Method for preparing sodium sulfate decahydrate crystals from high-concentration salt wastewater of secondary battery by aqueous solution crystal growth method, and recycling method using same

Abstract

The present invention relates to a method for preparing sodium sulfate decahydrate crystals from high-concentration salt wastewater of a secondary battery by an aqueous solution crystal growth method, and to a recycling method using same. The method comprises: a first step of transferring high-concentration salt wastewater of a secondary battery to a preheating tank; a second step of supplying high-temperature steam discharged from a hydrothermal reaction tube to the preheating tank and heating the salt wastewater introduced into the preheating tank to 30-40°C; a third step of transferring the salt wastewater preheated in the second step to a horizontal pipe-type hydrothermal reaction tube, heating same at 120-150°C for 30-60 minutes, and evaporating moisture through a hydrothermal reaction until the salinity of the introduced salt wastewater reaches 8-9%, thereby preparing a sodium sulfate supersaturated solution; a fourth step of supplying the high-temperature steam discharged in the third step to the preheating tank of the second step, and transferring the sodium sulfate supersaturated solution having a salinity of 8-9% to a supersaturated solution storage tank; a fifth step of removing nickel heavy metals contained in the sodium sulfate supersaturated solution by supplying carbon dioxide to the sodium sulfate supersaturated solution introduced into the supersaturated solution storage tank, precipitating nickel carbonate (NiCO3) while adjusting the pH to a range of 7-7.5, and separating and collecting the precipitate; a sixth step of transferring the sodium sulfate supersaturated solution having a pH adjusted to 7-7.5 and carbon dioxide to an aqueous solution crystal growth tank; a seventh step of growing and obtaining sodium sulfate decahydrate crystals by performing, for 12-24 hours, a vertical temperature gradient method of controlling an upper temperature of the aqueous solution crystal growth tank to a temperature range of 15-20°C and a lower temper

Description

Preparation of sodium sulfate decahydrate crystals from high-concentration brine wastewater for secondary batteries by aqueous solution crystal growth method and resource recovery method using the same

[0001] This technology relates to the appropriate treatment and resource recovery of high-concentration saline wastewater discharged during the production process of precursors for secondary battery cathodes. By utilizing an aqueous solution crystal growth method to produce sodium sulfate decahydrate crystals from the high-concentration saline wastewater, it is possible not only to properly treat the wastewater but also to create various added values ​​by utilizing the by-products generated during this process.

[0002] Looking at the origin of high-concentration saline wastewater from secondary batteries, since the 2000s, as the demand for secondary batteries needed for electric vehicles and the like has surged, related industries such as precursors, cathode materials (positive active materials), anode materials, and electrolytes, which are components of batteries, have been developing rapidly.

[0003] The precursor for cathode materials, which is the starting point of the battery industry, is produced by a co-precipitation method using a mixture of nickel sulfate (containing 80 to 90 weight percent), cobalt sulfate, and manganese sulfate, ammonia for complexing, and sodium hydroxide for pH adjustment. The filtrate discharged after solid-liquid separation is high-concentration salt wastewater containing serious contaminants such as sulfate ions, salts, and nickel heavy metals.

[0004] In the case of high-concentration saline wastewater subject to treatment, the sulfate ion concentration is generally 60,000 to 68,000 mg / L, salinity is 5 to 6%, pH is 9 to 10, nickel (Ni) heavy metal content is 400 to 450 mg / L, and ecotoxicity value (Toxic Unit) is TU 8 or higher. However, if we look at the permissible discharge standards for water pollutants [Table 13] of the Enforcement Rule of the Water Environment Conservation Act (related to Article 34), the effluent water quality standard is an ecotoxicity value of TU 1 or lower, so a treatment method suitable for these standards is required.

[0005] In order to purify the water to be treated to an ecotoxicity value of TU 1 or less, technology to remove sulfate ions, salts, nickel heavy metals, etc. is required. In particular, regarding nickel heavy metals, which have the greatest impact on ecotoxicity, it is reported that the nickel in the final treated water must be 7.2 mg / L or less (removal rate of 98% or more) and the sulfate must be 4,605 ​​mg / L or less (removal rate of 92% or more).

[0006] When sodium sulfate decahydrate crystals are obtained in large quantities from high-concentration saline wastewater to be treated, the concentrations of sulfate ions and salts contained in the wastewater are reduced, thereby promoting water purification effects. Furthermore, utilizing sodium sulfate decahydrate crystals as a raw material enables resource recovery, which can also contribute to revenue generation.

[0007] [Prior Art Literature]

[0008] Korean Patent Registration No. 10-2169490

[0009] Korean Patent Registration No. 10-2613721

[0010] Korean Published Patent No. 10-2021-0134544

[0011] The purpose of the present invention, created in accordance with the above-mentioned necessity, is as follows.

[0012] First, the objective of the present invention is to provide a new method for obtaining sodium sulfate decahydrate crystals and nickel carbonate powder simultaneously from high-concentration salt wastewater from secondary batteries using a vertical temperature gradient method based on an aqueous solution crystal growth method.

[0013] Secondly, another objective of the present invention is to provide a resource utilization method capable of creating new added value by manufacturing a valuable metal extractant, nickel sulfate powder, lithium carbonate powder, a salt removal desalination agent, an ammonia or hydrogen sulfide deodorizing agent for odor removal, a color and heavy metal removal agent for dyeing wastewater, and an ammonia nitrogen removal agent for water purification using sodium sulfate decahydrate crystals.

