KR102415603B1 - Sulfuric acid separating apparatus and method for separating and recovering sulfuric acid using separating apparatus - Google Patents

Abstract

The present invention relates to a sulfuric acid separation device and a method for separating and recovering highly concentrated sulfuric acid including the same, and more particularly, it has excellent separation efficiency of sulfuric acid from wastewater containing impurities and sulfuric acid, and purification performance that can occur in a long-term purification process of sulfuric acid The present invention relates to a sulfuric acid separation device that minimizes the decrease in , and facilitates additional recovery of rare metals contained in impurities separated in the filtration process, and a highly concentrated sulfuric acid separation and recovery method including the same.

Description

Sulfuric acid separating apparatus and highly concentrated sulfuric acid separation and recovery method comprising the same

The present invention relates to a sulfuric acid separation device and a method for separating and recovering highly concentrated sulfuric acid including the same, and more particularly, it has excellent separation efficiency of sulfuric acid from wastewater containing impurities and sulfuric acid, and purification performance that can occur in a long-term purification process of sulfuric acid The present invention relates to a sulfuric acid separation device that minimizes the decrease in , and facilitates additional recovery of rare metals contained in impurities separated in the filtration process, and a highly concentrated sulfuric acid separation and recovery method including the same.

In general, the separation membrane is classified into a microfiltration membrane (MF), an ultrafiltration membrane (UF), a nano membrane (NF), or a reverse osmosis membrane (RO) according to the pore size. Among them, the ultrafiltration membrane is usually defined as a membrane having the ability to separate colloidal substances having a molecular weight of 1,000 to 300,000 and a polymer solution.

Specifically, a cellulose membrane has been used for the ultrafiltration membrane in the past. Recently, with the development of synthetic polymer chemistry, a membrane excellent in permeability using a hydrophilic polymer such as polyvinyl alcohol has been developed. Contrary to reverse osmosis membranes, ultrafiltration membranes are often used to obtain concentrated water rather than permeate water, and are used in food wastewater treatment, pharmaceutical purification, electrical painting, etc., in Korea. Patent Registration No. 0815276 discloses a pharmaceutical composition comprising a high proportion of a panaxadiol-based saponin fraction separated from red ginseng by ultrafiltration, and ultrafiltration is also used for concentration and purification of food.

The nano separation membrane is generally defined as a membrane having the ability to separate compounds having a molecular weight of less than 1,000. Specifically, as a membrane with selective separation capability for nanometer-level solutes, it has a high salt removal rate for divalent ions, a relatively wide salt removal rate for monovalent ions of 40% or more, and multifunctionality. Compared to reverse osmosis membranes using aromatic amines, it has a permeability that is 5 to 10 times greater. In particular, there is an advantage in that it is possible to produce water quality from which substances such as geosmin, a representative taste substance, and contaminants generated during water treatment, such as nitrate nitrogen and trihalogen methane, are removed by the nano-membrane.

The reverse osmosis membrane is a separation membrane capable of removing monovalent ions or salts that cannot be removed in microfiltration (MF) or ultrafiltration (UF), etc. It is effectively used in the desalination process. In order for the reverse osmosis membrane to have characteristics suitable for the purpose of use, it must have high salt rejection and high flux. That is, the reverse osmosis membrane can be commercially applied to the desalination process only when a large amount of water can permeate through the membrane under a relatively low pressure.

On the other hand, sulfuric acid is generally manufactured after roasting sulfur or sulfite or iron sulfide to make sulfur dioxide, oxidizing it, and absorbing it in water. In general, high-purity sulfuric acid is produced by absorbing sulfur dioxide into water from waste gas produced during smelting at an ore smelter. At this time, the impurities contained in the waste gas are mixed with the sulfuric acid solution to sink, and the sulfuric acid wastewater remaining after the high-purity product sulfuric acid is collected is treated through a separate process. In this case, the treatment method is mainly used by neutralization or adsorption. The reason for neutralization or adsorption is to recover rare metals contained in sulfuric acid wastewater. However, neutralization and adsorption methods require different chemicals. Accordingly, there is a problem in that the consumption cost is large, which is not economical in terms of manufacturing cost. Republic of Korea Patent Application No. 2005-0012194 discloses a process for recovering acid using a solvent extraction method to separate acid from waste etching liquid or waste acid, and the prior document discloses an acid by adding a separate extractant, diluent, etc. There are problems in that recovery cost increases due to the use of extractants and diluents and it is difficult to recover acid in high yield. In addition, in the case of sulfuric acid, it is a strong acid unlike the conventional acids disclosed in the prior literature. In particular, in the purification, there is a problem in that it is difficult to adopt the above method through the recovery cost, the complexity of the process, the recovery time, and the like.

Therefore, there is an urgent need to develop a device that can economically and easily separate sulfuric acid from sulfuric acid wastewater with high purity and easily recover rare metals from impurities contained in sulfuric acid wastewater among various acids.

Japanese Laid-Open Patent Application Laid-Open No. 2000-24692 (published on January 1, 2000)

The present invention has been devised to solve the above problems, and the separation efficiency of sulfuric acid from wastewater containing impurities and sulfuric acid is excellent, and deterioration of purification performance that may occur in the purification process of sulfuric acid for a long period of time is minimized, and in the filtration process A sulfuric acid separation device that facilitates the additional recovery of rare metals contained in the separated impurities, a highly concentrated sulfuric acid separation and recovery method including the same, a reverse osmosis membrane for sulfuric acid separation, a reverse osmosis module for sulfuric acid separation including the same, and a highly concentrated sulfuric acid separation and recovery system is to provide

In order to solve the above problems, the present invention provides an inlet through which wastewater containing impurities and sulfuric acid is introduced; a filtering unit including a reverse osmosis module for filtering sulfuric acid by separating impurities and sulfuric acid from wastewater containing impurities and sulfuric acid introduced into the inlet; a first discharge unit for discharging the filtrate containing the sulfuric acid; and a second discharge unit for discharging the wastewater containing the unfiltered and separated impurities and sulfuric acid.

