A method for separating and extracting valuable resources of lithium, rubidium, cesium, bromine and iodine from salt lakes

Abstract

The present application relates to the field of comprehensive development of salt lake valuable resources, and particularly discloses a method for separating and extracting lithium, rubidium, cesium, bromine and iodine from salt lake valuable resources. The method is based on the flow capacitive deionization technology and the physicochemical properties of lithium, rubidium, cesium, bromine and iodine. Lithium ions and chlorine ions are separated and extracted from salt lake brine in the first flow capacitive deionization device chamber by the combined action of ion exchange membrane and alternating voltage. When the lithium-extracted brine passes through the second flow capacitive deionization device, rubidium ions, cesium ions, bromine ions and iodine ions are separated and extracted by the combined action of ion exchange membrane and alternating voltage. The method has the advantages of low cost, simple process and high efficiency of separating and extracting valuable elements, and can realize efficient development and comprehensive utilization of salt lake valuable resources, thus having a good industrialization prospect.

Description

Technical Field

[0001] This invention belongs to the field of comprehensive development technology of valuable resources in salt lakes, specifically relating to a method for separating and extracting lithium, rubidium, cesium, bromine and iodine from valuable resources in salt lakes. Background Technology

[0002] Salt lakes are lakes with a water salinity greater than 35 g / L. Besides containing elements such as potassium, sodium, chlorine, and magnesium, they also have considerable reserves of lithium, rubidium, cesium, boron, bromine, and iodine. As an important component of natural resources and a vast treasure trove of valuable inorganic salt resources, my country's salt lakes possess advantages such as large numbers, vast areas, abundant resources, diverse types, and high levels of rare elements. As a vital strategic resource, the efficient, rational, and comprehensive development and utilization of salt lake resources are of great significance for promoting the development of industries related to people's livelihoods and the economy, such as new materials and new energy, and for advancing social progress.

[0003] With the development of the social economy and the rise of new industries, the importance of lithium, rubidium, cesium, bromine, and iodine in salt lake resources is becoming increasingly prominent. Lithium, as the cornerstone of the new energy industry, is of great significance for ensuring future energy security. Rubidium is a key element in many high-tech fields such as atomic clocks, quantum computing, and energy conversion. Cesium has important applications in catalysis, optoelectronics, magnetohydrodynamics, the nuclear industry, and medicine. Bromine has wide applications in industries related to people's livelihoods, such as combustion improvers, gasoline additives, pesticides, pharmaceutical synthesis, emulsion preparation, high-refractive-index compounds, water purification, and disinfection compounds. Iodine is one of the essential trace elements for the human body, playing an important physiological role in human health; it is also an important raw material for medical disinfectants, food additives, pesticide synthesis, industrial dyes, and analytical chemical reagents.

[0004] For the separation and extraction of lithium, rubidium, cesium, bromine, and iodine, current technologies mainly employ extraction-adsorption methods. This method requires the addition of large amounts of adsorption reagents to adsorb and extract the target ions, followed by elution for purification. During extraction-adsorption, the performance of the adsorption materials is greatly affected by the liquid chemical environment, exhibiting characteristics of unstable material structure and rapid performance degradation. Furthermore, the subsequent desorption, which uses large amounts of acidic or alkaline reagents, can cause water pollution and hinders the recovery and utilization of other elemental resources. In short, extraction-adsorption methods still suffer from drawbacks such as high industrialization costs and susceptibility to secondary pollution. Therefore, for the comprehensive development and utilization of salt lake resources, especially for the separation and extraction of lithium, rubidium, cesium, bromine, and iodine, the development of new methods and technologies is still necessary. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the present invention provides a method for separating and extracting valuable resources such as lithium, rubidium, cesium, bromine and iodine from salt lakes, so as to reduce industrial costs and reduce environmental pollution.