[0014] Third, another objective of the present invention is to recycle the filtrate recovered after separating sodium sulfate decahydrate crystals as usable water required for the resource recovery process.

[0015] The configuration of the present invention created to achieve the above-mentioned purpose is as follows.

[0016] The present invention relates to the production of sodium sulfate decahydrate crystals from high-concentration brine wastewater from secondary batteries by an aqueous solution crystal growth method and a method for resource recovery using the same, comprising: a first step of transferring the high-concentration brine wastewater from secondary batteries to a preheating tank; a second step of supplying high-temperature steam (high-temperature vapor) discharged from a hydrothermal reaction tube to the preheating tank to heat the brine wastewater flowing into the preheating tank to 30 to 40°C; a third step of transferring the brine wastewater preheated in the second step to a horizontal pipe-type hydrothermal reaction tube and then heating it to 120 to 150°C for 30 to 60 minutes to produce a supersaturated sodium sulfate solution through a hydrothermal reaction that evaporates water until the salinity of the flowing brine wastewater reaches 8 to 9%; and a fourth step of supplying the high-temperature steam discharged in the third step to the preheating tank of the second step and transferring the sodium sulfate supersaturated solution with a salinity of 8 to 9% to a supersaturated solution storage tank. Step 5, supplying carbon dioxide to a sodium sulfate supersaturated solution introduced into a supersaturated solution storage tank to adjust the pH to a range of 7 to 7.5 while precipitating nickel carbonate (NiCO3), and then separating and recovering the precipitate to remove nickel heavy metal contained in the sodium sulfate supersaturated solution; Step 6, transferring the sodium sulfate supersaturated solution with a pH adjusted to 7 to 7.5 and carbon dioxide to an aqueous crystal growth tank; Step 7, performing a vertical temperature gradient method for 12 to 24 hours in which the upper temperature of the aqueous crystal growth tank is controlled to a temperature range of 15 to 20°C and the lower temperature is controlled to a temperature range of 2 to 4°C to grow and obtain sodium sulfate decahydrate crystals; Step 8, filtering and separating the sodium sulfate decahydrate crystals obtained in Step 7 using a 60 to 100 mesh screen and recovering the remaining filtrate; The method is characterized by including: a 9th step of naturally drying the sodium sulfate decahydrate crystals filtered and separated in the 8th step; and a 10th step of mixing the steam discharged from the preheating tank of the 2nd step with the filtrate recovered from the filtered and separated sodium sulfate decahydrate crystals in the 8th step to produce usable water for reuse in the resource recovery process.

[0017] The technical effects according to the configuration of the present invention are as follows.

[0018] First, by using a vertical temperature gradient method based on an aqueous solution crystal growth method to obtain sodium sulfate decahydrate crystals and nickel carbonate powder simultaneously from high-concentration salt wastewater from secondary batteries, serious environmental pollutants such as sulfate ions and nickel heavy metals contained in the high-concentration salt wastewater from secondary batteries can be effectively removed.

[0019] Second, new added value can be created by recycling sodium sulfate decahydrate crystals, which are byproducts of the process of treating high-concentration brine wastewater from secondary batteries, into various resources.

[0020] Third, by recycling the filtrate recovered after separating sodium sulfate decahydrate crystals into water for use in the resource recovery process, the amount of filtrate discharged externally can be minimized, thereby significantly improving environmental problems caused by high-concentration salt wastewater from secondary batteries. In other words, by recycling even the filtrate from which environmental pollutants have been effectively removed into water for use in the resource recovery process instead of discharging it as is, environmental problems can be fundamentally resolved.

[0021] FIG. 1 is a block diagram illustrating the process of obtaining sodium sulfate decahydrate crystals from high-concentration salt wastewater of a secondary battery according to the aqueous solution crystal growth method of the present invention, and includes the process from step 1 to step 10 of the present invention.

[0022] Figure 2 shows the results of X-ray diffraction analysis of nickel carbonate powder obtained through the carbonation reaction of a supersaturated sodium sulfate solution.

[0023] Figure 3 shows sodium sulfate decahydrate crystals prepared using a vertical temperature gradient method based on an aqueous solution crystal growth method.

[0024] FIG. 4 is a block diagram illustrating a resource recovery process using sodium sulfate decahydrate crystals obtained according to the present invention, and includes steps 11 through 22 of the present invention.

[0025] Figure 5 shows that the anode active material deposited on the surface of the waste crucible after calcination is peeled and extracted by a valuable metal extractant.

[0026] Figure 6 shows the results of X-ray diffraction analysis of nickel sulfate powder obtained using an extract obtained from a waste crucible by a valuable metal extractant.

[0027] Figure 7 shows the results of X-ray diffraction analysis of lithium carbonate powder obtained using an extract from a waste crucible by a valuable metal extractant.

[0028] Figure 8 shows a photograph of the results of cultivating income crop onions at the Saemangeum reclaimed land site after desalination treatment using a desalination agent.

[0029] Figure 9 shows the process of reducing the color intensity of dye wastewater.

[0030] Figure 10 shows the results of X-ray diffraction analysis of sodium sulfate powder obtained by high-temperature drying of sodium sulfate decahydrate crystals.

[0031] Fig. 11 shows an ammonia nitrogen removal agent (carrier type) for water purification.

[0032] Specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings.

[0033] The present invention relates to the production of sodium sulfate decahydrate crystals from high-concentration salt wastewater from secondary batteries by an aqueous solution crystal growth method and a method for resource recovery using the same, and the step-by-step process is illustrated in the block diagrams of FIGS. 1 and FIGS. 4.

