Method and system for extracting strontium from high-calcium brine

Abstract

The invention relates to the technical field of brine extraction, in particular to a method and system for extracting strontium from high-calcium brine. The high-calcium brine contains calcium, magnesium, barium and strontium, and the method comprises the following steps: carrying out first precipitation separation on the high-calcium brine by using an alkaline complexing agent to obtain a separated precipitate containing calcium, barium and strontium; sequentially dissolving and diluting the separated precipitate by using an acid solvent to obtain a dissolved solution; carrying out hot filtration on the dissolved solution by using first sodium hydroxide to obtain a first filtrate containing barium and strontium; performing secondary precipitation separation on the first filtrate by using sodium sulfate to obtain a strontium-containing second filtrate; performing third precipitation separation on the second filtrate by using a composite additive to obtain a strontium carbonate product; wherein the composite additive comprises first sodium carbonate, urea and ethylenediaminetetraacetic acid. The method is based on a dual strategy of cascade deep impurity removal and complexing homogeneous precipitation, and the purity and the extraction rate of strontium carbonate are greatly improved through the synergistic effect of a composite additive.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of brine extraction, and particularly relates to a method and system for extracting strontium from high-calcium brine. BACKGROUND

[0002] Brine refers to liquid mineral products with a salt content of more than 5%, which is generally formed in the ore mining stage or the process of natural rain washing the ore. The brine contains rich trace metal elements and noble metal elements, and therefore it is of great significance to extract rare earth elements from the brine. Among these rare earth elements, the extraction of strontium is particularly important, because the traditional method for extracting strontium is mainly to use strontium-containing ores as raw materials for leaching. If the brine is used as raw material for extraction, the high-energy consumption operations such as crushing and sintering required in the traditional strontium ore extraction stage can be avoided, thereby reducing the cost of strontium extraction. The brine can be divided into yellow brine and black brine according to the region. The yellow brine has a shallower burial depth than the black brine, and is mainly produced in the Jurassic and Cretaceous strata. It is named yellow brine because it contains yellow suspended matter, and its salt concentration is lower than that of the black brine. Compared with the black brine, the yellow brine has the characteristics of low extraction difficulty and high strontium content when used as raw material for strontium extraction.

[0003] At present, the methods for extracting strontium from brine include solvent extraction, ion exchange, membrane separation and precipitation separation. Among these methods, the precipitation separation method is widely used because of its low precipitant and short processing flow. However, the yellow brine contains a large amount of calcium and a small amount of barium. Since calcium, barium and strontium belong to the same group, it will increase the difficulty of strontium extraction. The current precipitation separation method cannot meet the demand of high-purity strontium extraction. SUMMARY

[0004] The present application provides a method and system for extracting strontium from high-calcium brine, to solve the technical problem of how to improve the purity of strontium obtained by the precipitation separation method.

[0005] In a first aspect, the embodiments of the present application provide a method for extracting strontium from high-calcium brine, wherein the high-calcium brine contains calcium, magnesium, barium and strontium, and the method comprises the following steps: performing first precipitation separation on the high-calcium brine by using an alkaline complexing agent, to remove magnesium, part of calcium and part of barium in the high-calcium brine, and obtain a separation precipitate containing calcium, barium and strontium; sequentially dissolving and diluting the separation precipitate containing calcium, barium and strontium by using an acid solvent, to obtain a dissolution liquid; performing hot filtration on the dissolution liquid by using first sodium hydroxide, to remove calcium in the dissolution liquid, and obtain a first filtrate containing barium and strontium; performing second precipitation separation on the first filtrate containing barium and strontium by using sodium sulfate, to remove barium in the first filtrate, and obtain a second filtrate containing strontium; Using a composite additive, the second filtrate containing strontium is subjected to a third precipitation separation to obtain a strontium carbonate product; Wherein, the composite additive comprises first sodium carbonate, urea and ethylenediaminetetraacetic acid.

[0006] Optionally, the amount n1 of the ethylenediaminetetraacetic acid and the amount n2 of the strontium in the first filtrate satisfy: n1:n2=(0.15 to 0.25):1; and / or The amount n3 of urea, the amount n4 of the first sodium carbonate, and the amount n2 of strontium in the first filtrate satisfy: n3:n4:n2=(3.0 to 3.5):(1.2 to 1.5):1.

[0007] Optionally, the method of using a composite additive to subject the second filtrate containing strontium to a third precipitation separation to obtain a strontium carbonate product comprises the following steps: heating the second filtrate containing strontium using urea and ethylenediaminetetraacetic acid to decompose the urea in the composite additive to form carbonate and promote the precipitation of strontium in the second filtrate, thereby obtaining a first suspension of solid and liquid phases; Insulating the first suspension in the solid phase and the liquid phase to initially precipitate strontium in the suspension to obtain a second suspension; cooling the second suspension to obtain a third suspension; The third suspension is subjected to a second precipitation using the first sodium carbonate to obtain a strontium carbonate product.

[0008] Optionally, the terminal temperature of the heating is 85° C. to 95° C., and the duration of the heating is 10 min to 15 min; and / or The insulation time is 25 min to 35 min; and / or The temperature of the second precipitation is 20° C. to 30° C., and the time of the second precipitation is 10 min to 15 min.

[0009] Optionally, the temperature of the hot filtration is 90° C. to 95° C., and the time of the hot filtration is 5 min to 10 min.

[0010] Optionally, the alkaline complex includes a second sodium carbonate and a second sodium hydroxide, and the amount n5 of the second sodium carbonate and the amount n6 of the second sodium hydroxide satisfy: n5:n6=1:(9.5 to 10.5).

[0011] Optionally, the high-calcium brine is subjected to a first precipitation separation using an alkaline composite agent to remove magnesium, part of the calcium and part of the barium in the high-calcium brine to obtain a separated precipitate containing calcium, barium and strontium, comprising the steps of: The high-calcium brine is separated by a first precipitation using a second sodium hydroxide to remove magnesium, part of calcium and part of barium in the high-calcium brine to obtain a brine filtrate; The brine filtrate is separated by a second first precipitation using a second sodium carbonate to remove part of barium and part of calcium in the brine filtrate to obtain a separated precipitate containing calcium, barium and strontium; The amount of substance n7 of the second sodium hydroxide and the volume V1 of the high-calcium brine satisfy: n7:V1=(0.070 to 0.080):100, if the unit of n7 is mol, the unit of V1 is L; The amount of substance n8 of the second sodium carbonate and the volume V1 of the high-calcium brine satisfy: n8:V1=(0.0070 to 0.0080):100, if the unit of n8 is mol, the unit of V1 is L.

[0012] Optionally, the amount of substance n9 of the acid solvent and the volume V1 of the high-calcium brine satisfy: n9:V1=(0.015 to 0.018):100, if the unit of n9 is mol, the unit of V1 is L; and / or The amount of substance n10 of the first sodium hydroxide and the volume V1 of the high-calcium brine satisfy: n10:V1=(0.022 to 0.026):100, if the unit of n10 is mol, the unit of V1 is L; and / or The amount of substance n11 of the sodium sulfate and the volume V1 of the high-calcium brine satisfy: n11:V1=(0.0012 to 0.0016):100, if the unit of n11 is mol, the unit of V1 is L.

