Systems and methods for low energy crystallization of minerals from brines

Abstract

A system for crystallizing a selected mineral from brine is described. The system includes a forward osmosis (FO) system including a semipermeable membrane comprising a material having a surface tension that is less than 50% of a surface tension of the selected mineral in a crystalline state, the membrane being arranged substantially vertically to provide fluid communication between a brine chamber containing brine and a draw chamber containing a draw solution; and a crystal collector disposed at a lowermost edge of the semipermeable membrane arranged substantially vertically, the crystal collector being configured to collect crystals of the selected mineral that form on the membrane and fall due to gravity.

Description

Technical Field

[0001] This disclosure relates to the low-energy crystallization of minerals from brine, and more specifically, but not exclusively, to the low-temperature membrane crystallization of seawater brine from a desalination plant. This disclosure also relates to systems and methods for regenerating draw liquid used in mineral crystallizers, enabling the system to be used as part of a zero-liquidity discharge process. Background Technology

[0002] The seawater desalination industry primarily focuses on maximizing the recovery of drinking water from seawater using energy-efficient methods. Desalination plants typically produce two streams: low-salinity drinking water (permeate) and brine containing salt and minerals from the seawater. Conventionally, the brine is discharged back into the sea, increasing salinity and thus causing environmental harm to aquatic habitats. Recently, more environmentally friendly solutions have been developed to reduce negative impacts on aquatic ecosystems and the natural environment.

[0003] Brine, also known as waste stream, is not potable and is generally considered to have little commercial value due to its salt content. An emerging industry is the brine value-added industry, which focuses on recovering and purifying individual salts / minerals from brine for commercial use. Recovering individual salts / minerals from brine can be complex and energy-intensive; conventional thermal evaporation concentrators and crystallizers use approximately 50 kWh to 75 kWh of energy per cubic meter of brine.

[0004] Recovering and crystallizing salts and minerals from brine or seawater requires processing large volumes of liquid to extract sufficient quantities of minerals for commercial use. Therefore, this is a continuous process that consumes significant amounts of energy, leading to a search for more energy-efficient systems. Any reduction in energy consumption during the crystallization process offers substantial advantages in reducing the overall energy consumption of the crystallization system and lowering operating costs.

[0005] A low-energy-consumption method for recovering salt and minerals from brine is membrane process technology, which is based on the physical separation of salt and water. Conventional membrane systems use standard polysulfone membranes, which are prone to fouling due to the hydrophobic nature of polysulfone. Membrane fouling reduces the number of crystals produced per unit membrane area per unit time and requires frequent membrane cleaning. This can shorten membrane life and lead to frequent membrane replacements, thus increasing operating costs.

[0006] Membrane crystallization systems have also been combined with forward osmosis (FO) technology. In such systems, brine and "draw solution" are applied across the membrane, creating a transmembrane osmotic pressure gradient. This causes water to pass from the brine through the membrane into the draw solution, thus diluting the draw solution. To maintain a sufficient transmembrane osmotic pressure gradient, the draw solution must be continuously replenished or regenerated (reconcentrated), which is a highly energy-intensive process.

[0007] US11040904B2 describes a method and system for treating wastewater by forward osmosis. Specifically, it describes using a forward osmosis membrane module to filter one or more precipitated salts from wastewater. The membrane module includes membrane sheets spirally wound around a draw tube. While this membrane module filters salts from wastewater, it recovers the salts in an amorphous form and does not describe a method for recovering the target crystalline salts. Furthermore, US11040904B2 describes utilizing a reverse osmosis process to further concentrate diluted draw solution using one or more standard reverse osmosis (RO) membrane modules, wherein the RO membrane modules extract only water from the draw solution to aid in its further concentration.

[0008] US10835870B2 describes a method for manufacturing multi-leaf membranes for filtering product fluids. These membranes can have a variety of applications, including wastewater treatment and seawater desalination. However, it does not describe a method or system for recovering crystallized target minerals from product fluids such as seawater or brine.

[0009] Therefore, one object of this disclosure is to at least address one of the aforementioned limitations. Summary of the Invention

[0010] According to one aspect of this disclosure, a system for crystallizing selected minerals from brine is provided, the system comprising a forward osmosis (FO) system, the FO system comprising: a semipermeable membrane comprising a material having a surface tension less than 50% of the surface tension of the selected mineral in a crystalline state, the membrane being arranged substantially vertically to provide fluid communication between a brine chamber containing brine and a draw solution chamber containing draw solution; and a crystal collector disposed at the lowest edge of the substantially vertically arranged semipermeable membrane, the crystal collector being configured to collect crystals of the selected mineral formed on the membrane that fall off due to gravity.

[0011] This aspect of the present disclosure enables crystallization to be performed using significantly less energy than in a thermal crystallizer. The scale of the energy difference lies in the fact that crystallization can be carried out at relatively low temperatures (e.g., room temperature), rather than at 100 degrees Celsius as in a thermal crystallizer. This lower operating temperature significantly reduces the operating and maintenance costs of the membrane crystallizer according to the present disclosure, by approximately 10 times compared to similar thermal crystallizers. Furthermore, the capital cost of the membrane crystallizer according to the present disclosure is approximately 50% lower than that of similar thermal crystallizers.

[0012] These advantages are achieved because this aspect of the disclosure uses natural forces rather than mechanical forces to influence crystallization. For example, the osmotic pressure of a forward osmosis system is used to increase the concentration of selected minerals by drawing water and unselected minerals from the brine into the draw solution. When this concentrates the selected minerals in the brine to its saturation, crystals form on the surface of a semipermeable membrane and eventually become large enough that the weight of these crystals pulls them down to the crystal collector by gravity.

[0013] In some exemplary embodiments, the semipermeable membrane comprises a polycellulose acetate material. Polycellulose acetate is a synthetic plastic material with the structure of natural cellulose and a very smooth surface. This, in turn, provides the membrane with a very low surface tension value, which is beneficial for meeting the requirements of this embodiment. However, semipermeable membranes composed of other materials can also be used, provided that the surface tension is low enough to allow the crystal to detach from the membrane by gravity. This brings a further advantage because, due to the orientation of the membrane, when the crystal grows large enough to overcome the surface tension of the semipermeable membrane in which it grows, the crystal will automatically fall into the crystal collector, thus eliminating the need for manual removal of the crystal from the membrane.

[0014] In some embodiments, the surface tension of the semipermeable membrane is between 30 N / m and 50 N / m. This provides the semipermeable membrane with a relatively low surface tension, which can be used to crystallize different minerals from brine.