[0034] (1) Stage 1

[0035] This is the process of transferring high-concentration salt wastewater from secondary batteries to a preheating tank.

[0036] High-concentration brine wastewater from secondary batteries has characteristics such as a sulfate ion concentration of 60,000 to 68,000 mg / L, salinity of 5 to 6%, pH of 9 to 10, nickel (Ni) heavy metal content of 400 to 450 mg / L, and an ecotoxicity value (Toxic Unit) of TU 8 or higher, and is stored in a storage tank and then transferred to a preheating tank.

[0037] (2) Stage 2

[0038] It is a process of supplying high-temperature steam (high-temperature steam) discharged from a hydrothermal reaction tube to a preheating tank to heat the salt wastewater flowing into the preheating tank to 30 to 40°C.

[0039] Steam piping is installed inside the preheating tank to supply high-temperature steam (high-temperature steam) discharged from the hydrothermal reaction tube to the steam piping, and as the salt wastewater flowing into the preheating tank passes through, it is naturally preheated to over 30°C.

[0040] (3) Stage 3

[0041] The process involves transferring the preheated salt wastewater from the second stage to a horizontal pipe-type hydrothermal reaction tube, heating it to 120 to 150°C for 30 to 60 minutes, and then evaporating the water through a hydrothermal reaction until the salinity of the incoming salt wastewater reaches 8 to 9%.

[0042] Here, the salinity % of the salt wastewater refers to the mass (g) of sodium sulfate contained in 100 ml of salt wastewater. For example, if 8 g of sodium sulfate is contained in 100 ml of salt wastewater, the salinity of the salt wastewater is 8%, and the salinity of the salt wastewater described in the claims of the present invention and the salinity of the salt wastewater described in the rest of the specification are all calculated in this manner.

[0043] Salt wastewater that has been preheated by passing through a preheating tank is introduced into a horizontal pipe-type hydrothermal reaction tube at a high temperature of 120 to 150°C, and a hydrothermal reaction is induced to quantitatively evaporate water until the salinity reaches 8 to 9% for a short period of 30 to 60 minutes to produce a supersaturated sodium sulfate solution.

[0044] (4) Stage 4

[0045] The high-temperature steam discharged in the third stage is circulated and supplied to the preheating tank of the second stage, and the supersaturated sodium sulfate solution with a salinity of 8 to 9% is transferred to the supersaturated solution storage tank.

[0046] (5) 5th stage

[0047] This is a process of removing nickel heavy metal contained in the sodium sulfate supersaturated solution by supplying carbon dioxide (CO2) to the sodium sulfate supersaturated solution introduced into the supersaturated solution storage tank to adjust the pH to a range of 7 to 7.5, precipitating nickel carbonate (NiCO3), and then separating and recovering the precipitate.

[0048] The nickel heavy metal is removed through a separate process in which nickel carbonate (NiCO3) is precipitated by supplying carbon dioxide to a sodium sulfate supersaturated solution with a pH of 9 to 10 that has been introduced into a supersaturated solution storage tank to adjust the pH to a range of 7 to 7.5, and the nickel is separated and recovered.

[0049] (6) Stage 6

[0050] This is a process of transferring a supersaturated sodium sulfate solution with a pH adjusted to 7 to 7.5 and carbon dioxide to an aqueous crystal growth tank.

[0051] A fluid containing a supersaturated sodium sulfate solution (Liquid) and carbon dioxide (Gas) is introduced into an aqueous crystal growth tank.

[0052] (7) 7th stage

[0053] This is a process of growing and obtaining sodium sulfate decahydrate crystals from a fluid by performing a vertical temperature gradient method for 12 to 24 hours, in which the upper temperature of an aqueous solution crystal growth tank is controlled to a temperature range of 15 to 20°C and the lower temperature is controlled to a temperature range of 2 to 4°C.

[0054] The fluid with good fluidity introduced into the aqueous crystal growth tank is in a state where sodium ions and sulfate ions diffuse well, and crystals of sodium sulfate decahydrate are grown using the vertical temperature gradient method.

[0055] A temperature control system is operated to maintain the temperature of the upper part of the aqueous crystal growth tank in the range of 15 to 20°C and the temperature of the lower part in the range of 2 to 4°C, thereby setting the temperature gradient (Δt) between the upper and lower parts of the aqueous crystal growth tank to be 11 to 18°C.

[0056] When a vertical temperature gradient is formed in this way, the diffusion of sodium ions and sulfate ions occurs well up and down, and sodium sulfate decahydrate crystals are obtained by maintaining this condition for 12 to 24 hours.

[0057] When the preparation of sodium sulfate decahydrate crystals was carried out using the Vertical Temperature Gradient (VTG) method based on the aqueous solution crystal growth method, the yield of sodium sulfate decahydrate crystals was about 5 to 10 weight percent higher compared to the conventional Horizontal Temperature Dropping (HTD) method. This is because the diffusion of sodium ions and sulfate ions proceeded well, and the dissolution and precipitation reaction mechanisms proceeded actively.

[0058] (8) Stage 8

[0059] The process involves filtering and separating the sodium sulfate decahydrate crystals obtained in the seventh step using a 60 to 100 mesh screen, and recovering the remaining liquid.

[0060] Sodium sulfate decahydrate crystals are filtered and separated using a mesh screen, and the remaining liquid is recovered. The liquid is cooled inside an aqueous crystal growth tank to a cold water state of 10°C or lower.

