Inorganic Tin Sulfide Adsorbent, Preparation Method Thereof and Application in Cesium Extraction

Abstract

The present invention belongs to the field of the development of new adsorbents and comprehensive utilization of resources, and discloses a preparation method of an inorganic tin sulfide adsorbent and its application in cesium extraction. The adsorbent is synthesized by a hydrothermal method and has a lamellar structure. It has excellent ion exchange performance for alkali metal cesium ions in an aqueous solution and exhibits excellent adsorption selectivity. The adsorbed material can be regenerated, thus realizing the recycling of the adsorption material. The preparation process of the adsorption material provided by the present invention is simple and low in cost. Therefore, the adsorption material prepared by the present invention can be used for the extraction of cesium in geothermal water, salt lake brine, and underground brine, and can also be applied to the separation and extraction of cesium in solid cesium ore or associated ore leaching solutions.

Description

Technical Field

[0001] The present invention belongs to the field of development of new adsorbents and comprehensive utilization of resources, and specifically relates to an inorganic tin sulfide adsorbent, a preparation method thereof, and its application in cesium extraction. Background Art

[0002] As an important strategic resource, cesium is widely used in high-tech fields such as perovskite solar cells, catalysis, atomic clocks, communication, and medical tracing due to its unique properties. The solid cesium resources in China are mainly associated with lepidolite ores in places such as Jiangxi, with relatively scarce resources and high extraction costs. In contrast, liquid cesium resources are relatively abundant, mainly distributed in salt lake brines and geothermal waters in Tibet, Qinghai and other places in China, with large resource reserves and good development prospects. Therefore, developing efficient and environmentally friendly separation and extraction technologies for liquid cesium resources is of great practical significance for the comprehensive utilization of resources and ensuring the strategic reserves of cesium resources in China.

[0003] At present, the methods for extracting cesium from solutions mainly include precipitation method, extraction method, electrochemistry method, adsorption method, etc. The precipitation method and the extraction method are relatively traditional separation methods, applicable to highly concentrated brines, and prone to secondary pollution. The electrochemistry method is a method to achieve the directional migration of ions under the control of an external electric field, with good selectivity and no pollution, but it has high requirements for equipment, and the research is still in its infancy.

[0004] The adsorption method is suitable for the separation and enrichment of low-concentration cesium. The process is simple and environmentally friendly, and it is a separation method with great industrial application prospects. The most commonly used adsorbents at present are ammonium phosphomolybdate and Prussian blue and their analogs. The adsorption capacities of these two types of adsorbents are low. The adsorption capacity of ammonium phosphomolybdate-based adsorbents is about 100 mg / g, such as patents CN106215906B and CN101518727; the adsorption capacity of Prussian blue and its analogs is about 200 mg / g, such as patents CN105561928A and CN106881068B. Therefore, there is an urgent need to develop a high-efficiency adsorption material with high adsorption capacity and good selectivity.

[0005] We found that tin sulfide adsorbents containing organic ligands such as methylamine, dimethylamine, and ethylamine have a significantly improved adsorption capacity compared to ammonium phosphomolybdate and Prussian blue-based adsorbents, which can reach 400 mg / g. However, the synthesis method of tin sulfide with organic amine ligands is complex and time-consuming. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a layered binary doped inorganic tin sulfide adsorption material and a preparation method thereof. The synthesis time of this adsorption material is greatly shortened, and no toxic substances are released during the adsorption process, and there is no organic pollution problem. Moreover, the adsorption capacity can reach more than 400 mg / g.

[0007] According to the first aspect of the present invention, an inorganic tin sulfide adsorbent is provided, which has a lamellar regular cuboid structure, with a crystal particle size of 5-35 μm, and its chemical composition includes potassium, metal A, metal B, tin, and sulfur.

[0008] The general formula of the adsorbent is: K2A x B y Sn 3-x-y S7. Wherein, A represents metal A, B represents metal B, x represents a stoichiometric coefficient with a value of 0.02-0.1; y represents a stoichiometric coefficient with a value of 0.02-0.1; 3-x-y represents a stoichiometric coefficient.

