Mineral extraction from brine by controlled precipitation process

Abstract

A method and a device obtain at least one mineral from a brine. The brine and a seed solution are provided and fed via pumps into a confined reaction zone, under controlled conditions, to produce a precipitant in aqueous solution. An extractor arrangement extracts the precipitant from the aqueous solution.

Description

[0001] MINERAL EXTRACTION FROM BRINE BY CONTROLLED PRECIPITATION

[0002] PROCESS

[0003] CROSS-REFERENCE TO RELATED APPLICATIONS

[0004] This application claims the benefit of US Provisional Patent Application No. US 63 / 641,482, filed May 2, 2024, and PCT Application PCT / IB2024 / 060617 filed October 28, 2024, whose disclosures are incorporated by reference in their entirety herein. TECHNICAL FIELD

[0005] The present disclosure relates to the extraction of minerals from reverse osmosis (RO) brine, based on precipitation processes, using a controlled process and a device or system which affect the product’s particles size and size distribution, composition and purity. Moreover, the present disclosure allows selective removal of a desired metal salt.

[0006] BACKGROUND OF THE INVENTION

[0007] Extraction of minerals from brine, such as brine obtained from reverse osmosis (RO), can be carried out by precipitation processes. The quality of the sediments depends on the filterability, sedimentation rate, and purity of the precipitants. To meet filterability and sedimentation challenges in largescale production, it is highly important to obtain pure precipitants composed of large particles, containing a minimum amount of filtrate (or water).

[0008] Crystallization can be considered a two-step process. The first step is nucleation, where crystals form, and the second step is crystal growth, during which these crystals increase in size. When a new nucleus crystallizes, it grows as follows: solute molecules diffuse toward the surface of the growing crystal, adsorb to its surface, and finally integrate into the crystal structure. Crystal growth is favored when supersaturation is low (in the metastable zone) and in the presence of seeds that are not large enough (Figs. 1 and 2).

[0009] New nuclei can form through either primary or secondary nucleation. Primary nucleation occurs directly in a supersaturated solution. Secondary nucleation, on the other hand, is influenced by the presence of larger, pre-existing crystals (macroscopic crystals). In this process, the energy required for nucleation is reduced, allowing it to occur at a lower concentration compared to primary nucleation, which typically requires supersaturation and is predominant only at the initiation of nonseeded crystallization.

[0010] In secondary nucleation, seed crystals significantly reduce the nucleation barrier, enabling nucleation at lower concentrations than primary nucleation. This leads to better control over the crystallization process and its outcomes. Additionally, it allows for the selective crystallization of specific polymorphic crystals and produces crystalline products with more consistent size and distribution. The rate of secondary nucleation increases with rising concentration, so it is important to ensure homogeneous mixing between the precipitating agent (alkali) and the brine to avoid variations in supersaturation levels throughout the solution. This can be achieved through co-current feeding of the two solutions, where supersaturation (correlated with pH levels and / or temperature) occurs immediately and uniformly, unlike batch feeding, where supersaturation is excessively high at the interface, even with vigorous stirring. However, controlling seed size and concentration, which directly influences secondary nucleation rates, particle size, and crystal growth during mixing, remains a challenge in batch mode reactors.

[0011] A part of the batch reactor (the mixing zone) ensures homogeneous mixing between the precipitant and precipitated agent solutions. However, when the recirculated solution with the seeds is being mixed with the precipitating solution, nuclei form. By that, the concentration in the whole batch reactor is relatively low. The crystals’ size is correlated to both seeds’ concentration and their size, according to the following equation: where Lspis the product crystal size, Lsis the seed size and Csis the concentration of seeds in solution. In addition, the seed crystal size influences the secondary nucleation rate. A larger crystals seed produces a faster growth in the suspension density leading to a higher secondary nucleation rate. Therefore, to maintain high seed concentration the circulation of the precipitated solution occurs in the bottom layer of the batch with the aid of adequate pipes located at the top layer of the batch reactor.

[0012] Regarding precipitation processes for the extraction of alkali metals from brine, various precipitating agents are commonly used, such as NaOH, NH4OH, NasPCU, and Ca(OH)2. A process for magnesium extraction from brine was developed as follows: First, most of the calcium (present as CaCh) and the sulfates (present as ISfeSCU) are removed by chemical precipitation using sodium carbonate (JS^CCh) and barium chloride (BaCh) solutions as a pre-treatment. Magnesium is then precipitated using NaOH as the precipitating agent. The resulting magnesium hydroxide had a purity of 51-58%, which is comparable to other commercial sources of Mg(OH)2. The precipitate also contained 19.5-23.3% CaCOs and 1.3-7.8% CaSO4 as impurities. By-products of this process included CaCOs with a purity of 95% and CaSO4 with a purity of 92%.

[0013] In another study, it was demonstrated that Na2COs and NaOH can be used as alkaline sources to precipitate Mg2+and Ca2+from mining and seawater desalination brines. The results showed calcium recovery yields higher than 94-96% at pH levels above 10 when using Na2COs, and magnesium recovery yields higher than 97-99% at pH levels above 11 with NaOH dosing. In a separate study, NaOH was used as the alkaline source to precipitate Mg2+, achieving magnesium precipitate purities of 98-100% in most experimental runs. Reactive precipitation allowed for total magnesium recovery from the brine using stoichiometric amounts of alkaline reactant. However, the main drawback is the formation of flaky particles, which incorporate large amounts of liquid, making separation difficult through simple sedimentation.