[0061] (9) Step 9

[0062] This is a process of obtaining sodium sulfate decahydrate crystals by naturally drying the sodium sulfate decahydrate crystals separated by filtration in Step 8.

[0063] (10) Step 10

[0064] This is a process of producing usable water for reuse in a resource recovery process by mixing the steam discharged from the preheating tank in stage 2 with the filtrate recovered after filtering and separating sodium sulfate decahydrate crystals in stage 8.

[0065] (11) Step 11

[0066] The process involves obtaining sodium sulfate powder by high-temperature drying the sodium sulfate decahydrate crystals obtained in step 9 at a temperature range of 200 to 300°C for 20 to 30 minutes.

[0067] (12) Step 12

[0068] The process involves adding 15 to 20 parts by weight of water prepared in step 10 and 20 to 30 parts by weight of additive (E) to 70 to 80 parts by weight of sodium sulfate powder obtained in step 11 and mixing them.

[0069] Here, the additive (E) is prepared by mixing 10 to 15 parts by weight of non-swelling mica powder, 5 to 7 parts by weight of calcium aluminate powder, 3 to 5 parts by weight of nanocarbon colloid solution, and 2 to 3 parts by weight of silver (Ag) colloid solution.

[0070] (13) Step 13

[0071] This is a process of forming the mixture in the slurry state mixed in step 12.

[0072] Molding is performed using various molds.

[0073] (14) Step 14

[0074] This is a process of manufacturing various types of ammonia nitrogen removers for water purification by naturally drying molded products formed by a mold.

[0075] (15) Step 15

[0076] This is a process of producing a valuable metal extractant by adding 10 kg of sodium sulfate decahydrate crystals obtained in step 9 to 20 L of water prepared in step 10 to dissolve them, and then adding an additive (A).

[0077] Here, additive (A) is prepared by mixing 0.5 L of a 35% concentration hydrochloric acid solution and 0.06 kg of ethylenediaminetetraacetic acid (EDTA).

[0078] Here, the % concentration of the hydrochloric acid solution refers to the mass (g) of hydrochloric acid contained in 100g of a hydrochloric acid solution mixed with water and hydrochloric acid. For example, if 100g of a hydrochloric acid solution is prepared by mixing 65g of water and 35g of hydrochloric acid, it becomes a hydrochloric acid solution with a concentration of 35%. The % concentration of the hydrochloric acid solution described in the claims of the present invention and the % concentration of the hydrochloric acid solution described in the remainder of the specification are all calculated in this manner.

[0079] (16) Step 16

[0080] This is a process of immersing the waste crucible after calcining the cathode active material in the valuable metal extractant prepared in Step 15 for 24 hours to extract the cathode active material attached to the surface of the waste crucible, and growing nickel sulfate crystals using the extract from which the valuable metal has been extracted under the same method and conditions as the vertical temperature gradient method of Step 7 to obtain the result.

[0081] That is, nickel sulfate crystals are grown using a vertical temperature gradient method. An extract from which a valuable metal has been extracted is introduced into a crystal growth tank, and a temperature control system is operated to maintain the temperature of the upper part of the crystal growth tank in the range of 15 to 20°C and the temperature of the lower part in the range of 2 to 4°C, so that the temperature gradient (Δt) between the upper and lower parts of the crystal growth tank is set to 11 to 18°C, and this state is maintained for 12 to 24 hours to obtain nickel sulfate crystals.

[0082] (17) Step 17

[0083] This is a process of filtering and separating the nickel sulfate crystals obtained in step 16 using a 60 to 100 mesh screen and recovering the remaining liquid.

[0084] (18) Step 18

[0085] The process of obtaining nickel sulfate powder by drying the nickel sulfate crystals separated by filtration in step 17 at a temperature range of 60 to 80°C for 10 to 12 hours.

[0086] (19) Step 19

[0087] The process involves adding sodium hydroxide to the filtrate recovered in step 17 to adjust the pH of the filtrate to 11 to 12, then supplying carbon dioxide to adjust the pH to a range of 8 to 8.5, and allowing a precipitation reaction to proceed for 12 hours, and then using a centrifuge to separate the solid and liquid components and drying the solid at a temperature range of 90 to 110°C for 12 hours to obtain lithium carbonate powder.

[0088] (20) Step 20

[0089] The process involves adding 25 to 40 parts by weight of additive (B) to 60 to 75 parts by weight of a solution in which 3 kg of sodium sulfate decahydrate crystals obtained in step 9 are dissolved in 20 L of water prepared in step 10 to produce a salt removal desalination agent in the form of a slurry.

[0090] Here, the additive (B) is prepared by mixing 7 to 10 parts by weight of colloidal amorphous calcium carbonate slurry, 5 to 8 parts by weight of amorphous magnesium hydroxide slurry, 5 to 8 parts by weight of aluminum hydroxide powder, and 3 to 4 parts by weight of nano-carbon colloidal solution.

[0091] (21) Step 21

[0092] The process involves adding 20 to 30 parts by weight of additive (C) to 70 to 80 parts by weight of a solution in which 5 kg of sodium sulfate decahydrate crystals obtained in step 9 are dissolved in 20 L of water prepared in step 10 to produce an ammonia or hydrogen sulfide deodorizer in the form of a slurry.

[0093] Here, the additive (C) for manufacturing an ammonia deodorizer is prepared by mixing 3 kg of colloidal aluminum phosphate slurry, 1.3 kg of anatase-type titanium dioxide powder, and 0.7 kg of nano-carbon colloidal solution, and the additive (C) for manufacturing a hydrogen sulfide deodorizer is prepared by adding 3 kg of amorphous magnesium hydroxide slurry, 1.3 kg of anatase-type titanium dioxide powder, and 0.7 kg of nano-carbon colloidal solution.