[0009] The metal A is a transition metal element with a melting point of 400-1600 °C. Further, the metal A is preferably iron powder, zinc powder, magnesium powder, or aluminum powder.

[0010] The role of metal A is to form polysulfide with sulfur, thereby increasing the reaction rate and shortening the reaction time.

[0011] The metal B is a trivalent metal element. Further, the metal B is preferably antimony powder or bismuth powder.

[0012] The atomic radius of metal B is It can increase the layer spacing of the adsorbent, thus being more conducive to the adsorption of cesium, and metal B is prone to form oligomers with sulfur, thereby increasing the stability of the material.

[0013] According to the second aspect of the present invention, a preparation method of the inorganic tin sulfide adsorbent is provided, including the following steps:

[0014] Step 1: Add anhydrous potassium carbonate, metal A, metal B, tin powder, and sulfur powder into a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene liner. Based on the total mass of the mixture, gradually add 5-20% deionized water, and mix and stir evenly;

[0015] Step 2: Tightly seal the high-pressure reaction kettle, place it in a vacuum drying oven preheated to 160-220 °C, carry out hydrothermal reaction at a constant temperature for 24-30 h, and take it out and naturally cool to room temperature;

[0016] Step 3: Wash it several times with deionized water and organic solvents, and centrifuge;

[0017] Step 4: Vacuum drying: Place it in a vacuum drying oven and vacuum dry at 50-80 °C for more than 12 h.

[0018] The role of anhydrous potassium carbonate is to provide a potassium source, fill between the lamellar skeletons, and perform ion exchange with cesium. The role of tin powder is to form a Sn-S main skeleton. The role of sulfur powder is to form the main skeleton and mineralizer.

[0019] Further, the molar ratio of potassium carbonate, metal A, metal B, tin powder, and sulfur powder is 6 to 24: 1 to 4: 1 to 4: 6 to 24: 40 to 120. Preferably, the molar ratio is: 10 to 20: 1 to 3: 1 to 3: 10 to 20: 50 to 100; More preferably, the molar ratio is: 10 to 15: 1 to 3: 1 to 3: 10 to 15: 50 to 80; Most preferably, the molar ratio is: 11 to 13: 1 to 2: 1 to 2: 11 to 13: 60 to 70.

[0020] Too low addition amounts of potassium carbonate, tin powder, and sulfur powder will result in incomplete reactions, while too high addition amounts will clog some pores of the adsorbent, thus causing a decrease in the adsorption capacity of the adsorbent; Too low addition amounts of metal A and metal B cannot achieve the effect of adjusting the framework structure, while too high addition amounts will damage the main framework of the adsorbent, resulting in a decrease in the chemical stability and thermal stability of the adsorbent.

[0021] Further, the present invention provides several most preferred ratios: 12:1:2:12:60, 12:2:2:12:60, 12:2:1:12:60, 12:2:2:12:50, 12:2:2:12:60, 12:2:2:12:70.

[0022] Further, the hydrothermal reaction temperature in the second step is preferably 200 °C, and the reaction time is preferably 24 h.

[0023] Further, in the third step, the organic solvent is acetone, carbon disulfide, or absolute ethanol.

[0024] Further, the drying temperature and time in the fourth step are 60 °C and 18 h respectively; the drying condition is vacuum drying.

[0025] According to the third aspect of the present invention, there is also provided the use of the above-mentioned layered binary-doped inorganic tin sulfide adsorbent material for extracting cesium from liquid cesium ore.

[0026] Place the above-mentioned layered binary-doped inorganic tin sulfide adsorbent material in a liquid containing cesium ions, exchange for no less than 60 min, and obtain a solid sample rich in cesium element through filtration.

[0027] Further, after the cesium element is enriched in the ion exchanger, it can be regenerated with an eluent.

