A detection reagent and a rapid detection method for high-purity lithium carbonate

Abstract

The application relates to a quality inspection technology of inorganic salt, and discloses a detection reagent and a rapid detection method for high-purity lithium carbonate. A water-soluble fluorescent probe detection reagent is obtained by using 2-(4-chlorophenyl) benzoxazole, 2-(2-hydroxyphenyl) benzoxazole and other benzoxazole compounds as a substrate, and by modifying the substrate with glycerol, tris(hydroxyl) aminomethane and other compounds; high-purity lithium carbonate is detected by using the detection reagent; the high-purity lithium carbonate is solid-phase prepared into lithium carbonate suspension liquid; the upper liquid phase of the lithium carbonate suspension liquid is taken; the fluorescent probe detection reagent is added into the upper liquid phase; and the high-purity lithium carbonate is rapidly detected according to the fluorescent spectrum and a working curve. The application can realize the rapid detection of the high-purity lithium carbonate in a water-soluble environment, and the detection response time can be as short as 3-10 seconds.

Description

TECHNICAL FIELD

[0001] The application relates to a detection technology of inorganic salts, and in particular to a detection reagent for high-purity lithium carbonate and a rapid detection method. BACKGROUND

[0002] Raw material sources of lithium carbonate include lithium mica ore, spodumene ore, waste batteries and salt lake brine, etc. Lithium carbonate obtained by processing solid minerals may contain impurities such as lead, copper, cobalt, nickel, iron, aluminum, calcium, magnesium, potassium, etc. In lithium carbonate products produced by using salt lake brine, sodium, magnesium, chlorine, boron and other salt components are main impurities. One of the main production areas of salt lake lithium products in China is the salt lake mining area in the Qaidam Basin of Qinghai Province. In the Qaidam salt lake mining area, old salt lake brine after potassium extraction from chloride type or sulfate type salt lake brine is mainly used for lithium extraction production. Under the production process conditions of lithium extraction from old salt lake brine, soluble magnesium salts such as magnesium chloride or magnesium sulfate are the main impurities. These impurities also affect the quality of the final product in the subsequent lithium salt refining and high-purity lithium carbonate production process. Therefore, if real-time tracking and preliminary screening rapid detection of product quality is required during production, the detection of magnesium impurities becomes an important means to evaluate the quality of this type of lithium carbonate product.

[0003] High-value utilization of lithium products is an important guarantee for deep development of salt lake lithium resources, and refining and producing high-purity lithium carbonate products is an important part of it. In the purification and refining of salt lake lithium carbonate, real-time detection of magnesium and other impurities is very important for process control and product quality control. However, the detection of impurities in lithium carbonate is often complex and slow. For example, the detection methods of trace magnesium and other impurities in lithium carbonate include chemical analysis, ion chromatography, inductively coupled plasma emission spectrometry, etc. In practical application, the detection limit is often high, the pretreatment procedure is complicated, and the detection time is generally several minutes to several hours. This time-consuming detection method makes it difficult to respond in a timely manner during the lithium carbonate refining process.

[0004] Compared with chemical analysis, ion chromatography, inductively coupled plasma emission spectrometry and other methods, the fluorescence probe method is suitable for the detection of trace salt components and has the characteristics of high sensitivity, good selectivity and fast response speed, which has certain advantages for the rapid detection of trace magnesium in high-purity lithium carbonate. For example, fluorescence probes based on diarylethylene derivatives, 3-hydroxy-4-pyridyl isoquinoline, and pyrazine hydrazone can realize the detection of impurity magnesium in high-purity lithium carbonate. However, these probes need to be detected in organic solvents, so although the response speed is very fast in the direct detection link, the sample still needs to be pretreated in the organic phase for a long time before detection, which means that the rapid detection of high-purity lithium carbonate cannot be realized in fact.