[0094] (22) Step 22

[0095] The process involves adding 30 to 40 parts by weight of additive (D) to 60 to 70 parts by weight of a solution in which 5 kg of sodium sulfate decahydrate crystals obtained in step 9 are dissolved in 20 L of water prepared in step 10, thereby producing a color and heavy metal removal agent for dyeing wastewater in the form of a slurry.

[0096] Here, the additive (D) is prepared by mixing 10 to 14 parts by weight of hollow silica powder, 8 to 10 parts by weight of calcined dolomite powder, 8 to 10 parts by weight of hydroxyapatite powder, and 4 to 6 parts by weight of nanocarbon colloid solution.

[0097]

[0098] Below, specific embodiments according to the present invention are examined.

[0099] (1) Example 1

[0100] Example 1 obtained sodium sulfate decahydrate crystals from high-concentration salt wastewater of a secondary battery using a vertical temperature gradient method based on an aqueous solution crystal growth method, and the acquisition of sodium sulfate decahydrate crystals was carried out according to the process diagram shown in Fig. 1.

[0101] The salt wastewater discharged from the production process of precursors for secondary battery cathode materials generally has a sulfate ion concentration of 60,000 to 68,000 mg / L, a salinity of 5 to 6%, a pH of 9 to 10, and a nickel (Ni) heavy metal content of 400 to 450 mg / L.

[0102] The salt wastewater is preheated to a temperature range of 30 to 40°C in a preheating tank by circulating high-temperature steam discharged from a hydrothermal reaction tube, and then introduced into a horizontal pipe-type hydrothermal reaction tube maintaining a temperature of 120 to 150°C to induce a hydrothermal reaction for 30 minutes to produce a supersaturated sodium sulfate solution with a salinity of 8 to 9% and transferred to a supersaturated solution storage tank.

[0103] Carbon dioxide is supplied to a supersaturated sodium sulfate solution in the pH range of 9 to 10 that has been introduced into a storage tank to induce a carbonation reaction until the pH reaches the range of 7 to 7.5, and the solution is precipitated for 12 hours, after which the precipitate is recovered using a centrifuge, and the precipitate is dried at 100°C for 12 hours to obtain nickel carbonate powder.

[0104] Figure 2 shows the results of X-ray diffraction (XRD) analysis of nickel carbonate (NiCO3) powder, and identification using a JCPDS (Joint Committee on Powder Diffraction Standard) card confirmed that the peak pattern matches that of nickel carbonate.

[0105] Then, the fluid containing a supersaturated sodium sulfate solution and carbon dioxide is introduced into an aqueous crystal growth tank capable of performing a vertical temperature gradient method.

[0106] Crystal growth is induced for 24 hours in a state where the upper temperature of the aqueous crystal growth tank of the vertical temperature gradient method is maintained at 18°C ​​and the lower temperature at 3°C, so that the temperature gradient (Δt) between the upper and lower parts is 15°C (a state where diffusion of sodium ions and sulfate ions occurs well).

[0107] Then, the crystals and the liquid are separated using a 100 mesh screen, and sodium sulfate decahydrate crystals are obtained through a natural drying process as shown in Fig. 3. The liquid obtained here is mixed with steam obtained by passing through a preheating tank with cold water at 10°C or lower, and is reused (resource-recovered) as water required for the resource recovery process.

[0108] As a result of requesting a test analysis of the nickel heavy metal content in the salt wastewater (raw water) and treated water (used water) of Example 1 to the Joint Laboratory and Practical Training Center of Kyungpook National University, as shown in Table 1, the nickel content in the salt wastewater (raw water) was 440.3 mg / L and nickel was not detected in the treated water (used water).

[0109] Test Item Raw Water (Saline Wastewater) Treated Water Nickel (Ni) 440.3 mg / LND (Not Detected)

[0110] And the nickel heavy metal content of the sodium sulfate decahydrate crystal and sodium sulfate powder obtained in Example 1 was analyzed by the Joint Laboratory and Practical Training Center of Kyungpook National University, and as shown in Table 2, it was not detected (ND).

[0111] Test Item Sodium Sulfate Decahydrate Crystals Sodium Sulfate Powder Nickel (Ni) ND (Not Detected) ND (Not Detected)

[0112] (2) Example 2

[0113] Example 2 shows the result of resource recovery using sodium sulfate decahydrate crystals, and the resource recovery method using sodium sulfate decahydrate crystals is carried out according to the process diagram of FIG. 4.

[0114] In Example 2, 0.5 L of a 35% hydrochloric acid solution is added to 20 L of water prepared using the filtrate discharged from Example 1, 10 kg of sodium sulfate decahydrate crystals and 60 g of ethylenediamine tetraacetic acid that promotes the extraction of the cathode active material are added, and then the mixture is stirred at a stirring speed of 100 rpm at room temperature for 1 hour to obtain a liquid form of a valuable metal extractant that is completely dissolved.

[0115] As a result of immersing the waste crucible after calcining the cathode active material in such a valuable metal extractant for 24 hours, the cathode active material attached to the surface of the waste crucible is extracted as shown in Fig. 5. Once the extraction of the cathode active material is complete, the waste crucible is separated, and nickel sulfate powder and lithium carbonate powder are manufactured using the extract from which the remaining valuable metal was extracted.