[0014] Another study describes the extraction of Mg(OH)2 from a mixture using membrane crystallization technology, where direct contact between the brine and the alkaline medium is avoided. In this process, an anion exchange membrane separates two compartments: one containing the brine and the other the alkali precipitating agent (calcium hydroxide), allowing only the transfer of hydroxyl ions through the membrane. This approach prevents the co-precipitation of calcium salts and magnesium hydroxide.

[0015] SUMMARY OF THE INVENTION

[0016] The present disclosure provides controlled precipitation processes, where the setup controls the concentration of the salt (containing the desired metal) seeds, the size and distribution of the particles, and the purity of low-solubility salts.

[0017] The embodiments according to present disclosure relate to a device (or system) that ensures homogeneous mixing of the precipitating and precipitated agents, while controlling the conditions of the precipitation reaction, as well as the size distribution and concentration of the seeds throughout the process.

[0018] Among various metal salt precipitation processes, magnesium hydroxide serves as a good example to illustrate the method. The process consists of three operational stages: seed formation under controlled conditions, crystal growth under controlled conditions, and extraction. Therefore, enabling the selective removal of high purity metal salt from a brine with consistent particle size and distribution.

[0019] As will be discussed in detail below, controlling the precipitants’ size and size distribution, purity and filterability in a continuous precipitation process, can be achieved by: a) homogeneous mixing (or reaction zone); b) control of reaction parameters) endurance (or retention) time in the reaction zone of all ingredients, temperature, and pH; c) control of seeds’ size in the reaction zone; and d) maintaining a steady state along the precipitation process.

[0020] According to the teachings of an embodiment of the present disclosure, there is provided a method for obtaining at least one mineral from a brine, the method comprising: providing the brine and a seed solution; feeding the brine and the seed solution into a confined reaction zone, under controlled conditions to produce a precipitant in aqueous solution; and extracting the precipitant from the aqueous solution. Optionally, the seed solution is formed by: providing the brine and a precipitating agent; mixing the brine and the precipitating agent in a reactor, thereby forming a second aqueous solution, under controlled conditions to produce the seed solution.

[0021] Optionally, the controlled conditions include: controlled flow rate of the brine and the precipitating agent; controlled pH of the second aqueous solution; controlled temperature of the second aqueous solution; controlled mixing time and intensity of the second aqueous solution; and controlled time available for seed formation.

[0022] Optionally, providing the brine includes pre-treating the brine to remove metal carbonates.

[0023] Optionally, the pre-treating the brine includes: providing the brine and an acid; adjusting the pH of the brine with the acid to less than three to release carbon dioxide (CO2) gas; providing an alkaline solution; and adjusting the pH of the brine with the alkaline solution to natural pH to produce pre-treated brine.

[0024] Optionally, the release of carbon dioxide is enhanced by an air stripper.

[0025] Optionally, the release of carbon dioxide is enhanced by a carbon dioxide membrane contactor.

[0026] Optionally, the pre-treating the brine includes: providing the brine and an acid; adjusting the pH of the brine with the acid to 6-8; providing a divalent selective nano filter (NF); filtering the brine using through the selective NF; providing an alkaline solution; and adjusting the pH of the brine with the alkaline solution to natural pH to produce pre-treated brine.

[0027] Optionally, the extracting the precipitant produces treated brine, wherein the method further comprising recirculating the treated brine to the confined reaction zone to produce a second precipitant.

[0028] Optionally, the second precipitant is the same as the precipitant

[0029] Optionally, the second precipitant is different from the precipitant.

[0030] Optionally, the brine is a product of reverse osmosis

[0031] Optionally, the controlled conditions include: controlled flow rate of the brine and the seed solution; controlled pH of the aqueous solution; controlled temperature of the aqueous solution; and controlled seed size of seeds in the seed solution.

[0032] Optionally, the extracting includes performing filtration.

[0033] Optionally, the extracting further includes performing sedimentation prior to the filtration.

[0034] Optionally, the at least one mineral includes alkali hydroxides.

[0035] Optionally, the at least one mineral includes alkaline-earth hydroxides.

[0036] Optionally, the alkaline-earth includes magnesium.

[0037] Optionally, the alkaline-earth includes calcium. According to the teachings of an embodiment of the present disclosure, there is provided a device for obtaining at least one mineral from a brine, the device comprising: a first pump for pumping the brine; a second pump for pumping a seed solution; a confined reaction zone in fluid communication with the first pump and the second pump, the confined reaction zone configured to receiving the pumped brine and the pumped seed solution and for precipitation of precipitant in an aqueous solution under controlled conditions; and an extractor arrangement in fluid communication with the confined reaction zone for extracting the precipitant from the aqueous solution.

[0038] Optionally, the device further comprising: a third pump for pumping a precipitating agent; a reactor in fluid communication with the first pump and the third pump; the reactor for receiving the pumped precipitating agent and the pumped brine or seed solution and for precipitation of precipitant in an aqueous solution under controlled conditions

[0039] Optionally, the device further comprising a valve arrangement in fluid communication with the reactor for selecting a portion of the seed solution according to seed size and feeding the seed solution into the confined reaction zone.

[0040] Optionally, the controlled conditions include: controlled flow rate of the brine and the seed solution; controlled pH of the aqueous solution; controlled temperature of the aqueous solution; and controlled seeds size of the seeds in the seed solution.

