Nickel sulfate and sulfuric acid recovery equipment

Abstract

This invention provides a nickel sulfate and sulfuric acid recovery device. The first inlet of a pretreatment component is connected to the first outlet of a raw material storage tank; the first inlet of a first nanofiltration component is connected to the first outlet of the pretreatment component; the first inlet of a cooler is connected to the first outlet of the first nanofiltration component; the first inlet of a primary cooling crystallizer is connected to the first outlet of the cooler; the first inlet of a secondary cooling crystallizer is connected to the first outlet of the primary cooling crystallizer; the first inlet of a solid-liquid separator is connected to the first outlet of the secondary cooling crystallizer; the first inlet of a second nanofiltration component is connected to the first outlet of the solid-liquid separator; and the first inlet of a third nanofiltration component is connected to the first outlet of the second nanofiltration component, with its first outlet connected to the second inlet of the raw material storage tank. Compared with traditional evaporation and concentration devices, this invention produces nickel sulfate with lower operating costs, better crystal quality, and higher purity.

Description

Technical Field

[0001] This utility model relates to the field of nickel sulfate recovery technology, specifically to a nickel sulfate and sulfuric acid recovery device, particularly a nickel sulfate recovery device in the lithium-ion battery or battery recycling industry, especially a high-purity, energy-saving recovery device for nickel sulfate and sulfuric acid in a nickel sulfate-sulfuric acid system solution, which is particularly suitable for mixed solutions containing nickel sulfate and sulfuric acid obtained by extraction with an extractant followed by sulfuric acid back-extraction. Background Technology

[0002] Current nickel sulfate processing technologies mainly include evaporation crystallization and evaporation + freeze crystallization. Evaporation crystallization directly yields crystalline products; it is a mature process suitable for high-concentration nickel sulfate solutions. However, it also has significant drawbacks: high temperatures easily lead to nickel sulfate decomposition, equipment is prone to scaling, requiring regular acid cleaning or the addition of scale inhibitors, and it is sensitive to impurities (such as Na₂SO₄). + Ca 2+ (Affects crystal purity). Evaporation + freeze crystallization method: complex equipment and high investment cost, nickel sulfate solution (especially containing free acid or Cl). - It is highly corrosive to carbon steel and stainless steel, and key equipment requires titanium or Hastelloy, which further increases costs. Utility Model Content

[0003] In view of the deficiencies in the prior art, the purpose of this utility model is to provide a device for recovering nickel sulfate and sulfuric acid.

[0004] A nickel sulfate and sulfuric acid recovery device according to this utility model includes:

[0005] Raw material storage tanks;

[0006] A pretreatment component, the first inlet of which is connected to the first outlet of the raw material storage tank, is used to retain macromolecular substances;

[0007] The first nanofiltration component has its first inlet connected to the first outlet of the pretreatment component for separating nickel sulfate and sulfuric acid;

[0008] A cooler, the first inlet of which is connected to the first outlet of the first nanofiltration component;

[0009] A primary cooling crystallizer, the first inlet of which is connected to the first outlet of the cooler, is used for the cooling crystallization of nickel sulfate;

[0010] A secondary cooling crystallizer, the first inlet of which is connected to the first outlet of the primary cooling crystallizer, is used for the cooling crystallization of nickel sulfate;

[0011] A solid-liquid separator, the first inlet of which is connected to the first outlet of the secondary cooling crystallizer, is used to separate nickel sulfate crystals;

[0012] The second nanofiltration component has its first inlet connected to the first outlet of the solid-liquid separator for separating nickel sulfate and sulfuric acid.

[0013] The third nanofiltration unit has its first inlet connected to the first outlet of the second nanofiltration unit, and its first outlet connected to the second inlet of the raw material storage tank, for separating nickel sulfate and sulfuric acid.

[0014] Preferably, the recovery device further includes: a material heat exchanger;

[0015] The first inlet of the second nanofiltration component is connected to the first outlet of the solid-liquid separator through the material heat exchanger.

[0016] The first inlet of the material heat exchanger is connected to the first outlet of the solid-liquid separator, and the first outlet of the material heat exchanger is connected to the first inlet of the second nanofiltration component.

[0017] The second inlet of the material heat exchanger is connected to the first outlet of the first nanofiltration component, and the second outlet of the material heat exchanger is connected to the first inlet of the cooler;

[0018] The material heat exchanger is used to achieve heat exchange between the separated mother liquor output from the solid-liquid separator and the nanofiltration mother liquor output from the first nanofiltration component.