[0116] In this embodiment, nickel sulfate crystals and a filtrate are obtained from an extract from which valuable metals have been extracted using a vertical temperature gradient method under the same method and conditions as in Example 1, the nickel sulfate crystals are filtered and separated using a 100 mesh screen, and the filtered nickel sulfate crystals are dried at 80°C for 12 hours to obtain nickel sulfate powder.

[0117] Then, sodium hydroxide is added to the filtrate to adjust the pH to 12, carbon dioxide is supplied to carry out a carbonation reaction until the pH reaches 8, and then a precipitation reaction is carried out at room temperature for 12 hours. After separating the solid and liquid using a centrifuge, the solid is dried at 100°C for 12 hours to obtain lithium carbonate powder.

[0118] Figures 6 and 7 show the results of X-ray diffraction analysis for nickel sulfate powder and lithium carbonate powder. As a result of identification using a JCPDS card, it was confirmed that the peak patterns matched nickel sulfate and lithium carbonate, respectively.

[0119] Although sulfuric acid solutions have been mostly used for the extraction of valuable metals in the past, the results of Example 2 can confirm that the valuable metal extractant according to the present invention can replace sulfuric acid solutions.

[0120] (3) Example 3

[0121] In Example 3, a salt removal desalination agent is prepared using sodium sulfate dehydrate crystals and the water prepared in Example 1.

[0122] Example 3 involves adding 3 kg of sodium sulfate decahydrate crystals obtained in Example 1 to 20 L of water and stirring at room temperature at a stirring speed of 100 rpm for 1 hour to completely dissolve the solution, and then mixing 6 kg of additives (2 kg of colloidal amorphous calcium carbonate slurry, 1.5 kg of amorphous magnesium hydroxide slurry, 1.5 kg of aluminum hydroxide powder, and 1 kg of nano-carbon colloidal solution) with 14 kg of this solution to produce a salt removal desalination agent in the form of a slurry in a 20 kg packaging unit.

[0123] Looking at a case of field application of the desalination agent, in the case of the reclaimed land in Gwanghwal-myeon, Gimje-si, Jeollabuk-do owned by 365 Agricultural Cooperative, the average soil salinity was 1.35%. When the desalination agent was diluted 50 times for the first desalination treatment, the salinity decreased to 0.41%, and when the desalination agent was diluted 100 times for the second desalination treatment three days later, the salinity decreased to 0.02%. These test analysis results can be confirmed in Table 3.

[0124] Classification | Salinity Concentration | Removal Rate Soil Salinity 1.35 % - 1st Desalination Treatment 0.41 % 69.6 % 2nd Desalination Treatment 0.02 % 98.5 %

[0125] Since the salt concentration of soil suitable for crop cultivation is generally reported to be 0.3% or less, in Example 3, we were able to successfully cultivate and harvest income crop onions in collaboration with 365 Farming Association Corporation as shown in Fig. 8.

[0126] (4) Example 4

[0127] In Example 4, an ammonia or hydrogen sulfide deodorizer for odor removal is prepared using sodium sulfate decahydrate crystals. Example 4 uses the waste water prepared in Example 1 as the solution required for the preparation of the ammonia or hydrogen sulfide deodorizer.

[0128] Example 4 involves adding 5 kg of sodium sulfate decahydrate crystals obtained in Example 1 to 20 L of water and stirring at room temperature at a stirring speed of 100 rpm for 1 hour to completely dissolve the crystals, then mixing 5 kg of additives with 15 kg of this solution to produce an ammonia or hydrogen sulfide deodorizer in the form of a slurry in a 20 kg packaging unit.

[0129] Here, the additive for the ammonia deodorizer is prepared by mixing 3 kg of colloidal aluminum phosphate slurry, 1.3 kg of anatase-type titanium dioxide powder, and 0.7 kg of nano-carbon colloidal solution, and the additive for the hydrogen sulfide deodorizer is prepared by adding 3 kg of amorphous magnesium hydroxide slurry, 1.3 kg of anatase-type titanium dioxide powder, and 0.7 kg of nano-carbon colloidal solution.

[0130] Test Item | Elapsed Time | Deodorization Rate Deodorization Test: Ammonia - 98.5% or higher after 30 minutes Deodorization Test: Hydrogen Sulfide - 99.0% or higher after 30 minutes

[0131] As shown in Table 4, the results of the deodorization test for such odor-removing ammonia or hydrogen sulfide deodorizers commissioned to the Korea Chemical Convergence Testing & Research Institute showed that after 30 minutes, the deodorization rate of ammonia was 98.5% or higher and the deodorization rate of hydrogen sulfide was 99.0% or higher.

[0132] (5) Example 5

[0133] In Example 5, a dyeing wastewater color and heavy metal removal agent is prepared using sodium sulfate decahydrate crystals. Example 5 uses the wastewater prepared in Example 1 as the solution required for preparing the dyeing wastewater color and heavy metal removal agent.

[0134] Example 5 involves adding 5 kg of sodium sulfate decahydrate crystals obtained in Example 1 to 20 L of water and stirring at room temperature at a stirring speed of 100 rpm for 1 hour to completely dissolve the crystals, and then mixing 7 kg of additives (2.3 kg hollow silica powder, 2 kg calcined dolomite powder, 2 kg hydroxyapatite powder, 0.7 kg nanocarbon colloid solution) with 13 kg of this solution to produce a dye wastewater color and heavy metal removal agent in the form of a slurry in a 20 kg packaging unit.