[0028] Advantages and beneficial effects of the present invention:

[0029] The layered binary-doped inorganic tin sulfide adsorption material provided by the present invention uses potassium carbonate as the cation source in the reaction. Compared with the organic cation source, it does not require protonation during the reaction. At the same time, the synergistic effect of the doped low-melting metal and an appropriate amount of sulfur increases the solubility of the reactants. These several effects significantly shorten the synthesis time, and no toxic substances are released during the adsorption process. When this adsorbent is used to extract the rare element cesium from liquid resources, it has the advantages of fast exchange speed and large adsorption capacity. The adsorption capacity can reach more than 400 mg / g, and it can be recycled and reused, which is of great significance for the efficient enrichment and recovery of cesium ions in liquid resources such as geothermal water, salt lake brine, and underground brine. Description of the Drawings

[0030] Figure 1(a) is a scanning electron microscope image (magnified 4000 times) of the adsorbent prepared in Example 1 of the present invention.

[0031] Figure 1(b) is a scanning electron microscope image (magnified 10000 times) of the adsorbent prepared in Example 1 of the present invention.

[0032] Figure 2 It is the experimental result of the exchange kinetics of cesium ions by the adsorbent prepared in Example 1 of the present invention.

[0033] Figure 3 It is the experimental result of the adsorption model of cesium ions by the adsorbent prepared in Example 1 of the present invention.

[0034] Figure 4(a) is a scanning electron microscope image (magnified 6000 times) of the adsorbent prepared in Example 2 of the present invention.

[0035] Figure 4(b) is a scanning electron microscope image (magnified 10000 times) of the adsorbent prepared in Example 2 of the present invention.

[0036] Figure 5 It is the experimental result of the exchange kinetics of cesium ions by the adsorbent prepared in Example 2 of the present invention.

[0037] Figure 6 It is the experimental result of the adsorption model of cesium ions by the adsorbent prepared in Example 2 of the present invention.

[0038] Figure 7 It is the experimental result of the adsorption model of cesium ions by the adsorbent prepared in Comparative Example 1 of the present invention.

[0039] Figure 8 It is the experimental result of the adsorption model of cesium ions by the adsorbent prepared in Comparative Example 2 of the present invention.

[0040] Figure 9 It is the experimental result of the adsorption model of cesium ions by the adsorbent prepared in Comparative Example 3 of the present invention.

[0041] Figure 10 Adsorption model experimental results of cesium ions by the adsorbent prepared in Comparative Example 4 of the present invention. Detailed implementation manners

[0042] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0043] In the following examples, unless otherwise specified, the experimental methods are all conventional methods; unless otherwise specified, the reagents can all be obtained through commercial channels.

[0044] Example 1:

[0045] A preparation method of a layered iron-antimony-doped tin sulfide adsorbent includes the following steps:

[0046] Step 1: Place K2CO3 (1.6585 g, 12 mmol), iron powder (0.1117 g, 2 mmol), antimony powder (0.2436 g, 2 mmol), tin powder (1.4317 g, 12 mmol), and sulfur powder (1.9434 g, 60 mmol) in a polytetrafluoroethylene reaction kettle, and gradually add 1 mL of deionized water dropwise, and mix and stir evenly;

[0047] Step 2: Seal and tighten the autoclave, place it in a vacuum drying oven preheated to 200 °C, carry out a hydrothermal reaction at a constant temperature for 24 h, and take it out and naturally cool it to room temperature;

[0048] Step 3: Wash the product obtained in Step 2 with deionized water, acetone, carbon disulfide, and absolute ethanol for several times, and centrifuge and separate;

[0049] Step 4: Place the product in a vacuum drying oven, vacuum dry it at 60 °C for 18 h to obtain K-Fe-Sb-Sn-S, marked as PIATS. Its scanning electron microscope images are shown in Fig. 1(a) and Fig. 1(b). It can be seen from the figures that it is a regular cuboid sheet-like structure.

