Method and system for recovering nickel anolyte

Abstract

The invention relates to the technical field of nickel metal hydrometallurgy, and discloses a nickel anolyte recovery method and system.The method comprises the extraction procedure, specifically, nickel anolyte makes contact with an organic phase A to be subjected to extraction treatment, organic phase extraction liquid and acid extraction raffinate are obtained, and the organic phase A contains an organic amine extraction agent; a washing process: enabling the organic phase extraction liquid to be in contact with water for washing treatment to obtain organic phase washing liquid and washing water; a reverse extraction process: contacting the organic phase washing liquid with the water phase A for reverse extraction treatment to obtain organic phase reverse extraction liquid and ammonium salt; the water phase A is ammonia water. According to the method, the recovery rate of nickel and acid in the nickel anolyte treatment process can be increased, the separation cost is reduced, and reasonable application of resources is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrometallurgy of nickel metal, and particularly relates to a method and a system for recovering nickel anode solution. Background Art

[0002] In the metal recovery production of the hydrometallurgy industry, a large amount of anode solution is generated in the electrolysis process section. How to recover nickel, acid, and boron in the nickel anode solution is an important topic in the industry.

[0003] In the existing nickel anode solution treatment process, there are problems of high separation cost and low recovery rate for nickel, acid, and boron, and the rational application of resources cannot be achieved. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for recovering nickel anode solution with high recovery rates of nickel and acid and low cost.

[0005] To achieve the above purpose, a first aspect of an embodiment of the present invention provides a method for recovering nickel anode solution, the method comprising:

[0006] Extraction process: contacting nickel anode solution and organic phase A for extraction treatment to obtain an organic phase extraction solution and an acid extraction residue solution, wherein the organic phase A contains an organic amine extractant;

[0007] Washing process: contacting the organic phase extraction solution and water for washing treatment to obtain an organic phase washing solution and washing water;

[0008] Back-extraction process: contacting the organic phase washing solution and aqueous phase A for back-extraction treatment to obtain an organic phase back-extraction solution and an ammonium salt; the aqueous phase A is ammonia water.

[0009] In an embodiment of the present invention, organic phase A containing an organic amine extractant is used to separate nickel, boron, and acid. Then, through the washing process, nickel and boron in the organic phase extraction solution are washed away. Then, ammonium salt is obtained by back-extraction with ammonia water. Nickel and boron are important elements of nickel electrolyte. The washing process further separates nickel and boron from acid in the organic phase extraction solution, which is beneficial to improving the recovery rates of nickel and boron. When nickel and boron are recovered and prepared into nickel electrolyte, the subsequent process flow and reagent consumption are reduced; at the same time, separating nickel and boron in the washing process can also reduce the nickel loss caused by nickel-ammonia complexation during the subsequent ammonia water back-extraction process and improve the purity of the ammonium salt. And in the back-extraction process, ammonia water is selected as the back-extraction reagent, which can avoid the formation of nickel precipitates, such as nickel hydroxide precipitate, when the nickel remaining in the washing water is back-extracted, thereby reducing equipment scaling and its cleaning and lowering the production cost.

[0010] Optionally, in the extraction process, the volume ratio of the organic phase A to the nickel anode solution is 0.5 - 10:1.

[0011] Optionally, the nickel anolyte contains: 60 - 80 g / L of nickel element, 2 - 3 g / L of boron element, and 0.8 - 1.2 mol / L of hydrogen ions.

[0012] Optionally, the mass fraction of the organic amine extractant in the organic phase A is 5 - 50%.

[0013] Optionally, the organic phase A further contains octanol and sulfonated kerosene. The octanol is n - octanol and / or isooctanol; the mass fraction of octanol in the organic phase A is 0 - 40%, and the mass fraction of sulfonated kerosene in the organic phase A is 10 - 90%.

[0014] Optionally, the extraction treatment method is centrifugal extraction and / or cross - flow extraction.

[0015] Optionally, in the washing process, the volume ratio of the organic phase extract to the water is 0.5 - 10:1.

[0016] Optionally, the washing treatment method is centrifugal washing and / or cross - flow washing.

[0017] Optionally, control the conditions of the washing treatment so that the nickel ion concentration in the organic phase washing solution ≤ 1 mg / L.

[0018] Optionally, in the stripping process, the volume ratio of the organic phase washing solution to the aqueous phase A is 0.5 - 5:1.

[0019] Optionally, the mass fraction of ammonia water in the aqueous phase A is 5 - 28%.

[0020] Optionally, the stripping treatment method is centrifugal stripping, and the separation factor of the centrifugal stripping is 550 - 650 g.

[0021] Optionally, the method further includes an evaporation and concentration process: subject the acid - remaining extract in the extraction process to evaporation and concentration treatment to obtain a nickel - containing concentrated solution; the concentration multiple of the evaporation and concentration treatment is 1.2 - 2.0 times.

[0022] Optionally, use an MVR system and / or a multi - effect evaporation system for the evaporation and concentration treatment.

[0023] Optionally, the method further includes a nickel precipitation process: subject the washing water in the washing process to nickel precipitation treatment and solid - liquid separation treatment in sequence to obtain nickel hydroxide and a filtrate. Through the nickel precipitation process, the separation of nickel and boron is achieved, which is beneficial to the targeted utilization of nickel hydroxide and the filtrate.