[0005] One of the representative routes for preparing high-purity lithium carbonate from salt lake brine is the production process of magnesium sulfate sub-type salt lake brine: a large amount of old salt lake brine is left after potassium extraction from magnesium sulfate sub-type salt lake brine, from which high-purity lithium carbonate products can be extracted and further purified by methods such as crystallization, extraction, adsorption, membrane separation, etc. In high-purity lithium carbonate prepared from old salt lake brine, magnesium and other salt components are mostly water-soluble and fast-dissolving impurities, so if the quality inspection can be realized in a water-soluble environment, the detection process does not need to be time-consuming for organic phase pretreatment of lithium carbonate, which will greatly improve the detection efficiency of lithium carbonate products. On this basis, the production process of high-purity lithium carbonate will have the advantages of high process efficiency, strong quality guarantee, and fast process response, which can track the product quality in real time and ensure the product quality. However, in the research and development of fluorescent probe detection technology, the fluorescent probe based on organic phase operation is still the main form of the probe, and the rapid detection of trace salt components in the water environment requires the development of water-soluble fluorescent probe detection reagents and the development of corresponding water environment rapid detection methods. SUMMARY

[0006] In view of the above problems, the present application develops a water-soluble fluorescent probe detection reagent, which has the ability to rapidly respond to magnesium ions in an aqueous solution, and can be used for rapid detection of lithium carbonate. A rapid detection method for high-purity lithium carbonate is developed. Compared with other fluorescent probe detection reagents that can detect lithium carbonate products, the fluorescent probe detection reagent of the present application has the characteristic of water solubility, so it does not need to be pretreated before detection. Compared with other detection methods for high-purity lithium carbonate, the present application is characterized by simultaneous detection in a water-soluble environment and simple and rapid detection. The detection method of the present application is based on the use of a fluorescence spectrophotometer, but the measured fluorescence spectrum is a lithium carbonate aqueous solution system, which is different from the traditional fluorescence spectrum test of the organic solution phase system of lithium carbonate in terms of detection steps, etc.

[0007] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0008] The present application provides a detection reagent for high-purity lithium carbonate, which is obtained by the following preparation steps:

[0009] a) Dissolve the solid benzoxazole heterocyclic compound in a solvent to obtain a mixed solution;

[0010] b) Dissolve the solid hexamethylenetetramine in the mixed solution of step a), stir while refluxing with a condenser, then cool the product, and then filter and wash with water to obtain a solid compound;

[0011] c) Dissolve the solid compound of step b) in an organic solvent to obtain a mixed solution;

[0012] d) adding a hydrophilic compound to the mixed solution of step c), stirring, and refluxing using a condenser, then cooling the product, and filtering and drying to obtain a solid fluorescent probe compound;

[0013] e) dissolving the solid fluorescent probe compound of step d) in a water-miscible organic solvent to obtain a fluorescent probe detection reagent, i.e., the detection reagent for the high-purity lithium carbonate.

[0014] Further, the base substance solid benzoxazole heterocyclic compound in step a) is any one of 2-phenylbenzoxazole, 2-(4-chlorophenyl)benzoxazole, and 2-(2-hydroxyphenyl)benzoxazole, and preferably 2-(2-hydroxyphenyl)benzoxazole; the solution is any one of trifluoroacetic acid and trifluoromethanesulfonic acid; and the liquid-solid mass ratio of the solution to the base substance in step a) is (20-100):1.

[0015] Further, the liquid-solid mass ratio of the solid hexamethylenetetramine to the mixed solution of step a) in step b) is (6-33):1, the stirring temperature is 60-95°C, the condensation reflux time is 3-7h, and the product is cooled to 15-35°C before being subjected to suction filtration and washing.

[0016] Further, the liquid-solid mass ratio of the organic solvent to the solid compound of step b) in step c) is (50-200):1, and the organic solvent is any one of toluene and ethyl acetate.

[0017] Further, the hydrophilic compound in step d) is any one of glycerol, tris(hydroxyl)aminomethane, and ribose; the mass ratio of the mixed solution of step c) to the compound is (75-500):1, the stirring temperature is 90-110°C, the condensation reflux time is 6-10h, and the product is cooled to 15-35°C before being subjected to filtration and drying.

[0018] Further, the liquid-solid mass ratio of the water-miscible organic solvent to the solid fluorescent probe compound of step d) in step e) is (140-1400):1, and the water-miscible organic solvent is any one of dimethyl sulfoxide and dimethylformamide.

[0019] The present application provides a rapid detection method for high-purity lithium carbonate, which uses the above detection reagent and comprises the following steps:

[0020] a) placing high-purity lithium carbonate solid phase in deionized water to prepare a potassium carbonate suspension, and recording the amount of high-purity lithium carbonate solid phase and deionized water;

[0021] b) taking the upper liquid phase of the lithium carbonate suspension of step a) and injecting it into the cuvette of a fluorescence spectrophotometer;

[0022] c) adding the fluorescent probe detection reagent into the cuvette, and using a fluorescence spectrophotometer to measure the fluorescence spectrum of the liquid phase in the cuvette at an excitation wavelength of 380-440 nm, wherein the time taken for the fluorescence intensity to change is the detection response time;

[0023] d) according to the fluorescence intensity value of the emission peak of the fluorescence spectrum of the liquid phase in the cuvette in step c), reading the corresponding magnesium concentration value on the working curve of the fluorescence intensity and magnesium concentration, which is the magnesium ion concentration in the liquid phase;

[0024] e) according to the calculation method of obtaining the content of the impurity magnesium in the high-purity lithium carbonate solid phase.