[0006] To address the above problems, this invention provides a method for separating and extracting valuable resources such as lithium, rubidium, cesium, bromine, and iodine from salt lakes. The method employs a flowing capacitor deionization device, which includes an intermediate chamber and, on opposite sides of the intermediate chamber, a protective layer of an exchange membrane, an ion exchange membrane, and a flowing electrode chamber, respectively. The separation and extraction method comprises the following steps:

[0007] S10. A cation exchange membrane for separating lithium ions is provided on the first side of the first flow capacitor deionization device and the lithium ion extract is pumped into the flow electrode chamber on the first side. An anion exchange membrane for separating chloride ions is provided on the second side of the first flow capacitor deionization device and the chloride ion extract is pumped into the flow electrode chamber on the second side.

[0008] S20. Salt lake brine containing lithium, rubidium, cesium, bromine and iodine is pumped into the intermediate chamber of the first flow capacitor deionization device, and an alternating voltage is applied to the two flow electrode chambers of the first flow capacitor deionization device, so that lithium ions migrate to the first flow electrode chamber and chloride ions migrate to the second flow electrode chamber and are enriched and extracted by electrochemical reaction in their respective flow electrode chambers.

[0009] S30. A cation exchange membrane for separating rubidium and cesium ions is provided on the first side of the second flow capacitor deionization device, and the rubidium and cesium ion extract is pumped into the flow electrode chamber on the first side. An anion exchange membrane for separating bromine and iodine ions is provided on the second side of the second flow capacitor deionization device, and the bromine and iodine ion extract is pumped into the flow electrode chamber on the second side.

[0010] S40. The brine after lithium extraction via the first flow capacitor deionization device is pumped into the intermediate chamber of the second flow capacitor deionization device, and an alternating voltage is applied to the two flow electrode chambers of the second flow capacitor deionization device, causing rubidium and cesium ions to migrate to the first flow electrode chamber, while bromine and iodine ions migrate to the second flow electrode chamber and undergo electrochemical reactions in their respective flow electrode chambers to be enriched and extracted.

[0011] Preferably, in steps S10 and S30, the M element ion extraction solution pumped into the corresponding flow electrode chamber comprises a mixed slurry of an active material with adsorption electrochemical activity and selectivity for the M element, a charge carrier conductor, and a gel polymer; the M element corresponds to lithium, chlorine, rubidium, cesium, bromine, and iodine, respectively.

[0012] Preferably, in the mixed slurry, the mass ratio of the active material to the charge carrier conductor is 1:0.5 to 1:5, and the molar concentration of the gel polymer is 0.01 mol / L to 1 mol / L.

[0013] Preferably, the solid content of the mixed slurry is 5 wt% to 50 wt%.

[0014] Preferably, the active material exhibiting adsorption electrochemical activity and selectivity for lithium ions is selected from lithium manganese oxide, lithium iron phosphate, lithium nickel molybdenum manganese oxide, or lithium nickel cobalt manganese oxide; the active material exhibiting adsorption electrochemical activity and selectivity for rubidium ions is selected from Prussian blue or similar materials; the active material exhibiting adsorption electrochemical activity and selectivity for cesium ions is selected from ammonium phosphomolybdate, Prussian blue, or ammonium phosphotungstenate; the active material exhibiting adsorption electrochemical activity and selectivity for chloride ions is selected from bismuth oxychloride; the active material exhibiting adsorption electrochemical activity and selectivity for bromide ions is selected from bismuth oxybromide or nickel-iron layered bimetallic oxide; and the active material exhibiting adsorption electrochemical activity and selectivity for iodide ions is selected from silver or bismuth oxyiodide.

[0015] Preferably, the charge carrier conductor is an electronic conductor or an electrochemical redox medium.

[0016] Preferably, the gel polymer is polyvinyl alcohol or polyurethane.

[0017] Preferably, in the flow capacitor deionization device, the protective layer of the exchange membrane is a titanium mesh or a polymer-based membrane with a mesh size of 100 to 300.

[0018] Preferably, in steps S20 and S40, the voltage values ​​of the alternating voltage applied to the two flow electrode chambers are 0.5V to 2V, and the frequency is 0.01Hz to 10Hz, respectively.

[0019] Preferably, in steps S10 and S30, the pumping flow rate of the corresponding ion extraction solution for each element is 1 mL / min to 10 mL / min, respectively; in steps S20 and S40, the pumping flow rate of the salt lake brine and the lithium-extracted brine is 10 min / BV to 30 min / BV, respectively.