[0024] Optionally, the nickel hydroxide is mixed with the nickel - containing concentrated solution to meet the pH requirement of the electrolytic nickel catholyte.

[0025] Optionally, the filtered liquid is sequentially subjected to ultrafiltration and reverse osmosis treatments to obtain pure water and concentrated water. In the evaporation and concentration process, the concentrated water is mixed with the acid extraction residue liquid and then subjected to evaporation and concentration treatment.

[0026] Optionally, in the extraction process, the organic amine extractant includes a tertiary amine extractant.

[0027] Optionally, the molecular structure of the organic amine extractant includes R3N, and the R group is at least one of octyl, nonyl, and decyl.

[0028] Optionally, the organic amine extractant includes one of Mextral 336A, N263, Liquat336, and TOMAC.

[0029] Optionally, the organic amine extractant includes Mextral 336A.

[0030] The second aspect of the embodiment of the present invention provides a nickel anode solution recovery system, which includes an extraction unit, a washing unit, and a stripping unit connected in sequence;

[0031] Among them, the extraction unit is used for extracting the nickel anode solution to obtain an organic phase extraction liquid and an acid extraction residue liquid;

[0032] The washing unit is used for washing the organic phase extraction liquid to obtain an organic phase washing liquid and washing water;

[0033] The stripping unit is used for stripping the organic phase washing liquid to obtain an organic phase stripping liquid and an ammonium salt.

[0034] Optionally, the extraction unit is further connected to an evaporation and concentration unit, and the evaporation and concentration unit is used for evaporating and concentrating the acid extraction residue liquid to obtain a nickel-containing concentrated liquid.

[0035] Optionally, the washing unit is further connected to a nickel precipitation unit and a solid-liquid separation unit in sequence to obtain nickel hydroxide and a filtered liquid.

[0036] Optionally, the system further includes an ultrafiltration and reverse osmosis unit, and the ultrafiltration and reverse osmosis unit is used for sequentially performing ultrafiltration and reverse osmosis treatments on the filtered liquid to obtain pure water and concentrated water.

[0037] Optionally, the reverse osmosis treatment unit is connected to the evaporation and concentration unit to return the concentrated water to the evaporation and concentration unit. Description of the Drawings

[0038] Figure 1 is a schematic process flow diagram of the method for recovering nickel anode solution according to an optional embodiment of the present invention. Detailed Embodiments

[0039] The endpoints and any values in the ranges disclosed herein are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0040] As mentioned above, the first aspect of the embodiment of the present invention provides a method for recovering nickel anode solution, and the method includes:

[0041] Extraction process: contacting the nickel anode solution with organic phase A for extraction treatment to obtain an organic phase extract and an acid extraction residue solution, and organic phase A contains an organic amine extractant;

[0042] Washing process: contacting the organic phase extract with water for washing treatment to obtain an organic phase washing solution and washing water;

[0043] Back-extraction process: contacting the organic phase washing solution with aqueous phase A for back-extraction treatment to obtain an organic phase back-extract and an ammonium salt; aqueous phase A is ammonia water.

[0044] In the embodiment of the present invention, organic phase A containing an organic amine extractant is used to separate nickel boron and acid. Then, through the washing process, nickel and boron in the organic phase extract are washed away. Then, ammonium salt is obtained by back-extraction with ammonia water. Nickel and boron are important elements of nickel electrolyte. The washing process further separates nickel boron and acid in the organic phase extract, which is beneficial to improving the recovery rates of nickel and boron. When nickel boron is recovered and prepared into nickel electrolyte, it reduces subsequent process flows and reagent consumption; at the same time, separating nickel boron in the washing process can also reduce the nickel loss caused by nickel ammonia complexation during the subsequent back-extraction with ammonia water and improve the purity of the ammonium salt. And in the back-extraction process, ammonia water is selected as the back-extraction reagent, which can avoid the formation of nickel precipitates, such as nickel hydroxide precipitate, by the residual nickel in the washing water during back-extraction, thereby reducing equipment scaling and its cleaning and reducing production costs.

[0045] In some embodiments, in the extraction process, the organic amine extractant includes one of Mextral 336A, N263, Liquat336, and TOMAC. Using the above organic amine extractants is beneficial to improving the separation effect of nickel and acid and reducing the entry of nickel into the organic phase extract during extraction.

[0046] In some embodiments, the organic amine extractant is Mextral 336A. Using Mextral 336A as the extractant is beneficial to further improve the separation effect of nickel boride and acid, and is also beneficial to elute a small amount of nickel boride that enters the organic phase extract in the washing process, further reducing the nickel content in the organic phase washing liquid, reducing nickel loss, reducing the entry of nickel boride into the ammonium salt during back extraction, and improving the purity of the ammonium salt.

[0047] In some embodiments, the ammonium salt is ammonium sulfate and / or ammonium chloride.

[0048] In some embodiments, the method of the present invention further includes, before performing the extraction process, controlling the temperature of the nickel anode solution first, so that the temperature of the nickel anode solution entering the extraction process is 30-70°C.

[0049] Optionally, in the extraction process, the volume ratio of the organic phase A to the nickel anode solution is 0.5-10:1, for example, it can be 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1 or any value between 0.5-10:1.