[0041] Optionally, the extractor arrangement includes a filter press for extracting the precipitant from the aqueous solution.

[0042] Optionally, the extractor arrangement further includes a reactor in fluid communication with the filter press for performing sedimentation of the precipitant from the aqueous solution to produce sediment, wherein the filter press is configured to filter the produced sediment.

[0043] Unless otherwise defined herein, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure pertains. Although methods and materials similar or equivalent to those described herein may be used in the practice or testing of embodiments of the disclosure, exemplary methods and / or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

[0044] BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Some embodiments of the present disclosure are herein described, by way of example only, with reference to the accompanying drawings. With specific reference to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the disclosure. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the disclosure may be practiced.

[0046] Attention is now directed to the drawings, where like reference numerals or characters indicate corresponding or like components. In the drawings:

[0047] Fig. 1 shows a plot of the crystallizable compound concentration against the precipitant concentration.

[0048] Fig. 2 shows a plot of crystal growth versus nuclei formation in the metastable zone.

[0049] Fig. 3 shows the average values of elements present in seawater reverse osmosis concentrates, according to an embodiment of the present disclosure;

[0050] Fig. 4 is a plot showing the mole fractions of the three different carbonate forms: carbonic acid ion, bicarbonate ion, and carbonate ion, as a function of pH of dissolved solution;

[0051] Figs. 5A, 5B, and 5C are flow diagrams illustrating three exemplary pre-treatment processes, according to embodiments of the present disclosure;

[0052] Fig. 6 is a schematic representation of a device for performing a precipitation process, according to an embodiment of the present disclosure;

[0053] Fig. 7 is an isometric view of a device for performing a precipitation process, according to an embodiment of the present disclosure, taken from behind the device;

[0054] Fig. 8 is an isometric view of the device of Fig. 7, taken from the front of the device;

[0055] Fig. 9 is a front view of the device of Figs. 7 and 8;

[0056] Fig. 10 is a back view of the device of Figs. 7 - 9;

[0057] Fig. 11 shows a real -world example implementation of the device of Figs. 7 - 10;

[0058] Fig. 12 shows a precipitant, in the form of white cakes of magnesium hydroxide, produced using a device according to embodiments of the present disclosure;

[0059] Fig. 13 is a plot illustrating time versus pH of titration with caustic soda for precipitation of Magnesium and calcium hydroxide, according to an embodiment of the present disclosure; and

[0060] Fig. 14 is a schematic representation of a device for Magnesium and Calcium hydroxide removal from brine, according to an embodiment of the present disclosure.

[0061] Fig. 15 is a schematic representation of a system for performing a precipitation process, according to one or more embodiments described herein.

[0062] DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0063] Certain embodiments of the present disclosure provide a method and device (or system) for obtaining at least one mineral from a brine and precipitating agent under controlled conditions. The principles and operation of the method and device according to the present disclosure may be better understood with reference to the drawings accompanying the description.

[0064] Before explaining at least one embodiment of the disclosure in detail, it is to be understood that the disclosure is not necessarily limited in its application to the details of construction and the arrangement of the components and / or methods set forth in the following description and / or illustrated in the drawings and / or the examples. The disclosure is capable of other embodiments or of being practiced or carried out in various ways.

[0065] By way of introduction, one of the main issues encountered when operating conventional precipitation systems is that the concentrated alkaline solution is introduced into a large volume of brine to initiate the precipitation process. The local pH in the area where the concentrated alkaline solution meets the brine is significantly higher than necessary — by at least one order of magnitude. This leads to increased impurities, such as calcium hydroxide precipitation when magnesium hydroxide is the desired precipitate. It can also affect particle size distribution.

[0066] In contrast, the method (process) and device (system) according to embodiments of the present disclosure mixes the brine within a confined reaction zone in the small volume of the pipeline, where the recirculated solution is already very close to the optimal pH required for the desired precipitation.

[0067] The process according to embodiments of the present disclosure enables the extraction of high-purity minerals from brine.

[0068] The brine can be of any type, for example, brine that is not treated in any prior process, or brine that is the concentrate rejected solution of reverse osmosis (RO), or brine that is the concentrate rejected solution of reverse osmosis (RO) that is pre-treated to remove carbonates (e.g. A505, B505, or C505 in Fig. 5).

[0069] An untreated brine will affect product purity due to the presence of organic contaminants, therefore, pre-treatment is desired.

[0070] In one embodiment the mineral includes alkali hydroxides.

[0071] In one embodiment the mineral includes alkaline-earth hydroxides.

[0072] In one embodiment the alkaline-earth hydroxide is magnesium hydroxide.

[0073] In one embodiment the alkaline-earth hydroxide is calcium hydroxide.

[0074] Referring now to the drawings, Fig. 1 shows a plot of the crystallizable compound concentration against the precipitant concentration. The process described in the present disclosure controls the crystallization process so that the crystallization occurs in favorable conditions for crystallization of optimal size crystals (the area labelled as “good” in Fig. 1). The favorable conditions are the metastable zone, that is illustrated in Fig. 2. Fig. 3 is a table that shows the average concentrations of ionic species present in brines, which are byproducts of desalination processes in reverse osmosis (RO) plants. These concentrations are more than double their levels in seawater. It is evident that, after sodium, magnesium is the most abundant metallic cation, followed by calcium. When the brine source is seawater, the selective separation of magnesium and calcium can be highly profitable due to their high concentrations and market value. The purer the extracted metal salt, the more valuable it becomes. The concentrate solution (a product and byproduct of RO plants) is pretreated to remove organic contaminants and small particles. This pretreatment helps to achieve a higher purity of the alkali hydroxide product in the process described in the present disclosure.