[0019] Preferably, the recovery device further includes: a reverse osmosis module;

[0020] The first inlet of the reverse osmosis component is connected to the second outlet of the third nanofiltration component, and the first outlet of the reverse osmosis component is connected to the second inlet of the third nanofiltration component.

[0021] The reverse osmosis component is used to reverse osmosis the dilute sulfuric acid solution output from the third nanofiltration component.

[0022] Preferably, the first outlet of the raw material storage tank is connected to the first inlet of the pretreatment component via a transfer pump.

[0023] Preferably, the second outlet of the pretreatment component is connected to the second inlet of the raw material storage tank, and the second outlet of the pretreatment component is used to output the retained solution;

[0024] The second outlet of the second nanofiltration module is connected to the second inlet of the raw material storage tank, and the second outlet of the second nanofiltration module is used to retain the solution.

[0025] Preferably, the second outlet of the first nanofiltration component is connected to the first inlet of the third nanofiltration component, and the second outlet of the first nanofiltration component is used to output the retained solution.

[0026] Preferably, the primary cooling crystallizer is provided with a first stirrer, which is used to stir the liquid in the primary cooling crystallizer.

[0027] Preferably, the secondary cooling crystallizer is provided with a second stirrer, which is used to stir the liquid in the secondary cooling crystallizer.

[0028] Preferably, the recycling device also includes a packaging machine;

[0029] The packaging machine is connected to the second outlet of the solid-liquid separator and is used to package the nickel sulfate crystals output by the solid-liquid separator.

[0030] Preferably, the recycling device further includes: a control unit;

[0031] The first nanofiltration component, the first-stage cooling crystallizer, the second-stage cooling crystallizer, the second nanofiltration component, and the third nanofiltration component are all electrically connected to the control unit.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The device of this utility model utilizes the combination of cooling crystallization and membrane separation to achieve high-purity and energy-saving recovery of nickel sulfate and sulfuric acid in the nickel sulfate-sulfuric acid system solution. Compared with the traditional evaporation and concentration device, the nickel sulfate produced by this utility model has low operating cost, good crystal quality, and higher purity.

[0034] 2. The device of this utility model can recover sulfuric acid and return it to the upstream device for reuse, reducing the amount of acidic wastewater discharge and treatment costs. It is energy-saving and environmentally friendly without phase change and without the emission of acidic waste gas generated by evaporation. Attached Figure Description

[0035] Other features, objects, and advantages of this invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0036] Figure 1 This is a schematic diagram of a nickel sulfate and sulfuric acid recovery device.

[0037] The diagram shows:

[0038] Raw material storage tank 1, second agitator 9

[0039] 2 transfer pumps, 10 solid-liquid separators

[0040] Pre-processing component 3 Packaging machine 11

[0041] First nanofiltration module 4, material heat exchanger 12

[0042] Cooler 5 Second nanofiltration module 13

[0043] Primary cooling crystallizer 6; Third nanofiltration module 14

[0044] First stirrer 7 Reverse osmosis module 15

[0045] Secondary cooling crystallizer 8 Control unit 16 Detailed Implementation

[0046] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0047] Example 1

[0048] like Figure 1 As shown, this embodiment provides a nickel sulfate and sulfuric acid recovery device, including: a raw material storage tank 1, a pretreatment component 3, a first nanofiltration component 4, a cooler 5, a primary cooling crystallizer 6, a secondary cooling crystallizer 8, a solid-liquid separator 10, a second nanofiltration component 13, and a third nanofiltration component 14.

[0049] The first inlet of the pretreatment component 3 is connected to the first outlet of the raw material storage tank 1, and the pretreatment component 3 is used to retain macromolecular substances; the first inlet of the first nanofiltration component 4 is connected to the first outlet of the pretreatment component 3, and the first nanofiltration component 4 is used to separate nickel sulfate and sulfuric acid; the first inlet of the cooler 5 is connected to the first outlet of the first nanofiltration component 4; the first inlet of the primary cooling crystallizer 6 is connected to the first outlet of the cooler 5, and the primary cooling crystallizer 6 is used for cooling and crystallizing nickel sulfate; the first inlet of the secondary cooling crystallizer 8 is connected to the first outlet of the primary cooling crystallizer 6, and the secondary cooling crystallizer 8 is used for cooling and crystallizing nickel sulfate; the first inlet of the solid-liquid separator 10 is connected to the first outlet of the secondary cooling crystallizer 8, and the solid-liquid separator 10 is used to separate nickel sulfate crystals; the first inlet of the second nanofiltration component 13 is connected to the first outlet of the solid-liquid separator 10, and the second nanofiltration component 13 is used to separate nickel sulfate and sulfuric acid; the first inlet of the third nanofiltration component 14 is connected to the first outlet of the second nanofiltration component 13, and its first outlet is connected to the second inlet of the raw material storage tank 1, and the third nanofiltration component 14 is used to separate nickel sulfate and sulfuric acid.

