Cobalt carbonate production wastewater treatment system and cobalt carbonate production system

Abstract

The utility model discloses a cobalt carbonate production wastewater treatment system and a cobalt carbonate production system, and solves the technical problems of high energy consumption and high ammonium chloride salt impurity content in the prior art. The treatment system comprises a mother liquor pretreatment unit used for pretreating mother liquor to reduce the SS content and pH of the mother liquor and outputting clear mother liquor; the washing water pretreatment unit is used for pretreating washing water to reduce the SS content and pH of the washing water and outputting the washing water; the first concentration unit is used for performing concentration treatment on the first mixed solution containing the cleaning water and the condensate water and outputting first concentrated water with high TDS content and first produced water with low TDS content; the evaporative crystallization unit is used for performing evaporative crystallization treatment on a second mixed solution containing the first concentrated water and the clear mother solution and outputting condensed water and ammonium chloride salt; the second concentration unit is used for performing concentration treatment on the first produced water and outputting second concentrated water with high TDS content and second produced water with low TDS content; the second produced water flows back to a washing unit in cobalt carbonate production.

Description

Technical Field

[0001] The utility model relates to the technical field of cobalt carbonate production, and in particular to a treatment system for wastewater in cobalt carbonate production and a cobalt carbonate production system. Background Art

[0002] Cobalt carbonate (CoCO3) is a compound mainly used in industry and laboratories, and has a wide range of uses. For example, it is a precursor of one of the cathode materials of lithium-ion batteries (such as lithium cobalt oxide, LiCoO2), and is used as a catalyst in organic compounds such as the Fischer-Tropsch process and the hydrogenation reaction of hydrocarbons, and is one of the raw materials for manufacturing magnetic materials (such as cobalt ferrite, CoFe2O4), and so on.

[0003] One production process of cobalt carbonate is: precipitation reaction → solid-liquid separation → washing → drying. Cobalt chloride (CoCl2), hydrochloric acid and ammonium bicarbonate (NH4HCO3) are mixed in a reaction kettle and subjected to a precipitation reaction to generate cobalt carbonate solid, ammonium chloride (NH4Cl), carbon dioxide and water. The chemical reaction formula is: CoCl2 + HCl + NH4HCO3 → CoCO3(s) + NH4Cl + CO2 + H2O. After the reaction is completed, the solid-liquid mixture containing cobalt carbonate solid, ammonium chloride and water is sent to a filter for solid-liquid separation. The cobalt carbonate solid is separated out to obtain mother liquor and cobalt carbonate solid attached with impurities. The cobalt carbonate solid is washed with pure water to remove impurities, and the generated washing water is called wash water. The washed cobalt carbonate solid is dried to obtain the final cobalt carbonate product.

[0004] In the above process, mother liquor and wash water will be generated. The existing treatment method is to mix the two and then perform evaporation crystallization treatment to recover ammonium chloride salt. However, the energy consumption of direct evaporation crystallization is high, and the impurities of the obtained ammonium chloride salt are high. Summary of the Utility Model

[0005] The main purpose of the utility model is to provide a treatment method for wastewater in cobalt carbonate production, a production method for cobalt carbonate, a treatment system for wastewater in cobalt carbonate production and a cobalt carbonate production system, so as to solve the technical problems of high energy consumption and high impurities of ammonium chloride salt in the prior art.

[0006] In order to achieve the above purpose, according to the first aspect of the utility model, a treatment method for wastewater in cobalt carbonate production and a production method for cobalt carbonate are provided, and the technical solutions are as follows:

[0007] A treatment method for wastewater in cobalt carbonate production, the production of cobalt carbonate includes a precipitation reaction process, a solid-liquid separation process and a washing process. The production wastewater includes mother liquor and wash water. The mother liquor comes from the solid-liquid separation process, and the wash water comes from the washing process. The treatment method includes the steps:

[0008] Step10, pre-treat the mother liquor to reduce the SS content and pH of the mother liquor, obtaining a clarified mother liquor;

[0009] Step20, pre-treat the washing water to reduce the SS content and pH of the washing water, obtaining cleaning water;

[0010] Step30, concentrate the first mixed liquor containing cleaning water and condensate to obtain first concentrated water with a high TDS content and first product water with a low TDS content;

[0011] Step40, perform evaporation crystallization on the second mixed liquor containing the first concentrated water and the clarified mother liquor to obtain condensate and ammonium chloride salt;

[0012] Step50, concentrate the first product water to obtain second concentrated water with a high TDS content and second product water with a low TDS content; the second product water is recycled to the washing process in cobalt carbonate production; the second concentrated water is recycled for treatment.

[0013] As a further improvement of the above treatment method for cobalt carbonate production wastewater: Step10 specifically includes:

[0014] Step11, filter the mother liquor to obtain a first filtrate with an SS content ≤ 0.2 mg / L;

[0015] Step12, adjust the pH of the first filtrate to obtain a clarified mother liquor with a pH of 7 - 8.