According to a preferred embodiment of the present invention, the reverse osmosis module of the filtering unit includes a reverse osmosis membrane including a support, a polymer support layer, and a polyamide layer, and the frequency of the infrared absorption spectrum by infrared spectroscopy for the polyamide layer A ratio of the absorbance at a frequency of 1540 cm ⁻¹ to the absorbance at 1585 cm ⁻¹ may be 1.7 or more.

According to another preferred embodiment of the present invention, the reverse osmosis module of the filter unit includes a reverse osmosis membrane including a support, a polymer support layer, and a polyamide layer, and an infrared absorption spectrum for the polyamide layer by infrared spectroscopy The ratio of the absorbance at the frequency of 1540 cm ^-1 to the absorbance at the medium frequency of 1585 cm ^-1 may be 3.2 or less.

According to another preferred embodiment of the present invention, the operating pressure for the reverse osmosis module included in the filter unit may be 80 kgf/cm 2 or less.

According to another preferred embodiment of the present invention, the sulfuric acid recovery rate of the reverse osmosis module included in the filter unit may be 90% or less.

According to another preferred embodiment of the present invention, the reverse osmosis module included in the filter unit may be a spiral wound type reverse osmosis module.

In addition, in order to solve the above problems, the present invention includes a plurality of sulfuric acid separation devices according to the present invention, wherein wastewater containing impurities and sulfuric acid or filtered sulfuric acid is included in any one of the plurality of separation devices. The wastewater containing the introduced impurities and sulfuric acid or the filtrate containing sulfuric acid is concentrated through filtration or re-filtration by the filtration unit and discharged to the first discharge unit, and the impurities and sulfuric acid separated without filtration are collected from the inlet. An object of the present invention is to provide a method for separating and recovering highly concentrated sulfuric acid, including discharging wastewater containing re-separated impurities and wastewater containing sulfuric acid through a second discharge unit.

In addition, the present invention in order to solve the above problems, the support; polymer support layer; and a polyamide layer, wherein the ratio of the absorbance at the frequency of 1540 cm ^-1 to the absorbance at the frequency of 1585 cm ^-1 in the infrared absorption spectrum by infrared spectroscopy for the polyamide layer is 1.7 or more. An object of the present invention is to provide a reverse osmosis membrane.

According to a preferred embodiment of the present invention, the thickness of the polyamide layer may be 0.05 ~ 0.3㎛.

According to another preferred embodiment of the present invention, the absorbance ratio may be 3.2 or less.

In addition, in order to solve the above problems, the present invention is to provide a reverse osmosis module for sulfuric acid separation including the reverse osmosis membrane for sulfuric acid separation according to the present invention.

In addition, in order to solve the above problems, the present invention is to provide a highly concentrated sulfuric acid separation and recovery system including a plurality of sulfuric acid separation devices according to the present invention.

The sulfuric acid separation device of the present invention has excellent separation efficiency of sulfuric acid from wastewater containing impurities and sulfuric acid, and minimizes the deterioration of purification performance that may occur in the long-term purification process of sulfuric acid, and the rare content contained in impurities separated during the filtration process Additional economic benefits can be secured by facilitating additional recovery of the metal.

1 is a schematic diagram of an apparatus for separating sulfuric acid according to a preferred embodiment of the present invention.
2 is a schematic cross-sectional view of a reverse osmosis membrane included in a sulfuric acid separation device according to a preferred embodiment of the present invention.
3 is an exploded perspective view of the reverse osmosis module included in the sulfuric acid separation device according to a preferred embodiment of the present invention.
4 is a schematic diagram of a sulfuric acid separation and recovery system according to a preferred embodiment of the present invention.

Hereinafter, the present invention will be described in more detail.

As described above, the conventional method for recovering sulfuric acid from wastewater containing sulfuric acid through neutralization or adsorption requires various chemicals. As a result, there was a problem that the consumption cost was high, and it was not economical in terms of manufacturing cost. In addition, in the case of recovering the acid using the solvent extraction method, a separate extractant or diluent is added to recover the acid, so the recovery cost increases due to the use of the extractant and the diluent and it is difficult to recover the acid in a high yield. There is this. Furthermore, in the case of sulfuric acid, it is a strong acid unlike conventional acids. In particular, in the purification, there is a problem in that it is difficult to adopt the above method in the recovery cost, the complexity of the process, the recovery time, and the like.

Specifically, FIG. 1 is a schematic diagram of a sulfuric acid separation device according to the present invention, in which wastewater (A) containing impurities and sulfuric acid is introduced into the separation device 10 through an inlet (1) and the inlet (1). A filtration unit (2) for filtering sulfuric acid from wastewater containing impurities and sulfuric acid, a first discharge unit (3) for discharging the filtrate (B) containing sulfuric acid filtered through the filtration unit (2) and a second discharge unit (4) for discharging wastewater (C) containing impurities and residual sulfuric acid that has not been filtered in the filtering unit (2), and applying pressure to the wastewater (A) flowing into the separation device It may include a high-pressure pump (5) for.

First, the inlet 1 will be described.

The inlet 1 is responsible for introducing wastewater (A) containing impurities and sulfuric acid into the separation device 10 for filtration, and the inlet 1 is included in a conventional sulfuric acid separation device. It may be an inlet, and may be used without limitation if it can perform a function of smoothly introducing wastewater A into the filtering unit 2 in the separation device 5, and accordingly, the specific shape, material, and size of the inlet Accordingly, the size, shape, material, etc. of the inlet 1 are not particularly limited in the present invention, and may be used by changing the purpose of the invention, the scale of the facility, and the like.

Next, the filtration unit 2 through which the wastewater A containing impurities and sulfuric acid introduced through the inlet 1 passes will be described.

The filtering unit (2) is responsible for separating the desired sulfuric acid from the wastewater containing impurities from the wastewater (A) containing impurities and sulfuric acid introduced through the inlet unit (1), and the filter unit (3) An included reverse osmosis module (not shown) is included for filtration of sulfuric acid.