[0050] Optionally, the nickel anode solution contains: 60-80 g / L of nickel element, 2-3 g / L of boron element, and 0.8-1.2 mol / L of hydrogen ion. The nickel anode solution can come from the anode solution after the electrolytic reaction for preparing metallic nickel, and the electrolytic reaction includes electrolytic deposition, electrolytic refining, or electrolytic extraction, etc.

[0051] Optionally, the mass fraction of the organic amine extractant in the organic phase A is 5-50%, for example, it can be 5%, 10%, 20%, 30%, 40%, 50% or any value between 5-50%.

[0052] Optionally, the organic phase A further contains octanol and sulfonated kerosene, and the octanol is n-octanol and / or isooctanol; the mass fraction of octanol in the organic phase A is 0-40%, for example, it can be 0%, 20%, 40% or any value between 0-40%; the mass fraction of sulfonated kerosene in the organic phase A is 10-90%, for example, it can be 10%, 20%, 40%, 60%, 80%, 90% or any value between 10-90%; the sum of Mextral 336A + octanol + sulfonated kerosene is 100%. By using octanol regulator and sulfonated kerosene with a specific mass ratio as the diluent, the generation of the third phase can be effectively prevented, the organic phase A system can be kept stable, and thus a more excellent extraction effect can be exerted.

[0053] It should be noted that in the embodiments of the present invention, the third phase refers to the immiscible second organic phase formed between the original organic phase and the aqueous phase during the solvent extraction process. The presence of the third phase will disrupt the extraction process and prevent the smooth progress of traditional extraction operations. It will cause difficulties in phase separation, reduce the extraction efficiency, increase the loss of extractant, and may also cause problems such as equipment blockage and flooding, affecting the normal operation of production.

[0054] According to a specific embodiment of the present invention, the conditions of the extraction treatment are controlled such that the amount of hydrogen ions extracted into the organic phase extractant accounts for more than 95 mol% of the total amount of hydrogen ions in the nickel anode solution, the amount of nickel elements entrained into the organic phase extractant accounts for less than 0.15 wt% of the total amount of nickel elements in the nickel anode solution, and the amount of boron elements entrained into the organic phase extractant accounts for less than 30 wt% of the total amount of boron elements in the nickel anode solution, and can be optionally less than 25 wt%.

[0055] Optionally, the extraction treatment method is centrifugal extraction and / or cross-flow extraction.

[0056] In some embodiments, the extraction treatment method is centrifugal extraction, and the separation factor of the centrifugal extraction is 550 - 650g, for example, it can be 550g, 580g, 600g, 620g, 640g, 650g, or any value between 550 - 650g.

[0057] In some embodiments, the extraction treatment is a multi-stage extraction treatment, and the extraction treatment method is cross-flow extraction.

[0058] Optionally, in the washing process, the volume ratio of the organic phase extractant to water is 0.5 - 10:1, for example, it can be 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, or any value between 0.5 - 10:1.

[0059] Optionally, the washing treatment method is centrifugal washing and / or cross-flow washing.

[0060] In some embodiments, the washing treatment method is centrifugal washing, and the separation factor of the centrifugal extraction is 550 - 650g, for example, it can be 550g, 580g, 600g, 620g, 640g, 650g, or any value between 550 - 650g.

[0061] In some embodiments, the washing treatment is a multi-stage washing treatment, and the washing treatment method is cross-flow washing.

[0062] Optionally, control the conditions of the washing process such that the nickel ion concentration in the organic phase washing liquid ≤ 1 mg / L. By controlling the nickel ion concentration in the organic phase washing liquid under this condition, nickel-ammonia complexation in the stripping process can be effectively reduced, and the purity of the subsequent ammonium salt obtained can be significantly improved.

[0063] Through the washing process, nickel and boron in the organic phase extract can be significantly reduced, and only no more than 10% of the acid extracted in the organic phase extract is washed into the aqueous phase, realizing the separation of nickel, boron, and acid entrained in the organic phase extract. The organic phase washing liquid obtained after the washing process can be stripped with ammonia water without residual nickel and boron affecting the purity of the stripped product ammonium salt, and the obtained ammonium salt can be sold as nitrogen fertilizer.

[0064] Optionally, in the stripping process, the volume ratio of the organic phase washing liquid to aqueous phase A is 0.5 - 5:1, for example, it can be 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, or any value between 0.5 - 5:1.

[0065] Optionally, the mass fraction of ammonia water in aqueous phase A is 5 - 28%, for example, it can be 5%, 10%, 15%, 20%, 25%, 28%, or any value between 5 - 28%.

[0066] Optionally, the stripping treatment method is centrifugal stripping, and the separation factor of centrifugal stripping is 550 - 650g, for example, it can be 550g, 580g, 600g, 620g, 640g, 650g, or any value between 550 - 650g.

[0067] It should be noted that in the stripping process of the embodiment of the present invention, ammonia water is used as aqueous phase A. Among them, ammonia water can be prepared in advance and then applied to the stripping process; it can also be that ammonia gas is introduced into the stripping treatment system and undergoes mass transfer stripping with the organic phase and aqueous phase therein. Exemplarily, the stripping treatment is carried out in a stripping tower, and ammonia gas is introduced into the stripping tower to enable mass transfer stripping between ammonia gas and the organic phase and aqueous phase therein.