[0013] In a second aspect, the embodiments of the present application provide a system for extracting strontium from high-calcium brine, which is suitable for the method of the first aspect, and the system comprises: A first precipitation part comprises a high-calcium brine feeding pipe, an alkaline complexing agent feeding pipe, a first precipitation tank group and a first filter group, the outlet of the high-calcium brine feeding pipe is connected to the inlet of the first precipitation tank group, the outlet of the alkaline complexing agent feeding pipe is connected to the inlet of the first precipitation tank group, and the outlet of the first precipitation tank group is connected to the inlet of the first filter group; A dissolving part comprises an acid solvent feeding pipe, a dissolving tank, a dilution liquid feeding pipe and a dilution tank, the solid phase outlet of the first filter is connected to the inlet of the dissolving tank, the outlet of the acid solvent feeding pipe is connected to the inlet of the dissolving tank, the outlet of the dissolving tank is connected to the inlet of the dilution tank, and the outlet of the dilution liquid feeding pipe is connected to the inlet of the dilution tank; a hot filtration unit, comprising a first sodium hydroxide feed pipe and a hot filter, wherein the discharge port of the first sodium hydroxide feed pipe is connected to the feed port of the hot filter, and the feed port of the hot filter is connected to the discharge port of the dilution tank; A second precipitation section includes a sodium sulfate feed pipe, a second precipitation tank, and a second filter, wherein the discharge port of the sodium sulfate feed pipe is connected to the feed port of the second precipitation tank, the discharge port of the hot filter is connected to the feed port of the second precipitation tank, and the discharge port of the second precipitation tank is connected to the feed port of the second filter; The third precipitation part includes a urea feed pipe, an ethylenediaminetetraacetic acid feed pipe, a first-stage third precipitation tank, a heater, a first-stage third filter, a first sodium carbonate feed pipe, a second-stage third precipitation tank, a cooler and a second-stage third filter; the discharge port of the second filter is connected to the feed port of the first-stage third precipitation tank, the discharge port of the urea feed pipe is connected to the feed port of the first-stage third precipitation tank, the discharge port of the ethylenediaminetetraacetic acid feed pipe is connected to the feed port of the first-stage third precipitation tank, the heater is arranged in the first-stage third precipitation tank to heat the solution entering the first-stage third precipitation tank; the discharge port of the first-stage third precipitation tank is connected to the feed port of the first-stage third filter, the discharge port of the first-stage third filter is connected to the feed port of the second-stage third precipitation tank, the discharge port of the first sodium carbonate feed pipe is connected to the feed port of the second-stage third precipitation tank, the discharge port of the second-stage third precipitation tank is connected to the feed port of the second-stage third filter, and the cooler is arranged in the second-stage third precipitation tank to cool the solution entering the second-stage third precipitation tank.

[0014] Optionally, the alkaline complex agent feed pipe includes a second sodium hydroxide feed pipe and a second sodium carbonate feed pipe, the first precipitation tank group includes a first stage first precipitation tank and a second stage first precipitation tank, and the first filter group includes a first stage first filter and a second stage first filter; the discharge port of the high-calcium brine feed pipe is connected to the feed port of the first stage first precipitation tank, the discharge port of the second sodium hydroxide feed pipe is connected to the feed port of the first stage first precipitation tank, the discharge port of the first stage first precipitation tank is connected to the feed port of the first stage first filter, the discharge port of the first stage first filter is connected to the feed port of the second stage first precipitation tank, the discharge port of the second sodium carbonate feed pipe is connected to the feed port of the second stage first precipitation tank, the discharge port of the second stage first precipitation tank is connected to the feed port of the second stage first filter, and the solid phase discharge port of the second stage first filter is connected to the feed port of the dissolution tank.

[0015] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art: The method for extracting strontium from high-calcium brine provided by the embodiment of the application first uses an alkaline complexing agent to form a batch of precipitates of magnesium, calcium, barium and strontium in the high-calcium brine, so as to separate magnesium, part of calcium, part of barium and strontium, and then dissolve the separated precipitates of calcium, barium and strontium into a solution by using an acid solvent, which is beneficial to subsequent hot filtration and impurity removal; then the calcium in the obtained solution is removed by hot filtration through sodium hydroxide, so as to obtain a first filtrate containing barium and strontium; then the first filtrate is subjected to third precipitation separation by using a composite additive; through the synergistic effect of the composite additive, urea in the composite additive will slowly generate carbonate in the heating stage, the carbonate will form barium carbonate precipitates with barium in the first filtrate, and the carbonate will form uniform strontium carbonate crystals with strontium in the first filtrate, so as to reduce the impurity content of the strontium carbonate; then ethylenediaminetetraacetic acid in the composite additive prevents the co-precipitation of calcium carbonate, barium carbonate and strontium carbonate, so as to reduce the wrapping of impurities in the strontium carbonate; finally, strontium is precipitated by sodium carbonate, so as to form a high-purity strontium carbonate product. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which are incorporated herein and constitute part of the specification, illustrate embodiments consistent with the application and, together with the description, serve to explain the principles of the application.

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the accompanying drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, those skilled in the art can obtain other drawings from these drawings without any creative effort.

[0018] Figure 1 A process flow diagram of a method for extracting strontium from high-calcium brine provided by the embodiment of the application; Figure 2 A detailed process flow diagram of a method for extracting strontium from high-calcium brine provided by the embodiment of the application; Figure 3 A logic structure diagram of a system for extracting strontium from high-calcium brine provided by the embodiment of the application; Figure 4 A comparison diagram of precipitation effects of a first precipitation separation in a first precipitation separation provided by the embodiment of the application; Figure 5 A comparison diagram of precipitation effects of a second precipitation separation in a first precipitation separation provided by the embodiment of the application; Figure 6 A comparison diagram of precipitation effects of high-temperature hot filtration and non-high-temperature hot filtration provided by the embodiment of the application; Figure 7 A comparison diagram of precipitation effects of different hot filtration temperatures provided by the embodiment of the application; Figure 8 A schematic diagram comparing the precipitation effects of the second precipitation separation provided in the embodiments of the present application; Figure 9 A schematic diagram comparing the precipitation effects of the composite additives provided in the examples of the present application; Among them, 1-high calcium brine feed pipe, 2-alkaline composite agent feed pipe, 201-second sodium hydroxide feed pipe, 202-second sodium carbonate feed pipe, 3-first precipitation tank group, 301-first stage first precipitation tank, 302-second stage first precipitation tank, 4-first filter group, 401-first stage first filter, 402-second stage first filter, 5-acid solvent feed pipe, 6-dissolution tank, 7-dilution liquid feed pipe, 8-dilution tank, 9-first sodium hydroxide feed pipe, 10-hot filter, 11-sodium sulfate feed pipe, 12-second precipitation tank, 13-second filter, 14-urea feed pipe, 15-ethylenediaminetetraacetic acid feed pipe, 16-first stage third precipitation tank, 17-heater, 18-first stage third filter, 19-first sodium carbonate feed pipe, 20-second stage third precipitation tank, 21-cooler, 22-second stage third filter. DETAILED DESCRIPTION

[0019] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0020] Range descriptions used in this application, such as numerical ranges and ratio ranges, include all possible subranges and single numerical values ​​within that range. For example, the range description "1 to 6" or "1~6" encompasses all subranges between 1 and 6 (e.g., 1 to 3, 2 to 5, etc.) and single numbers (e.g., 1, 2, 3, 4, 5, 6). Unless otherwise specified, the terms "comprising" and "including" as used herein mean "including but not limited to," "first" and "second" are used solely to distinguish between different entities or operations and do not imply a specific order or relationship. "and / or" indicates that multiple instances can exist individually or simultaneously. Expressions such as "at least one," "a plurality," and "at least one" refer to any combination of the corresponding objects, including single or multiple objects. Proportional relationships mentioned herein, such as mass ratios and molar ratios, should be understood as the corresponding relationship between the first and second terms of the ratio formula in the order described. The raw materials, reagents, instruments, and equipment used herein can all be purchased commercially or prepared by existing methods.