[0075] Fig. 4 shows the mole fractions of the three different carbonate forms: carbonic acid ion (H2CO3), bicarbonate ion (HCO3 ), and carbonate ion (CO32), as a function of pH of dissolved solution. Pre-treating the brine to remove carbonates is necessary for achieving high-purity magnesium hydroxide, but it is not essential for the main process of the embodiments of the present disclosure. Even without this step, the magnesium product can reach a purity of up to 95%. Figs. 5A, 5B, and 5C illustrate three example alternatives (though there may be other alternatives) for pretreatment processes for removing carbonates from brine (processes A500, B500, and C500, respectively).

[0076] In process A500, brine (illustrated in the example as RO brine) is provided (A501), and the pH of the provided brine is adjusted to less than three using an acid (e.g., HC1), to release carbon dioxide (CO2) gas (A502), wherein the release of carbon dioxide is enhanced by an air stripper (A503) to accelerate the removal rate of solvated CO2, which enhance the interaction of bubbled air with the brine by the use of high interaction surfaces that help release the CO2 back to the atmosphere. The pH of the brine is then adjusted with the alkaline solution to natural pH (A504) to produce the pretreated brine (A505).

[0077] In processes B500, brine (illustrated in the example as RO brine) is provided (B501), and the pH of the brine is adjusted to less than three using an acid (e.g., HC1), to release carbon dioxide (CO2) gas (B502), wherein the release of carbon dioxide is enhanced by a carbon dioxide membrane contactor column to capture the CO2 (B503), where air is bubbled from above to increase the CO2 capture by vacuum. The CO2 is then compressed to a CO2 tank (B506), which can be used later for other purposes. The pH of the brine is then adjusted with the alkaline solution to natural pH (B504) to produce the pre-treated brine (B505).

[0078] In process C500, brine (illustrated in the example as RO brine) is provided (C501), and the pH of the brine is adjusted to be in a range of 6-8 using an acid (e.g., HC1) (C502). The brine is then filtered using a selective nano filtration (NF) system for divalent ions (C503), and as a result, the concentration of carbonate anions in the filtrate is substantially reduced (by more than 90%). The pH of the brine is then adjusted with the alkaline solution to natural pH (C504) to produce the pre-treated brine (C505). The by-product (C506) is rich with monovalent ions (aqueous sodium chloride and bicarbonate) and can be used for the production of calcium carbonate (C507).

[0079] The acidic brine solutions from the pre-treatment intermediate stage (e.g., A504, B504, and C504) can be used directly in the main process of the embodiments of the present disclosure. In such cases, the flow rates in the cycle — such as the flow rate of various pumps (such as pump P3 for brine, pump P4 for the seed solution, and pump P2 for the precipitating agent, as shown in Fig. 6) — will be adjusted accordingly to regulate the pH and treat the acidic brine.

[0080] Although not illustrated in the drawings, another pre-treatment process that can be combined with carbonate removal is the use of anti-scalant. This method helps achieve a higher purity grade of magnesium by inhibiting the precipitation of calcium salts.

[0081] Referring now to Figs. 6 - 10, there is described a device (also referred to as a “system”) for performing a process for extracting at least one mineral from brine, according to one preferred but non-limiting example embodiment of the present disclosure. Initially, brine and alkaline solution are fed into a reactor (designated REACTOR 1) through pumps P3 and P2, respectively. The solution in REACTOR 1 is mixed using a stirrer (mixer) Ml. The mixing time and intensity can be controlled. The temperature of REACTOR 1 is controlled using a chiller (heat exchanger). The pH and temperature of the solution are monitored by probes located inside REACTOR 1 (pH / Tl component). The flow of the alkaline solution is such that the pH is adjusted to around 12 (for instance). The height of the solution inside REACTOR 1 (the solution level) is determined by measuring the change in pressure inside REACTOR 1 using the PT1 component.

[0082] At this stage, primary nucleation takes place. It is an essential stage that can take time. The flow rate of the brine and the precipitating agent, concentration of precipitant, pH, temperature, and time available for seed formation dictate the seeds size and concentration of the seed solution.

[0083] The seeds are dispersed within REACTOR 1 based on their size, creating a gradient where larger, heavier seeds settle at the bottom of the solution, and smaller, lighter seeds remain at the top. A portion of the seed solution can be selected by opening one of the valves — V4, V5, V6, or V7.

[0084] A confined reaction zone (demarcated by an oval in Fig. 6) is in fluid communication with both pump P3 and pump P4. As will be discussed, the brine and the seed solution are fed into the confined reaction zone, under controlled conditions, to produce a precipitant in aqueous solution.

[0085] According to certain non-limiting implementations, the confined reaction zone may be implemented using one or more pipes. Discussion of non-limiting example implementations of the confined reaction zone will be provided in subsequent sections of this document. In this stage of the process, a portion of the precipitating agent solution containing seeds from REACTOR 1 is selected by opening one of the valves (V4, V5, V6, or V7) and pumped into the confined reaction zone using pump P4 and valve VI 3. At the same time, additional brine is pumped into the confined reaction zone using pump P3. The two solution streams are mixed within the confined reaction zone before being recirculated to REACTOR 1. The pH level in REACTOR 1 is regulated by adding alkaline solution through pump P2, and the temperature is controlled via the chiller (the heat exchanger). Both pH and temperature are monitored by probes inside REACTOR 1 (component pH / Tl).