[0068] The embodiment of the present invention has no special restrictions on conditions such as the pressure and flow rate of ammonia gas introduced into the stripping treatment system, as long as ammonia gas can be introduced into the mixing system to form ammonia water with a specific concentration and mass transfer stripping can be carried out smoothly. Exemplarily, the pump pressure for introducing ammonia gas is 1.5 - 2.5 bar, for example, it can be 1.5 bar, 1.8 bar, 2.0 bar, 2.2 bar, 2.4 bar, 2.5 bar, or any value between 1.5 - 2.5 bar. The present invention will not elaborate further here, and those skilled in the art should not understand it as a limitation of the present invention. The embodiment of the present invention controls the amount of ammonia entering the stripping process to reduce the overflow of excessive unreacted ammonia gas. After the unreacted ammonia gas is collected at the top of the stripping tower, it can also be pressurized and introduced into the stripping tower.

[0069] In some embodiments, the tail gas overflowed during the process of ammonia gas being introduced into the stripping treatment system is absorbed by sulfuric acid to obtain ammonium sulfate.

[0070] Optionally, the method described in the present invention further comprises an ammonia washing step: subjecting the organic phase stripping solution obtained in the stripping step to an ammonia washing treatment to wash away the entrained ammonia to obtain a pure organic phase A.

[0071] The embodiment of the present invention has no particular limitation on the specific operation of the ammonia washing treatment. Those skilled in the art can make a selection according to the technical means known in the art. For example, the stripping solution is mixed with deionized water and stirred thoroughly. After standing and stratifying, the aqueous phase is separated. The organic phase A and the ammonia washing liquid can also be separated by centrifugal extraction at a ratio of 10:1.

[0072] Optionally, the method further comprises an evaporation and concentration step: evaporating and concentrating the acid extraction residual liquid in the extraction step to obtain a nickel-containing concentrated liquid. The nickel-containing concentrated liquid has a higher concentration than membrane concentration, which is beneficial to increasing the current density of nickel electrodeposition and reducing production costs.

[0073] It is understood that the nickel-containing concentrate includes nickel sulfate and / or nickel chloride, which is specifically related to the anion system in the nickel anode solution.

[0074] The concentration multiple of the evaporation concentration treatment is 1.2-2.0 times, for example, it can be 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2.0 times, or any value between 1.2-2.0 times.

[0075] The concentration multiple of the present invention refers to the ratio of the initial solution volume before concentration to the final solution volume after concentration. For example, if the initial solution volume is 100 mL and the final solution volume is 50 mL, the concentration multiple is 2 times.

[0076] Optionally, an MVR system and / or a multiple-effect evaporation system is used to carry out the evaporation concentration process.

[0077] The MVR system in the embodiment of the present invention refers to a mechanical vapor recompression system.

[0078] Optionally, the multiple-effect evaporation system is a triple-effect evaporation system.

[0079] Optionally, the nickel-containing concentrated solution obtained after evaporation and concentration treatment is used as cathode liquid in the nickel electrowinning production process.

[0080] Optionally, the acid extraction residue is preheated before the evaporation and concentration treatment.

[0081] There is no particular limitation on the preheating treatment method in the embodiments of the present invention. Those skilled in the art can select according to the known technical means in the art. Exemplarily, a plate-type or shell-and-tube heat exchanger is used for preheating treatment, which is not elaborated herein again. Those skilled in the art should not understand it as a limitation to the present invention.

[0082] Optionally, the method further includes a nickel precipitation step: subjecting the washing water in the washing step to nickel precipitation treatment and solid-liquid separation treatment in sequence to obtain nickel hydroxide and filtrate.

[0083] Optionally, the solid-liquid separation treatment is carried out by means of plate-and-frame filtration.

[0084] Optionally, the nickel hydroxide is mixed with the nickel-containing concentrated solution to meet the pH requirement of the electrolytic nickel cathode solution. In an acidic environment, nickel hydroxide can redissolve into the residual acid solution after extraction.

[0085] Optionally, the filtrate is subjected to ultrafiltration treatment and reverse osmosis treatment in sequence to obtain pure water and concentrated water. In the evaporation and concentration step, the concentrated water is mixed with the residual acid solution after extraction and then subjected to evaporation and concentration treatment.

[0086] Optionally, the obtained pure water is used in the washing step.

[0087] Optionally, the method of the present invention may further include discharging the filtrate to a biochemical treatment system, and after being treated by the biochemical system, finally discharging it.

[0088] In some embodiments, an MVR system and / or a multi-effect evaporation system is used for evaporation and concentration treatment. In the MVR system and / or the multi-effect evaporation system, the secondary steam evaporated is heated, pressurized by a compressor or live steam is used as a heat source for evaporation and concentration. If the distilled water obtained after the live steam is heat-exchanged or the secondary steam condensed from the evaporated solution needs to be further purified and reused in a higher-requirement occasion, the method of the present invention may further include subjecting the distilled water and the filtrate to ultrafiltration treatment and reverse osmosis treatment in sequence to obtain pure water and concentrated water.

[0089] In some embodiments, in the extraction step, the organic amine extractant includes a tertiary amine extractant; using a tertiary amine extractant has a better separation effect of nickel and acid compared with general organic amine extractants, such as primary amine extractants and secondary amine extractants, and is beneficial to improving the process economy.