The reverse osmosis module includes a reverse osmosis membrane that may be included in a conventional reverse osmosis module, and other members included in the module may be members included in a conventional reverse osmosis module.

2 is a schematic cross-sectional view of a reverse osmosis membrane according to a preferred embodiment of the present invention, a support 210, a polymer support layer 220 formed on at least one surface of the support 210, and the polymer support layer 220 formed on A polyamide layer 230 may be included.

More specifically, the support 210 is not particularly limited as long as it functions as a support for a reverse osmosis membrane, but may preferably be a fabric. Specifically, the fabric refers to a woven fabric, a knitted fabric or a nonwoven fabric, and the fabric has a vertical and horizontal direction as it is woven with warp and weft yarns, and the specific direction of the knitted fabric may vary depending on the knitting method, but in a broad sense, any one of vertical and horizontal directions. It may have a directionality in a direction. In addition, the nonwoven fabric does not have a vertical and horizontal direction unlike the woven or knitted fabric.

When the fabric is a fabric, physical properties such as porosity, pore size, strength, and permeability of the desired support can be controlled by controlling warp, the type of fibers forming the weft, fineness, the density of the warp and weft yarns, the texture of the fabric, and the like.

In addition, when the fabric is a knitted fabric, properties such as porosity, pore diameter, strength, and permeability of the desired support can be adjusted by controlling the type of fiber, fineness, knitted structure, gauge, cut, etc. included in the knitted fabric.

In addition, when the fabric is a nonwoven fabric, properties such as porosity, pore size, strength, and permeability of the desired support can be controlled by adjusting the type, fineness, fiber length, basis weight, density, etc. of fibers included in the nonwoven fabric.

The material of the support 210 may normally serve as a support for the membrane, and as long as it is used for a support of a conventional separator, it may be used without limitation. Non-limiting examples thereof include synthetic fibers selected from the group consisting of polyester, polypropylene, nylon and polyethylene; Or natural fibers containing cellulose; can be used.

The support 210 may have an average pore diameter of preferably 1 μm to 100 μm, more preferably 1 μm to 50 μm, and still more preferably 3 μm to 40 μm. If the average pore diameter is less than 1㎛, there may be problems such as a decrease in flow rate, and there may be problems such as generating a differential pressure in the filter. There may be unsolvable problems.

The thickness of the support 210 of the present invention is preferably 20 μm to 150 μm, preferably 50 μm to 130 μm, more preferably 50 μm to 130 μm, and if less than 20 μm, the strength of the entire membrane Insufficient in and support area, and if it exceeds 150 μm, it may cause a decrease in flow rate.

In addition, the polymer support layer 220 formed on at least one surface of the support 210 may use a polymer material included in a conventional reverse osmosis membrane polymer support layer, and in consideration of mechanical strength, the weight average molecular weight is in the range of 65,000 to 150,000, Preferably it is in the range of 70,000 to 135,000, more preferably in the range of 75,000 to 120,000, and as a preferred example, a polysulfone-based polymer, a polyamide-based polymer, a polyimide-based polymer, a polyester-based polymer, It may include any one or more selected from the group consisting of an olefin-based polymer, polyvinylidene fluoride, polybenzoimidazole polymer, and polyacrylonitrile.

The polymer support layer 220 used in the reverse osmosis membrane included in a preferred embodiment of the present invention is a general microporous support layer, and the type thereof is not particularly limited, but in general, it should be of a size sufficient to allow permeated water to permeate, and the It should not be large enough to interfere with the crosslinking of the ultra-thin film formed thereon. At this time, the pore diameter of the polymer support layer 220 is 1 nm to 500 nm, preferably 5 nm to 400 nm, more preferably 20 nm to 350 nm, and if the pore diameter exceeds 500 nm, after forming the thin film, the ultra-thin film is It can be recessed into the pore diameter, making it difficult to achieve the desired flat sheet structure.

In addition, the polymer support layer 220 has a thickness of 10 μm to 100 μm, preferably 20 μm to 50 μm, and if the thickness of the polymer support layer is less than 10 μm, the strength of the polymer support layer is weak, so that even with a small force, the polymer support layer is There may be a problem in that the separation efficiency of the separation membrane is peeled off and the interfacial polymerization is not uniform, and when the thickness exceeds 100 μm, the thickness is thickened and there may be a problem in that the flow rate is lowered.

Next, the polyamide layer 230 formed on the support 220 may be a polyamide layer included in a conventional reverse osmosis membrane, and the polymer support layer 220 is placed in an aqueous solution containing a polyfunctional amine for 0.1 to 10 minutes, preferably After immersion for 0.5 to 1 minute and removing excess solution, it is again immersed in an organic solution containing a polyfunctional acid halogen compound, contacted and interfacially polymerized, washed and dried to form a polyamide layer. The polyamide layer may include an aromatic polyamide obtained by interfacial polymerization of an aromatic polyfunctional amine having two primary amine groups and an aromatic acyl halide having two or more acyl halide functional groups. The aromatic polyfunctional amine containing two primary amine groups includes at least one of metaphenylenediamine, paraphenylenediamine, orthophenyldiamine and derivatives thereof, or the polyfunctional amine is 2-3 per monomer. The material having an open amine functional group may be a polyamine including a primary amine or a secondary amine. More preferably, metaphenylenediamine may be used as the polyfunctional amine.