[0050] The first outlet of the raw material storage tank 1 is connected to the first inlet of the pretreatment component 3 via a transfer pump 2. The second outlet of the pretreatment component 3 is connected to the second inlet of the raw material storage tank 1, and the second outlet of the pretreatment component 3 is used to output the retained solution. The second outlet of the second nanofiltration component 13 is connected to the second inlet of the raw material storage tank 1, and the second outlet of the second nanofiltration component 13 is used to output the retained solution. The second outlet of the first nanofiltration component 4 is connected to the first inlet of the third nanofiltration component 14, and the second outlet of the first nanofiltration component 4 is used to output the retained solution.

[0051] The recovery device also includes: a material heat exchanger 12; the first inlet of the second nanofiltration component 13 is connected to the first outlet of the solid-liquid separator 10 through the material heat exchanger 12; the first inlet of the material heat exchanger 12 is connected to the first outlet of the solid-liquid separator 10, and the first outlet of the material heat exchanger 12 is connected to the first inlet of the second nanofiltration component 13; the second inlet of the material heat exchanger 12 is connected to the first outlet of the first nanofiltration component 4, and the second outlet of the material heat exchanger 12 is connected to the first inlet of the cooler 5; the material heat exchanger 12 is used to realize heat exchange between the separated mother liquor output from the solid-liquid separator 10 and the nanofiltration mother liquor output from the first nanofiltration component 4.

[0052] The recovery device also includes: a reverse osmosis component 15; the first inlet of the reverse osmosis component 15 is connected to the second outlet of the third nanofiltration component 14, and the first outlet of the reverse osmosis component 15 is connected to the second inlet of the third nanofiltration component 14; the reverse osmosis component 15 is used to reverse osmosis the dilute sulfuric acid solution output from the third nanofiltration component 14.

[0053] A first agitator 7 is provided on the primary cooling crystallizer 6, which is used to agitate the liquid inside the primary cooling crystallizer 6. A second agitator 9 is provided on the secondary cooling crystallizer 8, which is used to agitate the liquid inside the secondary cooling crystallizer 8.

[0054] The recovery device also includes a packaging machine 11; the packaging machine 11 is connected to the second outlet of the solid-liquid separator 10 and is used to package the nickel sulfate crystals output by the solid-liquid separator 10. The recovery device also includes a control unit 16; the first nanofiltration assembly 4, the primary cooling crystallizer 6, the secondary cooling crystallizer 8, the second nanofiltration assembly 13, and the third nanofiltration assembly 14 are all electrically connected to the control unit 16.

[0055] Example 2

[0056] Those skilled in the art can understand this embodiment as a more specific description of Embodiment 1.

[0057] This embodiment provides a high-purity, energy-saving recovery device for nickel sulfate and sulfuric acid in a nickel sulfate-sulfuric acid system solution, comprising:

[0058] Raw material storage tank 1 stores raw materials and materials returned from downstream sources, with a nickel sulfate concentration.

[0059] Pump 2 delivers the materials to the downstream process.

[0060] Pretreatment component 3 is the ultrafiltration section. The ultrafiltration component uses the principle of physical sieving to retain large molecules such as bacteria, colloids, and proteins, while allowing solutes such as nickel sulfate and sulfuric acid to pass through, thus protecting the downstream membrane separation system.

[0061] The first nanofiltration component 4, under acidic conditions (pH 1-4), separates nickel sulfate and sulfuric acid through pore size sieving and charge effect (Donnan effect), achieving a nickel sulfate concentration of 25%-35%.

[0062] Cooler 5 cools the material temperature, with the outlet temperature controlled between 30℃ and 35℃.

[0063] The first-stage cooling crystallizer 6 has an outer jacket structure, with cooling water flowing through the jacket to control the crystallizer temperature from -5℃ to 10℃. It adopts a two-stage cooling system to avoid excessive supersaturation leading to too many crystal nuclei or excessively fine crystals. A stirrer is installed at the top.