[0090] In some embodiments, the molecular structure of the organic amine extractant includes R3N, and the R group is at least one of octyl, nonyl, and decyl; using an extractant including the above molecular structure is beneficial to promoting the separation effect of nickel boron and acid and improving the process economy.

[0091] In some embodiments, the organic amine extractant includes one of Mextral 336A, N263, Liquat336, and TOMAC; using the above extractants is beneficial to promoting the separation of nickel acid, and in some cases, is also beneficial to promoting the separation of nickel boron and acid, improving process economy.

[0092] In some embodiments, the organic amine extractant includes Mextral 336A; using Mextral 336A extractant is not only beneficial to promoting the separation effect of nickel boron and acid, but also beneficial to making nickel boron in the organic phase extractant enter the washing water during the washing stage, further improving the purity of ammonium salt and the recovery rates of nickel, boron, and acid.

[0093] As described above, the second aspect of the embodiments of the present invention provides a nickel anode liquid recovery system, which includes an extraction unit, a washing unit, and a stripping unit connected in sequence;

[0094] Among them, the extraction unit is used to perform extraction treatment on the nickel anode liquid to obtain an organic phase extract and an acid extraction residue liquid;

[0095] The washing unit is used to perform washing treatment on the organic phase extract to obtain an organic phase washing liquid and washing water;

[0096] The stripping unit is used to perform stripping treatment on the organic phase washing liquid to obtain an organic phase stripping liquid and ammonium salt.

[0097] In some embodiments, a shell-and-tube heat exchanger or a plate heat exchanger is used to control the temperature of the nickel anode liquid within a specific range to protect the equipment from the influence of temperature.

[0098] Optionally, the extraction unit is further connected to an evaporation and concentration unit, and the evaporation and concentration unit is used to perform evaporation and concentration treatment on the acid extraction residue liquid to obtain a nickel-containing concentrated liquid.

[0099] Optionally, the washing unit is further connected to a nickel precipitation unit and a solid-liquid separation unit in sequence to obtain nickel hydroxide and a filtrate.

[0100] Optionally, the system further includes an ultrafiltration and reverse osmosis unit, and the ultrafiltration and reverse osmosis unit is used to perform ultrafiltration treatment and reverse osmosis treatment on the filtrate in sequence to obtain pure water and concentrated water.

[0101] Optionally, the reverse osmosis treatment unit is connected to the evaporation and concentration unit to return the concentrated water to the evaporation and concentration unit.

[0102] In some embodiments, the ultrafiltration and reverse osmosis unit includes an ultrafiltration unit, a first-stage reverse osmosis unit, a second-stage reverse osmosis unit, and a third-stage reverse osmosis unit.

[0103] In the embodiments of the present invention, UF represents the ultrafiltration unit, the first-stage RO represents the first-stage reverse osmosis unit, the second-stage RO represents the second-stage reverse osmosis unit, and the third-stage RO represents the third-stage reverse osmosis unit.

[0104] According to a specific embodiment of the present invention, the feed liquid filtered by UF is pumped to the first-stage RO. The concentrated water of the first-stage RO enters the first-stage concentrated water tank and is pumped into the second-stage RO for further concentration. The concentrated water of the second-stage RO is incorporated into the acid extraction residue liquid and enters the evaporation concentration unit for concentration and then used as the cathode liquid in the electrowinning nickel production process section. The water produced by the first-stage RO and the second-stage RO flows by gravity to the first- and second-stage RO product water tank and is pumped into the third-stage RO for purification. The concentrated water of the third-stage RO is refluxed to the inlet of the second-stage RO to improve the total recovery rate of each component in the feed liquid filtered by UF. The water produced by the third-stage RO flows by gravity to the washing water tank and is used as pure water in the washing process section.

[0105] The method and system for recovering nickel and acid in the nickel anode liquid provided by the embodiments of the present invention reduce the number of equipment, floor area, and operating costs. Moreover, the process has a high degree of automation, reducing the labor intensity of personnel, and enabling resource utilization on both the nickel side and the acid side.

[0106] The present invention will be described in detail below through examples. In the following examples, unless otherwise specified, the raw materials used are commercially available products.

[0107] Example 1

[0108] (1) Cooling process: Cool 3 m3 / h of electrowinning nickel anode liquid I at a temperature of 80 °C to 35 °C.

[0109] (2) Extraction process: Contact the cooled nickel anode liquid with organic phase A for extraction treatment to obtain an organic phase extract and an acid extraction residue liquid. Organic phase A includes 90 wt% extractant Mextral 336A and 10 wt% diluent by mass fraction. The mass ratio of isooctanol to sulfonated kerosene in the diluent is 2:1. The extraction method is centrifugal extraction, and the number of extraction stages is two. The volume ratio of organic phase A to nickel anode liquid is 2:1 (i.e., O / A = 2:1).

[0110] (3) Washing process: Contact the organic phase extract in step (2) with water for washing treatment to obtain an organic phase washing liquid and washing water. The washing method is centrifugal washing, the separation factor is 600g, and the volume ratio of the organic phase extract to the aqueous phase in the washing process is 10:1 (i.e., O / A = 10:1).

[0111] (4) Nickel precipitation process: The washing water is precipitated with NaOH and filtered through a plate and frame to obtain nickel hydroxide precipitate and filtrate.