In addition, the polyfunctional amine-containing aqueous solution can be prepared by dissolving the polyfunctional amine in an alkyldiol-based aqueous solution, and the alkyldiol-based aqueous solution is 2-ethyl-1,3-hexanediol aqueous solution and 1,2-hexanediol aqueous solution , at least one selected from an aqueous solution of 1,3-heptanediol and an aqueous 1,6-hexanediol solution, preferably at least one selected from an aqueous solution of 2-ethyl-1,3-hexanediol and an aqueous 1,3-heptanediol solution may include And, the content of the polyfunctional amine in the alkyldiol-based aqueous solution is preferably in the form of an aqueous solution containing 0.5 to 10% by weight of metaphenylenediamine, more preferably 1.8 to 4% by weight of metaphenylenediamine, more preferably 2.0 to 3.5% by weight may be contained. At this time, if the polyfunctional amine content is less than 0.5% by weight, there may be a problem that the degree of crosslinking during interfacial polymerization is lowered and thus durability is weakened. there may be

In addition, the polyfunctional acid halogen compound may include at least one selected from trimesoyl chloride, isophthaloyl chloride and terephthaloyl chloride, preferably tri Mesoyl chloride can be used. In addition, the organic solution may include at least one organic solvent selected from liquid paraffin, hexane, cyclohexane and heptane, and 0.01 to 2 wt% of the polyfunctional acid halogen compound in the organic solvent, preferably 0.05 to An organic solution can be prepared by dissolving 1 wt%. At this time, if the content of the polyfunctional acid halogen compound is less than 0.01% by weight or exceeds 2% by weight, there is a problem that the degree of crosslinking may decrease during interfacial polymerization, which may cause deterioration of the performance of the separator.

Although the structure of the reverse osmosis membrane used in the present invention is not significantly different from that of a conventional reverse osmosis membrane, it has excellent filtration ability for sulfuric acid, a strong acid, and at the same time has excellent filtration performance without continuously lowering the filtration ability during long-term operation for the separation of sulfuric acid. In order to exhibit the desired filtration performance and durability against sulfuric acid at the same time by using a conventional reverse osmosis membrane as it is.

Specifically, conventionally, the reverse osmosis module was used to treat leachate from landfills or sewage (including manure, sewage, livestock wastewater, etc.) from homes and businesses, or to treat chemical wastewater containing pesticides. In the case of treatment, the reverse osmosis membrane included in the reverse osmosis module was damaged by the substances contained in the wastewater, so that long-term operation was impossible, and the use cycle of the reverse osmosis membrane was shortened. In addition, in order to solve this problem, damage to the polymer support layer included in the separation membrane was prevented by adding a separate membrane protective material, for example, SBS (sodium sulfate), before or during the separation process operation. However, when the solution to be treated is a solution containing a strong acid such as sulfuric acid, damage to the membrane cannot be avoided. In particular, in the case of a polyamide layer, which is an optional layer typically included in a reverse osmosis membrane, the separation ability is remarkably reduced as it is easily peeled off and/or damaged because it is vulnerable to acid. When used, there was a fatal problem in that the durability of the reverse osmosis module was lowered and the use cycle was reduced, and frequent replacement of the module caused a significant increase in the refining cost.

Accordingly, according to a preferred embodiment of the present invention, in the polyamide layer, the ratio of absorbance at frequency 1540 cm ^-1 to absorbance at frequency 1585 cm ^-1 in the infrared absorption spectrum by infrared spectroscopy may be 1.7 or more, preferably may be 1.7 to 3.2, more preferably 2.1 to 3.0, even more preferably 2.100 to 2.300. If a reverse osmosis membrane including a polyamide layer having an absorbance ratio of less than 1.7 is included to filter sulfuric acid in the beginning, even if there is no significant difference in filtration performance at the beginning, the decrease in filtration performance is significant as the operation period increases. There may be a problem in advancing the replacement time. The ratio of the absorbance may be more preferably 2.1 or more, and through this, there may be an advantage in that the use cycle is longer and a sulfuric acid separation device in which the decrease in filtration performance is minimized can be implemented.

In addition, the ratio of the absorbance to the polyamide layer may be preferably 3 or less. If it exceeds 3, the filtration efficiency and durability of sulfuric acid may be increased, but there may be a problem in that the obtained filtrate containing sulfuric acid (B of FIG. 1) is significantly reduced.

In addition, the thickness of the polyamide layer (230 in FIG. 2 ) is preferably 0.05 to 0.3 µm, preferably 0.05 to 0.25 µm, and more preferably 0.1 to 0.2 µm. If it is less than 0.05 μm, the durability of the polyamide layer may be deteriorated and thus it cannot be used for a long-term sulfuric acid separation process, and if it exceeds 0.3 μm, there may be a problem in that the yield of the obtained sulfuric acid filtrate may be reduced.

On the other hand, the sulfuric acid separation device including a reverse osmosis membrane according to a preferred embodiment of the present invention is suitable for use in the purification of sulfuric acid, but may not be suitable for purification of nitric acid mixed with impurities. Specifically, according to Example 1, which is a preferred example of the present invention, the recovery rate of sulfuric acid reached 79.94% as a result of operation for 30 days under the conditions of 25 and an operating pressure of 50 kgf/cm 2 , but the separation process for a solution containing impurities and nitric acid was performed. In the case of Comparative Example 1, it was confirmed that the recovery rate of nitric acid was only 21.6% and the removal rate of other impurities was also low. Therefore, it can be confirmed that the separation device according to the present invention is particularly effective for sulfuric acid among strong acids.

On the other hand, the present invention includes a reverse osmosis module including a reverse osmosis membrane for sulfuric acid separation according to the present invention. According to a preferred embodiment of the present invention, a plurality of reverse osmosis membranes as described above may be included in the reverse osmosis module, and these reverse osmosis membranes may be spirally wound and included in the module. When the separation membrane is a module wound in a spiral wound type, the surface area of the separation membrane included in the limited module volume can be increased, so that the effective filtration area is increased, thereby increasing the filtration efficiency and the number of products obtained.

In the reverse osmosis membrane of the present invention, the sulfuric acid recovery rate of the reverse osmosis module included in the filtration unit may be 90% or less, preferably 30% to 90%.

In addition, in the reverse osmosis membrane of the present invention, the concentration of sulfuric acid in the incoming wastewater is 100,000 ppm, and when the separation and recovery treatment is performed for 30 days under the condition of an operating pressure of 50kgf/cm2, the sulfuric acid concentration of the filtrate discharged from the first discharge unit is 70,000 ~ 90,000 ppm.