[0016] As a further improvement of the above treatment method for cobalt carbonate production wastewater: Step20 specifically includes:

[0017] Step21, filter the washing water and the recycled concentrated washing water to obtain a second filtrate with an SS content ≤ 0.2 mg / L;

[0018] Step22, adjust the pH of the second filtrate to obtain a third filtrate with a pH of 6 - 7;

[0019] Step23, perform ultrafiltration on the third filtrate to obtain cleaning water and concentrated washing water; the concentrated washing water is recycled to Step21 for filtration treatment.

[0020] As a further improvement of the above treatment method for cobalt carbonate production wastewater: Step30 specifically includes:

[0021] Step31, perform reverse osmosis concentration on the first mixed liquor to obtain first intermediate concentrated water and first intermediate product water; the TDS content of the first intermediate concentrated water is 3 - 6 times that of the first mixed liquor;

[0022] Step 32, subject the first intermediate concentrated water to reverse osmosis concentration treatment to obtain first concentrated water and second intermediate product water; the TDS content of the first concentrated water is 2 to 5 times that of the first intermediate concentrated water; the first intermediate product water and the second intermediate product water constitute the first product water.

[0023] As a further improvement to the above method for treating cobalt carbonate production wastewater: Step 40 specifically includes:

[0024] Step 41, subject the second mixed liquid to evaporation crystallization treatment to obtain crystal water and crystal salt;

[0025] Step 42, subject the crystal salt to drying treatment to obtain ammonium chloride salt;

[0026] Step 43, subject the crystal water to heat exchange treatment to obtain condensed water.

[0027] As a further improvement to the above method for treating cobalt carbonate production wastewater: Step 50 specifically includes:

[0028] Step 51, subject the intermediate liquid composed of the first product water and the refluxed second concentrated water to reverse osmosis concentration treatment to obtain second intermediate concentrated water and third intermediate product water; the second intermediate concentrated water is refluxed to Step 30 for concentration treatment; the TDS content of the second intermediate concentrated water is 4 to 7 times that of the intermediate liquid;

[0029] Step 52, subject the third intermediate product water to reverse osmosis concentration treatment to obtain second concentrated water and second product water; the second concentrated water is refluxed to Step 510 for concentration treatment; the TDS content of the second concentrated water is 4 to 7 times that of the third intermediate product water; the TDS content of the second product water ≤ 10 mg / L.

[0030] As a further improvement to the above method for treating cobalt carbonate production wastewater: the cobalt carbonate is obtained by reacting cobalt chloride, hydrochloric acid and ammonium bicarbonate, and hydrochloric acid with a mass fraction of 31% is used to adjust the pH in Step 10 and Step 20.

[0031] As a further improvement to the above method for treating cobalt carbonate production wastewater: the TDS content of the mother liquor is 75000 - 95000 mg / L, the SS content is 25 - 35 mg / L, and the pH is 8.5 - 9.5; the TDS content of the washing water is 500 - 1500 mg / L, the SS content is 5 - 15 mg / L, and the pH is 7 - 8.

[0032] As a further improvement to the above method for treating cobalt carbonate production wastewater: the TDS content of the first mixed solution is 1000 - 1300 mg / L, and the pH is 5.5 - 6.5; the TDS content of the second mixed solution is 70000 - 85000 mg / L, and the pH is 7.5 - 8.5.

[0033] The cobalt carbonate production method includes a precipitation reaction process, a solid-liquid separation process, and a washing process, and also includes treating the mother liquor from the solid-liquid separation process and the washing water from the washing process by the above method for treating cobalt carbonate production wastewater.

[0034] To achieve the above object, according to the second aspect of the present invention, a treatment system for cobalt carbonate production wastewater and a cobalt carbonate production system are provided, and the technical solutions are as follows:

[0035] The treatment system for cobalt carbonate production wastewater, the cobalt carbonate production includes a precipitation reaction unit, a solid-liquid separation unit, and a washing unit. The production wastewater includes mother liquor and washing water. The mother liquor comes from the solid-liquid separation unit, and the washing water comes from the washing unit. The treatment system includes:

[0036] The mother liquor pretreatment unit is used to pretreat the mother liquor to reduce the SS content and pH of the mother liquor and output clarified mother liquor;

[0037] The washing water pretreatment unit is used to pretreat the washing water to reduce the SS content and pH of the washing water and output cleaning water;

[0038] The first concentration unit is used to concentrate the first mixed solution containing cleaning water and condensate water and output the first concentrated water with a high TDS content and the first produced water with a low TDS content;

[0039] The evaporation crystallization unit is used to perform evaporation crystallization treatment on the second mixed solution containing the first concentrated water and the clarified mother liquor and output condensate water and ammonium chloride salt;

[0040] The second concentration unit is used to concentrate the first produced water and output the second concentrated water with a high TDS content and the second produced water with a low TDS content; the second produced water is recycled to the washing unit in the cobalt carbonate production.