[0021] Figure 1 The following is a schematic flow chart of a method for extracting strontium from high-calcium brine provided in an embodiment of the present application; like Figure 1 As shown, the embodiment of the present application provides a method for extracting strontium from high-calcium brine, wherein the high-calcium brine contains calcium, magnesium, barium and strontium, and the method comprises: S1. Using an alkaline complex agent to perform a first precipitation separation on the high-calcium brine to remove magnesium, part of the calcium and part of the barium in the high-calcium brine to obtain a separated precipitate containing calcium, barium and strontium; S2. The separated precipitate containing calcium, barium and strontium is dissolved and diluted sequentially using an acid solvent to obtain a dissolving solution; S3. The solution is hot filtered using a first sodium hydroxide to remove calcium from the solution to obtain a first filtrate containing barium and strontium; S4. The first filtrate containing barium and strontium is subjected to a second precipitation separation using sodium sulfate to remove barium from the first filtrate to obtain a second filtrate containing strontium; S5. The second filtrate containing strontium is subjected to a third precipitation separation using a composite additive to obtain a strontium carbonate product; Wherein, the composite additive comprises first sodium carbonate, urea and ethylenediaminetetraacetic acid.

[0022] It should be noted that the first sedimentation separation, the second sedimentation separation and the third sedimentation separation are all carried out by combining a sedimentation tank and a filter to separate the solid phase precipitate and the liquid phase material.

[0023] It should be noted that the third precipitation separation can be carried out under conditions where the pH is above 10.

[0024] It should be noted that the high-calcium brine may contain iron and ferrous ions in addition to calcium, magnesium, barium and strontium.

[0025] It should be noted that the acid solvent may be hydrochloric acid.

[0026] It should be noted that the method for extracting strontium from high-calcium brine provided in the examples of this application is based on the traditional precipitation separation method, with the addition of a composite additive. Through the synergistic effect of the composite additive (sodium carbonate + urea + EDTA), highly selective precipitation of strontium is achieved in the final precipitation step, significantly improving the purity of strontium carbonate. The specific mechanism is as follows: 1. Triple synergistic mechanism of composite additives: (1) Ethylenediaminetetraacetic acid: selective complexation of residual impurity ions: Action target: preferentially complex residual Ca 2+ 、Ba 2+(especially trace amounts of calcium which are difficult to completely remove); Chemical principle: The order of complex stability between ethylenediaminetetraacetic acid (EDTA) and metal ions is: Fe 3+ >Al 3+ >Ca 2+ >Ba 2+ >Sr 2+. 1) Key point: Ca 2+ The complexing ability of Sr is significantly stronger than that of 2+ , EDTA preferentially locks residual calcium; Ba 2+ Although its complexing ability is weaker than that of Sr 2+ , but high concentration of EDTA can still inhibit its precipitation; 2) Results: Prevents co-precipitation of CaCO3 / BaCO3 and SrCO3, reducing impurity inclusion; (2) Urea: homogeneous precipitation regulates crystal growth; 1) Mechanism of action: Urea can slowly hydrolyze under heating conditions to form ammonium ions and carbonate ions; 2) Advantage: The hydrolysis process of urea can slowly release CO3 2- → Maintain low supersaturation → avoid localized nucleation; Uniform nucleation → formation of SrCO3 crystals with uniform particle size → reduction of impurity adsorption; Dense crystallization → reduces the inclusion of impurities by crystal defects; (3) Sodium carbonate: provides the main precipitant and assists urea in supplementing CO3 2- The source of strontium to ensure complete precipitation; High pH environment: Enhanced EDTA for Ca 2+ / Ba 2+ The chelating ability of EDTA is the highest when pH>10.

[0027] 2. Collaborative impurity removal chain with the previous process: The role of composite additives is based on efficient impurity removal at the front end: (1) First precipitation (alkaline complex): remove most of the Mg 2+ (Producing Mg(OH)2↓) and some Ca 2+ / Ba 2+ , reducing the burden of impurity removal in the subsequent third precipitation separation; (2) Hot filtration to remove calcium (sodium hydroxide): Calcium is selectively precipitated by taking advantage of the fact that the solubility of Ca(OH)2 at high temperature is lower than that of Sr(OH)2; The remaining trace amounts of calcium become the main target of EDTA removal; (3) Sodium sulfate to remove barium: BaSO4 has very low solubility. When sodium sulfate is added, barium is precipitated first → ensuring that the residual barium content is less than 1ppm.

[0028] 3. Quantitative effect of purity improvement: Capture of residual Ca by EDTA complexation 2+ / Ba 2+ , avoid CaCO3 / BaCO3 mixed crystals; Through urea homogeneous precipitation, dense SrCO3 single crystals are generated to reduce the surface adsorption and lattice defect inclusion of SrCO3; Through the first precipitation separation, hot filtration and other front-end cascade impurity removal, most of the magnesium, calcium and barium can be removed, reducing the impurity load of the terminal precipitation.

[0029] In summary, the present invention provides a method for extracting strontium from high-calcium brine, which adopts the dual strategy of "step-by-step deep impurity removal + complexation homogeneous precipitation": (1) The front-end process gradually removes major impurities such as Mg / Ca / Ba; (2) The terminal composite additive uses EDTA to selectively lock calcium, urea to regulate crystallization kinetics, and sodium carbonate to provide a precipitation environment to achieve: 1) Deep isolation of impurity ions; 2) High crystallinity SrCO3 single-phase precipitation.

[0030] This method can break through the purity bottleneck of traditional precipitation separation methods and meet the requirements for the use of high-purity strontium compounds.

[0031] In some optional embodiments, the amount n1 of the ethylenediaminetetraacetic acid and the amount n2 of the strontium in the first filtrate satisfy: n1:n2=(0.15 to 0.25):1; and / or The amount n3 of urea, the amount n4 of the first sodium carbonate, and the amount n2 of strontium in the first filtrate satisfy: n3:n4:n2=(3.0 to 3.5):(1.2 to 1.5):1.

[0032] In these embodiments, the molar ratio of ethylenediaminetetraacetic acid to the first filtrate is (0.15 to 0.25):1, which ensures that there is sufficient ethylenediaminetetraacetic acid in the first filtrate. The ethylenediaminetetraacetic acid can preferentially complex the residual calcium and barium, facilitating the removal of calcium, barium and strontium. In addition, the molar ratio of urea, sodium carbonate and strontium in the first filtrate is (3.0 to 3.5): (1.2 to 1.5):1, which ensures that there is sufficient urea and sodium carbonate in the first filtrate. The urea can regulate the crystal growth of strontium carbonate by homogeneous precipitation to improve the purity of the strontium carbonate crystals. At the same time, the sodium carbonate can assist the urea in replenishing CO3. 2- source to ensure complete strontium precipitation.

[0033] The amount n1 of EDTA can be 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24 or 0.25.

[0034] The amount n3 of urea can be 3.0, 3.1, 3.2, 3.3, 3.4 or 3.5.

[0035] The amount n4 of sodium carbonate can be 1.2, 1.3, 1.4 or 1.5.

[0036] Figure 2 The following is a schematic diagram showing a detailed process of extracting strontium from high-calcium brine provided in an embodiment of the present application; In some optional embodiments, such as Figure 2 As shown, the method of using a composite additive to subject the second filtrate containing strontium to a third precipitation separation to obtain a strontium carbonate product comprises the steps of: S501. The second filtrate containing strontium is heated using urea and ethylenediaminetetraacetic acid to decompose the urea of ​​the composite additive to form carbonate and promote the precipitation of strontium in the second filtrate to obtain a first suspension of solid and liquid phases; S502. The solid and liquid phases of the first suspension are incubated to allow the initial precipitation of strontium in the suspension to obtain a second suspension; S503. Cooling the second suspension to obtain a third suspension; S504. Use the first sodium carbonate to perform a second precipitation on the third suspended matter to obtain a strontium carbonate product.

[0037] In these embodiments, urea and EDTA are first heated to decompose the second filtrate, thereby promoting the decomposition of urea to produce carbonate ions and ammonium ions. In some optional embodiments, the terminal temperature of the heating is 85° C. to 95° C., and the duration of the heating is 10 min to 15 min; and / or The insulation time is 25 min to 35 min; and / or The temperature of the second precipitation is 20° C. to 30° C., and the time of the second precipitation is 10 min to 15 min.