[0015] In some embodiments, the FO system is configured with a selected draw solution that applies an osmotic draw pressure at least twice that of the brine osmotic pressure. This provides sufficient osmotic force to make the system commercially viable. In other embodiments, more preferably, the FO system is configured with a selected draw solution that applies an osmotic draw pressure at least three times that of the brine osmotic pressure. The greater the osmotic draw pressure that can be applied, the faster and more efficient the process. In this regard, in some embodiments, the selected draw solution contains MgCl2. This has been found to be particularly useful for generating a large osmotic draw pressure for crystallizing NaCl (e.g., a major component of brine from seawater). Similarly, the selected draw solution can be NaCl, which has been found to generate a large osmotic pressure across a semipermeable membrane when the mineral to be crystallized from the brine is CaSO4. It should be noted that both examples are particularly useful for seawater desalination plants, where NaCl and CaSO4 are the most abundant mineral components in seawater and brine made from seawater.

[0016] In some embodiments, the concentration of the draw solution is selected to be between 100,000 mg / L and 330,000 mg / L. This is often several times higher than the concentration of brine, resulting in a relatively high osmotic pressure across the semipermeable membrane. In some embodiments, the FO system operates at a relatively low temperature of 15°C to 35°C, thereby reducing the system's energy requirements.

[0017] In one exemplary embodiment, the system also includes an osmosis-assisted reverse osmosis (OARO) system or cooling tower coupled to the FO system. This provides an efficient feedback loop for the draw solution. More specifically, the OARO system or cooling tower is configured to reconcentrate the draw solution by removing water from it and to recycle the reconcentrated draw solution back to the FO system. This advantageously provides a simple method for regenerating the draw solution for reuse in the FO system, which continuously dilutes the draw solution during the crystallization of selected minerals. It should be understood that the OARO system or cooling tower described above for concentrating the draw solution can provide the advantages described herein when used with any crystallizer system that requires concentrated draw solution to operate and crystallizes selected minerals from brine.

[0018] In some implementations, the OARO system, as part of the reverse osmosis process, applies a pressure of 68 to 72 bar to the draw fluid.

[0019] In some implementations, the OARO system includes multiple OARO units, each of which further concentrates the draw solution to a given amount. These multiple OARO units are connected in series, whereby a second OARO unit further concentrates the draw solution concentrated by the first OARO unit, and the further concentrated draw solution is then recycled to the FO system. This accommodates the limitations of individual OARO units and helps reduce costs, as cheaper OARO units with limited draw solution concentration capabilities can be used.

[0020] In some implementations, the OARO system further concentrates the draw solution containing MgCl2 or NaCl. As mentioned above, these are the most commonly used draw solutions for achieving maximum permeation across the semipermeable membrane to crystallize selected minerals.

[0021] In some implementations, the OARO system further concentrates the draw solution to a concentration of approximately 200,000 mg / L to 330,000 mg / L before recirculating it to the FO system. This concentration is considered to allow the system to operate at its optimal level.

[0022] In some implementations, the OARO system comprises a semi-permeable membrane with a molecular pore opening size of 5 to 15 nanometers. More preferably, the molecular pore opening size is 5 to 10 nm. This size allows water and small minerals to pass through the membrane as solutes, but is small enough to prevent drawlet molecules from passing through the semi-permeable membrane. Because these molecular pores are slightly larger than those of conventional seawater reverse osmosis (SWRO) membranes, they typically allow more minerals to pass through the OARO membrane to the permeate side compared to SWRO membranes, which primarily allow pure water and very few minerals to pass through. These additional minerals on the clean side of the membrane generate an additional natural permeate draw force of approximately 70 bar for water, which increases the feed pressure of the OARO membrane, thereby advantageously allowing more water to pass through the OARO membrane and thus concentrating the feed brine entering the OARO to a higher level than the feed pressure alone allows. This additional permeate draw force also reduces the energy required to re-concentrate the waste drawlet.

[0023] The OARO system of the implementation scheme can deliver the reverse osmosis permeate to another mineral extraction system, wherein the mineral extraction system uses a low-energy crystallization technique with a membrane having selective affinity for the mineral to be extracted to further extract the mineral from the permeate. Such a system is described in our co-pending U.S. patent application US 63 / 607,049 (the contents of which are incorporated herein by reference, a copy of which is provided in Annex 1).

[0024] In some implementations, the system also includes an additional osmosis-assisted reverse osmosis (OARO) system coupled to the FO system, which is configured to concentrate the brine and feed the concentrated brine into the FO system. Using an OARO system to concentrate the brine improves the efficiency of the FO system and thus improves salt crystallization.

[0025] This disclosure also relates to a low-energy multi-mineral crystallization system for extracting a first mineral and a second mineral from brine, the multi-mineral crystallization system comprising: a first system for crystallizing a first selected mineral from brine, having an FO system and an OARO system as described above; and a second system for crystallizing a second selected mineral from brine, having an FO system and an OARO system as described above; wherein the OARO system of the first system delivers the permeate from reverse osmosis to the input of the FO system of the second system.

[0026] According to another aspect of this disclosure, a method for crystallizing selected minerals from brine is provided, the method comprising: providing brine to a forward osmosis (FO) system; providing fluid communication in the FO system between a brine chamber containing brine and a draw solution chamber containing draw solution by providing a substantially vertically arranged semipermeable membrane, the semipermeable membrane comprising a material having a surface tension less than 50% of the surface tension of the selected mineral in a crystalline state; and collecting crystals of the selected mineral formed on the membrane and falling off due to gravity in a crystal collector disposed at the lowest edge of the substantially vertically arranged semipermeable membrane.

[0027] According to another aspect of this disclosure, a system for crystallizing selected minerals from brine is provided. This system includes a forward osmosis system comprising: a brine chamber for receiving a brine feed containing brine; a draw liquid chamber for containing a draw liquid; a semipermeable membrane disposed between the brine chamber and the draw liquid chamber, the semipermeable membrane comprising a cellulose acetate material with a surface tension less than 50% of the surface tension of the selected mineral in a crystalline state, the semipermeable membrane being arranged substantially vertically to provide fluid communication between the brine chamber and the draw liquid chamber; and a collector disposed at the lowest edge of the substantially vertically arranged semipermeable membrane; wherein, in use, the draw liquid generates an osmotic pressure gradient across the semipermeable membrane, drawing unselected minerals and water from the brine into the draw liquid chamber, such that the selected minerals in the brine are saturated in the brine chamber and form at least one crystal of the selected mineral on the surface of the semipermeable membrane; and wherein when the weight of at least one crystal exceeds the selected surface tension, at least one crystal falls into the collector under gravity.