[0041] As a further improvement to the above treatment system for cobalt carbonate production wastewater: the mother liquor pretreatment unit includes:

[0042] The mother liquor raw water tank is used to store the mother liquor from the solid-liquid separation unit;

[0043] The first filtering device is used to filter the mother liquor output from the mother liquor raw water tank and output the first filtrate with an SS content ≤ 0.2 mg / L and the first filter residue; the first filtrate is stored in the first filtrate storage tank; the first filter residue is stored in the first filter residue storage tank;

[0044] The first pH adjustment tank is used to adjust the pH of the first filtrate output from the first filtrate storage tank and input clarified mother liquor with a pH of 7-8 into the second mixed liquor storage tank;

[0045] The first feeding device is used to add an acidic reagent into the first pH adjustment tank.

[0046] As a further improvement of the above-mentioned treatment system for cobalt carbonate production wastewater: The mother liquor pretreatment unit further includes a first pressure filtration device for pressure-filtering the first filter residue in the first filter residue storage tank.

[0047] As a further improvement of the above-mentioned treatment system for cobalt carbonate production wastewater: The wash water pretreatment unit includes:

[0048] The wash water raw water tank is used to store the wash water from the washing unit and the recycled concentrated wash water;

[0049] The second filtration device is used to filter the wash water output from the wash water raw water tank and output a second filtrate with an SS content ≤ 0.2 mg / L and a second filter residue; the second filtrate is stored in the second filtrate storage tank; the second filter residue is stored in the second filter residue storage tank;

[0050] The second pH adjustment tank is used to adjust the pH of the second filtrate output from the second filtrate storage tank and output a third filtrate with a pH of 6-7;

[0051] The second feeding device is used to add an acidic reagent into the second pH adjustment tank;

[0052] The ultrafiltration device is used to ultrafilter the third filtrate output from the second pH adjustment tank and output cleaning water and concentrated wash water; the cleaning water is stored in the first mixed liquor storage tank; the concentrated wash water is stored in the wash water raw water tank.

[0053] As a further improvement of the above-mentioned treatment system for cobalt carbonate production wastewater: The wash water pretreatment unit further includes a second pressure filtration device for pressure-filtering the second filter residue in the second filter residue storage tank.

[0054] As a further improvement of the above-mentioned treatment system for cobalt carbonate production wastewater: The first concentration unit includes:

[0055] The first reverse osmosis device is used to concentrate the first mixed liquor output from the first mixed liquor storage tank and output first intermediate concentrated water and first intermediate product water;

[0056] The second reverse osmosis device is used to concentrate the first intermediate concentrated water and output first concentrated water and second intermediate product water; the first concentrated water is stored in the second mixed liquor storage tank; the first intermediate product water and the second intermediate product water form first product water and are stored in the intermediate tank.

[0057] As a further improvement of the above-mentioned treatment system for cobalt carbonate production wastewater: The evaporation and crystallization unit includes:

[0058] An evaporation and crystallization device for performing evaporation and crystallization treatment on the second mixed liquid output from the second mixed liquid storage tank and outputting crystal water and crystal salts;

[0059] A drying device for drying the crystal salts and outputting ammonium chloride salts;

[0060] A heat exchange device for performing heat exchange treatment on the crystal water and outputting condensed water, and the condensed water is stored in the first mixed liquid storage tank.

[0061] As a further improvement of the above-mentioned treatment system for cobalt carbonate production wastewater: The second concentration unit includes:

[0062] A third reverse osmosis device for performing reverse osmosis concentration treatment on the intermediate liquid composed of the first produced water and the refluxed second concentrated water and outputting the second intermediate concentrated water and the third intermediate produced water; the second intermediate concentrated water is stored in the first mixed liquid storage tank;

[0063] A fourth reverse osmosis device for performing reverse osmosis concentration treatment on the third intermediate produced water and outputting the second concentrated water and the second produced water; the second concentrated water is refluxed to the intermediate tank to be mixed with the first produced water to form an intermediate liquid.

[0064] A cobalt carbonate production system includes a precipitation reaction unit, a solid-liquid separation unit, and a washing unit, and also includes the above-mentioned treatment system for cobalt carbonate production wastewater, and the treatment system is used to treat the mother liquor from the solid-liquid separation unit and the washing water from the washing unit.

[0065] It can be seen that the present invention has the following advantages:

[0066] (1) The present invention fully considers the differences in water volume and composition between the mother liquor and the washing water. First, different pre-treatment means are used to treat the mother liquor and the washing water separately, and then the two mixed liquids (the first mixed liquid and the second mixed liquid) suitable for concentration treatment and evaporation and crystallization treatment are obtained by combining them. This can reduce the mutual interference between the mother liquor and the washing water caused by production fluctuations, enable each treatment unit to operate in the best state, make the treatment process more controllable and stable, reduce the impact of production fluctuations on the system, and improve the stability, operability and treatment efficiency of the overall process. Each stage treatment unit of the present invention has a clear division of labor, and the modular design and segmented treatment can be flexibly adjusted according to production needs, are applicable to different production scales and conditions, and enhance the adaptability and flexibility of the system.