[0020] This invention provides a method for separating and extracting lithium, rubidium, cesium, bromine, and iodine from valuable resources in salt lakes. Targeting the physicochemical properties of lithium, rubidium, cesium, bromine, and iodine, the method utilizes the combined action of an ion exchange membrane and an alternating voltage electric field. In a first flowing capacitor deionization device, lithium and chloride ions are preferentially separated and extracted from the salt lake brine. After lithium extraction, the brine passes through a second flowing capacitor deionization device, where rubidium, cesium, bromine, and iodine ions are further separated and extracted using the same ion exchange membrane and alternating voltage. The method provided by this invention has the advantages of low cost, simple process, high efficiency in separating and extracting valuable elements, and is environmentally friendly with no pollution. It enables the efficient development and comprehensive utilization of valuable resources in salt lakes and has good industrialization prospects. Attached Figure Description

[0021] Figure 1This is a schematic diagram of the structure of the flow capacitor deionization device provided in an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram illustrating the separation and extraction process of lithium, rubidium, cesium, bromine, and iodine in an embodiment of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Examples of these preferred embodiments are illustrated in the drawings. The embodiments of the present invention shown in and described with reference to the drawings are merely exemplary, and the present invention is not limited to these embodiments.

[0024] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0025] Figure 1 This is a schematic diagram of the structure of the flowing capacitor deionization device provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the flowing capacitive deionization device includes an intermediate chamber 1 and an exchange membrane protective layer 2, an ion exchange membrane 3, and a flowing electrode chamber 4, which are sequentially arranged on opposite sides of the intermediate chamber 1. The flowing electrode chamber 4 is also provided with a window 41 for the inlet and outlet of the electrolyte for the ion extraction of the element to be separated and extracted.

[0026] Among them, the ion exchange membrane 3 selectively separates ions, the alternating electric field controls the diffusion rate of different ions, and the exchange membrane protective layer 2 protects the ion exchange membrane 3 from the wear of chemical slurry particles, thus protecting the ion exchange membrane 3 and transmitting impurity ions.

[0027] Based on the above-described flow capacitance deionization device, this invention provides a method for separating and extracting valuable resources such as lithium, rubidium, cesium, bromine, and iodine from salt lakes. (See attached document.) Figure 2 Two flow capacitor deionization devices as described above are used, and the two flow capacitor deionization devices as described above are connected in series.

[0028] Specifically, the separation and extraction method includes the following steps:

[0029] S10. A cation exchange membrane for separating lithium ions is provided on the first side of the first flow capacitor deionization device, and the lithium ion extract is pumped into the flow electrode chamber on the first side. An anion exchange membrane for separating chloride ions is provided on the second side of the first flow capacitor deionization device, and the chloride ion extract is pumped into the flow electrode chamber on the second side.

[0030] S20. Salt lake brine containing lithium, rubidium, cesium, bromine and iodine is pumped into the intermediate chamber of the first flow capacitor deionization device, and an alternating voltage is applied to the two flow electrode chambers of the first flow capacitor deionization device, so that lithium ions migrate to the first flow electrode chamber and chloride ions migrate to the second flow electrode chamber, and are enriched and extracted by electrochemical reaction in their respective flow electrode chambers.

[0031] S30. A cation exchange membrane for separating rubidium and cesium ions is provided on the first side of the second flow capacitor deionization device, and the rubidium and cesium ion extract is pumped into the flow electrode chamber on the first side. An anion exchange membrane for separating bromine and iodine ions is provided on the second side of the second flow capacitor deionization device, and the bromine and iodine ion extract is pumped into the flow electrode chamber on the second side.

[0032] S40. The brine after lithium extraction via the first flow capacitor deionization device is pumped into the intermediate chamber of the second flow capacitor deionization device, and an alternating voltage is applied to the two flow electrode chambers of the second flow capacitor deionization device, causing rubidium and cesium ions to migrate to the first flow electrode chamber, while bromine and iodine ions migrate to the second flow electrode chamber and undergo electrochemical reactions in their respective flow electrode chambers to be enriched and extracted.