In addition, the reverse osmosis membrane of the present invention is not wound, and after it is prepared as a flat membrane, it is measured under the conditions of 2,000 ppm NaCl, pressure 15.8 kg/cm ² , temperature 25° C., and feed flow rate of 3.5 L/min. A flow rate of 12 to 35 GFD and a NaCl removal rate of 99.0% or more, preferably a flow rate of 14 to 35 GFD and a NaCl removal rate of 99.2 to 99.9%, more preferably a flow rate of 14 to 34 GFD and a NaCl removal rate of 99.3 to 99.8% can

Specifically, FIG. 3 is an exploded perspective view of a reverse osmosis module included in a preferred embodiment of the present invention, in which the reverse osmosis membrane 22 is wound around the reverse osmosis membrane production water inlet pipe 20 in the outer case 30 in a spiral wound type. may be included, and the production water may be introduced into the inlet pipe through the hole 21 perforated in the inlet pipe 20 . More specifically, the reverse osmosis membrane may be spirally wound on the reverse osmosis membrane production water inlet pipe together with a spacer for the purpose of forming a flow path, and may include an end cap (not shown, endcap) for shape stability of the separation membrane wound at both ends of the wound membrane. have. The material, shape, and size of the spacer and the end cap may be those of the spacer and the end cap used in a conventional reverse osmosis module. The reverse osmosis membrane wound as described above may be housed in an outer case, and the material, size, and shape of the outer case may also be the material, size, and shape of the outer case used in a typical reverse osmosis module.

In addition, the operating pressure of the above-described reverse osmosis module may be preferably 80 kgf/cm 2 or less, and more preferably 30 to 60 kgf/cm 2 . If the operating pressure exceeds 80 kgf/cm2, there may be a problem that the module may be damaged. However, it is preferable that the operating pressure be operated at a pressure of 30 kgf/cm 2 or more in order to separate sulfuric acid at a high concentration.

On the other hand, the separation device according to a preferred embodiment of the present invention may include a filtration unit including a plurality of reverse osmosis modules as described above. By including a plurality of reverse osmosis modules, more improved sulfuric acid separation efficiency and a flow rate of the obtained sulfuric acid may be increased, and more preferably, 3 to 8 reverse osmosis modules may be included in the filtration unit.

In addition, when the separation device according to a preferred embodiment of the present invention includes a plurality of reverse osmosis modules, they may be arranged in parallel. By disposing the reverse osmosis modules in parallel, there is an advantage in that the yield of a higher concentration of sulfuric acid can be increased compared to when the reverse osmosis modules are arranged in series.

The filter unit including the reverse osmosis module described above may be operated by setting the sulfuric acid recovery rate to 90% or less. If the recovery rate of sulfuric acid is set to exceed 90%, the yield of sulfuric acid filtered through the filter can be increased, but the contamination of the reverse osmosis membrane is accelerated by impurities contained in the wastewater, so There may be a problem in that the filtration capacity for sulfuric acid is significantly reduced and the filtration ability for sulfuric acid is reduced due to membrane contamination.

Next, the first discharge unit 3 included in the separation device 10 according to the present invention will be described. The first discharge unit 3 is responsible for discharging the filtrate (B) containing the sulfuric acid filtered by the filtering unit 2 to the separation device, and has a typical shape, material, The outlet of the structure may be used. The filtrate (B) containing sulfuric acid discharged from the first discharge unit (3) is introduced into a storage for sulfuric acid recovery or to further separate other impurities contained in the filtrate (B) and to obtain a high concentration of sulfuric acid. It may be introduced into an inlet included in another sulfuric acid separation device and undergo re-filtration.

Next, the second discharge unit 4 included in the separation device 10 according to the present invention will be described. The second discharge unit 4 plays a role in discharging the wastewater (c) containing unfiltered impurities and sulfuric acid in the filtering unit 2, and has a typical shape, material, and structure capable of performing this function. of the outlet may be used. The wastewater (C) containing the impurities and sulfuric acid discharged from the second discharge part (4) is introduced into an inlet part included in another separation device to re-filter and utilize the sulfuric acid contained in the wastewater (C) or as raw water. It may be transferred to the used wastewater storage and mixed with raw water and re-introduced into the same sulfuric acid separation device, or may be transferred to the wastewater concentration storage to end the separation process.

On the other hand, the present invention includes a plurality of the above-described sulfuric acid separation device, wastewater containing impurities and sulfuric acid or filtered sulfuric acid is introduced into an inlet included in any one of the plurality of separation devices, and the introduced impurities and sulfuric acid Wastewater or filtered sulfuric acid containing The wastewater includes a method for separating and recovering highly concentrated sulfuric acid, which includes being discharged through a second discharge unit.

Specifically, FIG. 4 is a schematic diagram of a highly concentrated sulfuric acid separation and recovery treatment system according to a preferred embodiment of the present invention. The wastewater 12 containing impurities and sulfuric acid flows into the inlet included in the first sulfuric acid separation device 13. and the filtrate 13 containing the filtered sulfuric acid is introduced into the inlet included in the second sulfuric acid separation device 14, and the filtrate containing the more concentrated sulfuric acid filtered by the second sulfuric acid separation device 14 (16) can be introduced into the third sulfuric acid separation device (not shown) to produce a highly concentrated sulfuric acid filtrate or transferred to a storage for sulfuric acid recovery. Wastewater 16 containing impurities and sulfuric acid separated without being filtered by the first sulfuric acid separator 13 and the second sulfuric acid separator 15 is a storage in which raw wastewater is stored in order to further recover the sulfuric acid contained therein. It may be transferred to the effluent or a wastewater concentration storage so that no further separation process may be performed, or it may be introduced into another sulfuric acid separation device (not shown). If it is introduced into another sulfuric acid separator (not shown) and filtered, unfiltered impurities can be obtained in high concentration in addition to the advantage of obtaining a filtrate containing filtered sulfuric acid, and in this process (another sulfuric acid separator) filtration process), the concentration of impurities in the wastewater containing impurities is increased, so that rare metals included in the impurities, for example, metals such as nickel, copper, iron, etc., can be more easily obtained. In the case of rare metals, it is desirable to further consider their additional harvesting, especially if the wastewater containing impurities and sulfuric acid may be from the ore smelting process.