[0067] (2) The utility model first pre-treats the mother liquor and washing water, effectively removing larger particles and suspended solid impurities. On the one hand, it reduces the blockage risk of the two-stage concentration unit (the first concentration unit and the second concentration unit) and the evaporation crystallization unit, thus reducing the maintenance requirements of the system. On the other hand, it makes the content of ammonium chloride salt impurities generated during the evaporation crystallization process lower, improving the purity of the final by-product. Secondly, through the further separation and purification using the two-stage concentration unit, not only is the volume of the liquid that needs to be treated by evaporation crystallization effectively reduced, the energy consumption during the evaporation process is reduced, but also the liquid entering the evaporation crystallization unit is more pure, and the purity of the finally crystallized ammonium chloride salt is higher, significantly enhancing the commercial value of the by-product and helping to increase additional income.

[0068] (3) The second produced water treated by the second concentration unit of the utility model can be directly recycled to the washing unit, reducing the dependence of the cobalt carbonate production system on fresh water resources. Recycling the condensed water not only saves water resources, but also reduces wastewater discharge and the negative impact on the environment.

[0069] The following further describes the utility model in conjunction with the drawings and specific embodiments. The additional aspects and advantages of the utility model will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the utility model. Description of the Drawings

[0070] The drawings constituting a part of the utility model are used to assist in understanding the utility model. The content provided in the drawings and the related descriptions in the utility model can be used to explain the utility model, but do not constitute an improper limitation to the utility model.

[0071] In the drawings:

[0072] Figure 1 is a schematic structural diagram of an embodiment of the cobalt carbonate production system of the utility model.

[0073] Figure 2 is a schematic structural diagram of an embodiment of the treatment system for cobalt carbonate production wastewater of the utility model.

[0074] The relevant markings in the above-mentioned drawings are:

[0075] 110 - precipitation reaction unit, 120 - solid - liquid separation unit, 130 - washing unit, 140 - drying unit, 210 - mother liquor raw water tank, 220 - first filtration equipment, 230 - first pH adjustment tank, 240 - first feeding equipment, 250 - first pressure filtration equipment, 310 - washing water raw water tank, 320 - second filtration equipment, 330 - second pH adjustment tank, 340 - second feeding equipment, 350 - second pressure filtration equipment, 360 - ultrafiltration equipment, 410 - first reverse osmosis equipment, 420 - second reverse osmosis equipment, 510 - evaporation crystallization equipment, 520 - drying equipment, 530 - heat exchange equipment, 610 - third reverse osmosis equipment, 620 - fourth reverse osmosis equipment, 710 - first mixed liquid storage tank, 720 - second mixed liquid storage tank, 730 - intermediate tank. Detailed implementation manners

[0076] The present utility model will be described clearly and completely below with reference to the accompanying drawings. Those of ordinary skill in the art will be able to implement the present utility model based on these descriptions. Before describing the present utility model with reference to the accompanying drawings, it should be particularly noted that:

[0077] The technical solutions and technical features provided in each part including the following description in the present utility model can be combined with each other without conflict.

[0078] In addition, the embodiments of the present utility model involved in the following description are usually only a part of the embodiments of the present utility model, rather than all the embodiments. Therefore, all other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts should fall within the protection scope of the present utility model.

[0079] Regarding the terms and units in the present utility model. The terms "comprising", "having" and any variations thereof in the specification, claims and relevant parts of the present utility model are intended to cover non - exclusive inclusion.

[0080] Figure 1 It is a schematic structural diagram of an embodiment of the cobalt carbonate production system of the present utility model.

[0081] As Figure 1As shown, the cobalt carbonate production system includes a precipitation reaction unit 110, a solid-liquid separation unit 120, a washing unit 130, a drying unit 140, and a treatment system for cobalt carbonate production wastewater. The precipitation reaction unit 110 includes a reaction kettle, where cobalt chloride, hydrochloric acid, and ammonium bicarbonate are mixed in the reaction kettle and undergo a precipitation reaction to generate solid cobalt carbonate, ammonium chloride, carbon dioxide, and water. After the reaction is completed, the solid-liquid mixture composed of solid cobalt carbonate, ammonium chloride, and water is sent to the solid-liquid separation unit 120. The solid-liquid separation unit 120 includes a filter, and the solid cobalt carbonate is separated by the filter to obtain mother liquor and solid cobalt carbonate attached with impurities. The solid cobalt carbonate attached with impurities is sent to the washing unit 130. The washing unit 130 uses pure water and / or second produced water (produced by Figure 2 the cobalt carbonate production wastewater treatment system shown) to wash the solid cobalt carbonate to remove impurities, obtaining washing water and clean solid cobalt carbonate. The drying unit 140 dries the clean solid cobalt carbonate to obtain the cobalt carbonate product. The cobalt carbonate production wastewater treatment system is used to treat the mother liquor from the solid-liquid separation unit 120 and the washing water from the washing unit 130.