[0028] According to another aspect of this disclosure, a system for crystallizing selected minerals from brine is provided, the system comprising: a forward osmosis (FO) system comprising: a semipermeable membrane comprising a polyacetal cellulose material having a surface tension less than 50% of the surface tension of the selected mineral in a crystalline state, the membrane being arranged substantially vertically to provide fluid communication between a brine chamber containing brine and a draw solution chamber containing draw solution; and a collector disposed at the lowest edge of the substantially vertically arranged semipermeable membrane; wherein, in use, the draw solution generates an osmotic pressure gradient across the semipermeable membrane, drawing unselected minerals and water from the brine into the draw solution chamber, such that the selected minerals in the brine are saturated in the brine chamber and form at least one crystal of the selected mineral on the surface of the semipermeable membrane; and wherein when the weight of at least one crystal exceeds the selected surface tension, at least one crystal falls into the collector under gravity.

[0029] According to another aspect of this disclosure, a method is provided for crystallizing selected minerals from brine using a forward osmosis system, the method comprising: providing a semipermeable membrane for the forward osmosis system, the semipermeable membrane comprising a material having a surface tension less than 50% of the surface tension of the selected mineral in a crystalline state; arranging the membrane substantially vertically in the forward osmosis system to provide fluid communication between a brine chamber containing brine and a draw solution chamber containing draw solution; positioning a collector at the lowest edge of the substantially vertically arranged semipermeable membrane; operating the forward osmosis system such that the draw solution generates an osmotic pressure gradient across the semipermeable membrane, drawing unselected minerals and water from the brine into the draw solution chamber, such that the selected minerals in the brine are saturated in the brine chamber; forming at least one crystal of the selected mineral on the surface of the semipermeable membrane; and collecting the at least one crystal in the collector when the weight of the at least one crystal exceeds the selected surface tension and the at least one crystal falls into the collector under gravity. Attached Figure Description

[0030] The above and other features and advantages of this disclosure will become apparent to those skilled in the art from the following detailed description of exemplary embodiments with reference to the accompanying drawings, in which:

[0031] Figure 1 This is a block diagram of a crystallization system according to one embodiment of the present disclosure, showing a forward osmosis (FO) crystallization system and an osmosis-assisted reverse osmosis (OARO) unit, as well as the inputs and outputs of the crystallization system;

[0032] Figure 1A This is a block diagram of a crystallization system according to another embodiment of the present disclosure, the crystallization system including an FO crystallization system and an OARO unit including two OARO processing sections connected in series;

[0033] Figure 2 This is a block diagram of a multi-mineral crystallization system according to another embodiment of the present disclosure, wherein the multi-mineral crystallization system is configured to recover at least two target minerals from brine, the multi-mineral crystallization system comprising Figure 1 One crystallization system and another crystallization system were used to recover crystals of the two target minerals;

[0034] Figure 3 These are a series of schematic penetration transport diagrams, each showing... Figure 1 The different operating stages of the FO crystallization system over time;

[0035] Figure 4 These are a series of schematic permeation transport diagrams, showing... Figure 1 The changes in the OARO system over time;

[0036] Figure 5 It is shown Figure 1 A flowchart of the operation method of the crystallization system;

[0037] Figure 6 This is a graph showing the osmotic pressure of different solutions at different concentrations, enabling the selection of a suitable draw solution for the recovery of a given crystal in any embodiment of this disclosure; and

[0038] Figure 7 This is a block diagram of a crystallization system according to another embodiment of the present disclosure, the crystallization system including an FO crystallization system and a cooling tower. Detailed Implementation Plan

[0039] Various exemplary embodiments and details are described below with reference to the accompanying drawings. It should be noted that the drawings may be drawn to scale or not, and elements with similar structures or functions are indicated by the same reference numerals in the various drawings. It should also be noted that the drawings are intended only to facilitate the description of embodiments. They are not intended to be an exhaustive description of this disclosure or to limit the scope of this disclosure. Furthermore, the illustrated embodiments do not need to have all the aspects or advantages shown. Aspects or advantages described in connection with a particular embodiment are not necessarily limited to that embodiment and may be practiced in any other embodiment, even if not so stated or explicitly described.

[0040] The accompanying drawings are schematic and simplified for clarity; they show only details that aid in understanding this disclosure, while other details have been omitted. Throughout the text, the same reference numerals are used for the same or corresponding parts.

[0041] Figure 1 An overview of an exemplary system 100 including a crystallization system 118 is shown. The crystallization system 118 includes a forward osmosis (FO) crystallization system 106 and an osmosis-assisted reverse osmosis (OARO) unit 110. The FO crystallization system 106 receives brine 102 (typically from a desalination plant, i.e., the output of a SWRO system) and draw liquid 104, and outputs crystallized minerals 112 and diluted draw liquid 108. The diluted draw liquid 108 is then fed to the OARO unit 110, which outputs a reconcentrated draw liquid 116, which is recycled back to the FO crystallization system 106 for reuse in the FO process. Although Figure 1 The illustrated embodiment uses seawater-derived brine as input to the FO crystallization system 106, but in other embodiments, the input may include brine or brackish water from other sources. In some embodiments, the input to the FO crystallization system 106 is concentrated brine, which includes brine 102 concentrated in an OARO unit, where the OARO unit also produces permeate. Figure 1 In the illustrated embodiment, OARO unit 110 is used to further concentrate the diluted draw liquid 108; however, in other embodiments, the diluted draw liquid 108 is further concentrated using a cooling tower.

[0042] In addition to the reconcentrated draw solution 116, the OARO unit 110 outputs a permeate 114 (water) containing other salts / minerals that may have entered the diluted draw solution 108 during the crystallization process of the FO crystallization system 106. These other salts / minerals are typically smaller than water molecules and therefore pass through the FO membrane under osmotic pressure. The permeate 114 can be treated by a selective membrane system comprising a chemically modified membrane that is semi-permeable to water and has an affinity for the target mineral. Such a selective membrane system is described in the applicant's co-pending U.S. patent application US63 / 607,049 (the contents of which are incorporated herein by reference, a copy of which is provided in Annex 1).

[0043] Figure 1A It shows Figure 1 An alternative embodiment of the system 100 shown includes a crystallization system 118. (As in...) Figure 1 In the implementation scheme, the FO crystallization system 106 is used in conjunction with... Figure 1 The same operation occurs where crystallization system 106 receives brine 102 and extract 104, and outputs crystallized minerals 112 and diluted extract 108, which is then sent to OARO unit 110 for further concentration. However, in Figure 1A In one embodiment, the OARO unit 110 includes two OARO sections (110a, 110b). The diluted draw solution 108 is fed into the first OARO section (110a), where it is partially reconcentrated. The partially reconcentrated draw solution is then passed through the second OARO section (110b), where it is further reconcentrated. The second OARO section (110b) outputs a fully reconcentrated draw solution 116, which is recycled to the FO crystallization system 106. The solutes from the first OARO section 110a and the second OARO section 110b are combined and output as a permeate containing the remaining mineral 114.