[0050] Take 50 mg of PIATS and place it in 100 mL of a solution containing cesium chloride for adsorption at room temperature. Take the supernatant to measure the ion concentration every 10, 20, 30, 40, 50, 60, 70, 80, 90 min respectively. Figure 2 For the ion exchange kinetics measurement results, from Figure 2 it can be seen that the exchange of cesium ions by the adsorbent can reach equilibrium within 40 min.

[0051] Take 50 mg of PIATS and place it in 100 mL of a solution containing different concentrations of cesium chloride (50 - 1500 ppm) and stir at room temperature for 60 min, then sample and analyze the concentration of cesium ions. The results are as Figure 3 shown, from Figure 3It can be seen that the adsorption capacity of PIATS for cesium ions can reach 401.23 mg / g.

[0052] Take 50 mg of PIATS and place it in 100 mL of geothermal water. The adsorption time is 60 min at room temperature. After adsorption, rinse it with deionized water, then place it in the desorption solution for elution for 30 min, and then perform adsorption again. Repeat the adsorption-elution-adsorption cycle 5 times, and the performance is stable.

[0053] Example 2:

[0054] A preparation method of a layered zinc-bismuth-doped tin sulfide adsorbent includes the following steps:

[0055] Step 1: Place K2CO3 (1.6585 g, 12 mmol), zinc powder (0.1308 g, 2 mmol), bismuth powder (0.4180 g, 2 mmol), tin powder (1.4317 g, 12 mmol), and sulfur powder (1.9434 g, 60 mmol) in a polytetrafluoroethylene reaction kettle, and gradually add 1 mL of deionized water dropwise, and mix and stir evenly;

[0056] Step 2: Seal and tighten the autoclave, place it in a vacuum drying oven preheated to 200 °C, carry out hydrothermal reaction at a constant temperature for 24 h, and take it out and naturally cool to room temperature;

[0057] Step 3: Wash the product obtained in Step 2 with deionized water, acetone, carbon disulfide, and absolute ethanol several times, and centrifuge;

[0058] Step 4: Place the product in a vacuum drying oven and vacuum dry it at 60 °C for 18 h to obtain K-Zn-Bi-Sn-S, marked as PZBTS. Its scanning electron microscope images are shown in Fig. 4(a) and Fig. 4(b). It can be seen from the figures that it is a regular flaky cuboid structure.

[0059] Take 50 mg of PZBTS and place it in 100 mL of a solution containing cesium chloride for adsorption at room temperature. Take the supernatant to measure the ion concentration every 10, 20, 30, 40, 50, 60, 70, 80, 90 min respectively. Figure 5 For the ion exchange kinetics measurement results, from Figure 5 it can be seen that the exchange of the adsorbent for cesium ions can reach equilibrium within 30 min.

[0060] Take 50 mg of PZBTS and place it in 100 mL of a solution containing different concentrations of cesium chloride (50 - 1500 ppm), stir at room temperature for 60 min, and then take a sample to analyze the concentration of cesium ions. The results are as Figure 6 shown. From Figure 6 it can be seen that the adsorption capacity of PZBTS for cesium ions can reach 422.27 mg / g.

[0061] Take 50 mg of actual PZBTS and place it in 100 mL of geothermal water. The adsorption time is 60 min at room temperature. After adsorption, rinse with deionized water, then place it in the desorption solution for 30 min of elution, and then perform adsorption again. Repeat the adsorption-elution-adsorption cycle 5 times, and the performance is stable.