[0112] (5) Stripping process: 15 wt% ammonia water is added to the organic phase washing solution obtained in step (3) for centrifugal stripping, with a separation factor of 600 g. The volume ratio of the organic phase washing solution to ammonia water is 2:1 (i.e., O / A = 2:1), obtaining an organic phase stripping solution and an ammonium sulfate solution. The ammonium sulfate is sold externally as fertilizer.

[0113] (6) Evaporation and concentration process: After preheating, the acid extraction residue liquid is subjected to evaporation and concentration. The heat source for evaporation and concentration includes raw steam or secondary steam heated by a compressor. A nickel sulfate concentrated solution and secondary steam are obtained, with a concentration multiple of 1.5 times. It is controlled by a densitometer and then pumped to a nickel sulfate pH adjustment tank. By adding the nickel hydroxide precipitate in step (3) and adjusting the pH value to 4, it is pumped to the cathode solution of electrowinning nickel for reuse. The raw steam and secondary steam are heat-exchanged during the evaporation and concentration process to obtain condensed water, and the condensed water is further cooled to 35°C.

[0114] (7) Ultrafiltration process: The condensed water cooled in step (6) is mixed with the filtrate in step (3) and subjected to ultrafiltration treatment to obtain ultrafiltration concentrated water and ultrafiltration product water. The ultrafiltration concentrated water is discharged after biochemical treatment. The recovery rate of ultrafiltration treatment is 90%, the maximum operating pressure is 2 Bar, and the maximum operating temperature is 35°C.

[0115] (8) Reverse osmosis process:

[0116] The ultrafiltration product water in step (7) is subjected to primary RO treatment to obtain primary RO concentrated water and primary RO product water. The membrane flux of primary RO treatment is 20 LMH, the recovery rate is 80%, the maximum operating pressure is 15 Bar, and the maximum operating temperature is 35°C.

[0117] The primary RO concentrated water is subjected to secondary RO treatment to obtain secondary RO concentrated water and secondary RO product water. The membrane RO flux of secondary RO treatment is 27 LMH, the recovery rate is 75%, the maximum operating pressure is 60 Bar, and the maximum operating temperature is 35°C. The secondary RO concentrated water is mixed with the acid extraction residue liquid and then subjected to evaporation and concentration treatment.

[0118] The primary RO product water and secondary RO product water are subjected to tertiary RO treatment to obtain tertiary RO concentrated water and tertiary RO product water. The membrane flux of tertiary RO treatment is 27 LMH, the recovery rate is 85%, the maximum operating pressure is 12 bar, and the maximum operating temperature is 35°C. The conductivity of the tertiary RO product water ≤ 15 μS / cm and can be used as pure water; the tertiary RO concentrated water is returned for secondary RO treatment.

[0119] The material components of this embodiment are shown in Table 1:

[0120] Table 1

[0121]

[0122] The obtained ammonium sulfate is white.

[0123] Example 2

[0124] It is carried out using a process similar to that of Example 1, except that: the electrowinning nickel anolyte II is used as the liquid to be treated, and the volume ratio of the organic phase extractant to the aqueous phase in the washing process of step (3) is adjusted to 5:1, and the rest remain unchanged. The material components of this example are shown in Table 2.

[0125] Table 2

[0126]

[0127] The obtained ammonium sulfate is white.

[0128] Example 3

[0129] It is carried out using a process similar to that of Example 2, except that: the electrowinning nickel anolyte III is used as the liquid to be treated, and the rest remain unchanged. The material components of this example are shown in Table 3.

[0130] Table 3

[0131]

[0132] The obtained ammonium sulfate is white.

[0133] Comparative Example 1

[0134] It is carried out using a process similar to that of Example 2, except that: an equal mass of N235 is used to replace Mextral 336A; the washing process is not carried out; sodium hydroxide is used in the stripping process; specifically:

[0135] (1) Cooling process: Cool 3 m3 / h of the electrowinning nickel anolyte I at 80 °C to 35 °C.

[0136] (2) Extraction process: Contact the cooled nickel anolyte with organic phase A for extraction treatment to obtain an organic phase extract and an acid-remaining extract. Organic phase A includes 90 wt% extractant N235 and 10 wt% diluent by mass fraction. The mass ratio of isooctanol to sulfonated kerosene in the diluent is 2:1; the extraction method is centrifugal extraction, and the number of extraction stages is two; the volume ratio of organic phase A to nickel anolyte is 2:1 (i.e., O / A = 2:1).

[0137] (3) Stripping process: Add a 20 wt% sodium hydroxide solution to the organic phase extract obtained in step (2) for centrifugal stripping, with a separation factor of 600 g. The volume ratio of the organic phase extract to the sodium hydroxide solution is 2:1 (i.e., O / A = 2:1) to obtain an organic phase stripping solution and a sodium sulfate solution.

[0138] (4) Evaporation and concentration process: The residual acid extraction solution is preheated and then subjected to evaporation and concentration. The heat sources for evaporation and concentration include raw steam or secondary steam whose temperature is increased by compression with a compressor, obtaining nickel-containing concentrated solution and secondary steam. The concentration multiple is 1.5 times. It is controlled by a densitometer and then pumped to the nickel sulfate pH adjustment tank to adjust the pH value to 4, and then pumped to the electrowinning nickel cathode solution for reuse. The raw steam and secondary steam obtain condensed water after heat exchange during the evaporation and concentration process, and further cool the condensed water to 35°C.