[0033] In a preferred embodiment, in steps S10 and S30, the M-element ion extraction solution pumped into the corresponding flow electrode chamber comprises a mixed slurry of an active material with adsorption electrochemical activity and selectivity for the M-element, a charge carrier conductor, and a gel polymer; the M-element corresponds to lithium, chlorine, rubidium, cesium, bromine, and iodine, respectively.

[0034] In the mixed slurry, the mass ratio of the active material to the charge carrier conductor is preferably set to 1:0.5 to 1:5, and the molar concentration of the gel polymer is preferably 0.01 mol / L to 1 mol / L. The solid content of the mixed slurry is preferably 5 wt% to 50 wt%. Specifically, the active material and the charge carrier conductor are added to a 0.01 mol / L to 1 mol / L saline solution containing the dissolved gel polymer at a mass ratio of 1:0.5 to 1:5, and the mixture is stirred to form the mixed slurry.

[0035] Among them, the active materials with adsorption electrochemical activity and selectivity for lithium ions can be lithium manganese oxide, lithium iron phosphate, lithium nickel molybdenum manganese oxide, or lithium nickel cobalt manganese oxide; the active materials with adsorption electrochemical activity and selectivity for rubidium ions can be Prussian blue or similar materials; the active materials with adsorption electrochemical activity and selectivity for cesium ions can be ammonium phosphomolybdate, Prussian blue or ammonium phosphotungsten; the active materials with adsorption electrochemical activity and selectivity for chloride ions can be bismuth oxychloride; the active materials with adsorption electrochemical activity and selectivity for bromide ions can be bismuth oxybromide or nickel iron layered bimetallic oxide; and the active materials with adsorption electrochemical activity and selectivity for iodide ions can be silver or bismuth oxyiodide.

[0036] The charge carrier conductor is an electronic conductor or an electrochemical redox medium, such as conductive carbon black or p-benzoquinone. The gel polymer can be polyvinyl alcohol or polyurethane.

[0037] In a preferred embodiment, in the flow capacitor deionization device, the protective layer of the exchange membrane is a titanium mesh or a polymer-based membrane with a mesh size of 100 to 300.

[0038] In a preferred embodiment, in steps S20 and S40, the voltage values ​​of the alternating voltage applied to the two flow electrode chambers are 0.5V to 2V, and the frequency is 0.01Hz to 10Hz, respectively.

[0039] In a preferred embodiment, in steps S10 and S30, the pumping flow rate of the corresponding ion extraction solution for each element is 1 mL / min to 10 mL / min, respectively; in steps S20 and S40, the pumping flow rate of the salt lake brine and the lithium-extracted brine is 10 min / BV to 30 min / BV, respectively.

[0040] Example 1

[0041] (1) Salt lake brine containing lithium, rubidium, cesium, chloride, bromine, and iodine is pumped into the first flowing capacitive deionization device via a circulating pump. Under an alternating voltage of 0.6–1.0 V and a frequency of 0.1–2 Hz, lithium ions enter one of the flowing electrode chambers, and chloride ions enter the other. Lithium and chloride ions are selectively adsorbed and enriched by their respective ion extraction solutions in the corresponding flowing electrode chambers. After treatment by the first flowing capacitive deionization device, the salt lake brine becomes lithium-free brine and enters the second flowing capacitive deionization device.

[0042] The first flow capacitor deionization device includes: a monovalent ion selective membrane, lithium nickel cobalt manganese oxide as the lithium ion selective electrode active material, and bismuth oxychloride as the chloride ion selective electrode active material.

[0043] (2) The lithium-extracted brine after treatment in the first flow capacitor deionization unit enters the second flow capacitor deionization unit. Under an alternating voltage of 0.8–1.2V and a frequency of 0.1–10Hz, rubidium and cesium ions enter one of the flow electrode chambers, while bromine and iodine ions enter the other. Rubidium, cesium, bromine, and iodine ions are selectively adsorbed and enriched by their respective ion extraction solutions in the corresponding flow electrode chambers. After treatment in the second flow capacitor deionization unit, the brine becomes lithium-free, rubidium-free, cesium-free, bromine-free, and iodine-free brine.