[0025] Further, the high-purity lithium carbonate in step a) is prepared from old brine of a salt lake, and the liquid-solid mass ratio of deionized water to the high-purity lithium carbonate solid phase is (10-3000):1; in step b), the upper liquid phase of the potassium carbonate suspension liquid is absorbed using a needle filter or a pipette after the lithium carbonate suspension liquid is left to stand and settle; in step c), the amount of the fluorescent probe detection reagent is 1 / 300-1 / 50 of the volume of the upper liquid phase absorbed in step b).

[0026] Further, in step d), the working curve refers to the relationship curve between the concentration of the used fluorescent probe detection reagent and the detected magnesium ion concentration, which is drawn according to the fluorescence spectrum measurement results of the suspension liquid of a mixture of lithium carbonate and magnesium chloride with a known ratio, and the ordinate of the relationship curve is the fluorescence intensity at the fluorescence emission peak when the fluorescent probe detection reagent responds to magnesium ions, and the abscissa is the magnesium concentration value.

[0027] Further, the high-purity lithium carbonate in step a) is prepared from old brine of a salt lake of a magnesium sulfate subtype after potassium extraction.

[0028] Compared with the prior art, the present application has the following advantages:

[0029] The process method is easy to operate, and the detection limit of magnesium ions in the liquid phase can reach 2.0 mmol / L. In the synthesis method of the detection reagent, the hydrophilic group on the substrate is modified by condensation reaction to increase the water solubility of the molecule or optimize the optical performance, so as to realize the detection of impurity magnesium in the aqueous solution, and effectively shorten the detection time. In the detection method, the working curve and the calculation method of the content of impurity magnesium in the high-purity lithium carbonate solid phase can be preset in the computer program. In this case, the detection response time of trace magnesium in the high-purity lithium carbonate is 3-10 s, which can shorten the detection time of the high-purity lithium carbonate from the traditional minute level and hour level to the level of seconds, which is better than the detection methods such as chemical analysis, ion chromatography, inductively coupled plasma emission spectrometry and the like. The present application can greatly improve the quality inspection and production efficiency of lithium carbonate, meet the requirements of large quantities and rapid detection, and enable the lithium carbonate production process control to respond in time. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 . High-purity lithium carbonate detection response time diagram.

[0031] Figure 2 . Fluorescence intensity and magnesium concentration working curve diagram. DETAILED DESCRIPTION

[0032] The technical solutions of the present application will be specifically and detailedly described below in combination with the embodiments of the present application and the drawings. It should be pointed out that, for those skilled in the art, without departing from the principles of the present application, a number of variations and improvements can be made, which should be regarded as belonging to the protection scope of the present application.

[0033] Example 1

[0034] The present embodiment illustrates a detection reagent and a rapid detection method for high-purity lithium carbonate.

[0035] The detection reagent for high-purity lithium carbonate illustrated in the present embodiment is obtained by the following preparation steps:

[0036] a) 2-(2-hydroxyphenyl)benzoxazole is used as a substrate, the liquid-solid mass ratio is 20:1, 1 g of the substrate is dissolved in 20 g of trifluoroacetic acid to obtain a mixed solution;

[0037] b) 3 g of solid hexamethylenetetramine is dissolved in the mixed solution in step a) according to the liquid-solid mass ratio of 6:1, stirring is carried out at 60℃, a condenser is used for reflux cooling for 3 h, then the product is cooled, water is added after cooling to 15℃, and filtration and washing are carried out to obtain a solid compound;

[0038] c) 0.3 g of the solid compound in step b) is dissolved in 15 g of toluene according to the liquid-solid mass ratio of 50:1 to obtain a mixed solution;

[0039] d) according to the mass ratio of mixed solution to hydrophilic compound 75:1, 0.2 g of tris(hydroxy)aminomethane is added to the mixed solution in step c), stirred at 90℃, and refluxed for 6 h using a condenser, then the product is cooled, and when the temperature is lowered to 15℃, filtration and drying are carried out to obtain a solid fluorescent probe compound;

[0040] e) according to the liquid-solid mass ratio 1400:1, the solid fluorescent probe compound in step d) is dissolved in dimethyl sulfoxide to obtain a fluorescent probe detection reagent.