[0139] (5) Ultrafiltration process: The condensed water cooled in step (4) is subjected to ultrafiltration treatment to obtain ultrafiltration concentrated water and ultrafiltration product water. The ultrafiltration concentrated water is discharged after biochemical treatment. The recovery rate of ultrafiltration treatment is 90%, the maximum operating pressure is 2 Bar, and the maximum operating temperature is 35°C.

[0140] (6) Reverse osmosis process:

[0141] The ultrafiltration product water in step (5) is subjected to primary RO treatment to obtain primary RO concentrated water and primary RO product water. The membrane flux of primary RO treatment is 20 LMH, the recovery rate is 80%, the maximum operating pressure is 15 Bar, and the maximum operating temperature is 35°C.

[0142] The primary RO concentrated water is subjected to secondary RO treatment to obtain secondary RO concentrated water and secondary RO product water. The membrane RO flux of secondary RO treatment is 27 LMH, the recovery rate is 75%, the maximum operating pressure is 60 Bar, and the maximum operating temperature is 35°C. The secondary RO concentrated water is mixed with the residual acid extraction solution and then subjected to evaporation and concentration treatment.

[0143] The primary RO product water and secondary RO product water are subjected to tertiary RO treatment to obtain tertiary RO concentrated water and tertiary RO product water. The membrane flux of tertiary RO treatment is 27 LMH, the recovery rate is 85%, the maximum operating pressure is 12 bar, and the maximum operating temperature is 35°C. The conductivity of the tertiary RO product water ≤ 15 μS / cm and can be used as pure water; the tertiary RO concentrated water is returned for secondary RO treatment.

[0144] The material components of this comparative example are shown in Table 4.

[0145] Table 4

[0146]

[0147] Comparative Example 2

[0148] The process similar to that of Example 1 is adopted, and the difference is that: the washing process in step (3) is not carried out. Specifically:

[0149] (1) Cooling process: Cool 3 m3 / h of electrowinning nickel anode solution I at a temperature of 80°C to 35°C.

[0150] (2) Extraction process: The cooled nickel anolyte is contacted with the organic phase A for extraction treatment to obtain an organic phase extract and an acid extraction residual solution. The organic phase A includes 90 wt% of the extractant Mextral 336A and 10 wt% of the diluent, and the mass ratio of isooctyl alcohol to sulfonated kerosene in the diluent is 2:1; the extraction method is centrifugal extraction, and the extraction stage is two; the volume ratio of the organic phase A to the nickel anolyte is 2:1 (i.e., O / A=2:1).

[0151] (3) Stripping process: 15 wt % ammonia water is added to the organic phase washing liquid obtained in step (2) for centrifugal stripping, with a separation factor of 600 g, and a volume ratio of the organic phase washing liquid to the ammonia water of 2:1 (i.e., O / A=2:1), to obtain an organic phase stripping liquid and an ammonium sulfate solution; the ammonium sulfate material after separation becomes hazardous waste due to its high nickel content, and a large amount of high-value nickel is lost.

[0152] (4) Evaporation and concentration process: After the acid extraction residual liquid is preheated, it is evaporated and concentrated. The heat source for evaporation and concentration includes raw steam or secondary steam compressed and heated by a compressor to obtain nickel-containing concentrated liquid and secondary steam, with a concentration multiple of 1.5 times; it is controlled by a density meter and then transported to a nickel sulfate pH adjustment tank by a pump to adjust the pH value to 4, and then pumped to the electrodeposition nickel cathode liquid for reuse; condensed water is obtained after heat exchange between raw steam and secondary steam during the evaporation and concentration process, and the condensed water is further cooled to 35°C.

[0153] (5) Ultrafiltration process: The condensed water after cooling in step (4) is subjected to ultrafiltration treatment to obtain ultrafiltration concentrated water and ultrafiltration product water, and the ultrafiltration concentrated water is discharged after biochemical treatment. The ultrafiltration treatment recovery rate is 90%, the maximum operating pressure is 2 Bar, and the maximum operating temperature is 35°C.

[0154] (6) Reverse Osmosis Process:

[0155] The ultrafiltration water produced in step (5) is subjected to primary RO treatment to obtain primary RO concentrated water and primary RO produced water. The membrane flux of the primary RO treatment is 20LMH, the recovery rate is 80%, the maximum operating pressure is 15Bar, and the maximum operating temperature is 35°C.

[0156] The primary RO concentrated water is treated by secondary RO to obtain secondary RO concentrated water and secondary RO produced water. The membrane RO flux of the secondary RO treatment is 27LMH, the recovery rate is 75%, the maximum operating pressure is 60Bar, and the maximum operating temperature is 35℃. The secondary RO concentrated water is mixed with the acid extraction residual liquid and then evaporated and concentrated.

[0157] The primary RO product water and the secondary RO product water are subjected to tertiary RO treatment to obtain tertiary RO concentrate water and tertiary RO product water. The membrane flux of the tertiary RO treatment is 27 LMH, the recovery rate is 85%, the maximum operating pressure is 12 bar, and the maximum operating temperature is 35 °C. The conductivity of the tertiary RO product water is ≤ 15 μS / cm and can be used as pure water; the tertiary RO concentrate water is returned for secondary RO treatment.

[0158] The material components of this comparative example are shown in Table 5.