[0044] The second flow capacitor deionization device includes: a monovalent ion selective membrane, a rubidium ion selective electrode active material (a rubidium blue analog material), a bromide oxybismuth bromine ion selective electrode active material, a cesium ion selective electrode active material (ammonium phosphotungstenate), and an iodide ion selective electrode active material (barium silver iodate).

[0045] Example 2

[0046] (1) After potassium extraction, the old brine is pumped into the first flow capacitor deionization device via a circulating pump. Under the action of an alternating voltage of 0.6–1.0V and a frequency of 0.1–4Hz, lithium ions enter one of the flow electrode chambers, and chloride ions enter the other. Lithium ions and chloride ions are selectively adsorbed and enriched by the corresponding ion extraction solutions in their respective flow electrode chambers. After several cycles of treatment in the first flow capacitor deionization device (until the lithium concentration in the brine is below 10ppm), the salt lake brine becomes lithium-free and enters the second flow capacitor deionization device.

[0047] The first flow capacitor deionization device includes: a monovalent ion selective membrane, lithium nickel molybdenum manganese oxide as the lithium ion selective electrode active material, and bismuth oxychloride as the chloride ion selective electrode active material.

[0048] (2) The lithium-free brine, after being treated by the first flow capacitor deionization device, enters the second flow capacitor deionization device. Under the action of an alternating voltage of 0.6–1.0V and a frequency of 0.1–8Hz, rubidium and cesium ions enter one of the flow electrode chambers, while bromine and iodine ions enter the other. Rubidium, cesium, bromine, and iodine ions are selectively adsorbed and enriched by their respective ion extraction solutions in the corresponding flow electrode chambers. After treatment by the second flow capacitor deionization device, the salt lake brine becomes lithium-free, rubidium-free, cesium-free, bromine-free, and iodine-free brine.

[0049] The second flow capacitor deionization device includes: a monovalent ion selective membrane, a rubidium ion selective electrode active material (a roszolium blue analog material), a bromide oxybismuth bromine ion selective electrode active material, a cesium ion selective electrode active material (ammonium phosphomolybdate), and an iodide ion selective electrode active material (bismuth oxyiodide).

[0050] Based on the methods of Examples 1 and 2 above, and after multiple experimental tests, the separation and extraction method provided by the embodiments of the present invention has high separation and extraction efficiency for various salt lake brines containing lithium, rubidium, cesium, chloride, bromine and iodine, with lithium ion extraction rates ranging from 70% to 95%, chloride ion extraction rates ranging from 70% to 95%, rubidium ion extraction rates ranging from 70% to 90%, cesium ion extraction rates ranging from 70% to 90%, bromide ion extraction rates ranging from 70% to 90%, and iodide ion extraction rates ranging from 70% to 90%.

[0051] In summary, the present invention provides a method for separating and extracting lithium, rubidium, cesium, bromine, and iodine, valuable resources from salt lakes. Targeting the physicochemical properties of lithium, rubidium, cesium, bromine, and iodine, the method utilizes the combined action of an ion exchange membrane and an alternating voltage electric field to preferentially separate and extract lithium and chloride ions from the salt lake brine in a first flowing capacitor deionization device. After lithium extraction, the brine passes through a second flowing capacitor deionization device, where rubidium, cesium, bromine, and iodine ions are further separated and extracted using the combined action of an ion exchange membrane and alternating voltage. The method provided by this invention has the advantages of low cost, simple process, and high efficiency in separating and extracting valuable elements. Furthermore, it is environmentally friendly, reducing environmental pollution, and can achieve efficient development and comprehensive utilization of valuable salt lake resources, demonstrating good industrialization prospects.