[0038] In these embodiments, the terminal temperature is 85 DEG C to 95 DEG C and the duration is 10min to 15min of heating can make urea hydrolyze to form carbonate radical and ammonia, is conducive to the precipitation of strontium in the second filtrate, and promotes strontium carbonate to be evenly dispersed. In addition, the time is 25min to 35min of insulation can make the carbonate radical formed by urea precipitate with strontium in the second filtrate, is conducive to the distribution of strontium carbonate crystals. In addition, the temperature is 20 DEG C to 30 DEG C and the second precipitation time is 10min to 15min, and the carbonate radical formed by urea can be assisted by sodium carbonate to ensure that strontium precipitation is complete.

[0039] The endpoint temperature of the heating may be 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 91°C, 92°C, 93°C, 94°C or 95°C.

[0040] The duration of the heating may be 10 min, 11 min, 12 min, 13 min, 14 min or 15 min.

[0041] The insulation time can be 25 min, 26 min, 27 min, 28 min, 29 min, 30 min, 31 min, 32 min, 33 min, 34 min or 35 min.

[0042] The temperature of the precipitation may be 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C or 30°C.

[0043] The precipitation time can be 10 min, 11 min, 12 min, 13 min, 14 min or 15 min.

[0044] In some optional embodiments, the temperature of the hot filtration is 90° C. to 95° C., and the time of the hot filtration is 5 min to 10 min.

[0045] In these embodiments, the hot filtration is performed at a temperature of 90°C to 95°C and a time of 5 min to 10 min. The temperature of the hot filtration may be 90°C, 91°C, 92°C, 93°C, 94°C or 95°C.

[0046] The hot filtration time can be 5 min, 6 min, 7 min, 8 min, 9 min or 10 min.

[0047] In some optional embodiments, the alkaline complex includes a second sodium carbonate and a second sodium hydroxide, and the amount n5 of the second sodium carbonate and the amount n6 of the second sodium hydroxide satisfy: n5:n6=1:(9.5 to 10.5).

[0048] In these embodiments, the molar ratio of the second sodium carbonate to the second sodium hydroxide is 1:(9.5 to 10.5), which can promote the presence of sufficient second sodium carbonate and second sodium hydroxide in the alkaline complex to precipitate magnesium, part of calcium and part of barium in the high-calcium brine, thereby effectively reducing the impurity ions in the high-calcium brine.

[0049] The amount n6 of the second sodium hydroxide can be 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4 or 10.5.

[0050] In some optional embodiments, the high-calcium brine is subjected to a first precipitation separation using an alkaline complex agent to remove magnesium, part of the calcium and part of the barium in the high-calcium brine to obtain a separated precipitate containing calcium, barium and strontium, comprising the steps of: S101. Using a second sodium hydroxide to perform a first precipitation separation on the high-calcium brine to remove magnesium, part of the calcium and part of the barium in the high-calcium brine to obtain a brine filtrate; S102. Using a second sodium carbonate, the brine filtrate is subjected to a second first precipitation separation to remove a portion of barium and a portion of calcium in the brine filtrate to obtain a separated precipitate containing calcium, barium, and strontium; Wherein, the amount of substance n7 of the second sodium hydroxide and the volume V1 of the high calcium brine satisfy: n7:V1=(0.070 to 0.080):100, if the unit of n7 is mol, the unit of V1 is L; The amount n8 of the second sodium carbonate and the volume V1 of the high-calcium brine satisfy: n8:V1=(0.0070 to 0.0080):100, where if the unit of n8 is mol, the unit of V1 is L.

[0051] In these embodiments, a second sodium hydroxide and high-calcium brine in a molar mass ratio of (0.070 to 0.080):100 can be used to induce initial precipitation of magnesium, calcium, and barium in the high-calcium brine by the second sodium hydroxide, and separation of these precipitates from the high-calcium brine can be achieved through a first precipitation separation stage. Alternatively, a second sodium carbonate and high-calcium brine in a molar mass ratio of (0.0070 to 0.0080):100 can be used to induce precipitation of most of the calcium, barium, and strontium in the brine filtrate by the second sodium carbonate, thereby facilitating subsequent dissolution to form a solution and ensuring the yield of strontium carbonate.

[0052] The amount n7 of the second sodium hydroxide can be 0.070, 0.071, 0.072, 0.073, 0.074, 0.075, 0.076, 0.077, 0.078, 0.079 or 0.080.

[0053] The amount n8 of the second sodium carbonate can be 0.0070, 0.0071, 0.0072, 0.0073, 0.0074, 0.0075, 0.0076, 0.0077, 0.0078, 0.0079 or 0.0080 In some optional embodiments, the amount n9 of the acid solvent and the volume V1 of the high calcium brine satisfy: n9:V1=(0.015 to 0.018):100, if the unit of n9 is mol, the unit of V1 is L; and / or The amount n10 of the first sodium hydroxide in the hot filtration and the volume V1 of the high calcium brine satisfy: n10:V1=(0.022 to 0.026):100, if the unit of n10 is mol, the unit of V1 is L; and / or The amount of substance n11 of the sodium sulfate and the volume V1 of the high-calcium brine satisfy: n11:V1=(0.0012 to 0.0016):100, and if the unit of n11 is mol, the unit of V1 is L.

[0054] In these embodiments, the acid solvent and high-calcium brine are present in a molar mass ratio of (0.015 to 0.018):100. The acid solvent allows the separated precipitate to be fully dissolved and the pH of the dissolved solution to be adjusted to a weakly acidic range, which is beneficial for subsequent hot filtration and thus ensures the removal of calcium. Furthermore, the first sodium hydroxide and high-calcium brine in the hot filtration are present in a molar mass ratio of (0.022 to 0.026):100. The first sodium hydroxide and high-calcium brine form a calcium hydroxide precipitate under high temperature conditions to effectively remove calcium and partially remove barium. Furthermore, the sodium sulfate and high-calcium brine are present in a molar mass ratio of (0.0012 to 0.0016):100. The sodium sulfate can completely precipitate the barium in the first filtrate, thereby obtaining a relatively pure second filtrate containing strontium.

[0055] The amount n9 of the acid solvent can be 0.0150, 0.0155, 0.0160, 0.0165, 0.0170, 0.0175 or 0.0180.

[0056] The amount n10 of the first sodium hydroxide in the hot filtration can be 0.022, 0.023, 0.024, 0.025 or 0.026.

[0057] The amount n11 of sodium sulfate can be 0.0012, 0.0013, 0.0014, 0.0015 or 0.0016.