[0086] An extractor arrangement is provided in fluid communication with the confined reaction zone for extracting the precipitant from the aqueous solution. In one embodiment, to extract the precipitant from the aqueous solution, the aqueous solution can be transferred directly to a filter press (e.g. by opening valve VI 5 and using pump , or P7 in figure 15). Alternatively, the aqueous solution can be transferred to a second reactor, designated REACTOR 2, for example by opening a valve on a fluid stream connecting an outlet of said first reactor to an inlet of said second reactor (e.g., V14 in Figure 6) and operating pump P4, for sedimentation prior to the filtration.

[0087] The system may operate continuously. Hence one of valves: V4, V5, V6 or V7 may be open and valve VI 3 may be open, where the flow rate distribution between the solution that pump P4 transfers through valve VI 3 (for mixing mode - mixes the solution of the brine with the solution of the rector. They interact in the reaction zone) and valve V14 - for sedimentation in REACTOR 2 (as described above), or distribution between valve VI 3 and valve VI 5 - to send the solution to the filter press. The continuous flow rate, where valve VI 5 is open and the precipitant flow to the filter press, may be controlled manually. The flow rate may beequal to the flow rate of the entering brine [A505, or B505, or C505] that the system pump (through pump P3) plus the rate of the pumped alkaline solution (through pump P2).

[0088] The system may comprise two or more valves along two or more output material streams from the reactor. The two or more materials stream outlets may be located at different heights of the reactor wall. In some cases, the reactor may have at least 2, 3, 4, 5, 6 or more outlet material streams with corresponding valves. The valves may be used to control the material streams. The system may be configured to control which outlet is open to control a property of the outlet material stream. For example, opening a valve of an outlet located higher along the side of the reactor wall may control for a material stream with a property of having smaller nucleating seeds. In some cases, the material stream property may comprise seed concentration, seed size, precipitate concentration, precipitate size, homogeneity, or other material property that varies along the height of the reactor. Figure 6 shows a valve arrangement along the height axis of REACTOR 1 or REACTOR 2 for selecting a portion of the seed solution according to seed size (in REACTOR 1) or portion of sediment according to homogeneity (in REACTOR 2), e.g. valves V4, V5, V6 or V7 in REACTOR 1 and valves V8, V9, VI 0, or VI 1 in REACTOR 2.

[0089] The seeds or the precipitate are dispersed within REACTOR 1 or within REACTOR 2 according to the mass, creating a gradient where larger, heavier seeds / sediment settle at the bottom of the solution, and smaller, lighter seeds / sediment remain at the top. A portion of the seed solution or sediment can be selected by opening one of the valves - V4, V5, V6, or V7 in REACTOR 1 and V8, V9, VI 0, or VI 1 in REACTOR 2.

[0090] Pumping from different heights along the reactors helps determine particle size and distribution. When pumped from the bottom of the reactors (e.g., V7 of REACTOR 1 or Vl l of REACTOR 2), the concentration of seeds and particles is high. Conversely, pumping from the top (e.g., V4 of REACTOR 1 or V8 of REACTOR 2) results in a lower concentration of seeds and particles. In this way, smaller particles are created in REACTOR 1. When sending material to the filter press via valve VI 5, the final particle size can be controlled based on the pumping height levels.

[0091] During execution of the process, the system controls the flow of brine and precipitating agent (alkali) into the reaction zone, for example by controlling the flow of the reacted solution in REACTOR 1 that contain seeds (from primary or secondary nucleation) in a closed loop circle and evacuation rate of solution from REACTOR 1 to REACTOR 2, for further settlement process in REACTOR 2, or directly to filtration process, e.g., filter press. The higher the seed solution flow rate is (in conjunction to fast evacuation of solution from REACTOR 1) the smaller the particles will be (an example to the controlling capability).

[0092] Furthermore, REACTOR 2 has the ability to transfer flocculates, using pump P6 to enhance the buildup of the particles speed and the temperature can be controlled also with a chiller to encourage the process. In REACTOR 2 as well as REACTOR 1 the solution can be recycled for better interaction with the flocculants using pump P5, while opening valves: V8, V9, V10, or Vl l, and valve V12. The mixer speed in REACTOR 2 can be controlled, the solution height is monitored by a pressure difference (PT2 component) and the temperature and pH are monitored as well. The solution can be then transferred, using pump P5 and opening valve VI 6 to a filter press to remove the water and obtain a cake of Magnesium hydroxide, or Calcium hydroxide particles with high purity. In a continuous process, the transfer to the filter press is carried out while valve V8, V9, VI 0, or VI 1 is open, and while valve VI 6 is open, and the flow rate of pump P5 is adjusted to match with the flow rate of the solution that flows from pump P2 of the precipitating agent and pump P3 of the brine, where REACTOR 1 is connected to REACTOR 2 from the bottom of the two reactors through the drains. The flow rate of the pumps can be described by the following relationship: P5=P2+P3. Fig. 11 shows an image of a real-world implementation of the system according to an embodiment described above. The implemented system was operational at the time of preparing this document, using real brine in a purification plant to produce minerals with a purity level of up to 97%.