[0044] Each OARO segment (110a, 110b) increases the concentration of the diluted draw solution 108 by a limited amount. In a non-limiting embodiment, each OARO segment increases the total dissolved solids (TDS) concentration of the diluted draw solution 108 by 60,000 mg / L to 70,000 mg / L. In this embodiment, after two OARO segments (110a, 110b), the concentration of the diluted draw solution 116 increases by 120,000 mg / L to 140,000 mg / L of TDS. Although the current embodiment shows two OARO segments (110a, 110b), other embodiments may include fewer or more OARO segments. The required number of segments depends on the mineral being crystallized, and in particular, the saturation of the mineral being crystallized. For example, for the crystallization of NaCl, two OARO segments are considered optimal due to its high saturation point of 330,000 mg / L TDS (at standard atmospheric pressure and 25 degrees Celsius). Crystallization of other minerals with lower saturation points requires lower concentrations of extract, thus allowing the use of fewer OARO segments.

[0045] Figure 2 An embodiment of a multi-mineral crystallization system 200 is shown, which includes Figure 1 The crystallization system 118 shown is followed by a second crystallization system 218 positioned sequentially after the first crystallization system 118. A brine 102 containing target mineral A and mineral B, as well as other salts / minerals, is fed into the first crystallization system 118. The first crystallization system 118 is connected to... Figure 1 The same manner is used to crystallize mineral A (112). The second crystallization system 218 also operates in a similar manner to the first crystallization system 118 (e.g., ...). Figure 1 The difference is that the extractant 210 is different from the extractant 104 of the first crystallization system 118, so as to crystallize different minerals (mineral B 212).

[0046] The first crystallization system 118 outputs crystallized mineral A (112) and permeate 114 (water) containing target mineral B and other salts / minerals. Permeate 114 containing target mineral B and other salts / minerals is fed into a second crystallization system 218. The second crystallization system 218 outputs crystallized mineral B 212 and permeate 214 containing other salts / minerals (i.e., salts / minerals in the original brine 102 other than the crystallized minerals A and B). Although the current embodiment shows two crystallization systems 118, 218 for producing crystallized mineral A (112) and crystallized mineral B (212), other embodiments may include additional crystallization systems arranged sequentially with the current system 200. For example, a third crystallization system (not shown) may receive permeate 214 containing other salts / minerals output from the second crystallization system 218, wherein permeate 214 contains a third target mineral (not shown) crystallized in the third crystallization system.

[0047] Figure 3 A series of schematic permeation transport diagrams are shown, each illustrating... Figure 1 and Figure 2 The forward osmosis (FO) crystallization system 106 is shown in different operating phases over time. A first block diagram 106a illustrates the first phase, i.e., the FO crystallization system 106 at the start of the crystallization process. The FO crystallization system 106 includes a single flat semi-permeable membrane 302 that separates a brine chamber 324 containing brine 102 from a draw solution chamber 322 containing draw solution 104. In this embodiment, the semi-permeable membrane 302 is arranged substantially vertically, as shown... Figure 3 As shown. The brine 102 is essentially composed of water molecules 312, target salt / mineral molecules 308, and other salt / mineral molecules 310. The difference in saturation between the draw solution 104 and the brine 102 creates an osmotic pressure difference 304, which drives water molecules 312 through the membrane 302 into the draw solution chamber 322 along a first direction 306. The osmotic pressure of the draw solution 104 is initially at least twice the osmotic pressure of the brine 102.

[0048] although Figure 3The current embodiment shown illustrates a single flat sheet membrane, but the optimal number of membranes depends on the membrane's sustainable flux. The membrane's sustainable flux depends on the target salt / mineral. For example, consider a system where draw solution 104 contains a magnesium chloride (MgCl2) solution, and membrane 302 comprises a low surface tension polyacetic acid cellulose membrane with a surface tension of 30 to 50 N / m. The sustainable flux required to produce sodium chloride (NaCl) crystals and calcium sulfate (CaSO4) crystals are different. Specifically, the sustainable flux required to produce sodium chloride crystals is 3 liters / m² / hour, where the surface tension of sodium chloride crystals is 114 N / m. However, the sustainable flux required to produce calcium sulfate crystals is 8 liters / m² / hour, where the surface tension of calcium sulfate crystals is 156 N / m. The sustainable flux can also influence the required membrane area and the choice of draw solution 104.

[0049] Although the current embodiment shows brine 102 as the input, seawater can also be fed into the FO crystallization system 106. The salt / mineral concentration of seawater is much lower than that of brine. For example, the concentration of sodium chloride in seawater may be an order of magnitude lower than in brine. Therefore, to treat seawater, a larger membrane surface area is required when the input contains seawater than when the input contains brine. When the input contains brine, a smaller membrane surface area is required due to the higher mineral concentration, making it more cost-effective to treat brine than seawater. In an embodiment where the brine is concentrated by an OARO unit to output concentrated brine and fed into the FO crystallization system 106, system 100 is even more cost-effective.

[0050] Block diagram 106b illustrates the second stage of the crystallization process. In this stage, water molecules 312 are “drawn” from the brine chamber 324 through the membrane 302 into the draw solution chamber 322 due to the high osmotic pressure of the draw solution 104. In addition to water molecules 312, other salt / mineral molecules 310 are also drawn through the membrane 302. This causes the saturation of the target mineral 308 in the brine solution 102 to increase over time, while the draw solution 104 becomes increasingly dilute. At the saturation point of the target mineral 308, crystals 320 naturally form on the membrane surface 318 as tiny nuclei due to the expulsion effect of the osmotic draw force on the other side of the membrane 302. The naturally generated draw force is produced by the osmotic pressure difference 304 between the draw solution 104 on one side of the membrane 302 and the brine 102 on the other side. Crystallization stops when the osmotic pressure difference 304 between the brine 102 and the draw solution 104 is less than 10%.

[0051] Block diagram 106c illustrates the third stage of the crystallization process. In this stage, once the crystals 320 of the target salt 308 reach a critical weight, they roll off (fall off) from the membrane surface 318 due to gravity and the relatively low surface tension of the membrane, and are collected in the collection pool 316. The critical weight depends on the surface tension of the crystals 320, which in turn depends on the size of the formed crystals 320 and thus varies depending on the target mineral. Depending on the surface tension difference between the target mineral crystals and the membrane surface 318, and the osmotic pressure difference 304 between the brine and the extract, the crystals 320 can accumulate over a period of 20 minutes to 2 hours. Advantageously, the FO membrane crystallization system 106 described herein uses 7.85 kWh of energy per cubic meter of brine, which is approximately ten times less than the energy used in conventional thermal crystallizers.