[0064] The first stirrer 7 adjusts its rotation speed according to the crystallization stage, such as high speed for mixing in the initial stage and low speed for protecting the crystals in the growth stage.

[0065] The secondary cooling crystallizer 8 has an outer jacket structure, with cooling water flowing through the jacket to control the crystallizer temperature from -15℃ to 5℃. It adopts a two-stage cooling system to avoid excessive supersaturation leading to too many crystal nuclei or excessively fine crystals. A stirrer is installed at the top.

[0066] The second stirrer 9 adjusts its speed according to the crystallization stage, such as high speed for mixing in the initial stage and low speed for protecting the crystals in the growth stage.

[0067] Solid-liquid separator 10 can be configured as follows: piston pusher centrifuge: continuous operation, high separation factor (1000-1500), low mother liquor moisture content (<3%), suitable for large particle crystals such as nickel sulfate; screw discharge centrifuge: suitable for medium and low solid content (5%~30%) and fine particles (50μm~200μm).

[0068] Packaging machine 11 is used for packaging nickel sulfate.

[0069] Material heat exchanger 12 uses the cooling capacity of the mother liquor to cool the feed to the crystallizer. The mother liquor is heated, which is beneficial for the separation in the downstream process and aims to save energy.

[0070] The second nanofiltration unit 13 separates nickel sulfate from sulfuric acid in the centrifuged mother liquor, where the concentration is 5%–25%, thereby concentrating the nickel sulfate to 30%–35%.

[0071] The third nanofiltration module 14, under the dilution of downstream reverse osmosis water absorption, dilutes the feed liquid, reduces the concentration of nickel sulfate and sulfuric acid in the feed, and further reduces the sulfuric acid content in the concentrate.

[0072] The upstream product water component of the reverse osmosis module 15 is mainly a dilute sulfuric acid solution. After passing through the reverse osmosis module, the concentration meets the requirements of the upstream application.

[0073] The control unit 16 enables intelligent diagnosis and control. In this embodiment, the operating units include a membrane separation unit and a freeze crystallization unit. The membrane separation unit includes a first nanofiltration module 4, a second nanofiltration module 13, and a third nanofiltration module 14, etc. The freeze crystallization unit includes a primary cooling crystallizer 6 and a secondary cooling crystallizer 8, etc. The intelligent diagnosis and control includes functions of information collection, processing, diagnosis, and command and control. The information collected by the control unit 16 includes the operating parameters of the membrane separation unit and the freeze crystallization unit. The operating parameters of the membrane separation unit include concentration, differential pressure, conductivity, and pH. The operating parameters of the freeze crystallization unit include temperature, solid content, pH, and cooling curve, etc. The control signal output of the control unit 16 includes control signals for the membrane separation unit and the freeze crystallization unit. The control signals for the membrane separation unit include reflux ratio, motor frequency, flow rate adjustment, and online cleaning, etc. The control signals for the freeze crystallization unit include cooling water flow rate and agitator stirring rate, etc.

[0074] This embodiment utilizes a combination of cooling crystallization and membrane separation to achieve high-purity and energy-saving recovery of nickel sulfate and sulfuric acid in a nickel sulfate-sulfuric acid system solution. Compared with traditional evaporation and concentration devices, this embodiment produces nickel sulfate with low operating costs, good crystal quality, and higher purity. Furthermore, sulfuric acid can be recovered and returned to upstream devices for reuse, reducing acidic wastewater discharge and treatment costs. It is also energy-saving and environmentally friendly, with no phase change and no acidic waste gas emissions from evaporation.

[0075] This embodiment can achieve: 1) Nanofiltration (NF) can retain Ni 2+ (>99% recovery rate) Acid-nickel separation is achieved through H2SO4; 2) No phase change or reagent addition is required, reducing secondary pollution; 3) No evaporation unit is required, and energy consumption is only 1 / 3 of that of the evaporation method; 4) No acidic waste gas emissions are generated by evaporation; 5) Good crystal quality and higher purity.

[0076] Compared with traditional evaporation and concentration devices, this invention produces nickel sulfate with lower operating costs, better crystal quality, and higher purity.