[0058] Figure 3 The following is a schematic diagram showing the logical structure of a system for extracting strontium from high-calcium brine provided in an embodiment of the present application; Based on a general inventive concept, such as Figure 3 As shown, an embodiment of the present application provides a system for extracting strontium from high-calcium brine, the system is adapted to the method, and the system includes: The first precipitation section includes a high-calcium brine feed pipe 1, an alkaline compound agent feed pipe 2, a first precipitation tank group 3 and a first filter group 4, wherein the discharge port of the high-calcium brine feed pipe 1 is connected to the feed port of the first precipitation tank group 3, the discharge port of the alkaline compound agent feed pipe 2 is connected to the feed port of the first precipitation tank group 3, and the discharge port of the first precipitation tank group 3 is connected to the feed port of the first filter group 4; The dissolution part includes an acid solvent feed pipe 5, a dissolution tank 6, a diluent feed pipe 7 and a dilution tank 8, wherein the solid phase discharge port of the first filter is connected to the feed port of the dissolution tank 6, the discharge port of the acid solvent feed pipe 5 is connected to the feed port of the dissolution tank 6, the discharge port of the dissolution tank 6 is connected to the feed port of the dilution tank 8, and the discharge port of the dilution feed pipe 7 is connected to the feed port of the dilution tank 8; The hot filtration part includes a first sodium hydroxide feed pipe 9 and a hot filter 10, wherein the discharge port of the first sodium hydroxide feed pipe 9 is connected to the feed port of the hot filter 10, and the feed port of the hot filter 10 is connected to the discharge port of the dilution tank 8; The second precipitation part includes a sodium sulfate feed pipe 11, a second precipitation tank 12 and a second filter 13, wherein the discharge port of the sodium sulfate feed pipe 11 is connected to the feed port of the second precipitation tank 12, the discharge port of the hot filter 10 is connected to the feed port of the second precipitation tank 12, and the discharge port of the second precipitation tank 12 is connected to the feed port of the second filter 13; The third precipitation part includes a urea feed pipe 14, an ethylenediaminetetraacetic acid feed pipe 15, a first stage third precipitation tank 16, a heater 17, a first stage third filter 18, a first sodium carbonate feed pipe 19, a second stage third precipitation tank 20, a cooler 21 and a second stage third filter 22; the discharge port of the second filter 13 is connected to the feed port of the first stage third precipitation tank 16, the discharge port of the urea feed pipe 14 is connected to the feed port of the first stage third precipitation tank 16, the discharge port of the ethylenediaminetetraacetic acid feed pipe 15 is connected to the feed port of the first stage third precipitation tank 16, and the heater 17 is provided at the first stage third precipitation tank. The third precipitation tank 16 is used to heat the solution entering the first-stage third precipitation tank 16; the discharge port of the first-stage third precipitation tank 16 is connected to the feed port of the first-stage third filter 18, the discharge port of the first-stage third filter 18 is connected to the feed port of the second-stage third precipitation tank 20, the discharge port of the first sodium carbonate feed pipe 19 is connected to the feed port of the second-stage third precipitation tank 20, the discharge port of the second-stage third precipitation tank 20 is connected to the feed port of the second-stage third filter 22, and the cooler 21 is provided in the second-stage third precipitation tank 20 to cool the solution entering the second-stage third precipitation tank 20.

[0059] The system is implemented based on the above method. The specific steps of the method can refer to the above embodiments. Since the system adopts part or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0060] It should be noted that different pump groups can be used before the feed ports of different sedimentation tanks to provide material transportation power to promote sufficient sedimentation and separation.

[0061] In some optional embodiments, the alkaline composite agent feed pipe 2 includes a second sodium hydroxide feed pipe 201 and a second sodium carbonate feed pipe 202, the first precipitation tank group 3 includes a first precipitation tank 301 and a second first precipitation tank 302, and the first filter group 4 includes a first filter 401 and a second first filter 402; the discharge port of the high-calcium brine feed pipe 1 is connected to the feed port of the first precipitation tank 301, and the discharge port of the second sodium hydroxide feed pipe 201 is connected to the first precipitation tank 3 01, the discharge port of the first stage first sedimentation tank 301 is connected to the feed port of the first stage first filter 401, the discharge port of the first stage first filter 401 is connected to the feed port of the second stage first sedimentation tank 302, the discharge port of the second sodium carbonate feed pipe 202 is connected to the feed port of the second stage first sedimentation tank 302, the discharge port of the second stage first sedimentation tank 302 is connected to the feed port of the second stage first filter 402, and the solid phase discharge port of the second stage first filter 402 is connected to the feed port of the dissolution tank 6.

[0062] In these embodiments, by dividing the alkaline composite agent feed pipe 2 into a second sodium hydroxide feed pipe 201 and a second sodium carbonate feed pipe 202, an alkaline composite agent is formed by sodium hydroxide and sodium carbonate to effectively remove magnesium from the high-calcium brine, and to remove ferric ions and ferrous ions (if present), which is beneficial to the subsequent formation of a separation precipitate containing calcium, barium, and strontium.

[0063] The present application is further described below with reference to specific examples. Experimental methods in the following examples where specific conditions are not specified are generally measured in accordance with national / industry standards. If there are no corresponding national / industry standards, the methods are carried out in accordance with commonly used international standards, conventional conditions, or conditions recommended by the manufacturer.

[0064] Example 1

[0065] The high calcium brine used was yellow brine from Zigong, Sichuan, and its composition is shown in Table 1.

[0066] Table 1 Composition of high calcium brine

[0067] like Figure 1 A method for extracting strontium from high-calcium brine containing calcium, magnesium, barium and strontium is provided, comprising: S101. The high calcium brine is subjected to a first precipitation separation using a second sodium hydroxide to remove magnesium, part of the calcium and part of the barium in the high calcium brine to obtain a brine filtrate; S102. The brine filtrate is subjected to a second-stage first precipitation separation using a second sodium carbonate to remove a portion of barium and a portion of calcium from the brine filtrate, thereby obtaining a separated precipitate containing calcium, barium, and strontium. The amount of the second sodium hydroxide, n7, and the volume of the high-calcium brine, V1, satisfy the following ratio: n7:V1 = (0.070 to 0.080):100, where n7 is in mol and V1 is in L. S2. The separated precipitate containing calcium, barium and strontium is dissolved and diluted in sequence using an acid solvent to obtain a dissolving solution; S3. The solution was hot filtered using a first sodium hydroxide to remove calcium from the solution to obtain a first filtrate containing barium and strontium; S4. The first filtrate containing barium and strontium is subjected to a second precipitation separation using sodium sulfate to remove barium from the first filtrate to obtain a second filtrate containing strontium; S501 using urea and ethylenediaminetetraacetic acid to heat the second filtrate containing strontium, so that the urea composite additive decomposes to form carbonate and promotes precipitation of strontium in the second filtrate to obtain a first suspension of solid and liquid phases; S502. The solid and liquid phases of the first suspension are insulated to allow initial precipitation of strontium in the suspension to obtain a second suspension; S503. Cooling the second suspension to obtain a third suspension; S504. The third suspension is subjected to a second precipitation using the first sodium carbonate to obtain a strontium carbonate product; Among them, the composite additive includes sodium carbonate, urea and ethylenediaminetetraacetic acid The amount of substance n1 of ethylenediaminetetraacetic acid and the amount of substance n2 of strontium in the first filtrate satisfy: n1:n2=0.2:1; The amount of urea n3, the amount of the first sodium carbonate n4, and the amount of strontium in the first filtrate n2 satisfy the following ratio: n3:n4:n2 = 3.0:1.5:1. The molar concentration of EDTA is 0.2 mol / L, and the amount of EDTA used is 2 mL; the molar concentration of the first sodium carbonate is 1.5 mol / L, and the amount of the first sodium carbonate used is 2 mL; and the molar concentration of urea is 3.0 mol / L, and the amount of urea used is 2 mL.

[0068] The end temperature of heating was 90°C and the duration of heating was 12 min; The holding time is 30 minutes; The temperature of the second precipitation was 25° C., and the time of the second precipitation was 13 min.

[0069] The temperature of hot filtration is 90°C and the time of hot filtration is 8 minutes.

[0070] The alkaline complex includes a second sodium carbonate and a second sodium hydroxide, wherein the amount of the second sodium carbonate n5 and the amount of the second sodium hydroxide n6 satisfy the following ratio: n5:n6 = 1:10. In this case, the molar concentration of the second sodium carbonate is 1.5 mol / L, and the amount of the second sodium carbonate used is 5 mL; the molar concentration of the second sodium hydroxide is 15 mol / L, and the amount of the second sodium hydroxide used is 5 mL.

[0071] The amount of substance n9 of the acid solvent and the volume V1 of the high calcium brine satisfy: n9:V1=0.018:100. If the unit of n9 is mol, the unit of V1 is L; at this time, the molar concentration of the acid solvent is 2.0 mol / L, and the amount of the acid solvent used is 9 mL; The amount n10 of the first sodium hydroxide in the hot filtration and the volume V1 of the high-calcium brine satisfy: n10:V1=0.024:100, if the unit of n10 is mol, then the unit of V1 is L; the molar concentration of the first sodium hydroxide is 1.5 mol / L, and the amount of the first sodium hydroxide used is 1.6 mL; The amount of sodium sulfate n11 and the volume of high-calcium brine V1 satisfy: n11:V1=0.0014:100. If the unit of n11 is mol, the unit of V1 is L; at this time, the molar concentration of sodium sulfate is 1.0 mol / L, and the amount of sodium sulfate used is 1.4 mL.