[0093] Fig. 12 shows the magnesium hydroxide cake produced using the system according to a preferred but non-limiting implementation with real brine from an RO desalination plant. The purity of the cake was above 95%.

[0094] Fig. 13 illustrates the relationship between the precipitation of magnesium and calcium and the pH level. Based on this figure, calcium hydroxide precipitation is avoided by adjusting the pH to around 10. Above a pH of 12, calcium hydroxide begins to precipitate. It is important to note that Fig. 13 is based on titrations conducted under different conditions using a different system. Nevertheless, it highlights the critical pH ranges in which calcium hydroxide either precipitates or remains in solution.

[0095] Results of operating the system shown in Fig. 11 indicate that calcium hydroxide precipitation occurs at pH levels above 12.5, and in some cases even above 13. This means that below these pH levels, the precipitation of calcium hydroxide is negligible.

[0096] Fig. 14 illustrates a device (system) for performing a multi-stage continuous process for the removal of magnesium hydroxide and calcium hydroxide from brine, according to an embodiment of the present disclosure. To initiate the process, a pre-treatment for carbonate removal is recommended, as described above and shown in Fig. 5. To operate the system in a steady-state continuous flow, both reactors need to be pre-filled. REACTOR 1 should preferably be filled with brine and circulated with a precipitating agent at a pH in a range between 9.5 and 12.5. REACTOR 2 should preferably be filled with brine that contains low magnesium cation concentration (<5 ppm) and circulated with a precipitating agent at a pH in a range between 12.5 and 14. The reactor volumes should preferably be at least 10 times greater than the brine flow rate, measured in L / min. Once the reactors are filled and prepared, the system can operate in steady-state mode.

[0097] Brine flows through Pump P3 and is mixed with the solution inside REACTOR 1 by Pump P4. The two solutions react as previously described, with magnesium hydroxide seeds forming and growing in the alkaline pH reaction zone before entering REACTOR 1. This technique promotes the formation of homogeneous magnesium hydroxide particle sizes. Pump P2 introduces the precipitating agent at a rate that stabilizes the pH at a fixed value, ensuring the brine reacts with the hydroxide. The pH is continuously monitored both inside the reactor and in the reaction zone. REACTOR 1 and REACTOR 2 are continuously mixed, aided by both a mixer and pumps P4 and P5, respectively. The flow rate of mixing pumps P4 and P5 is five times faster than the brine inflow from pumps P3 and P8, respectively. This high ratio ensures the brine interacts with more magnesium hydroxide seeds circulating in the reactor at lower pH ranges. The solution is then transferred from REACTOR 1 to a filter press, with Pump 7 matching the combined flow rate of pump P3 and pump P2. The resulting brine, now free of magnesium ions, is transferred to the reaction zone by pump P8, where it mixes with the solution in REACTOR 2 using mixing pump P5. The pH in REACTOR 2 is regulated by adding a precipitating agent with pump P6, while the pH is monitored both in the reactor and in the reaction zone.

[0098] The solution is transferred to another filter press using pump P9, which matches the combined flow rate of pumps P8 and P6. The resulting brine is free of both calcium and magnesium. To maintain a fully continuous process, multiple filter presses are used. When one filter press is filled with magnesium hydroxide or calcium hydroxide cakes, the other filter press takes over while the filled press is cleared. This ensures uninterrupted operation of the system.

[0099] The system may detect that a filter press is at capacity by measuring the monitored flow rate of material stream of the system (e.g., the material stream exiting the reactor chamber). The system may flush the filter press with water, without cycling the reactor 1 or reactor 2 solutions. For example, clean water (e.g., not containing substantial concentrations of magnesium or calcium ions) flows through valves 18 and 20 to the filter presses.

[0100] In some cases, an acid (e.g., hydrochloric acid) may be used to clean impurities from the filter press. The acid may have a concentration of between 0.1M and 2M. Once the acid has reacted with calcium or magnesium carbonates on the filter press, the effluent is collected back into the brine material stream into the first reactor or second reactor. The effluent of the filter press in this stage is collected back to the initial obtained brine for second use (this way Magnesium and calcium are not wasted), and according to the pretreatment of the brine (which is described in the PCT) the acidic solution is used for the removal of carbonate as carbon dioxide gas using stripper, or membrane extraction system as described in the PCT. This optional process allows the system to reach high purity of more than 99%.

[0101] In some cases, the system may provide an air stream to the filter press to further dry the precipitates. The air stream may be provided at a pressure of about 6 to 7 bar.

[0102] In some cases, more than one filter press is used for each reactor, so the system can operate continuously. For example, one filter press is cleaned and dried while a second filter press collected the precipitates from the reactor system. Throughout this description, reference has been made to a confined reaction zone that functions to produce precipitant in aqueous solution. The confined reaction zone, although only schematically represented in the drawings (e.g., Figs. 6 and 14), can be implemented in various ways. Examples of implementations of the confined reaction include: (a) Using multiple narrow pipes with diameters between 5 mm and 30 mm and lengths of at least 0.5 meters, with one pipe used for each flow rate between 1 L / min and 5 L / min; (b) Filling a pipe (with no specific diameter limit) with Raschig rings, sized between 5 mm and 30 mm in diameter, up to a length of at least 0.5 meters; and (c) Filling a pipe (with no specific diameter limit) with a perforated surface or foam with hole diameters between 1 mm and 10 mm, up to a length of at least 0.5 meters. It will be appreciated that the above are non-limiting examples of implementations of the confined rection zone, and that additional implementations, though not expressly stated above, may be available according to the teachings of the present disclosure.