[0052] The FO membrane crystallization system 106 operates at the crystallization temperature of the target salt (i.e., 15 to 35 degrees Celsius). In contrast, other crystallization methods, such as thermal crystallization, require temperatures above 100 degrees Celsius. Therefore, the FO membrane crystallization system 106 advantageously requires less energy than conventional thermal crystallization systems.

[0053] Figure 4 Two schematic permeation transport diagrams are shown, illustrating... Figure 1 , Figure 1A and Figure 2 The variation of the OARO segments (110a / 110b) included in any OARO unit 110 over time. The OARO segments (110a / 110b) include a reconcentration chamber 400, a semi-permeable membrane 402, and a solute chamber 404. In the first stage ( Figure 4 (As shown in the diagram above), the diluted draw solution 108 is fed into the reconcentration chamber 400 of the OARO section on one side of membrane 402. The diluted draw solution 108 contains draw solution molecules 314, water molecules 312, and other salts / minerals 310 from the FO crystallization system 106, as described above. In the second stage (as... Figure 4 As shown in the diagram below, in the OARO process, water 312 and other salts / minerals 310 are driven through membrane 402 (as indicated by arrow 406), thereby reconcentrating the draw solution 108. The reconcentrated draw solution 116 is then recycled to the FO crystallization system 106.

[0054] The membrane 402 used in the OARO sections (110a / 110b) has a membrane separation layer that is slightly larger than that of conventional seawater reverse osmosis (SWRO) membranes. Furthermore, conventional SWRO membranes typically have pore sizes less than 2 nm, generally 1 to 2 nm, thus allowing only water molecules to pass through, with very few minerals able to pass, resulting in a TDS salinity of approximately 100 mg / L to 200 mg / L. However, the chemical structure of the OARO membrane 402 used herein results in molecular pore openings greater than 5 nm, preferably 5 nm to 15 nm, and more preferably 5 nm to 10 nm in some embodiments. The larger pore openings of the OARO membrane 402 allow water molecules and small mineral molecules to pass through the membrane 402 into the solute chamber 404. The water and minerals passing through the OARO membrane 402 contain permeate 114 with a salinity of approximately 35,000 mg / L. The minerals contained in the permeate 114 generate a natural osmotic draw force of approximately 70 bar for water. This additional natural draw pressure increases the feed pressure applied to the OARO membrane 402, thereby driving more water through the membrane 402. The additional draw pressure allows the diluted draw solution 108 to be concentrated to a higher level than when using the feed pressure alone, thus improving the efficiency of the OARO process.

[0055] In implementations with two or more OARO segments, for example Figure 1A In the illustrated embodiment, each OARO segment further concentrates the diluted draw solution 108 as described above. Furthermore, each OARO segment increases the mineral concentration in the permeate 114. As the mineral concentration in the permeate 114 increases, the osmotic draw capacity also increases. This improves the efficiency of the OARO unit 110. The required number of OARO segments will depend on the required osmotic draw capacity and the osmotic pressure of the reconcentrated draw solution 116.

[0056] Figure 5 A method 500 for crystallizing a target mineral from brine 102 and then concentrating the waste draw liquid (or diluted draw liquid 108) is illustrated in a FO crystallization system 106 and an OARO unit 110. In one embodiment of the system, brine 102 is fed into crystallization system 118 in step 502, and draw liquid 104 is fed into crystallization system 118 in step 504. In step 506, the target salt / mineral is crystallized using forward osmosis (FO) membrane crystallization. In step 508, the crystallized target salt / mineral 112 is collected in collection tank 316 in the form of crystals 320. The crystallization process outputs waste draw liquid in step 508, which is treated in step 510 by a first OARO section included in OARO unit 110 to further concentrate the waste draw liquid. (The last sentence appears to be incomplete and possibly refers to a different implementation.) Figure 1A In some implementation schemes, two or more OARO stages (110a, 110b) may be required to reconcentrate the waste extract 108 back to its initial concentration. Therefore, in Figure 1A In the illustrated embodiment, the waste draw liquor is subsequently treated by the second OARO section 110b in step 512. Then, in step 514, the reconcentrated draw liquor 116 is recycled to the FO crystallization system 106. Therefore, the reconcentrated draw liquor 116 can be used to continue the crystallization process of the target salt / mineral in step 506.

[0057] This system 100 can be used to recover various target minerals from brine, including calcium sulfate, sodium chloride, potassium chloride, and magnesium sulfate. The same type of polyacetic acid cellulose membrane with the same surface tension can be used, but different draw solutions can be used because different solutions have different osmotic pressure differentials. The higher the osmotic pressure differential between brine 102 and draw solution 104, the faster the target mineral crystallizes, because the number of times the draw solution 108 must be further concentrated and diluted is reduced. Therefore, preferably, the osmotic pressure of draw solution 104 is at least twice that of brine 102, and more preferably at least three times higher in some embodiments. To determine the appropriate draw solution 104 for a specific target mineral solution, methods such as... Figure 6 The diagram shown.

[0058] Figure 6 A graph 600 shows the osmotic pressure of various solutions as a function of their concentration at 25 degrees Celsius. This experimental data can be used to design any embodiment of this disclosure. For example, magnesium chloride is a preferred draw solution for crystallizing sodium chloride crystals from a concentrated sodium chloride solution (e.g., brine derived from seawater desalination) because it has the largest osmotic pressure difference with the sodium chloride solution at all concentrations. However, graph 600 indicates that another suitable draw solution candidate is calcium chloride solution, although the osmotic draw pressure will be lower than that when using magnesium chloride. Other suitable draw solution compositions and concentrations can be determined from this graph by comparing osmotic draw pressures, wherein the osmotic pressure of the draw solution must be at least twice the osmotic pressure of the target mineral solution. More preferably, as from Figure 6 The curve shows that the osmotic pressure of the extractant can be selected to be at least three times that of the target mineral solution.

[0059] Having described the structure of systems 100 and 200 and their general operation to achieve the crystallization of desired minerals from brine, some more detailed but non-limiting implementation schemes of the above systems are now described.

[0060] In a non-limiting embodiment of system 100, the brine 102 fed into crystallization system 118 is derived from seawater desalination. The target mineral is sodium chloride, the most abundant salt in seawater-derived brine. One advantage of treating the brine in system 100 is that its salinity level is too high for organisms to survive, thus avoiding biofouling of the membranes used in system 100. Draw-out solution 104 contains a magnesium chloride solution with an initial total dissolved solids (TDS) concentration of 300,000 mg / L. In FO crystallization system 106, the semi-permeable membrane 302 separating brine 102 from draw-out solution 104 is substantially perpendicular to maximize the gravitational pull during crystal formation. This membrane comprises a single flat polyacetal cellulose membrane with a surface tension of 30 N / m to 50 N / m. To reduce the environmental burden of using magnesium chloride as draw-out solution, a selective membrane system (such as the system described above and set forth in Annex 1 in the applicant's co-pending U.S. patent application (US 63 / 607,049)) can be used to recover magnesium chloride from seawater.