[0072] like Figure 3 As shown, a system for extracting strontium from high-calcium brine is adapted to the method, and the system comprises: The first precipitation section includes a high-calcium brine feed pipe 1, an alkaline compound agent feed pipe 2, a first precipitation tank group 3 and a first filter group 4. The discharge port of the high-calcium brine feed pipe 1 is connected to the feed port of the first precipitation tank group 3, the discharge port of the alkaline compound agent feed pipe 2 is connected to the feed port of the first precipitation tank group 3, and the discharge port of the first precipitation tank group 3 is connected to the feed port of the first filter group 4; The dissolution part includes an acid solvent feed pipe 5, a dissolution tank 6, a diluent feed pipe 7 and a dilution tank 8. The solid phase discharge port of the first filter is connected to the feed port of the dissolution tank 6. The discharge port of the acid solvent feed pipe 5 is connected to the feed port of the dissolution tank 6. The discharge port of the dissolution tank 6 is connected to the feed port of the dilution tank 8. The discharge port of the dilution feed pipe 7 is connected to the feed port of the dilution tank 8. The hot filtration part includes a first sodium hydroxide feed pipe 9 and a hot filter 10, wherein the discharge port of the first sodium hydroxide feed pipe 9 is connected to the feed port of the hot filter 10, and the feed port of the hot filter 10 is connected to the discharge port of the dilution tank 8; The second precipitation part includes a sodium sulfate feed pipe 11, a second precipitation tank 12 and a second filter 13. The discharge port of the sodium sulfate feed pipe 11 is connected to the feed port of the second precipitation tank 12. The discharge port of the hot filter 10 is connected to the feed port of the second precipitation tank 12. The discharge port of the second precipitation tank 12 is connected to the feed port of the second filter 13. The third precipitation part includes a urea feed pipe 14, an EDTA feed pipe 15, a first stage third precipitation tank 16, a heater 17, a first stage third filter 18, a first sodium carbonate feed pipe 19, a second stage third precipitation tank 20, a cooler 21 and a second stage third filter 22; the discharge port of the second filter 13 is connected to the feed port of the first stage third precipitation tank 16, the discharge port of the urea feed pipe 14 is connected to the feed port of the first stage third precipitation tank 16, the discharge port of the EDTA feed pipe 15 is connected to the feed port of the first stage third precipitation tank 16, the heater 17 is provided In the first-stage third precipitation tank 16, the solution entering the first-stage third precipitation tank 16 is heated; the discharge port of the first-stage third precipitation tank 16 is connected to the feed port of the first-stage third filter 18, the discharge port of the first-stage third filter 18 is connected to the feed port of the second-stage third precipitation tank 20, the discharge port of the first sodium carbonate feed pipe 19 is connected to the feed port of the second-stage third precipitation tank 20, and the discharge port of the second-stage third precipitation tank 20 is connected to the feed port of the second-stage third filter 22. A cooler 21 is provided in the second-stage third precipitation tank 20 to cool the solution entering the second-stage third precipitation tank 20.

[0073] The alkaline composite agent feed pipe 2 includes a second sodium hydroxide feed pipe 201 and a second sodium carbonate feed pipe 202, the first precipitation tank group 3 includes a first stage first precipitation tank 301 and a second stage first precipitation tank 302, and the first filter group 4 includes a first stage first filter 401 and a second stage first filter 402; the discharge port of the high-calcium brine feed pipe 1 is connected to the feed port of the first stage first precipitation tank 301, the discharge port of the second sodium hydroxide feed pipe 201 is connected to the feed port of the first stage first precipitation tank 301, the discharge port of the first stage first precipitation tank 301 is connected to the feed port of the first stage first filter 401, the discharge port of the first stage first filter 401 is connected to the feed port of the second stage first precipitation tank 302, the discharge port of the second stage first precipitation tank 302 is connected to the feed port of the second stage first filter 402, and the solid phase discharge port of the second stage first filter 402 is connected to the feed port of the dissolution tank 6.

[0074] Example 2

[0075] Compared with Example 1, this embodiment has the following differences, and the rest are the same: The amount of substance n1 of ethylenediaminetetraacetic acid and the amount of substance n2 of strontium in the first filtrate satisfy: n1:n2=0.15:1; The amount of urea n3, the amount of the first sodium carbonate n4, and the amount of strontium in the first filtrate n2 satisfy the following ratio: n3:n4:n2 = 3.2:1.2:1. The molar concentration of EDTA is 0.15 mol / L, and the amount of EDTA used is 2 mL; the molar concentration of the first sodium carbonate is 1.2 mol / L, and the amount of the first sodium carbonate used is 2 mL; and the molar concentration of urea is 3.2 mol / L, and the amount of urea used is 2 mL.

[0076] The end temperature of heating was 85°C and the duration of heating was 15 min; The holding time is 25 to 35 minutes; The temperature of the second precipitation was 20° C., and the time of the second precipitation was 15 min.

[0077] The temperature of hot filtration is 90°C and the time of hot filtration is 10 minutes.

[0078] The amount of substance n5 of the second sodium carbonate and the amount of substance n6 of the second sodium hydroxide satisfy: n5:n6 = 1:9.5. In this case, the molar concentration of the second sodium carbonate is 1.5 mol / L, and the amount of the second sodium carbonate used is 5 mL; the molar concentration of the second sodium hydroxide is 14.25 mol / L, and the amount of the second sodium hydroxide used is 5 mL.

[0079] The amount of substance n9 of the acid solvent and the volume V1 of the high calcium brine satisfy: n9:V1=0.015:100. If the unit of n9 is mol, the unit of V1 is L; at this time, the molar concentration of the acid solvent is 1.5 mol / L, and the amount of the acid solvent used is 10 mL; The amount n10 of the first sodium hydroxide in the hot filtration and the volume V1 of the high-calcium brine satisfy: n10:V1=0.0225:100, if the unit of n10 is mol, then the unit of V1 is L; the molar concentration of the first sodium hydroxide is 1.5 mol / L, and the amount of the first sodium hydroxide used is 1.5 mL; The amount of sodium sulfate n11 and the volume of high-calcium brine V1 satisfy: n11:V1=0.0012:100. If the unit of n11 is mol, the unit of V1 is L; at this time, the molar concentration of sodium sulfate is 1.0 mol / L, and the amount of sodium sulfate used is 1.2 mL.

[0080] Example 3 Compared with Example 1, this embodiment has the following differences, and the rest are the same: The amount n1 of ethylenediaminetetraacetic acid and the amount n2 of strontium in the first filtrate satisfy: n1:n2=0.25:1; The amount of urea n3, the amount of the first sodium carbonate n4, and the amount of strontium in the first filtrate n2 satisfy the following ratio: n3:n4:n2 = 3.5:1.3:1. The molar concentration of EDTA is 0.25 mol / L, and the amount of EDTA used is 2 mL; the molar concentration of the first sodium carbonate is 1.3 mol / L, and the amount of the first sodium carbonate used is 2 mL; and the molar concentration of urea is 3.5 mol / L, and the amount of urea used is 2 mL.

[0081] The end point temperature of heating was 95°C and the duration of heating was 10 min; The holding time is 35 minutes; The temperature of the second precipitation was 30° C., and the time of the second precipitation was 10 min.

[0082] The temperature of hot filtration was 95°C and the time of hot filtration was 5 minutes.

[0083] The alkaline complex includes a second sodium carbonate and a second sodium hydroxide, wherein the amount of the second sodium carbonate n5 and the amount of the second sodium hydroxide n6 satisfy the following ratio: n5:n6 = 1:10.5. In this case, the molar concentration of the second sodium carbonate is 1.5 mol / L, and the amount of the second sodium carbonate used is 5 mL; the molar concentration of the second sodium hydroxide is 15.75 mol / L, and the amount of the second sodium hydroxide used is 5 mL.