[0082] Figure 2 It is a schematic structural diagram of an embodiment of the cobalt carbonate production wastewater treatment system of the present utility model.

[0083] As Figure 2 shown, the cobalt carbonate production wastewater treatment system includes a mother liquor pretreatment unit, a washing water pretreatment unit, a first concentration unit, an evaporation crystallization unit, and a second concentration unit. The mother liquor pretreatment unit is used to pretreat the mother liquor to reduce the SS content and pH of the mother liquor and output clarified mother liquor. The washing water pretreatment unit is used to pretreat the washing water to reduce the SS content and pH of the washing water and output cleaning water. The first concentration unit is used to concentrate the first mixed liquid containing cleaning water, condensate water, and second intermediate concentrated water and output first concentrated water with a high TDS content and first produced water with a low TDS content. The evaporation crystallization unit is used to perform evaporation crystallization treatment on the second mixed liquid containing the first concentrated water and the clarified mother liquor and output condensate water and ammonium chloride salt. The second concentration unit is used to concentrate the first produced water and output second concentrated water with a high TDS content and second produced water with a low TDS content. The second produced water is refluxed to Figure 1 the washing unit 130 in the cobalt carbonate production system shown to wash the solid cobalt carbonate.

[0084] The mother liquor pretreatment unit includes a mother liquor raw water tank 210, a first filtration device 220, a first pH adjustment tank 230, a first feeding device 240, and a first pressure filtration device 250. The mother liquor raw water tank 210 is used to store the mother liquor from the solid-liquid separation unit 120. The first filtration device 220 is used to filter the mother liquor output from the mother liquor raw water tank 210 and output a first filtrate with an SS content ≤ 0.2 mg / L and a first filter residue. The first filtrate is stored in the first filtrate storage tank, and the first filter residue is stored in the first filter residue storage tank. The first pH adjustment tank 230 is used to adjust the pH of the first filtrate output from the first filtrate storage tank and input a clear mother liquor with a pH of 7-8 into the second mixed liquid storage tank 720. The first feeding device 240 is used to add an acidic reagent to the first pH adjustment tank 230. The first pressure filtration device 250 is used to perform pressure filtration on the first filter residue in the first filter residue storage tank.

[0085] The washing water pretreatment unit includes a washing water raw water tank 310, a second filtration device 320, a second pH adjustment tank 330, a second feeding device 340, a second pressure filtration device 350, and an ultrafiltration device 360. The washing water raw water tank 310 is used to store the washing water from the washing unit 130 and the recycled concentrated washing water. The second filtration device 320 is used to filter the washing water output from the washing water raw water tank 310 and output a second filtrate with an SS content ≤ 0.2 mg / L and a second filter residue. The second filtrate is stored in the second filtrate storage tank, and the second filter residue is stored in the second filter residue storage tank. The second pH adjustment tank 330 is used to adjust the pH of the second filtrate output from the second filtrate storage tank and output a third filtrate with a pH of 6-7. The second feeding device 340 is used to add an acidic reagent to the second pH adjustment tank 330. The second pressure filtration device 350 is used to perform pressure filtration on the second filter residue in the second filter residue storage tank. The ultrafiltration device 360 is used to perform ultrafiltration on the third filtrate output from the second pH adjustment tank 330 and output cleaning water and concentrated washing water. The cleaning water is stored in the first mixed liquid storage tank 710; the concentrated washing water is stored in the washing water raw water tank 310.

[0086] The first concentration unit includes a first reverse osmosis device 410 and a second reverse osmosis device 420. The first reverse osmosis device 410 is used to concentrate the first mixed liquid output from the first mixed liquid storage tank 710 and output a first intermediate concentrated water and a first intermediate product water. The second reverse osmosis device 420 is used to concentrate the first intermediate concentrated water and output a first concentrated water and a second intermediate product water. The first concentrated water is stored in the second mixed liquid storage tank 720, and the first intermediate product water and the second intermediate product water form the first product water and are stored in the intermediate tank 730.

[0087] The evaporation and crystallization unit includes an evaporation and crystallization device 510, a drying device 520, and a heat exchange device 530. The evaporation and crystallization device 510 is used to perform evaporation and crystallization treatment on the second mixed liquid output from the second mixed liquid storage tank 720 and output crystal water and crystal salts. The drying device 520 is used to dry the crystal salts and output ammonium chloride salts. The heat exchange device 530 is used to perform heat exchange treatment on the crystal water and output condensed water, and the condensed water is stored in the first mixed liquid storage tank 710.