[0135] Using Example 5, the removal of color and heavy metals from dyeing wastewater discharged from the J Industrial Complex in Pocheon-si, Gyeonggi-do was carried out, and as shown in Fig. 9, it can be seen that the color of the dyeing wastewater decreases from left to right. Furthermore, the color and heavy metals of the dyeing wastewater (raw water) and treated water were subjected to a test analysis by the Korea Environment Corporation, and the results showed that the color removal rate was 84.8% and the heavy metal removal rate was 100%. These test analysis results are shown in Tables 5 and 6.

[0136] Test Item Dyeing Wastewater (Raw Water) Treatment Water Color Diagram 204 Diagram 31 Diagram

[0137] Test Item Dyeing Wastewater (Raw Water) Treated Water Copper (Cu) 0.099 mg / L Not Detected Chromium (Cr) 0.369 mg / L Not Detected Lead (Pb) Not Detected - Arsenic (As) Not Detected - Cadmium (Cd) Not Detected -

[0138] (6) Example 6

[0139] Example 6 prepares sodium sulfate powder using sodium sulfate decahydrate crystals. Example 6 obtains sodium sulfate powder by drying sodium sulfate decahydrate crystals at 250°C for 30 minutes.

[0140] Figure 10 shows the results of X-ray diffraction analysis of sodium sulfate powder. Identification using a JCPDS card confirmed that the peak pattern matches that of sodium sulfate.

[0141] (7) Example 7

[0142] Example 7 prepares an ammonia nitrogen removal agent for water purification using sodium sulfate powder. 10 kg of a mixture of 7.5 kg of sodium sulfate powder and 2.5 kg of additives (1.3 kg of non-swelling mica powder, 0.6 kg of calcium aluminate powder, 0.4 kg of nano-carbon colloidal solution, and 0.2 kg of silver (Ag) colloidal solution) is mixed with 2 kg of recycled water to produce a slurry. This mixture is then poured into various molds and subjected to a natural drying process to produce ammonia nitrogen removal agents (carrier type) of various sizes and shapes as shown in FIG. 11.

[0143] As a result of commissioning Korea E&C Co., Ltd. to analyze the ammonia nitrogen of the ammonia nitrogen removal agent (carrier type), the removal rate of ammonia nitrogen was 62.4%, and the results of this analysis are shown in Table 7.

[0144] Test Item Removal Rate Ammonia Nitrogen 62.4%

[0145] As described above, specific embodiments of the present invention have been explained with reference to the accompanying drawings; however, the scope of protection of the present invention is not necessarily limited to these embodiments. It is made clear that various design changes, the addition or deletion of known technologies, and simple numerical limitations fall within the scope of protection of the present invention as long as they do not alter the technical essence of the present invention.

Claims

1. The invention relates to the production of sodium sulfate decahydrate crystals from high-concentration brine wastewater for secondary batteries by an aqueous solution crystal growth method and a method for resource recovery using the same, wherein First step of transferring high-concentration salt wastewater from a secondary battery to a preheating tank; A second step of supplying high-temperature steam (high-temperature steam) discharged from a hydrothermal reaction tube to a preheating tank to heat the salt wastewater flowing into the preheating tank to 30 to 40℃; A third step of preparing a supersaturated sodium sulfate solution by transferring the brine wastewater preheated in the second step to a horizontal pipe-type hydrothermal reaction tube, heating it to 120 to 150°C for 30 to 60 minutes, and evaporating the water through a hydrothermal reaction until the salinity of the incoming brine wastewater reaches 8 to 9%; A fourth step in which the high-temperature steam discharged in the third step is supplied to the preheating tank of the second step, and a supersaturated sodium sulfate solution with a salinity of 8 to 9% is transferred to a supersaturated solution storage tank; Step 5, supplying carbon dioxide to a supersaturated sodium sulfate solution introduced into a supersaturated solution storage tank to adjust the pH to a range of 7 to 7.5 while precipitating nickel carbonate (NiCO3), and then separating and recovering the precipitate to remove nickel heavy metal contained in the supersaturated sodium sulfate solution; Step 6, transferring a supersaturated sodium sulfate solution with a pH adjusted to 7 to 7.5 and carbon dioxide to an aqueous crystal growth tank; Step 7, growing and obtaining sodium sulfate decahydrate crystals by performing a vertical temperature gradient method for 12 to 24 hours, controlling the upper temperature of an aqueous solution crystal growth tank to a temperature range of 15 to 20℃ and the lower temperature to a temperature range of 2 to 4℃; Step 8, filtering and separating the sodium sulfate decahydrate crystals obtained in Step 7 using a 60 to 100 mesh screen and recovering the remaining liquid; Step 9, naturally drying the sodium sulfate decahydrate crystals separated by filtration in Step 8; and, Step 10, which involves mixing the steam discharged from the preheating tank of Step 2 with the filtrate recovered from filtering and separating sodium sulfate decahydrate crystals in Step 8 to produce usable water for reuse in the resource recovery process; A method for producing sodium sulfate decahydrate crystals from high-concentration salt wastewater of a secondary battery by an aqueous solution crystal growth method characterized by including the above, and a method for resource recovery using the same.