[0084] The amount of substance n9 of the acid solvent and the volume V1 of the high calcium brine satisfy: n9:V1=0.018:100. If the unit of n9 is mol, the unit of V1 is L; at this time, the molar concentration of the acid solvent is 1.8 mol / L, and the amount of the acid solvent used is 10 mL; The amount of substance n10 of the first sodium hydroxide in the hot filtration and the volume V1 of the high-calcium brine satisfy: n10:V1=0.0255:100, if the unit of n10 is mol, then the unit of V1 is L; the molar concentration of the first sodium hydroxide is 1.5 mol / L, and the amount of the first sodium hydroxide used is 1.7 mL; The amount of sodium sulfate n11 and the volume of high-calcium brine V1 satisfy: n11:V1=0.0016:100. If the unit of n11 is mol, the unit of V1 is L; at this time, the molar concentration of sodium sulfate is 1.0 mol / L, and the amount of sodium sulfate used is 1.6 mL.

[0085] Comparative Example 1 Compared with Example 1, the differences of this comparative example are as follows, and the rest are the same: No composite additives are used, and the first sodium carbonate is directly used as a precipitant.

[0086] Comparative Example 2 Compared with Example 1, the differences of this comparative example are as follows, and the rest are the same: The composite additive does not use ethylenediaminetetraacetic acid, and directly uses a mixture of the first sodium carbonate and urea as the composite additive.

[0087] Comparative Example 3 Compared with Example 1, the differences of this comparative example are as follows, and the rest are the same: The composite additive does not use urea, and directly uses a mixture of ethylenediaminetetraacetic acid and first sodium carbonate as the composite additive.

[0088] Comparative Example 4 Compared with Example 1, the differences of this comparative example are as follows, and the rest are the same: The temperature of hot filtration is changed to room temperature.

[0089] Comparative Example 5 Compared with Example 1, the differences of this comparative example are as follows, and the rest are the same: No sodium sulfate was used for the second precipitation separation.

[0090] Related experiments and effect data: 1. For each stage in Example 1, the precipitation data were statistically analyzed: (1) Separation effect of the first precipitation separation: Using 15 mol / L sodium hydroxide as the precipitation reagent, the precipitation effect of 100 mL of high calcium brine was calculated. The results are as follows: Figure 4 This shows that controlling the amount of sodium hydroxide added to about 5 mL has a good precipitation effect (the precipitation rates of iron and magnesium are close to 100%, while the majority of calcium precipitation is 87.75%).

[0091] (2) Separation effect of the first precipitation separation in the second stage: 1.5 mol / L sodium carbonate was used as the precipitation reagent. Based on the amount determined in the above step (1), the precipitation effect of the brine filtrate obtained after precipitation of 100 mL of high calcium brine was calculated. The results are as follows: Figure 5 This indicates that controlling the amount of sodium carbonate added to about 5 mL has a good precipitation effect (21.01% of calcium and barium are separated, while 95.42% of strontium is retained).

[0092] (3) Separation effect of hot filtration: The hot filtration temperature of comparative example 4 was compared with that of example 1. 15 mol / L sodium hydroxide was used as the hot filtration reagent. The precipitation effect of the first filtrate treated under the above optimal conditions was statistically analyzed. The results are as follows: Figure 6 This shows that the hot filtration at around 90°C and the amount of sodium hydroxide added controlled at around 1.6mL has a good precipitation effect (most of the calcium is precipitated, and the precipitation rate of calcium is 96.69%). At the same time, the precipitation effect was measured using different hot filtration temperatures. The results are as follows Figure 7As shown, this indicates that the hot filtration temperature at around 90°C has a good precipitation effect.

[0093] (4) Separation effect of the second precipitation separation: 1.4 mol / L sodium sulfate was used as the precipitation reagent to precipitate the first filtrate obtained in the above step. The precipitation effect was statistically analyzed. The results are as follows: Figure 8 This indicates that controlling the amount of sodium sulfate added to about 1.4 mL has a good extraction effect.

[0094] (5) Separation effect of the third precipitation separation: A composite additive of 1.5 mol / L sodium carbonate, 3.0 mol / L urea and 0.2 mol / L ethylenediaminetetraacetic acid was used as a precipitation reagent. The heating temperature was controlled at about 90 °C and the cooling temperature was at room temperature. The results are as follows: Figure 9 As shown, this indicates that the total addition amount of the composite additive is about 1.4 mL, which has a good precipitation effect and a theoretical extraction rate of more than 94%.

[0095] In the above experiment, extraction rate = corresponding ion content in the precipitate / corresponding ion content in the treated material × 100%. For example, in hot filtration, the precipitation effect is primarily the extraction of calcium ions. Here, the calcium ion content of the precipitate / the calcium ion content of the first filtrate is the calcium ion extraction rate.

[0096] 2. The strontium carbonate products obtained in each embodiment and comparative example were collected respectively, and their purity and extraction rate were statistically analyzed. The results are shown in Table 2.

[0097] Table 2 Purity and extraction rate data of strontium carbonate products in various examples and comparative examples

[0098] As can be seen from Table 1, the embodiment of the present application provides a method for extracting strontium from high-calcium brine. This method adopts the dual strategy of "step-by-step deep impurity removal + complex homogeneous precipitation" and the synergistic effect of composite additives (sodium carbonate + urea + ethylenediaminetetraacetic acid) to achieve highly selective precipitation of strontium in the final precipitation step, significantly improving the purity of strontium carbonate to more than 90%.

[0099] Compared with Example 1, Comparative Example 1 directly uses sodium carbonate as a composite additive. Although the extraction rate of its strontium carbonate product is less affected, its product purity is low and it is difficult to meet the purity requirements of subsequent use.

[0100] Compared with Example 1, Comparative Example 2 does not use ethylenediaminetetraacetic acid, which makes it difficult to selectively complex the residual impurity ions in the third precipitation separation stage, resulting in lower purity and extraction rate of the final product.

[0101] Compared with Example 1, Comparative Example 3 does not use urea, which makes it difficult to fully carry out the third precipitation separation using sodium carbonate as the main precipitant, and the purity of the strontium carbonate product is also affected.

[0102] Compared with Example 1, Comparative Example 4 uses room temperature as hot filtration, which results in the presence of more calcium ion impurities in the strontium carbonate product, greatly affecting the purity and extraction rate of the strontium carbonate product.

[0103] Compared with Example 1, Comparative Example 5 does not perform the second precipitation separation, which results in the presence of more barium ion impurities in the strontium carbonate product, greatly affecting the purity of the strontium carbonate product and partially affecting its extraction rate.

[0104] In summary, the embodiments of the present application provide a method for extracting strontium from high-calcium brine. This method is based on the dual strategy of "step-by-step deep impurity removal + complex homogeneous precipitation". Through the synergistic effect of composite additives (sodium carbonate + urea + ethylenediaminetetraacetic acid), the purity of strontium carbonate is greatly improved, and the extraction rate of the strontium carbonate product is effectively improved.

[0105] In addition, an embodiment of the present application provides a method for extracting strontium from high-calcium brine. This method can extract a high-purity strontium carbonate product from yellow brine with high calcium, high barium and high strontium content at a relatively low cost, and can also achieve graded recovery of calcium and barium, which is beneficial to the continuous treatment of yellow brine and does not affect the subsequent salt production process of the yellow brine.

[0106] In addition, the embodiment of the present application provides a system for extracting strontium from high-calcium brine. The system has a simple overall structure and a convenient operation process, which is conducive to the large-scale production of yellow brine.