On the other hand, the present invention includes a high concentration sulfuric acid separation and recovery system including a plurality of the above-described sulfuric acid separation device.

The sulfuric acid separation and recovery system may further include other devices such as a conventional high-pressure pump required for sulfuric acid purification in addition to the sulfuric acid separation device, and specific other devices are not particularly limited.

The arrangement of the separation device may implement a separation and recovery system either alone or in combination among series and parallel types, and may be implemented by changing the concentration of sulfuric acid to be obtained, the amount of rare metal to be additionally obtained, and the like.

The present invention will be described in more detail through the following examples, but the following examples are not intended to limit the scope of the present invention, which should be construed to aid understanding of the present invention.

[ Example ]

Example One

A 120 μm thick porous polysulfone support including a polyester nonwoven fabric (non-woven support 90 μm + polymer support layer 30 μm) was mixed with 2.0% by weight of meta-phenylenediamine (MPD) and 0.2% by weight of 2-ethyl-1, After being immersed in an aqueous solution containing 3-hexanediol for 40 seconds and taken out, the excess aqueous solution on the support was removed. Thereafter, the coated support was immersed in a solution containing 0.1% by weight of trimesoyl chloride (TMC) in a liquid paraffin solvent (ISOPAR, Exxon Corp.) for 1 minute to remove the excess organic solution from the support. The resulting separation membrane was washed with water at room temperature for 30 minutes in 0.2% by weight of sodium carbonate aqueous solution, washed with distilled water and dried to complete a reverse osmosis membrane.

The reverse osmosis membrane prepared as described above, including the configuration used in a conventional reverse osmosis module, was wound around the porous permeate outlet pipe in a spiral wound type according to a conventional method of manufacturing a module to prepare a reverse osmosis module. .

These three reverse osmosis modules are included in the filtration unit of the separation device as shown in FIG. 1 and arranged in parallel to allow raw water to pass through the individual modules. A sulfuric acid separator was prepared. Thereafter, the sulfuric acid separation and recovery system as shown in FIG. 4 was designed to include two separation devices as described above. At this time, the unfiltered concentrated water (eg, 17 in FIG. 4 ) was introduced into the raw water tank containing wastewater so that it could go through the filtration process again.

Using the sulfuric acid separation and recovery system designed as described above, the measured pressure of each module was set to 50 kgf under 25 conditions in a positive pressure operation method set to have a recovery rate of 40% for each reverse osmosis module included in the filter unit included in each separation device. /cm ² Sulfuric acid separation and recovery treatment was performed for wastewater containing sulfuric acid and impurities as shown in Table 1 below for 30 days.

Sulfuric acid (ppm) Impurities (ppm) H ₂ SO ₄ As Ca Cu Fe K Mg 100,000 3,124 112 4426 750 214 75 Ni Pb Zn Cl F Na 3 10 1047 1748 1328 331

Example 2

Sulfuric acid separation and recovery treatment was performed using a reverse osmosis membrane prepared in the same manner as in Example 1, except that meta-phenylenediamine (MPD) for forming the polyamide layer was used in 2.5 wt% instead of 2.0 wt% did

Example 3

Sulfuric acid separation and recovery treatment was carried out using a reverse osmosis membrane prepared in the same manner as in Example 1, except that meta-phenylenediamine (MPD) for forming the polyamide layer was used at 3.4 wt% instead of 2.0 wt% did

Example 4

The same procedure as in Example 1, except that meta-phenylenediamine (MPD) was immersed in an aqueous solution containing meta-phenylenediamine (MPD) to form a polyamide layer, the excess solution was removed, and then trimesoyl chloride was added to a liquid paraffin solvent (ISOPAR, Exxon Corp.). (TMC) After immersion in a solution containing 0.5% by weight, washing with water, and drying to prepare a reverse osmosis membrane, sulfuric acid separation and recovery treatment was performed in the same manner as in Example 1 using this.

comparative example One

It was carried out in the same manner as in Example 1, except that the wastewater containing nitric acid and impurities as shown in Table 2 below was subjected to nitric acid separation and recovery treatment for 30 days.

Nitric acid (ppm) Impurities (ppm) HNO ₃ As Ca Cu Fe K Mg 124,000 2,414 462 3954 934 432 56 Ni Pb Zn Cl F Na 17 46 1725 1485 1129 247

comparative example 2

Sulfuric acid was carried out in the same manner as in Example 1, but using a reverse osmosis membrane prepared by using meta-phenylenediamine (MPD) at 1.6 wt% instead of 2.0 wt% as shown in Table 3 below to form a polyamide layer Separation and recovery treatment was performed.

comparative example 3

Sulfuric acid was carried out in the same manner as in Example 1, but using a reverse osmosis membrane prepared by using meta-phenylenediamine (MPD) in 1.47 wt% instead of 2.0 wt% as shown in Table 3 below for forming a polyamide layer Separation and recovery treatment was performed.

comparative example 4

Sulfuric acid was carried out in the same manner as in Example 1, but using a reverse osmosis membrane prepared by using meta-phenylenediamine (MPD) in 5 wt% instead of 2.0 wt% as shown in Table 3 below for forming a polyamide layer Separation and recovery treatment was performed.

comparative example 5

The same procedure as in Example 1, except that meta-phenylenediamine (MPD) was immersed in an aqueous solution containing meta-phenylenediamine (MPD) to form a polyamide layer, excess solution was removed, and trimesoyl chloride was placed in a liquid paraffin solvent (ISOPAR, Exxon Corp.) (TMC) After immersion in a solution containing 2.5% by weight, washing with water, and drying to prepare a reverse osmosis membrane, a sulfuric acid separation and recovery treatment was performed in the same manner as in Example 1 using this.

division Metaphenylenediamine content
(weight%) polyfunctional acid halogen compound
content (wt%) Example 1 2.0 0.1 Example 2 2.5 0.1 Example 3 3.4 0.1 Example 4 2.0 0.5 Comparative Example 1 2.0 0.1 Comparative Example 2 1.6 0.1 Comparative Example 3 1.47 0.1 Comparative Example 4 5.0 0.1 Comparative Example 5 2.0 2.5

