry of step S1; or first adding a precipitant to the aqueous phase raffinate to control the pH value to 3.0-3.5 to precipitate iron hydroxide, completing the recovery operation of iron in the iron-aluminum waste slag, and then continuing to add a precipitant to the filtrate after filtering to control the pH value to 4.0-4.5 to precipitate aluminum hydroxide, completing the recovery operation of aluminum in the iron-aluminum waste slag.

4. The method for recycling nickel-cobalt-iron-aluminum waste slag as claimed in claim 1 or 2, characterized in that: The resource recovery method further comprises step S5-2: adding sulfuric acid to the organic phase extract obtained in step S4 to perform at least one stripping operation to obtain a stripping solution rich in nickel and cobalt sulfate.

5. The method for recycling nickel-cobalt-iron-aluminum waste slag as claimed in claim 1 or 2, characterized in that: The solid-liquid ratio of the slurry is 1:1-3, the reaction temperature is 50-90°C, and the reaction time is 1-5h.

6. The method for recycling nickel-cobalt-iron-aluminum waste slag as claimed in claim 1 or 2, characterized in that: The oxidant is at least one of hydrogen peroxide, sodium chlorate, sodium hypochlorite and potassium chlorate.

7. The method for recycling nickel-cobalt-iron-aluminum waste slag as claimed in claim 1 or 2, characterized in that: The concentration of the extractant in the organic phase is 45-50%; the extraction phase ratio (O / A) of the extraction operation is 1-2:

1.

8. The method for recycling nickel-cobalt-iron-aluminum waste slag as claimed in claim 1 or 2, characterized in that: The extractant is a lipid extractant, and the preferred model is HBL 110 extractant.

9. The method for recycling nickel-cobalt-iron-aluminum waste slag as claimed in claim 3, characterized in that: The precipitant is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate.

10. The method for recycling nickel-cobalt-iron-aluminum waste slag as claimed in claim 1, characterized in that: In the resource recovery method, the nickel and cobalt recovery rates of the iron and aluminum waste slag are not less than 99%, and the copper recovery rate is not less than 95%.

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