[0062] Comparative Example 1:

[0063] A preparation method of an iron-doped tin sulfide adsorbent includes the following steps:

[0064] Step 1: Place K2CO3 (1.6585 g, 12 mmol), iron powder (0.1117 g, 2 mmol), tin powder (1.4317 g, 12 mmol), and sulfur powder (1.9434 g, 60 mmol) in a polytetrafluoroethylene reaction kettle, and dropwise add 1 mL of deionized water, and mix and stir evenly;

[0065] Step 2: Seal and tighten the autoclave, put it into a vacuum drying oven preheated to 200 °C, carry out hydrothermal reaction at a constant temperature for 24 h, take it out and naturally cool to room temperature;

[0066] Step 3: Wash the product obtained in Step 2 with deionized water, acetone, carbon disulfide, and absolute ethanol several times, and perform centrifugal separation;

[0067] Step 4: Place the product in a vacuum drying oven and vacuum dry it at 60 °C for 18 h to obtain K-Fe-Sn-S, marked as PITS. Take 50 mg of PITS and place it in 100 mL of a solution containing different concentrations of cesium chloride (50 - 1500 ppm), stir at room temperature for 60 min, and then take samples to analyze the concentration of cesium ions. The results are as Figure 7 shown, and it can be seen from Figure 7 that the adsorption capacity of PITS for cesium ions is 348.98 mg / g, and its adsorption capacity is significantly reduced compared with the adsorption capacity of the adsorbent in Example 1.

[0068] Comparative Example 2:

[0069] A preparation method of a bismuth-doped tin sulfide adsorbent includes the following steps:

[0070] Step 1: Place K2CO3 (1.6585 g, 12 mmol), bismuth powder (0.4180 g, 2 mmol), tin powder (1.4317 g, 12 mmol), and sulfur powder (1.9434 g, 60 mmol) in a polytetrafluoroethylene reaction kettle, and dropwise add 1 mL of deionized water, and mix and stir evenly;

[0071] Step 2: Tighten the autoclave seal and place it in a vacuum drying oven preheated to 200 °C for hydrothermal reaction at a constant temperature for 24 h. After taking it out, let it cool naturally to room temperature;

[0072] Step 3: Wash the product obtained in Step 2 several times with deionized water, acetone, carbon disulfide and absolute ethanol, and centrifuge for separation;

[0073] Step 4: Place the product in a vacuum drying oven and vacuum dry it at 60 °C for 18 h to obtain K-Bi-Sn-S, marked as PBTS. Take 50 mg of PBTS and place it in 100 mL of a solution containing cesium chloride at different concentrations (50 - 1500 ppm), stir at room temperature for 60 min, and then take a sample to analyze the concentration of cesium ions. The results are as Figure 8 shown. The adsorption capacity of PBTS for cesium ions is 366.98 mg / g, which is still lower than the adsorption capacity of the adsorbent in Example 1.

[0074] Comparative Example 3:

[0075] A preparation method of a metal-doped organic amine tin sulfide adsorbent, comprising the following steps:

[0076] Step 1: Weigh 0.96 g of sulfur powder, 0.48 g of tin powder, 0.006 g of magnesium powder, and 2 mL of dimethylamine, place them in a 50 mL polytetrafluoroethylene inner liner, add 2 mL of deionized water and 2 mL of methanol, and stir evenly.

[0077] Step 2: Seal the reaction kettle and place it in a drying oven at 180 °C for constant temperature heating for 24 h.

[0078] Step 3: After the reaction product obtained in Step 2 is naturally cooled, wash it three times with deionized water and ethanol respectively to remove impurities; then place it in a vacuum drying oven at 60 °C for drying for 18 h to obtain a yellow organic amine tin sulfide solid powder. Take 50 mg of the adsorbent and place it in 100 mL of a solution containing cesium chloride at different concentrations (50 - 1500 ppm), stir at room temperature for 60 min, and then take a sample to analyze the concentration of cesium ions. The results are as Figure 9 shown. Its adsorption capacity for cesium ions is 258.26 mg / g. It can be seen that by shortening the reaction time, the adsorption capacity of the organic amine tin sulfide adsorbent decreases significantly.

[0079] Comparative Example 4:

[0080] A preparation method of an iron-antimony doped organic amine tin sulfide adsorbent, comprising the following steps:

[0081] Step 1: Place 2 mL of dimethylamine, iron powder (0.1117 g, 2 mmol), antimony powder (0.2436 g, 2 mmol), tin powder (1.4317 g, 12 mmol), and sulfur powder (1.9434 g, 60 mmol) into a polytetrafluoroethylene reaction kettle, and slowly add 1 mL of deionized water drop by drop, then mix and stir evenly.