[0061] In use, a magnesium chloride solution draws water and other minerals 306 from the brine through membrane 302, thereby increasing the concentration of sodium chloride. At the saturation point of sodium chloride (330,000 mg / L TDS), sodium chloride crystals spontaneously form on the membrane surface 318 (the brine side of membrane 302). When the crystals 320 reach a critical size of 1 nm to 4 nm and a surface tension of 114 N / m, gravity causes them to roll off the membrane surface 318 (fall) into the collection tank 316. The purity of the initially collected sodium chloride crystals is 99.9%. As the crystallization process continues, the purity of the sodium chloride crystals decreases. The crystallization process is stopped when the purity of the sodium chloride crystals reaches 99.6%, which is the lower limit for commercially viable crystals. Advantageously, the FO crystallization process described herein allows for control over the purity of the produced crystals and also produces commercially viable crystals.

[0062] Designing membrane 302 with a surface tension less than 50% of the surface tension of the generated crystals 320 has two main advantages. First, collecting crystals 320 requires no mechanical intervention or other energy-intensive recovery methods. Recovery advantageously relies solely on natural gravity. Second, the smoothness of membrane 302 prevents the formation of other crystals on membrane surface 318, which could lead to fouling or clogging of membrane 302, thus allowing the membrane to be used for a longer period without manual cleaning intervention.

[0063] During sodium chloride crystallization, water is drawn through membrane 302 to the draw solution side of membrane 302. This causes the draw solution 104 to become increasingly dilute over time. At a TDS concentration of 100,000 mg / L, the osmotic pressure of the magnesium chloride draw solution 104 becomes comparable to that of the brine 102. Therefore, water can no longer be effectively drawn from the brine side of membrane 302 to the draw solution side of membrane 302. To reuse the diluted draw solution 108, it is sent to the OARO unit 110 for further concentration.

[0064] In this embodiment, the OARO unit 110 includes, as follows: Figure 1A The embodiment shows two OARO sections, each of which further concentrates the diluted draw solution to a TDS of 60,000 mg / L to 70,000 mg / L. The pressure used is a combination of a feed pressure of 70 bar and an additional permeation draw pressure of 68 bar to 72 bar naturally generated by other minerals in solute 114. OARO unit 110 further concentrates the diluted draw solution to its initial concentration of 300,000 mg / L TDS. To further concentrate the diluted draw solution 108, each OARO section removes permeate 114 from the magnesium chloride solution. Permeate 114 contains water, other minerals in the brine from the FO crystallization membrane 302, and less than 10% magnesium chloride draw solution. The permeate is collected on the low-salinity side of the OARO membrane 402 and can be fed into a second crystallization system 218, for example... Figure 2 The system shown in the embodiment of the polycrystalline system 200 is used to crystallize other minerals.

[0065] In another non-limiting embodiment, the target mineral contained in the input brine 102 is calcium sulfate. To recover the calcium sulfate crystals, the draw solution 104 contains a sodium chloride solution with an initial total dissolved solids (TDS) concentration of 330,000 mg / L. As described in the above embodiment, the semi-permeable membrane separating the brine from the draw solution in the FO crystallization system 106 is substantially perpendicular and comprises a single flat polyacetal cellulose membrane with a surface tension of 30 N / m to 50 N / m.

[0066] The sodium chloride extract increases the concentration of calcium sulfate to its saturation point of 260,000 mg / L (at standard atmospheric pressure and 25°C), causing crystals 320 to spontaneously form on membrane surface 318 (the brine side of membrane 302). When the calcium sulfate crystals reach a critical size of 1 nm to 4 nm and a surface tension of 156 N / m, gravity causes them to roll off surface 318 into collection tank 316. The initial collected calcium sulfate crystals have a purity of 99.9%. As described in the sodium chloride crystallization embodiment, the purity of the calcium sulfate crystals decreases over time. The crystallization process is stopped when the purity of the calcium sulfate crystals reaches 99.6%, thus making them suitable for commercial use.

[0067] At a TDS concentration of 100,000 mg / L, the osmotic pressure of the sodium chloride draw solution 104 becomes comparable to that of the brine 102. Therefore, water can no longer be drawn from the brine side of membrane 302 to the draw solution side of membrane 302, and the diluted sodium chloride draw solution 108 is sent to the OARO unit 110 for further concentration.

[0068] In this embodiment, the OARO unit 110 includes, as follows: Figure 1A The embodiment shows two OARO sections. The pressure used is a combination of a feed pressure of 70 bar and an additional permeate draw pressure of 68 to 72 bar. OARO unit 110 reconcentrates the diluted sodium chloride draw solution to its initial concentration of 330,000 mg / L. To reconcentrate the diluted draw solution, OARO unit 110 removes permeate from the sodium chloride solution. The permeate contains water, other minerals in the brine that has passed through FO crystallization membrane 302, and less than 10% sodium chloride draw solution. The permeate is collected on the low-salinity side of OARO membrane 402 and can be fed into a second crystallization system 218, for example... Figure 2 The system shown in the embodiment of the multi-mineral crystallization system 200 is used for crystallizing other minerals.

[0069] In another non-limiting embodiment, various target salts / minerals can be crystallized, such as Figure 2 An embodiment of the multi-mineral crystallization system 200 is shown. In this embodiment, one of the target minerals A and B contains sodium chloride, and the other contains calcium sulfate. A brine containing target minerals A and B, as well as other salts / minerals, is fed into a first crystallization system 118. The first crystallization system outputs crystallized mineral A (sodium chloride or calcium sulfate), and the permeate containing mineral B is then fed into a second crystallization system 218 to crystallize mineral B 212. The two FO crystallization systems 106 included in the two crystallization systems 118, 218 comprise a single flat polyacetal polyvinyl acetate membrane of the same type with a surface tension of 30 N / m to 50 N / m. The difference between the two FO crystallization systems 106 lies in the composition of the draw solution 104, as detailed in the above embodiment. That is, for crystallizing sodium chloride, draw solutions 104, 210 contain a magnesium chloride solution, while for crystallizing calcium sulfate, draw solutions 104, 210 contain a sodium chloride solution. Advantageously, membranes of the same type and with the same surface tension can be used to extract multiple target minerals.