2. In Paragraph 1, Step 11, obtaining sodium sulfate powder by drying the sodium sulfate decahydrate crystals obtained in Step 9 at a temperature range of 200 to 300°C for 20 to 30 minutes; Step 12, adding and mixing 15 to 20 parts by weight of water prepared in Step 10 and 20 to 30 parts by weight of additive (E) to 70 to 80 parts by weight of sodium sulfate powder obtained in Step 11; Step 13, forming the mixture mixed in Step 12; and, Step 14, manufacturing an ammonia nitrogen removal agent for water purification by naturally drying the molded product formed in Step 13; Includes more, The additive (E) is, A method for producing sodium sulfate decahydrate crystals from high-concentration salt wastewater of a secondary battery by an aqueous solution crystal growth method characterized by mixing 10 to 15 parts by weight of non-swelling mica powder, 5 to 7 parts by weight of calcium aluminate powder, 3 to 5 parts by weight of a nanocarbon colloidal solution, and 2 to 3 parts by weight of a silver (Ag) colloidal solution, and a method for resource recovery using the same.

3. In Paragraph 1, Step 15, in which 10 kg of sodium sulfate decahydrate crystals obtained in Step 9 are dissolved in 20 L of water prepared in Step 10, and then an additive (A) is added to produce a valuable metal extractant; Includes more, The additive (A) is, A method for producing sodium sulfate decahydrate crystals from high-concentration salt wastewater of a secondary battery by an aqueous solution crystal growth method characterized by mixing 0.5 L of a 35% concentration hydrochloric acid solution and 0.06 kg of ethylenediamine tetraacetic acid, and a method for resource recovery using the same.

4. In Paragraph 3, Step 16, in which the waste crucible after calcining the cathode active material is immersed in the valuable metal extractant prepared in Step 15 for 24 hours to extract the cathode active material attached to the surface of the waste crucible, and the extract from which the valuable metal has been extracted is used to grow nickel sulfate crystals under the same conditions as the vertical temperature gradient method of Step 7 to obtain the crystals; Step 17, filtering and separating the nickel sulfate crystals obtained in Step 16 using a 60 to 100 mesh screen and recovering the remaining liquid; and, Step 18, obtaining nickel sulfate powder by drying the nickel sulfate crystals filtered and separated in Step 17 at a temperature range of 60 to 80°C for 10 to 12 hours; A method for producing sodium sulfate decahydrate crystals from high-concentration salt wastewater of a secondary battery by an aqueous solution crystal growth method characterized by further including [a specific component], and a method for resource recovery using the same.

5. In Paragraph 4, Step 19, in which sodium hydroxide is added to the filtrate recovered in Step 17 to adjust the pH of the filtrate to 11 to 12, carbon dioxide is supplied to adjust the pH to a range of 8 to 8.5, and a precipitation reaction is carried out for 12 hours, and the solid separated using a centrifuge is dried at a temperature range of 90 to 110°C for 12 hours to obtain lithium carbonate powder; A method for producing sodium sulfate decahydrate crystals from high-concentration salt wastewater of a secondary battery by an aqueous solution crystal growth method characterized by further including [a specific component], and a method for resource recovery using the same.

6. In Paragraph 1, Step 20, preparing a salt removal desalination agent in the form of a slurry by adding 25 to 40 parts by weight of additive (B) to 60 to 75 parts by weight of a solution obtained by dissolving 3 kg of sodium sulfate decahydrate crystals obtained in Step 9 in 20 L of water prepared in Step 10; is additionally included, The additive (B) is, A method for producing sodium sulfate decahydrate crystals from high-concentration salt wastewater of a secondary battery by an aqueous solution crystal growth method characterized by mixing 7 to 10 parts by weight of colloidal amorphous calcium carbonate slurry, 5 to 8 parts by weight of amorphous magnesium hydroxide slurry, 5 to 8 parts by weight of aluminum hydroxide powder, and 3 to 4 parts by weight of a nano-carbon colloidal solution, and a method for resource recovery using the same.

7. In Paragraph 1, Step 21, preparing an ammonia or hydrogen sulfide deodorizer in the form of a slurry by adding 20 to 30 parts by weight of an additive (C) to 70 to 80 parts by weight of a solution obtained by dissolving 5 kg of sodium sulfate decahydrate crystals obtained in Step 9 in 20 L of water prepared in Step 10; is additionally included, The additive (C) used when manufacturing an ammonia deodorizer is, Prepared by mixing 3 kg of colloidal aluminum phosphate slurry, 1.3 kg of anatase-type titanium dioxide powder, and 0.7 kg of nanocarbon colloidal solution, and The additive (C) used when manufacturing a hydrogen sulfide deodorizer is, A method for producing sodium sulfate decahydrate crystals from high-concentration salt wastewater for secondary batteries by an aqueous solution crystal growth method characterized by adding 3 kg of amorphous magnesium hydroxide slurry, 1.3 kg of anatase-type titanium dioxide powder, and 0.7 kg of nanocarbon colloidal solution, and a method for resource recovery using the same.

8. In Paragraph 1, Step 22, preparing a color and heavy metal removal agent for dyeing wastewater in the form of a slurry by adding 30 to 40 parts by weight of additive (D) to 60 to 70 parts by weight of a solution obtained by dissolving 5 kg of sodium sulfate decahydrate crystals obtained in Step 9 in 20 L of water prepared in Step 10; is additionally included, The additive (D) is, A method for producing sodium sulfate decahydrate crystals from high-concentration salt wastewater of a secondary battery by an aqueous solution crystal growth method characterized by mixing 10 to 14 parts by weight of hollow silica powder, 8 to 10 parts by weight of calcined dolomite powder, 8 to 10 parts by weight of hydroxyapatite powder, and 4 to 6 parts by weight of a nanocarbon colloidal solution, and a method for resource recovery using the same.

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