[0088] The second concentration unit includes a third reverse osmosis device 610 and a fourth reverse osmosis device 620. The third reverse osmosis device 610 is used to perform reverse osmosis concentration treatment on the intermediate liquid composed of the first produced water and the refluxed second concentrated water and output the second intermediate concentrated water and the third intermediate produced water. The second intermediate concentrated water is refluxed to the first mixed liquid storage tank 710 to be mixed with the cleaning water and the condensed water to form a first mixed liquid. The fourth reverse osmosis device 620 is used to perform reverse osmosis concentration treatment on the third intermediate produced water and output the second concentrated water and the second produced water. The second concentrated water is refluxed to the intermediate tank 730 to be mixed with the first produced water to form an intermediate liquid, and the second produced water is refluxed to Figure 1 the washing unit 130 in the shown cobalt carbonate production system to wash the cobalt carbonate solid.

[0089] An embodiment of the treatment method for the cobalt carbonate production wastewater of the present utility model is to adopt the above-mentioned cobalt carbonate production wastewater treatment system. The TDS content of the mother liquor is 75000 - 95000 mg / L, the SS content is 25 - 35 mg / L, the pH is 8.5 - 9.5, the TDS content of the washing water is 500 - 1500 mg / L, the SS content is 5 - 15 mg / L, the pH is 7 - 8. The treatment system specifically includes steps Step10 - Step50, which are as follows:

[0090] Step10, pre-treat the mother liquor with the mother liquor pre-treatment unit to reduce the SS content and pH of the mother liquor and obtain a clarified mother liquor. Step10 specifically includes steps Step11 - Step12, which are as follows:

[0091] Step11, filter the mother liquor with the first filtering device 220 to obtain a first filtrate with an SS content ≤ 0.2 mg / L;

[0092] Step12, adjust the pH of the first filtrate with 31% hydrochloric acid by mass in the first pH adjustment tank 230 to obtain a clarified mother liquor with a pH of 7 - 8.

[0093] Step20, pre-treat the washing water with a washing water pre-treatment unit to reduce the SS content and pH of the washing water, obtaining cleaning water; Step20 specifically includes steps Step21 - Step23, which are as follows:

[0094] Step21, filter the washing water and the recycled concentrated washing water with a second filtration device 320 to obtain a second filtrate with an SS content ≤ 0.2 mg / L;

[0095] Step22, adjust the pH of the second filtrate with hydrochloric acid with a mass fraction of 31% in a second pH adjustment tank 330 to obtain a third filtrate with a pH of 6 - 7;

[0096] Step23, perform ultrafiltration on the third filtrate with an ultrafiltration device 360 to obtain cleaning water and concentrated washing water; the concentrated washing water is recycled to Step21 for pre-treatment.

[0097] Step30, concentrate a first mixed solution containing cleaning water, condensed water, and a second intermediate concentrated water with a first concentration unit to obtain a first concentrated water with a high TDS content and a first product water with a low TDS content; the TDS content of the first mixed solution is 1000 - 1300 mg / L, and the pH is 5.5 - 6.5; Step30 specifically includes steps Step31 - Step32, which are as follows:

[0098] Step31, perform reverse osmosis concentration on the first mixed solution with a first reverse osmosis device 410 to obtain a first intermediate concentrated water and a first intermediate product water; the TDS content of the first intermediate concentrated water is 3 - 6 times that of the first mixed solution;

[0099] Step33, perform reverse osmosis concentration on the first intermediate concentrated water with a second reverse osmosis device 420 to obtain a first concentrated water and a second intermediate product water; the TDS content of the first concentrated water is 2 - 5 times that of the first intermediate concentrated water; the first intermediate product water and the second intermediate product water constitute the first product water.

[0100] Step40, perform evaporation crystallization on a second mixed solution containing the first concentrated water and clear mother liquor with an evaporation crystallization unit to obtain condensed water and ammonium chloride salt, the TDS content of the second mixed solution is 70000 - 85000 mg / L, and the pH is 7.5 - 8.5; Step400 specifically includes steps Step41 - Step43, which are as follows:

[0101] Step41, perform evaporation crystallization on the second mixed solution with an evaporation crystallization device 510 to obtain crystallization water and crystalline salt;

[0102] Step 42, using a drying device 520 to dry the crystallized salt to obtain ammonium chloride salt;

[0103] Step 43, using heat exchange equipment 530 to perform heat exchange treatment on the crystallization water to obtain condensed water.