[0103] It is noted that the various components of the device / system of the embodiments of the present disclosure, such as the pumps, valves, reactors, confined reaction zone, etc., are placed into fluid communication with each other via an arrangement of conduits, for example, such as, tubing or piping. Such conduits, although not explicitly provided with reference in the foregoing description are illustrated in the accompanying drawings.

[0104] In certain embodiments, control and / or actuation of some or all of the components of the device, such as one or more of the pumps, valves, stirrers, etc., can be provided by a control system, having a computer processor coupled to a computer storage medium. Power is provided to the various components of the device, such as one or more of the pumps, valves, stirrers, etc., by a power supply (as shown in Figs. 7 and 8).

[0105] The descriptions of the various embodiments of the present disclosure have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

[0106] As used herein, the singular form, “a”, “an” and “the” include plural references unless the context clearly dictates otherwise.

[0107] The word “exemplary” is used herein to mean “serving as an example, instance or illustration”. Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments and / or to exclude the incorporation of features from other embodiments.

[0108] It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the disclosure. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

[0109] To the extent that the appended claims have been drafted without multiple dependencies, this has been done only to accommodate formal requirements in jurisdictions which do not allow such multiple dependencies. It should be noted that all possible combinations of features which would be implied by rendering the claims multiply dependent are explicitly envisaged and should be considered part of the disclosure.

[0110] Although the disclosure has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

[0111] Examples

[0112] Example 1 - Magnesium Salt Production (Reactor 1 of Fig, 15)

[0113] A seed material stream comprising a plurality of seeds is provided to a mixer (Ml). The seed material stream has a pH of about 10-13. The seed material stream is mixed at about 150 cycles per minute (CPM). The mixed seed solution is provided to Reactor #1. The solution of Reactor 1 is cycled by pump (P4) at about 9.5 L / min. The mixed solution is cycled through Reactor 1 by exiting Reactor 1 through one valve of several valves on the side wall of the reactor, and entering Reactor 1 through the seed material stream. The valves are controlled by the system to select an output location for the mixed material stream according to the operating conditions and material stream properties. For example, valve 13 (V13) and at least one valve selected from valves 4 through 7 (V4-7) are opened. The at least one valve of the two or more valves on the side wall of the reactor is chosen based on the seed size requirements of the seed material stream. A brine solution that contains Magnesium salt and other salts like Calcium salts and sodium salts is pumped (P3) to reactor #1. The brine solution may be combined with the mixed seed material stream. The brine solution and the seed material stream are pumped and mixed together using the same pipe while transferred to reactor #1. A pH probe (pH3) gives indication of the mixing pH and a second pH probe (pHl) is located inside reactor #1 where concentrated precipitating solution is Pumped (P2) to reactor #1 to stabilize the pH inside the reactor at a fixed pH. VI 7 and VI 5 are opened and allow the grown seeds to flow by Pump (P7) to the filter press at flow rate which equals the sum of flow rate of P3 and P2. When pressure inside the filter press rises to 6 Bar the flow solution of P7 changes according to the filter press filling. The pressure is fixed at 6 Bar by pressure regulator using inside bypass. The system monitors the change in the flow rate by flow meter and the system changes the flow meter of the brine (P3) and the precipitating solution (P2) accordingly. Where P2 = ((measured flow rate) / P7)*P2 and P3 = (( measured flow rate) / P7)*P3.

[0114] Example 2 - Calcium Salt Production (Reactor 2 of Fig 15)

[0115] After the filter press removes magnesium precipitates, the permeate solution exits the filter press and is provided to a second reactor (Reactor 2). The permeate solution has a concentration of magnesium ions of 66 ppb. A second seed material stream comprising calcium ions, at a pH of between 10 and 13, is mixed with a second mixer (M2) at about 150 CPM. The mixed seed material stream is cycled through the second reactor at about 9.5 1 / min. The material stream exits the second reactor through at least one valve selected from two or more valves located along a side of the wall of the second reactor. The exiting material stream is selected to exit through at least one valve based at least in part on the seed size required for the seed material stream. The seed material stream and permeate stream from the filter press are pumped and mixed together using the same pipe and provided to reactor 2. A pH probe measures the mixing pH and a second pH prove located inside reactor 2 measured the pH where the concentrated precipitating solution is provided to the reactor. The pH inside the reactor may be controlled to be constant. The mature precipitate solids exit the reactor 2 through the bottom of the reactor (valves 19 and 16). The flow rate of the exiting material stream through valve 19 equals the sum of the material flow rate of the brine and precipitating solution (pumps 8 and 6).

[0116] When pressure inside the 2ndfilter press rises to 6 Bar, the flow solution of P9 changes according to a limiting flow rate of the 2nd filter press. The pressure is fixed at 6 Bar by a pressure regulator using inside bypass. The system monitors the change in the flow rate by flow meter and the system changes the flow meter of the brine (P8) and the precipitating solution (P6) accordingly. Where P6 = ((measured flow rate) / P9)*P6 and P8 = (( measured flow rate) / P9)*P8. The permeate from the second filter press is a solution with calcium and magnesium ions removed.