[0082] Step 2: Seal and tighten the autoclave, place it in a vacuum drying oven preheated to 200 °C, carry out a hydrothermal reaction at a constant temperature for 24 h, and then take it out and let it cool naturally to room temperature.

[0083] Step 3: Wash the product obtained in Step 2 with deionized water, acetone, carbon disulfide, and absolute ethanol several times, and then perform centrifugal separation.

[0084] Step 4: Place the product in a vacuum drying oven and dry it under vacuum at 60 °C for 18 h to obtain an adsorption material. Take 50 mg of the adsorbent and place it in 100 mL of a solution containing cesium chloride with different concentrations (50 - 1500 ppm), stir at room temperature for 60 min, and then take a sample to analyze the concentration of cesium ions. The results are as Figure 10 shown. Its adsorption capacity for cesium ions is 277.51 mg / g, and its adsorption capacity has decreased significantly compared with that of the adsorbent in Example 1.

[0085] The above shows and describes the embodiments of the present invention, or the technical solutions in the drawings, all of which embody the layered binary doped tin sulfide adsorption material of the present invention and its preparation method, which can be applied to the separation and extraction of cesium in liquid cesium resources. It can also be used for the separation and extraction of cesium in leaching solutions of solid cesium ores or associated ores. It should be understood that for those skilled in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present invention.

Claims

1. A preparation method of an inorganic tin sulfide adsorbent, First, potassium carbonate anhydrous, metal A, metal B, tin powder, and sulfur powder are mixed evenly in a molar ratio of 6 - 24:1 - 4:1 - 4:6 - 24:40 - 120 to obtain a first mixture. Based on the total mass of the mixture, 5 - 20% deionized water is added dropwise and mixed and stirred evenly to obtain a second mixture. The metal A is iron powder or zinc powder; the metal B is antimony powder or bismuth powder; Then, the second mixture is subjected to a constant-temperature hydrothermal reaction at 160 - 220 °C for 24 - 30 h and then naturally cooled to room temperature; Finally, after washing, it is vacuum dried at 50 - 80 °C for more than 12 h.

2. The preparation method according to claim 1, wherein The molar ratio of the potassium carbonate anhydrous, metal A, metal B, tin powder, and sulfur powder is 10 - 20:1 - 3:1 - 3:10 - 20:50 - 100.

3. The preparation method according to claim 2, characterized in that, The molar ratio of the potassium carbonate anhydrous, metal A, metal B, tin powder, and sulfur powder is 10 - 15:1 - 3:1 - 3:10 - 15:50 - 80.

4. The preparation method according to claim 3, characterized in that, The molar ratio of the potassium carbonate anhydrous, metal A, metal B, tin powder, and sulfur powder is: 11 - 13:1 - 2:1 - 2:11 - 13:60 - 70.

5. An inorganic tin sulfide adsorbent obtained by the preparation method according to any one of claims 1 to 4, characterized in that, The adsorbent has a regular cuboid structure with lamellar shape, and its crystal particle size is 5 - 35 μm. The general formula of the adsorbent is: K2A x B y Sn 3-x-y S7, where A represents metal A, B represents metal B, x represents the stoichiometric coefficient with a value of 0.02 - 0.1; y represents the stoichiometric coefficient with a value of 0.02 - 0.1; 3 - x - y represents the stoichiometric coefficient.

6. An application of the inorganic tin sulfide adsorbent according to claim 5 in extracting cesium from liquid cesium ore.

7. The application according to claim 6, characterized in that, The liquid cesium ore is geothermal water or salt lake brine or underground brine or solid cesium ore or leaching solution of associated ore. The liquid-solid ratio dosage of the inorganic tin sulfide is 1000 - 5000:1.

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