[0052] The above description is only a specific embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for separating and extracting valuable resources of lithium, rubidium, cesium, bromine, and iodine from salt lakes, employing a flow capacitor deionization device, wherein the flow capacitor deionization device comprises an intermediate chamber and, on opposite sides of the intermediate chamber, an exchange membrane protective layer, an ion exchange membrane, and a flow electrode chamber, respectively arranged sequentially, characterized in that... The separation and extraction method includes the following steps: S10. A cation exchange membrane for separating lithium ions is provided on the first side of the first flow capacitor deionization device and the lithium ion extract is pumped into the flow electrode chamber on the first side. An anion exchange membrane for separating chloride ions is provided on the second side of the first flow capacitor deionization device and the chloride ion extract is pumped into the flow electrode chamber on the second side. S20. Salt lake brine containing lithium, rubidium, cesium, bromine and iodine is pumped into the intermediate chamber of the first flow capacitor deionization device, and an alternating voltage is applied to the two flow electrode chambers of the first flow capacitor deionization device, so that lithium ions migrate to the first flow electrode chamber and chloride ions migrate to the second flow electrode chamber, and are enriched and extracted by electrochemical reaction in their respective flow electrode chambers. S30. A cation exchange membrane for separating rubidium and cesium ions is provided on the first side of the second flow capacitor deionization device, and the rubidium and cesium ion extract is pumped into the flow electrode chamber on the first side. An anion exchange membrane for separating bromine and iodine ions is provided on the second side of the second flow capacitor deionization device, and the bromine and iodine ion extract is pumped into the flow electrode chamber on the second side. S40. The brine after lithium extraction via the first flow capacitor deionization device is pumped into the intermediate chamber of the second flow capacitor deionization device, and an alternating voltage is applied to the two flow electrode chambers of the second flow capacitor deionization device, so that rubidium and cesium ions migrate to the first flow electrode chamber and bromine and iodine ions migrate to the second flow electrode chamber, and are enriched and extracted by electrochemical reactions in their respective flow electrode chambers.

2. The separation extraction method according to claim 1, characterized by, In steps S10 and S30, the M element ion extraction solution pumped into the corresponding flow electrode chamber includes a mixed slurry of an active material with adsorption electrochemical activity and selectivity for M element, a charge carrier conductor, and a gel polymer; the M element corresponds to lithium, chlorine, rubidium, cesium, bromine, and iodine, respectively.

3. The separation extraction method according to claim 2, characterized by, In the mixed slurry, the mass ratio of the active material to the charge carrier conductor is 1:0.5 to 1:5, and the molar concentration of the gel polymer is 0.01 mol / L to 1 mol / L.

4. The separation extraction method according to claim 3, characterized by, The solid content of the mixed slurry is 5 wt% to 50 wt%.

5. The separation extraction method according to claim 3, wherein, The active materials with adsorption electrochemical activity and selectivity for lithium ions are lithium manganese oxide, lithium iron phosphate, lithium nickel molybdenum manganese oxide, or lithium nickel cobalt manganese oxide; the active materials with adsorption electrochemical activity and selectivity for rubidium ions are Prussian blue or similar materials; the active materials with adsorption electrochemical activity and selectivity for cesium ions are ammonium phosphomolybdate, Prussian blue or ammonium phosphotungsten; the active materials with adsorption electrochemical activity and selectivity for chloride ions are bismuth oxychloride; the active materials with adsorption electrochemical activity and selectivity for bromide ions are bismuth oxybromide or nickel-iron layered bimetallic oxides; and the active materials with adsorption electrochemical activity and selectivity for iodide ions are silver or bismuth oxyiodide.

6. The separation extraction method according to claim 3, wherein, The charge carrier conductor is an electronic conductor or an electrochemical redox medium.

7. The separation extraction method according to claim 3, characterized by, The gel polymer is polyvinyl alcohol or polyurethane.

8. The separation and extraction method according to claim 1, characterized in that, In the flowing capacitor deionization device, the protective layer of the exchange membrane is a titanium mesh or a polymer-based membrane with a mesh size of 100-300.

9. The separation process according to any one of claims 1 to 8, wherein In steps S20 and S40, the voltage values ​​of the alternating voltage applied to the two flow electrode chambers are 0.5V to 2V, and the frequency is 0.01Hz to 10Hz, respectively.

10. The separation extraction method according to claim 9, wherein, In steps S10 and S30, the pumping flow rate of the corresponding ion extraction solution for each element is 1 mL / min to 10 mL / min, respectively; in steps S20 and S40, the pumping flow rate of the salt lake brine and the lithium-extracted brine is 10 min / BV to 30 min / BV, respectively.

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