[0107] The foregoing is merely a detailed description of the present invention, intended to enable those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein, but rather is intended to conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for extracting strontium from high-calcium brine, wherein the high-calcium brine contains calcium, magnesium, barium and strontium, the method comprising: Using an alkaline composite agent to perform a first precipitation separation on the high-calcium brine to remove magnesium, part of the calcium and part of the barium in the high-calcium brine to obtain a separation precipitate containing calcium, barium and strontium; dissolving and diluting the separated precipitate containing calcium, barium and strontium in sequence using an acid solvent to obtain a dissolved solution; Hot filtering the solution using a first sodium hydroxide to remove calcium from the solution to obtain a first filtrate containing barium and strontium; performing a second precipitation separation on the first filtrate containing barium and strontium using sodium sulfate to remove barium from the first filtrate to obtain a second filtrate containing strontium; Using a composite additive, the second filtrate containing strontium is subjected to a third precipitation separation to obtain a strontium carbonate product; Wherein, the composite additive comprises first sodium carbonate, urea and ethylenediaminetetraacetic acid.

2. The method according to claim 1, characterized in that The amount n1 of the ethylenediaminetetraacetic acid and the amount n2 of the strontium in the first filtrate satisfy the following conditions: n1:n2=(0.15 to 0.25):1; and / or The amount n3 of urea, the amount n4 of the first sodium carbonate, and the amount n2 of strontium in the first filtrate satisfy: n3:n4:n2=(3.0 to 3.5):(1.2 to 1.5):

1.

3. The method according to claim 1, characterized in that The method of using the composite additive to subject the second filtrate containing strontium to a third precipitation separation to obtain a strontium carbonate product comprises the following steps: heating the second filtrate containing strontium using urea and ethylenediaminetetraacetic acid to decompose the urea in the composite additive to form carbonate and promote the precipitation of strontium in the second filtrate, thereby obtaining a first suspension of solid and liquid phases; Insulating the first suspension in the solid phase and the liquid phase to initially precipitate strontium in the suspension to obtain a second suspension; cooling the second suspension to obtain a third suspension; The third suspension is subjected to a second precipitation using sodium carbonate to obtain a strontium carbonate product.

4. The method according to claim 3, characterized in that The terminal temperature of the heating is 85° C. to 95° C., and the duration of the heating is 10 min to 15 min; and / or The insulation time is 25 min to 35 min; and / or The temperature of the second precipitation is 20° C. to 30° C., and the time of the second precipitation is 10 min to 15 min.

5. The method according to claim 1, wherein The temperature of the hot filtration is 90° C. to 95° C., and the time of the hot filtration is 5 min to 10 min.

6. The method according to claim 1, characterized in that The alkaline complex includes a second sodium carbonate and a second sodium hydroxide, and the amount n5 of the second sodium carbonate and the amount n6 of the second sodium hydroxide satisfy: n5:n6=1:(9.5 to 10.5).

7. The method according to claim 6, characterized in that The method of using an alkaline composite agent to perform a first precipitation separation on the high-calcium brine to remove magnesium, part of calcium and part of barium from the high-calcium brine to obtain a separated precipitate containing calcium, barium and strontium comprises the following steps: Using a second sodium hydroxide to perform a first precipitation separation on the high-calcium brine to remove magnesium, part of calcium and part of barium from the high-calcium brine to obtain a brine filtrate; Using a second sodium carbonate, the brine filtrate is subjected to a second first precipitation separation to remove a portion of barium and a portion of calcium from the brine filtrate to obtain a separated precipitate containing calcium, barium, and strontium; Wherein, the amount of substance n7 of the second sodium hydroxide and the volume V1 of the high calcium brine satisfy: n7:V1=(0.070 to 0.080):100, if the unit of n7 is mol, the unit of V1 is L; The amount n8 of the second sodium carbonate and the volume V1 of the high-calcium brine satisfy: n8:V1=(0.0070 to 0.0080):100, where if the unit of n8 is mol, the unit of V1 is L.

8. The method according to claim 1, characterized in that The amount of substance n9 of the acid solvent and the volume V1 of the high calcium brine satisfy: n9:V1=(0.015 to 0.018):100, if the unit of n9 is mol, the unit of V1 is L; and / or The amount n10 of the first sodium hydroxide in the hot filtration and the volume V1 of the high calcium brine satisfy: n10:V1=(0.022 to 0.026):100, if the unit of n10 is mol, the unit of V1 is L; and / or The amount of substance n11 of the sodium sulfate and the volume V1 of the high-calcium brine satisfy: n11:V1=(0.0012 to 0.0016):100, and if the unit of n11 is mol, the unit of V1 is L.

9. A system for extracting strontium from high-calcium brine, the system being adapted to the method according to any one of claims 1 to 8, the system comprising: A first precipitation section includes a high-calcium brine feed pipe, an alkaline compound agent feed pipe, a first precipitation tank group, and a first filter group, wherein the discharge port of the high-calcium brine feed pipe is connected to the feed port of the first precipitation tank group, the discharge port of the alkaline compound agent feed pipe is connected to the feed port of the first precipitation tank group, and the discharge port of the first precipitation tank group is connected to the feed port of the first filter group; The dissolution section includes an acid solvent feed pipe, a dissolution tank, a diluent feed pipe, and a dilution tank, wherein the solid phase discharge port of the first filter is connected to the feed port of the dissolution tank, the discharge port of the acid solvent feed pipe is connected to the feed port of the dissolution tank, the discharge port of the dissolution tank is connected to the feed port of the dilution tank, and the discharge port of the dilution feed pipe is connected to the feed port of the dilution tank; a hot filtration unit, comprising a first sodium hydroxide feed pipe and a hot filter, wherein the discharge port of the first sodium hydroxide feed pipe is connected to the feed port of the hot filter, and the feed port of the hot filter is connected to the discharge port of the dilution tank; A second precipitation section includes a sodium sulfate feed pipe, a second precipitation tank, and a second filter, wherein the discharge port of the sodium sulfate feed pipe is connected to the feed port of the second precipitation tank, the discharge port of the hot filter is connected to the feed port of the second precipitation tank, and the discharge port of the second precipitation tank is connected to the feed port of the second filter; The third precipitation part includes a urea feed pipe, an ethylenediaminetetraacetic acid feed pipe, a first-stage third precipitation tank, a heater, a first-stage third filter, a first sodium carbonate feed pipe, a second-stage third precipitation tank, a cooler and a second-stage third filter; the discharge port of the second filter is connected to the feed port of the first-stage third precipitation tank, the discharge port of the urea feed pipe is connected to the feed port of the first-stage third precipitation tank, the discharge port of the ethylenediaminetetraacetic acid feed pipe is connected to the feed port of the first-stage third precipitation tank, the heater is arranged in the first-stage third precipitation tank to heat the solution entering the first-stage third precipitation tank; the discharge port of the first-stage third precipitation tank is connected to the feed port of the first-stage third filter, the discharge port of the first-stage third filter is connected to the feed port of the second-stage third precipitation tank, the discharge port of the first sodium carbonate feed pipe is connected to the feed port of the second-stage third precipitation tank, the discharge port of the second-stage third precipitation tank is connected to the feed port of the second-stage third filter, and the cooler is arranged in the second-stage third precipitation tank to cool the solution entering the second-stage third precipitation tank.

10. The system according to claim 9, characterized in that The alkaline composite agent feed pipe includes a second sodium hydroxide feed pipe and a second sodium carbonate feed pipe, the first precipitation tank group includes a first stage first precipitation tank and a second stage first precipitation tank, and the first filter group includes a first stage first filter and a second stage first filter; the discharge port of the high-calcium brine feed pipe is connected to the feed port of the first stage first precipitation tank, the discharge port of the second sodium hydroxide feed pipe is connected to the feed port of the first stage first precipitation tank, the discharge port of the first stage first precipitation tank is connected to the feed port of the first stage first filter, the discharge port of the first stage first filter is connected to the feed port of the second stage first precipitation tank, the discharge port of the second sodium carbonate feed pipe is connected to the feed port of the second stage first precipitation tank, the discharge port of the second stage first precipitation tank is connected to the feed port of the second stage first filter, and the solid phase discharge port of the second stage first filter is connected to the feed port of the dissolution tank.

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