[0077] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0078] The specific embodiments of this utility model have been described above. It should be understood that this utility model is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the substantive content of this utility model. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A device for recovering nickel sulfate and sulfuric acid, characterized in that, include: Raw material storage tank (1); The pretreatment component (3) has its first inlet connected to the first outlet of the raw material storage tank (1) for retaining macromolecular substances; The first nanofiltration component (4) has its first inlet connected to the first outlet of the pretreatment component (3) for separating nickel sulfate and sulfuric acid; The cooler (5) has its first inlet connected to the first outlet of the first nanofiltration component (4); A primary cooling crystallizer (6) has its first inlet connected to the first outlet of the cooler (5) for cooling and crystallizing nickel sulfate; The secondary cooling crystallizer (8) has its first inlet connected to the first outlet of the primary cooling crystallizer (6) and is used for the cooling crystallization of nickel sulfate; A solid-liquid separator (10) has its first inlet connected to the first outlet of the secondary cooling crystallizer (8) for separating nickel sulfate crystals; The second nanofiltration unit (13) has its first inlet connected to the first outlet of the solid-liquid separator (10) for separating nickel sulfate and sulfuric acid; The third nanofiltration unit (14) has its first inlet connected to the first outlet of the second nanofiltration unit (13) and its first outlet connected to the second inlet of the raw material storage tank (1), and is used to separate nickel sulfate and sulfuric acid.

2. The nickel sulfate and sulfuric acid recovery device according to claim 1, characterized in that, The recovery device also includes: a material heat exchanger (12); The first inlet of the second nanofiltration assembly (13) is connected to the first outlet of the solid-liquid separator (10) through the material heat exchanger (12); The first inlet of the material heat exchanger (12) is connected to the first outlet of the solid-liquid separator (10), and the first outlet of the material heat exchanger (12) is connected to the first inlet of the second nanofiltration assembly (13). The second inlet of the material heat exchanger (12) is connected to the first outlet of the first nanofiltration assembly (4), and the second outlet of the material heat exchanger (12) is connected to the first inlet of the cooler (5); The material heat exchanger (12) is used to achieve heat exchange between the separated mother liquor output by the solid-liquid separator (10) and the nanofiltration mother liquor output by the first nanofiltration component (4).

3. The nickel sulfate and sulfuric acid recovery device according to claim 1, characterized in that, The recovery unit also includes: a reverse osmosis module (15); The first inlet of the reverse osmosis component (15) is connected to the second outlet of the third nanofiltration component (14), and the first outlet of the reverse osmosis component (15) is connected to the second inlet of the third nanofiltration component (14). The reverse osmosis component (15) is used to reverse osmosis the dilute sulfuric acid solution output from the third nanofiltration component (14).

4. The nickel sulfate and sulfuric acid recovery device according to claim 1, characterized in that, The first outlet of the raw material storage tank (1) is connected to the first inlet of the pretreatment component (3) via a transfer pump (2).

5. The nickel sulfate and sulfuric acid recovery device according to claim 1, characterized in that, The second outlet of the pretreatment component (3) is connected to the second inlet of the raw material storage tank (1), and the second outlet of the pretreatment component (3) is used to output the retained solution; The second outlet of the second nanofiltration component (13) is connected to the second inlet of the raw material storage tank (1), and the second outlet of the second nanofiltration component (13) is used to retain the solution.

6. The nickel sulfate and sulfuric acid recovery device according to claim 1, characterized in that, The second outlet of the first nanofiltration component (4) is connected to the first inlet of the third nanofiltration component (14), and the second outlet of the first nanofiltration component (4) is used to output the retained solution.

7. The nickel sulfate and sulfuric acid recovery device according to claim 1, characterized in that, The first-stage cooling crystallizer (6) is equipped with a first stirrer (7), which is used to stir the liquid inside the first-stage cooling crystallizer (6).

8. The nickel sulfate and sulfuric acid recovery device according to claim 1, characterized in that, The secondary cooling crystallizer (8) is equipped with a second stirrer (9), which is used to stir the liquid in the secondary cooling crystallizer (8).

9. The nickel sulfate and sulfuric acid recovery device according to claim 1, characterized in that, The recycling device also includes a packaging machine (11); The packaging machine (11) is connected to the second outlet of the solid-liquid separator (10) for packaging the nickel sulfate crystals output by the solid-liquid separator (10).

10. The nickel sulfate and sulfuric acid recovery apparatus according to claim 1, characterized in that, The recycling device also includes: a control unit (16); The first nanofiltration component (4), the first-stage cooling crystallizer (6), the second-stage cooling crystallizer (8), the second nanofiltration component (13), and the third nanofiltration component (14) are all electrically connected to the control unit (16).

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