[0104] Step 50, using a second concentration unit to concentrate the first produced water to obtain a second concentrated water with a high TDS content and a second produced water with a low TDS content, and the second produced water is refluxed to the washing process in the cobalt carbonate production; Step 50 specifically includes steps Step 51-Step 52, which are respectively as follows:

[0105] Step 51, using the third reverse osmosis device 610 to perform reverse osmosis concentration treatment on the intermediate liquid composed of the first produced water and the second concentrated water flowing back, to obtain the second intermediate concentrated water and the third intermediate produced water; the second intermediate concentrated water flows back to Step 30 for concentration treatment; the TDS content of the second intermediate concentrated water is 4 to 7 times the TDS content of the intermediate liquid;

[0106] Step 52, use the fourth reverse osmosis equipment 620 to perform reverse osmosis concentration treatment on the third intermediate produced water to obtain second concentrated water and second produced water; the second concentrated water is returned to Step 51 for concentration treatment; the TDS content of the second concentrated water is 4 to 7 times the TDS content of the third intermediate produced water; the TDS content of the second produced water is ≤10 mg / L.

[0107] The beneficial effects of the present invention are described below through application examples.

[0108] In the mother liquor and wash water produced by a cobalt carbonate manufacturer, the TDS content of the mother liquor is 84070 mg / L, the SS content is 30 mg / L, and the pH is 9. The TDS content of the wash water is 1034.5 mg / L, the SS content is 10 mg / L, and the pH is 7.8. Among them, TDS (Total Dissolved Solids) is the total dissolved solids, which refers to the total amount of all solid substances dissolved in the water, including inorganic salts (such as calcium, magnesium, sodium, potassium, bicarbonate, chloride, sulfate, etc.) and a small amount of organic matter, usually expressed in milligrams per liter (mg / L). SS (Suspended Solids) is suspended solids, which refers to solid particles suspended in the water, including organic matter, inorganic matter, microorganisms, etc., usually expressed in milligrams per liter (mg / L). In addition, both the mother liquor and the wash water also contain a large amount of NH4 + Mg 2+ and Cl - .

[0109] The mother liquor was pretreated using a mother liquor pretreatment unit. The water quality parameters of each water sample are shown in Table 1.

[0110] As can be seen from Table 1, after pretreatment, the SS content of the obtained clear mother liquor is only 0.1 mg / L.

[0111] Table 1

[0112]

[0113] The washing water is treated by the washing water pretreatment unit, and the water quality parameters of each water sample are shown in Table 2.

[0114] As can be seen from Table 2, after pretreatment, the SS content of the obtained cleaning water is only 0.1 mg / L.

[0115] Table 2

[0116]

[0117] The first concentration unit is used to concentrate the first mixed liquid containing cleaning water, condensed water (obtained by cooling the crystal water to 35 °C through a heat exchange device) and the second intermediate concentrated water, and the water quality parameters of each water sample are shown in Table 3.

[0118] As can be seen from Table 3, by controlling the concentration multiples of the first reverse osmosis device 410 and the second reverse osmosis device 420, the TDS content of the first intermediate concentrated water is 3 to 6 times that of the first mixed liquid, and the TDS content of the first concentrated water is 2 to 5 times that of the first intermediate concentrated water. Finally, the TDS is enriched in the first concentrated water, and its TDS content is as high as 22157.7 mg / L. The TDS content of the first concentrated water is 18.2 times that of the first mixed liquid, and the water volume is as low as 29.6 m 3 / day, so the energy consumption of the subsequent evaporation crystallization device 510 can be significantly reduced.

[0119] Table 3

[0120]

[0121] Then, the evaporation crystallization unit is used to treat the second mixed liquid composed of the first concentrated water and the clear mother liquor, and the water quality parameters of each water sample are shown in Table 4.

[0122] Table 4

[0123]

[0124] Then, the second concentration unit is used to treat the intermediate liquid composed of the first produced water (including the first intermediate produced water and the second intermediate produced water) and the refluxed second concentrated water, and the water quality parameters of each water sample are shown in Table 5.

[0125] As shown in Table 5, by controlling the concentration multiples of the third reverse osmosis device 610 and the fourth reverse osmosis device 620, the TDS content of the second intermediate concentrated water is 4 to 7 times that of the intermediate liquid, and the TDS content of the second concentrated water is 4 to 7 times that of the third intermediate product water. Finally, the TDS content of the second product water is as low as 3.4 mg / L, and the daily water production is 466 m 3 / day. When recycled to the washing process in cobalt carbonate production, it can not only significantly save the consumption of new water resources, but also will not introduce impurities that affect the purity of cobalt carbonate.

[0126] Table 5

[0127]

[0128] The above describes the relevant content of the present utility model. Those of ordinary skill in the art will be able to implement the present utility model based on these descriptions. Based on the above content of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present utility model.