[0070] Now we will combine Figure 7 Another embodiment of system 100, including crystallization system 118, is described. Crystallization system 118 includes FO crystallization system 106 and cooling tower 702. FO crystallization system 106 is configured to... Figure 1The same procedure applies; however, the FO crystallization system 106 receives concentrated brine 708 instead of the brine 102 typically output from a desalination plant. In this embodiment, brine 102 is fed into an OARO unit 706, which outputs concentrated brine 708. The FO crystallization system 106 receives concentrated brine 708 and draw liquid 104, and outputs crystallized minerals 112 and diluted draw liquid 108. The diluted draw liquid 108 is then fed into a cooling tower 702, which outputs reconcentrated draw liquid 116, which is recycled back to the FO crystallization system 106 for reuse in the FO process.

[0071] The operating mode of OARO unit 706 and Figure 4 The illustrated OARO unit 110 is identical; OARO unit 706 comprises one or more OARO segments, each including a reconcentration (or concentration) chamber 400, a semipermeable membrane 402, and a solute chamber 404. In this embodiment, brine 102 is fed into the reconcentration chamber 400 located on one side of membrane 402. Water and other salts / minerals, typically smaller than the pores of membrane 402, are driven through membrane 402, thereby concentrating brine 102. The concentrated brine 708 is then fed into the FO crystallization system 106, whereby the water and other salts / minerals constitute the permeate (water) 710 containing the remaining minerals.

[0072] OARO unit 706 increases the concentration of brine 102 by a limited amount, as mentioned above. Figure 1 and Figure 1A As described in OARO unit 110, OARO unit 706 may include one or more OARO segments. The solutes from each OARO segment are combined and output as permeate 710 containing residual minerals. Permeate 710 is drinking water, as described above. Figure 2 The permeate 710 can be fed into another crystallization system 118 to crystallize different minerals. Alternatively, the permeate 710 can be treated by a selective membrane system (such as the system described above), which includes a chemically modified membrane that is semi-permeable to water and has an affinity for the target mineral.

[0073] Those skilled in the art are familiar with cooling towers as devices for removing waste heat from a material (e.g., a solution) and transferring the waste heat to the atmosphere to reduce the temperature of the material. In practice, cooling towers can use the evaporation of water to reduce the temperature of the material. Cooling tower 702 includes a storage tank and optionally includes one or more heaters. Diluted draw solution 108 is fed into the storage tank and heated using natural heat or a heater to evaporate water, increasing the concentration of the diluted draw solution 108 to that of the draw solution 104 fed into the FO crystallization system 106.

[0074] Figure 7One advantage of the illustrated embodiment is that the crystallization system 118 requires less draw liquid 104 than the embodiment described above. Once the initial amount of draw liquid 104 is introduced into the crystallization system 118, the crystallization system 118 becomes a closed-loop system, and no further draw liquid 104 is subsequently added. Instead, the draw liquid 104 is regenerated using a cooling tower 702.

[0075] In one embodiment of system 100, a feed solution (e.g., brine 102 or concentrated brine 708) is contained in a feed tank that feeds brine 102 or concentrated brine 708 into a crystallization tank, such as an acrylic acid crystallization tank. For example, the feed tank has a volume of about 300 liters to about 1000 liters, and the crystallization tank has a fluid volume of about 75 liters. The crystallization tank includes an FO crystallization system (e.g., FO crystallization system 106) comprising a semi-permeable membrane (e.g., semi-permeable membrane 302) separating a brine chamber (e.g., brine chamber 324) from a draw chamber (e.g., draw chamber 322). The crystallization tank also includes a filter plate containing the semi-permeable membrane 302 and two jet pumps that cause feed circulation within the crystallization tank. The filter plate typically has a diameter of about 1.1 m and a height of about 1.4 m. The crystallization tank may include one or more filter plates arranged substantially vertically, wherein the surface area of ​​each plate is about 1 m². 2 The membrane is covered by a semi-permeable membrane. Typically, the total surface area of ​​the semi-permeable membrane 302 is approximately 4 m². 2 In an embodiment where the feed solution contains saturated sodium chloride, the water flux of the feed solution is approximately 1.5 L / m³ at approximately 35°C. 2 / h. Therefore, the four filter plates remove 6 L of water per hour.

[0076] The feed level in the crystallizer is monitored by one or more sensors (such as ultrasonic level sensors), which activate peristaltic pumps to draw the feed solution into the crystallizer and maintain the crystallizer level. As described above, the feed solution is processed in the crystallizer to crystallize the target salt / mineral 308, with the crystals falling to the bottom of the crystallizer due to gravity. To remove the crystals from the crystallizer, the crystals (e.g., salt) are vacuum-drawn into one or more filter bags using one or more hoses connected to the crystallizer. Each filter bag includes one or more conventional water filters that separate the crystals from any feed solution transferred to the filter bag during the vacuum process. The filtered feed solution is then returned to the crystallizer via a jet pump. In some embodiments, the filter bag volume is approximately 60 liters. In one embodiment, three filter bags are used to collect the crystals (e.g., salt), with a total feed volume of approximately 180 liters. The jet pump causes the feed solution to flow downwards and upwards along the side of the filter plate through a semi-permeable membrane 302. Simultaneously, a peristaltic pump located outside the crystallizer and substantially above the filter plate draws draw-in liquid 104 into the crystallizer. This causes the extract 104 to flow through the port at the bottom of the crystallization tank, through the diaphragm in the filter plate, where the extract 104 is diluted, and the diluted extract 108 flows out through the port at the top of the filter plate.

[0077] The diluted draw solution 108 is directed to a cooling tower, such as an all-plastic cooling tower, with a diameter of approximately 0.7 m and a height of approximately 1.5 m. Depending on the climate, a heater may not be required to heat the diluted draw solution 108; natural heat from the air can be used to concentrate the diluted draw solution 108. Therefore, the cooling tower is typically located outdoors to utilize natural heat. The draw solution tank is also typically located outdoors, while other components of the crystallization system 118 are typically located indoors. For system 100 to operate most efficiently, indoor and outdoor components should be located at substantially the same height. Furthermore, in embodiments where brine 102 is concentrated using an OARO unit 706, the OARO unit 706 may be located in a different location from the FO crystallization system 106. For example, the OARO unit 706 may be located away from the FO crystallization system 106, and the concentrated brine 708 may be transported and stored near the FO crystallization system, such as near the crystallization tank.

[0078] In practice, the FO crystallization system 106 can be located near a drain pipe that uses a suction pipe and an automatic valve to allow the draw liquid to be discharged intermittently, causing the crystals attached to the membrane 302 to fall to the bottom of the crystallization tank. The discharged draw liquid is then returned to the draw liquid tank. Furthermore, this automatic draw liquid discharge also prevents membrane damage that could occur if the feed tank level suddenly drops, especially if the draw pressure exceeds the feed pressure.