Experimental example One

Infrared spectroscopy was performed on the polyamide layer included in the reverse osmosis membrane prepared in the above Examples, and the results are shown in Tables 4 and 5.

division 1540cm ^{- 1} absorbance 1585 cm ^-1 absorbance 1540cm ^-1 /1585cm ^-1 Absorbance Ratio Example 1 0.217 0.103 2.107 Example 2 0.281 0.121 2.320 Example 3 0.351 0.113 3.106 Example 4 0.231 0.133 1.737 Comparative Example 1 0.217 0.103 2.107 Comparative Example 2 0.211 0.166 1.271 Comparative Example 3 0.196 0.175 1.149 Comparative Example 4 0.472 0.121 3.885 Comparative Example 5 0.194 0.115 1.687

Specifically, as can be seen in Table 3, the ratio of the absorbance at the frequency of 1540 cm ^-1 to the absorbance at the frequency of 1585 cm ^-1 in the infrared absorption spectrum for the polyamide layer was 2.107 in the case of Example 1 and Comparative Example 1, Example 2 had an absorbance ratio of 2.320, Comparative Example 2 had an absorbance ratio of 1.271, and Comparative Example 3 had an absorbance ratio of 1.120. And, Examples 3 to 4 had an absorbance ratio of 1.7 to 3.2, whereas Comparative Examples 3 to 5 showed a result outside this range.

Experimental example 2

In Examples 1 to 4 and Comparative Examples 1 to 5, the concentration of sulfuric acid and each impurity contained in the recovered production water of sulfuric acid (or nitric acid) after separation and recovery treatment was measured, and the recovery rate of sulfuric acid, removal rate of other impurities, etc. was measured, and the results are shown in Tables 5 to 7 below.

Raw water (ppm) Example 1 Example 2 Example 3 Example 4 number of production
(ppm) recovery rate
(%) number of production
(ppm) recovery rate
(%) number of production
(ppm) recovery rate
(%) number of production
(ppm) recovery rate
(%) H ₂ SO ₄ 100,000 84,880 84.88 79,940 79.94 66,780 66.78 56,790 56.79 Raw water (ppm) number of production
(ppm) removal rate
(%) removal rate
(%) removal rate
(%) number of production
(ppm) removal rate
(%) number of production
(ppm) removal rate
(%) As 3,124 2,122 32.07 2,245 28.14 2,511 19.62 3,022 3.27 Ca 112 0.03 99.97 0.05 99.96 0.20 99.82 3.57 96.81 Cu 4426 1.80 99.96 1.9 99.96 5.40 99.88 12.30 99.72 Fe 750 0.28 99.96 0.32 99.96 1.45 99.81 2.50 99.67 K 214 0.34 99.84 0.36 99.83 1.33 99.38 3.30 98.46 Mg 75 0.03 99.96 0.03 99.96 0.21 99.72 1.20 98.40 Na 331 0.51 99.85 0.56 99.83 0.91 99.73 7.50 97.73 Ni 3 0 - 0 - 0 - 0 - Pb 10 0.02 99.80 0.02 99.8 0.05 99.50 0.70 93.00 Zn 1047 0.43 99.96 0.45 99.96 1.23 99.88 15.10 98.56 Cl 1748 2.88 99.84 2.95 99.83 4.78 99.73 5.89 99.66 F 1328 42.40 96.81 49.4 96.28 58.70 95.58 85.30 93.58

Raw water (ppm) Comparative Example 1 Production (ppm) Recovery (%) HNO ₃ 124,000 37,216 69.99 Raw water (ppm) Production (ppm) Removal rate (%) As 2,414 1958.48 18.87 Ca 462 214.74 53.52 Cu 3954 1146.26 71.01 Fe 934 704.80 24.54 K 432 223.76 45.89 Mg 56 33.31 40.51 Na 247 239.91 2.87 Ni 17 8.55 49.73 Pb 46 23.81 48.23 Zn 1725 1410.71 18.22 Cl 1485 970.75 34.63 F 1129 698.85 38.1

Raw water (ppm) Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 number of production
(ppm) recovery rate
(%) number of production
(ppm) recovery rate
(%) number of production
(ppm) recovery rate
(%)) number of production
(ppm) recovery rate
(%) H ₂ SO ₄ 100,000 14,600 14.6 12,880 12.88 11,790 11.79 2,140 2.14 Raw water (ppm) number of production
(ppm) removal rate
(%) number of production
(ppm) removal rate
(%) number of production
(ppm) removal rate
(%) number of production
(ppm) removal rate
(%) As 3,124 2,500 19.97 2,670 14.53 2,773 11.24 3,011 3.62 Ca 112 56 50 75 33.04 77 31.25 87 22.32 Cu 4426 1120 74.69 1,151 73.99 1,320 70.18 3,215 27.36 Fe 750 550 26.67 572 23.73 612 18.40 673 10.27 K 214 120 43.93 143 33.18 134 37.38 191 10.75 Mg 75 43 42.67 57 24.00 58 22.67 57 24.00 Na 331 311 6.04 320 3.32 321 3.02 331 0.00 Ni 3 One 66.67 One 60.00 One 56.67 3 16.67 Pb 10 5.7 43 7 33.00 7 31.00 8 19.00 Zn 1047 832 20.53 912 12.89 915 12.61 978 6.59 Cl 1748 1123 35.76 1,334 23.68 1,418 18.88 1,510 13.62 F 1328 867 34.71 973 26.73 991 25.38 1,122 15.51

Specifically, as can be seen in Tables 5 and 6, when Example 1 and Comparative Example 1 are compared, it can be confirmed that the separation and recovery for sulfuric acid shows significantly better efficiency than that of nitric acid even though the same separation device is used.

In addition, in Table 7, it can be seen that the recovery rate of sulfuric acid and the separation efficiency of impurities are not good in Comparative Examples 2 and 3 compared to Example 1, which is performed by the reverse osmosis membranes included in Comparative Examples 2 and 3 Compared to Example 1, it is not good in durability, so it can be expected that the separation efficiency is lowered.