[0159] Table 5

[0160]

[0161]

[0162] The obtained ammonium sulfate is blue, indicating that there is more nickel complexed in the ammonium sulfate.

[0163] From the above results, it can be seen that by using the technical solution provided by the present invention for the recovery of nickel and boron in the nickel anode solution, nickel, boron, and acid can be recovered in a hierarchical manner, with high recovery rates of nickel and acid. There is no longer a need to consume a large amount of sodium carbonate or sodium hydroxide to neutralize the surplus hydrogen ions in the electrolysis process, thereby greatly reducing the process cost.

[0164] The optional embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A method for recovering nickel anode solution, characterized in that, The method includes: Extraction process: contacting a nickel anode solution with organic phase A for extraction treatment to obtain an organic phase extraction solution and an acid extraction residue solution, wherein the organic phase A contains an organic amine extractant; Washing process: contacting the organic phase extraction solution with water for washing treatment to obtain an organic phase washing solution and washing water; Back-extraction process: contacting the organic phase washing solution with aqueous phase A for back-extraction treatment to obtain an organic phase back-extraction solution and an ammonium salt; the aqueous phase A is ammonia water.

2. The method according to claim 1, wherein In the extraction process, the volume ratio of the organic phase A to the nickel anode solution is 0.5 - 10:1; And / or, the nickel anode solution contains: 60 - 80 g / L of nickel element, 2 - 3 g / L of boron element, 0.8 - 1.2 mol / L of hydrogen ions; And / or, the mass fraction of the organic amine extractant in the organic phase A is 5 - 50%; And / or, the organic phase A further contains octanol and sulfonated kerosene, the octanol is n-octanol and / or isooctanol; the mass fraction of octanol in the organic phase A is 0 - 40%, and the mass fraction of sulfonated kerosene in the organic phase A is 10 - 90%; And / or, the extraction treatment method is centrifugal extraction and / or cross-flow extraction.

3. The method according to claim 1 or 2, characterized in that, In the washing process, the volume ratio of the organic phase extraction solution to the water is 0.5 - 10:1; And / or, the washing treatment method is centrifugal washing and / or cross-flow washing; And / or, controlling the conditions of the washing treatment such that the nickel ion concentration in the organic phase washing solution ≤ 1 mg / L.

4. The method according to claim 1 or 2, characterized in that In the back-extraction process, the volume ratio of the organic phase washing solution to the aqueous phase A is 0.5 - 5:1; And / or, the mass fraction of ammonia water in the aqueous phase A is 5 - 28%; And / or, the back-extraction treatment method is centrifugal back-extraction, and the separation factor of the centrifugal back-extraction is 550 - 650 g.

5. The method according to claim 1 or 2, characterized in that, The method further includes: Evaporation and concentration process: performing evaporation and concentration treatment on the acid extraction residue solution in the extraction process to obtain a nickel-containing concentrated solution; the concentration multiple of the evaporation and concentration treatment is 1.2 - 2.0 times; and / or Nickel precipitation process: sequentially performing nickel precipitation treatment and solid-liquid separation treatment on the washing water in the washing process to obtain nickel hydroxide and a filtrate; Optionally, an MVR system and / or a multi-effect evaporation system are used for the evaporation and concentration treatment; Optionally, the nickel hydroxide is mixed with the nickel-containing concentrated solution to meet the pH requirement of the electrolytic nickel cathode solution; Optionally, the filtrate is sequentially subjected to ultrafiltration treatment and reverse osmosis treatment to obtain pure water and concentrated water. In the evaporation and concentration process, the concentrated water is mixed with the acid extraction residue solution and then subjected to evaporation and concentration treatment.

6. The method according to claim 1, wherein In the extraction process, the organic amine extractant includes a tertiary amine extractant; And / or, the molecular structure of the organic amine extractant includes R3N, and the R group is at least one of octyl, nonyl, and decyl; And / or, the organic amine extractant includes one of Mextral 336A, N263, Liquat336, and TOMAC; And / or, the organic amine extractant includes Mextral 336A.

7. A nickel anode solution recovery system, characterized in that, The system includes an extraction unit, a washing unit, and a stripping unit connected in sequence; Among them, the extraction unit is used to extract the nickel anode solution to obtain an organic phase extraction solution and an acid extraction residue solution; The washing unit is used to wash the organic phase extraction solution to obtain an organic phase washing solution and washing water; The stripping unit is used to strip the organic phase washing solution to obtain an organic phase stripping solution and ammonium salts.

8. The system according to claim 7, wherein The extraction unit is further connected to an evaporation and concentration unit, and the evaporation and concentration unit is used to evaporate and concentrate the acid extraction residue solution to obtain a nickel-containing concentrated solution.

9. The system according to claim 7 or 8, characterized in that, The washing unit is further connected to a nickel precipitation unit and a solid-liquid separation unit in sequence to obtain nickel hydroxide and a filtrate.

10. The system according to claim 9, characterized in that, The system further includes an ultrafiltration and reverse osmosis unit, and the ultrafiltration and reverse osmosis unit is used to perform ultrafiltration treatment and reverse osmosis treatment on the filtrate in sequence to obtain pure water and concentrated water; Optionally, the reverse osmosis treatment unit is connected to the evaporation and concentration unit to return the concentrated water to the evaporation and concentration unit.

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