[0079] In another implementation of system 100, such as Figure 1As shown, crystallization system 118 includes FO crystallization system 106 and OARO unit 110. However, FO crystallization system 106 is used in conjunction with the above. Figure 7 The same operation is described above, whereby the FO crystallization system 106 receives concentrated brine 708 from the OARO unit 706 and outputs crystallized minerals 112 and diluted extract 104. The OARO unit 706 operates in the same manner as described above and outputs permeate 710 (drinking water), which can be further processed in the second crystallization system 218 or via a selective membrane system. The diluted extract 108 is further concentrated in the OARO unit 110, which operates in the same manner as described above and outputs permeate 114 (drinking water), which can also be further processed in the second crystallization system 218 or via a selective membrane system.

[0080] Although features have been shown and described, it should be understood that they are not intended to limit the claimed disclosure, and it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the claimed disclosure. Therefore, the specification and drawings should be considered illustrative rather than restrictive. The claimed disclosure is intended to cover all alternatives, modifications, and equivalents.

Claims

1. A system for selecting minerals by crystallization from brine, the system comprising: Forward osmosis (FO) system, the FO system comprising: A semi-permeable membrane comprising a material with a surface tension less than 50% of the surface tension of a selected mineral in a crystalline state, the membrane being arranged substantially vertically to provide fluid communication between a brine chamber containing brine and a draw solution chamber containing draw solution; and A crystal collector is disposed at the lowest edge of a semi-permeable membrane arranged substantially vertically, and the crystal collector is configured to collect crystals of selected minerals formed on the membrane and falling off due to gravity.

2. The system of claim 1, wherein the semipermeable membrane comprises a polycellulose acetate material.

3. The system according to claim 1 or 2, wherein the surface tension of the semipermeable membrane is 30 N / m to 50 N / m.

4. The system according to any one of claims 1 to 3, wherein the FO system is configured with a selected draw solution to which an osmotic draw pressure at least twice that of the saline osmotic pressure is applied.

5. The system according to any one of claims 1 to 3, wherein the FO system is configured with a selected draw solution that applies an osmotic draw pressure at least three times that of the saline osmotic pressure.

6. The system according to any one of claims 1 to 5, wherein the selected extract contains MgCl2.

7. The system according to any one of claims 1 to 6, wherein the concentration of the extract is from 100,000 mg / L to 330,000 mg / L.

8. The system according to any one of claims 1 to 7, wherein the selected mineral comprises NaCl.

9. The system according to any one of claims 1 to 7, wherein the selected mineral comprises CaSO4.

10. The system of claim 9, wherein the selected extractant comprises NaCl.

11. The system according to any one of claims 1 to 10, wherein the operating temperature of the FO system is 15 degrees Celsius to 35 degrees Celsius.

12. The system according to any one of claims 1 to 11, further comprising an osmosis-assisted reverse osmosis (OARO) system coupled to the FO system, the OARO system being configured to reconcentrate the draw solution by removing water from the draw solution and to recycle the reconcentrated draw solution back to the FO system.

13. The system according to any one of claims 1 to 11, wherein the system includes a cooling tower coupled to the FO system, the cooling tower being configured to reconcentrate the draw liquid by removing water from the draw liquid and to recycle the reconcentrated draw liquid back to the FO system.

14. The system of claim 12, wherein the OARO system applies a pressure of 68 bar to 72 bar to the draw solution as part of a reverse osmosis process.

15. The system according to claim 12 or 14, wherein the OARO system comprises a plurality of OARO units, each OARO unit further concentrating the extract by a given amount, the plurality of OARO units being connected in series, wherein a second OARO unit further concentrates the extract concentrated by the first OARO unit, and the further concentrated extract is then recycled to the FO system.

16. The system according to any one of claims 12, 14 or 15, wherein the OARO system further concentrates the extract containing MgCl2 or NaCl.

17. The system according to any one of claims 12 or 14 to 16, wherein the OARO system further concentrates the extract to a concentration of about 200,000 mg / L to 330,000 mg / L, and then recycles the extract to the FO system.

18. The system according to any one of claims 12 or 14 to 17, wherein the semipermeable membrane of the OARO system comprises molecular pore openings with a size of 5 nanometers to 15 nanometers.

19. The system of claim 18, wherein the semipermeable membrane of the OARO system comprises molecular pore openings with a size of 5 nanometers to 10 nanometers.

20. The system according to any one of claims 12 or 14 to 19, wherein the OARO system delivers the reverse osmosis permeate to another FO mineral extraction system, wherein the mineral extraction system uses a low-energy crystallization technique with a membrane having selective affinity for the mineral to be extracted to further extract the mineral from the permeate.

21. The system according to any one of claims 1 to 20, further comprising another osmosis-assisted reverse osmosis (OARO) system coupled to the FO system, the other OARO system being configured to concentrate brine and feed the concentrated brine into the FO system.

22. The system of claim 21, wherein the other OARO system applies a pressure of 68 to 72 bar to the brine as part of a reverse osmosis process.

23. The system according to claim 21 or 22, wherein the other OARO system comprises a plurality of OARO units, each OARO unit concentrating the brine to a given amount, the plurality of OARO units being connected in series, wherein a second OARO unit further concentrates the brine concentrated by the first OARO unit, and then inputs the concentrated brine into the FO system.

24. The system according to any one of claims 21 to 23, wherein the semipermeable membrane of the other OARO system comprises molecular pore openings with a size of 5 nanometers to 15 nanometers.

25. The system of claim 24, wherein the semipermeable membrane of the other OARO system comprises molecular pore openings with a size of 5 nanometers to 10 nanometers.

26. The system according to any one of claims 21 to 25, wherein the other OARO system delivers the reverse osmosis permeate to another FO mineral extraction system, wherein the mineral extraction system uses a low-energy crystallization technique with a membrane having selective affinity for the mineral to be extracted to further extract the mineral from the permeate.

27. A low-energy multi-mineral crystallization system for extracting a first mineral and a second mineral from brine, the multi-mineral crystallization system comprising: The first system for crystallizing a first selected mineral from brine, as described in any one of claims 12 to 26; and The second system for crystallizing a second selected mineral from brine, as described in any one of claims 12 to 26; The OARO system of the first system delivers the reverse osmosis permeate to the input of the FO system of the second system.

28. A method for selecting minerals by crystallization from brine, comprising: Provide brine to the forward osmosis (FO) system; By providing a semipermeable membrane arranged substantially vertically, fluid communication is provided in the FO system between a brine chamber containing brine and a draw solution chamber containing draw solution, the semipermeable membrane comprising a material with a surface tension less than 50% of the surface tension of a selected mineral in a crystalline state; as well as In a crystal collector located at the lowest edge of a semi-permeable membrane arranged in a substantially vertical manner, crystals of selected minerals that have formed on the membrane and fallen off due to gravity are collected.

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