In addition, when comparing Example 3 with Comparative Example 4 in which metaphenylenediamine exceeds 4% by weight, it can be seen that during interfacial polymerization, the separation membrane is not formed properly, so that the separation efficiency is lowered.

Similarly, comparing Example 4 with Comparative Example 5, in which the polyfunctional acid halogen compound was used in an amount exceeding 2 wt%, it can be confirmed that the separation efficiency was lowered due to poor formation of the separation membrane during interfacial polymerization.

Experimental example 3: Flow rate, removal rate measurement

The reverse osmosis membranes of Examples 1 to 4 and Comparative Examples 2 to 5 were prepared as flat membranes without winding them, and then this was prepared as a flat membrane, with a concentration of 2,000 ppm NaCl, a pressure of 15.8 kg/cm ² , a temperature of 25° C., and a feed flow rate of 3.5 Flow rate and NaCl removal rate were measured under L/min conditions, and the results are shown in Table 8 below.

division Flow (GFD) NaCl removal rate (%) Example 1 31 99.3 Example 2 25 99.4 Example 3 14 99.3 Example 4 27 99.1 Comparative Example 2 35 98.1 Comparative Example 3 43 97.6 Comparative Example 4 11 98.2 Comparative Example 5 47 91.1

Looking at the flow rate and NaCl removal rate measurement results in Table 8, it can be seen that Examples 1 to 4 show a very high NaCl removal rate of 99% or more while having an appropriate flow rate of 12 to 35 GFD. However, in the case of Comparative Examples 2 and 3 using meta-phenylenediamine (MPD) in an amount of less than 2% by weight, when compared with Example 1, the flow rate increased, but there was a problem in that the NaCl removal rate fell to less than 99%. , In the case of Comparative Example 4, in which the MPD was used in excess of 4 wt%, the flow rate was greatly reduced, and the NaCl removal rate was also poor. And, in the case of Comparative Example 5, although the flow rate was the highest, there was a problem that the NaCl removal rate was very low.

Through the above Examples and Experimental Examples, it was confirmed that sulfuric acid could be separated and recovered at a high concentration through the sulfuric acid separation device and sulfuric acid separation and recovery method proposed by the present invention.

Claims (11)

an inlet through which wastewater containing impurities and sulfuric acid is introduced;
a filtration unit including a reverse osmosis module for filtering sulfuric acid by separating impurities and sulfuric acid from the wastewater containing impurities and sulfuric acid introduced into the inlet, wherein the sulfuric acid recovery rate is set to 30 to 90%;
a first discharge unit for discharging the filtrate containing the filtered sulfuric acid; and
a second discharge unit for discharging the wastewater containing the unfiltered and separated impurities and sulfuric acid;
The reverse osmosis module includes a support, a polymer support layer including porous polysulfone, and a reverse osmosis membrane including a polyamide layer,
The polyamide layer is formed by immersing the polymer support layer in an aqueous alkyldiol solution containing 2.0 to 3.5 wt% of meta-phenylenediamine, and then removing the excess aqueous solution; Forming a polyamide layer by performing interfacial polymerization by immersing the polyfunctional acid halogen compound in an organic solution containing 0.01 to 2% by weight; And it is formed by performing a process comprising a; and the step of washing and drying,
The polymer support layer has a thickness of 20 μm to 50 μm, and the thickness of the polyamide layer is 0.05 μm to 0.3 μm,
The ratio of the absorbance at the frequency of 1540 cm ^-1 to the absorbance at the frequency of 1585 cm ^-1 in the infrared absorption spectrum by infrared spectroscopy for the polyamide layer is 1.7 to 3.2,
3 to 8 of the reverse osmosis modules are arranged in parallel in the filter unit, and the operating pressure for the reverse osmosis module is 30 to 60 kgf/cm 2 ,
The concentration of sulfuric acid in the wastewater flowing into the inlet is 100,000 ppm, and the sulfuric acid concentration of the filtrate discharged from the first outlet is 70,000 ~ 90,000 ppm during separation and recovery treatment for 30 days under the condition of an operating pressure of 50 kgf/cm2 Sulfuric acid separation device with
delete delete The sulfuric acid separation device according to claim 1, wherein the polymer support layer comprises porous polysulfone having a weight average molecular weight of 65,000 to 150,000 and a pore diameter of 1 to 500 nm.
According to claim 1, wherein the alkyldiol aqueous solution is at least one selected from 2-ethyl-1,3-hexanediol aqueous solution, 1,2-hexanediol aqueous solution, 1,3 heptanediol aqueous solution and 1,6-hexanediol aqueous solution including,
The polyfunctional acid halogen compound is a sulfuric acid separation device, characterized in that it comprises at least one selected from trimesoyl chloride, isophthaloyl chloride and terephthaloyl chloride.
The sulfuric acid separation device according to claim 1, wherein the support has a thickness of 20 μm to 150 μm.
delete delete It comprises the sulfuric acid separation device according to any one of claims 1 and 4 to 6,
Wastewater containing impurities and sulfuric acid or filtrate containing sulfuric acid is introduced into an inlet included in any one of the plurality of separation devices,
The wastewater containing the introduced impurities and sulfuric acid or the filtrate containing sulfuric acid is concentrated through filtration or re-filtration by the filtration unit and discharged to the first discharge unit,
A method for separating and recovering highly concentrated sulfuric acid, characterized in that the wastewater containing impurities and sulfuric acid separated without filtration or wastewater containing re-separated impurities and sulfuric acid is discharged through a second discharge unit.
10. The method of claim 9, wherein the concentration of sulfuric acid in the wastewater flowing into the inlet is 100,000 ppm, and when the separation and recovery treatment is carried out for 30 days under the condition of an operating pressure of 50 kgf/cm 2 , the sulfuric acid concentration of the filtrate discharged from the first outlet is 70,000 A highly concentrated sulfuric acid separation and recovery method, characterized in that ~ 90,000 ppm. delete

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