[0117] Table 1 - the parameters of Magnesium salts removal system described in figure 15

[0118] Table 2 - the parameters of Calcium salts removal system described in figure 15

Claims

CLAIMSWHAT IS CLAIMED IS:

1. A method for obtaining at least one mineral from a brine, the method comprising: providing the brine and a seed solution; feeding the brine and the seed solution into a confined reaction zone, under controlled conditions, to produce a precipitant in aqueous solution; and extracting the precipitant from the aqueous solution.

2. The method of claim 1 wherein the seed solution is formed by: providing the brine and a precipitating agent; mixing the brine and the precipitating agent in a reactor, thereby forming a second aqueous solution, under controlled conditions to produce the seed solution.

3. The method of claim 2, wherein the controlled conditions include: controlled flow rate of the brine and the precipitating agent; controlled pH of the second aqueous solution; controlled temperature of the second aqueous solution; controlled mixing time and intensity of the second aqueous solution; and controlled time available for seed formation.

4. The method of claim 1, wherein providing the brine includes pre-treating the brine to remove metal carbonates.

5. The method of claim 4, wherein pre-treating the brine includes: providing the brine and an acid; adjusting the pH of the brine with the acid to less than three to release carbon dioxide (CO2) gas; providing an alkaline solution; and adjusting the pH of the brine with the alkaline solution to natural pH to produce pre-treated brine.

6. The method of claim 5, wherein the release of carbon dioxide is enhanced by an air stripper.

7. The method of claim 5, wherein the release of carbon dioxide is enhanced by a carbon dioxide membrane contactor.

8. The method of claim 4, wherein pre-treating the brine includes: providing the brine and an acid; adjusting the pH of the brine with the acid to 6-8; providing a divalent selective nano filter (NF); filtering the brine using through the selective NF; providing an alkaline solution; and adjusting the pH of the brine with the alkaline solution to natural pH to produce pre-treated brine.

9. The method of claim 1 wherein extracting the precipitant produces treated brine, wherein the method further comprising recirculating the treated brine to the confined reaction zone to produce a second precipitant.

10. The method of claim 9, wherein the second precipitant is the same as the precipitant11. The method of claim 9, wherein the second precipitant is different from the precipitant.

12. The method of claim 1, wherein the brine is a concentrate of reverse osmosis.

13. The method of claim 1, wherein the controlled conditions include: controlled flow rate of the brine and the seed solution; controlled pH of the aqueous solution; controlled temperature of the aqueous solution; and controlled seed size of seeds in the seed solution.

14. The method of claim 1, wherein the extracting includes performing filtration.

15. The method of claim 14, wherein the extracting further includes performing sedimentation prior to the filtration.

16. The method of claim 1, wherein the at least one mineral includes alkali hydroxides.

17. The method of claim 1, wherein the at least one mineral includes alkaline-earth hydroxides.

18. The method of claim 17, wherein the alkaline-earth includes magnesium.

19. The method of claim 17, wherein the alkaline-earth includes calcium.

20. A device for obtaining at least one mineral from a brine, the device comprising: a first pump for pumping the brine; a second pump for pumping a seed solution; a confined reaction zone in fluid communication with the first pump and the second pump, the confined reaction zone configured to receiving the pumped brine and the pumped seed solution and for precipitation of precipitant in an aqueous solution under controlled conditions; and an extractor arrangement in fluid communication with the confined reaction zone for extracting the precipitant from the aqueous solution.

21. The device of claim 20, further comprising: a third pump for pumping a precipitating agent; a reactor in fluid communication with the first pump and the third pump; the reactor for receiving the pumped precipitating agent and the pumped brine or seed solution and for precipitation of precipitant in an aqueous solution under controlled conditions.

22. The device of claim 21, further comprising a valve arrangement in fluid communication with the reactor for selecting a portion of the seed solution according to seed size and feeding the seed solution into the confined reaction zone.

23. The device of claim 21, wherein the controlled conditions include: controlled flow rate of the brine and the seed solution; controlled pH of the aqueous solution; controlled temperature of the aqueous solution; and controlled seeds size of the seeds in the seed solution.

24. The device of claim 20, wherein the extractor arrangement includes a filter press for extracting the precipitant from the aqueous solution.

25. The device of claim 24, wherein the extractor arrangement further includes a reactor in fluid communication with the filter press for performing sedimentation of the precipitant from the aqueous solution to produce sediment, wherein the filter press is configured to filter the produced sediment.

26. A method for precipitating at least one mineral from a brine material stream, comprising(a) Providing said brine material stream and a seed material stream to a mixing zone, wherein said seed material stream comprises a plurality of nucleating seeds comprising said at least one mineral;(b) Mixing said brine material stream and said seed material stream to produce a mixed brine and seed material stream;(c) Directing said mixed brine and seed material stream to a reactor;(d) Adjusting, within the reactor, a pH of the mixed brine and seed material stream to precipitate said at least one mineral on said nucleating seeds,Wherein said seed material stream is provided from a output of the reactor.

27. The method of claim 26, wherein said output of the reactor is selected from two or more output locations of the reactor.

28. The method of claim 26, wherein a flow rate of the seed material stream, a flow rate of the brine material stream, or the pH within the reactor are based at least in part on the size or concentration of the seeds of the seed material stream.

29. The method of claim 26, wherein said output of said reactor is controlled between at least two output valves based at least in part on a desired seed concentration or size of said seed material stream.

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