Claims

1. Treatment system for cobalt carbonate production wastewater. The cobalt carbonate production includes a precipitation reaction unit (110), a solid-liquid separation unit (120), and a washing unit (130). The production wastewater includes mother liquor and washing water. The mother liquor comes from the solid-liquid separation unit (120), and the washing water comes from the washing unit (130). It is characterized in that: The processing system includes: A mother liquor pretreatment unit for pretreating the mother liquor to reduce the SS content and pH of the mother liquor and output clarified mother liquor; A washing water pretreatment unit for pretreating the washing water to reduce the SS content and pH of the washing water and output cleaning water; A first concentration unit for concentrating a first mixed solution containing cleaning water and condensate and outputting first concentrated water with a high TDS content and first product water with a low TDS content; An evaporation crystallization unit for performing evaporation crystallization treatment on a second mixed solution containing first concentrated water and clarified mother liquor and outputting condensate and ammonium chloride salt; A second concentration unit for concentrating the first product water and outputting second concentrated water with a high TDS content and second product water with a low TDS content; the second product water is recycled to the washing unit (130) in cobalt carbonate production.

2. The treatment system for cobalt carbonate production wastewater according to claim 1, characterized in that: The mother liquor pretreatment unit includes: A mother liquor raw water tank (210) for storing the mother liquor from the solid-liquid separation unit (120); A first filtration device (220) for filtering the mother liquor output from the mother liquor raw water tank (210) and outputting a first filtrate with an SS content ≤ 0.2 mg / L and first filter residue; the first filtrate is stored in a first filtrate storage tank; the first filter residue is stored in a first filter residue storage tank; A first pH adjustment tank (230) for adjusting the pH of the first filtrate output from the first filtrate storage tank and inputting clarified mother liquor with a pH of 7 - 8 into a second mixed solution storage tank (720); A first feeding device (240) for adding an acidic reagent into the first pH adjustment tank (230).

3. The treatment system for cobalt carbonate production wastewater according to claim 2, characterized in that: The mother liquor pretreatment unit further includes a first pressure filtration device (250) for pressure-filtering the first filter residue in the first filter residue storage tank.

4. The treatment system for cobalt carbonate production wastewater according to claim 1, wherein: The washing water pretreatment unit includes: A washing water raw water tank (310) for storing the washing water from the washing unit (130) and the recycled concentrated washing water; A second filtration device (320) for filtering the washing water output from the washing water raw water tank (310) and outputting a second filtrate with an SS content ≤ 0.2 mg / L and second filter residue; the second filtrate is stored in a second filtrate storage tank; the second filter residue is stored in a second filter residue storage tank; A second pH adjustment tank (330) for adjusting the pH of the second filtrate output from the second filtrate storage tank and outputting a third filtrate with a pH of 6 - 7; A second feeding device (340) for adding an acidic reagent into the second pH adjustment tank (330); An ultrafiltration device (360) for ultrafiltering the third filtrate output from the second pH adjustment tank (330) and outputting cleaning water and concentrated washing water; the cleaning water is stored in a first mixed solution storage tank (710); the concentrated washing water is stored in the washing water raw water tank (310).

5. The treatment system for cobalt carbonate production wastewater according to claim 4, characterized in that: The washing water pretreatment unit further includes a second pressure filtration device (350) for pressure-filtering the second filter residue in the second filter residue storage tank.

6. The treatment system for cobalt carbonate production wastewater according to claim 4, characterized in that: The first concentration unit includes: A first reverse osmosis device (410) for concentrating the first mixed solution output from the first mixed solution storage tank (710) and outputting first intermediate concentrated water and first intermediate product water; The second reverse osmosis device (420) is used for concentrating the first intermediate concentrated water and outputting the first concentrated water and the second intermediate product water; the first concentrated water is stored in the second mixed liquid storage tank (720); the first intermediate product water and the second intermediate product water form the first product water and are stored in the intermediate tank (730).

7. The treatment system for cobalt carbonate production wastewater according to claim 1, characterized in that: The evaporation crystallization unit includes: An evaporation crystallization device (510) is used for performing evaporation crystallization treatment on the second mixed liquid output from the second mixed liquid storage tank (720) and outputting crystal water and crystal salt; A drying device (520) is used for drying the crystal salt and outputting ammonium chloride salt; A heat exchange device (530) is used for performing heat exchange treatment on the crystal water and outputting condensed water, and the condensed water is stored in the first mixed liquid storage tank (710).

8. The treatment system for cobalt carbonate production wastewater according to claim 1, wherein: The second concentration unit includes: A third reverse osmosis device (610) is used for performing reverse osmosis concentration treatment on the intermediate liquid formed by the first product water and the refluxed second concentrated water and outputting the second intermediate concentrated water and the third intermediate product water; the second intermediate concentrated water is stored in the first mixed liquid storage tank (710); A fourth reverse osmosis device (620) is used for performing reverse osmosis concentration treatment on the third intermediate product water and outputting the second concentrated water and the second product water; the second concentrated water is refluxed to the intermediate tank (730) to be mixed with the first product water to form an intermediate liquid.

9. Cobalt carbonate production system, comprising a precipitation reaction unit (110), a solid-liquid separation unit (120) and a washing unit (130), characterized in that: It further includes the treatment system for cobalt carbonate production wastewater according to any one of claims 1-8, and the treatment system is used for treating the mother liquor from the solid-liquid separation unit (120) and the washing water from the washing unit (130).

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