[0041] The embodiment illustrates a rapid detection method of high-purity lithium carbonate, which uses the above-mentioned detection reagent and comprises the following steps:

[0042] a) according to the liquid-solid mass ratio 10:1, the high-purity lithium carbonate solid phase prepared from the old brine of a magnesium sulfate sub-type salt lake after potassium extraction is placed in deionized water to prepare a suspension, and it is recorded that the high-purity lithium carbonate solid phase is 10 g and the amount of deionized water used is 100 g;

[0043] b) the upper liquid phase of the lithium carbonate suspension is sucked using a needle filter and injected into a cuvette of a fluorescence spectrophotometer;

[0044] c) according to 1 / 300 of the volume of the sucked liquid phase, 10 mL of the fluorescent probe detection reagent is added to the cuvette; at the same time, the fluorescence spectrum of the liquid phase in the cuvette is measured at an excitation wavelength of 440 nm using the fluorescence spectrophotometer, and the time consumed when the fluorescence intensity of the fluorescence spectrum mutates is the detection response time, and the fluorescence intensity mutation is as shown in Figure 1 The schematic diagram of the detection response time of high-purity lithium carbonate is shown;

[0045] d) according to the fluorescence intensity value of the emission peak of the fluorescence spectrum of the liquid phase in the cuvette in step c), the corresponding magnesium concentration value 0.49121 mg / L is read on the working curve of the fluorescence intensity and the magnesium concentration, which is the magnesium ion concentration in the liquid phase;

[0046] e) according to the calculation method of the content of impurity magnesium in the high-purity lithium carbonate solid phase is 0.0005%.

[0047] The above-mentioned rapid detection method of high-purity lithium carbonate, the working curve in step d) refers to the concentration curve of the used fluorescent probe detection reagent and the detected magnesium ion concentration, which is drawn according to the fluorescence spectrum measurement results of the suspension of lithium carbonate and magnesium chloride mixtures with known mass ratios of 49:1, 73:1, 98:1 and 196:1, the ordinate of the relationship curve is the fluorescence intensity at the fluorescence emission peak when the fluorescent probe detection reagent responds to magnesium ions, and the abscissa is the magnesium ion concentration, as shown in Figure 2A schematic diagram of the working curve is shown.

[0048] In this embodiment, the detection response time is 5.25 s, i.e. 0.0875 min.

[0049] Example 2

[0050] The method and workflow are the same as in Example 1, except that in step a) of the rapid detection method for high-purity lithium carbonate, 0.1 g of high-purity lithium carbonate solid phase is taken according to a liquid-solid mass ratio of 3000:1, and is placed in 300 g of deionized water to prepare a lithium carbonate suspension. The upper liquid phase of the lithium carbonate suspension is taken after the lithium carbonate suspension is allowed to stand and settle using a pipette.

[0051] In this embodiment, the detection response time is 3.42 s.

[0052] Example 3

[0053] The method and workflow are the same as in Example 1, except that in step c) of the rapid detection method for high-purity lithium carbonate, the fluorescence probe detection reagent is added to the cuvette according to 1 / 50 of the volume of the liquid phase taken, and the fluorescence spectrum of the liquid phase in the cuvette is measured at an excitation wavelength of 380 nm using a fluorescence spectrophotometer.

[0054] In this embodiment, the detection response time is 4.75 s.

[0055] Example 4

[0056] The method and workflow are the same as in Example 1, except that a detection reagent for high-purity lithium carbonate is used, which is prepared using the following steps:

[0057] a) 1 g of substrate is dissolved in 100 g of trifluoroacetic acid according to a liquid-solid mass ratio of 100:1 to obtain a mixed solution, using 2-(2-hydroxyphenyl)benzoxazole as the substrate;

[0058] b) 3 g of solid hexamethylenetetramine is dissolved in the mixed solution in step a) according to a liquid-solid mass ratio of 33:1, and is stirred at 95°C while being cooled by refluxing using a condenser for 7 h. The product is then cooled, and water is added after cooling to 35°C for filtration and washing to obtain a solid compound;

[0059] c) 0.3 g of the solid compound in step b) is dissolved in 60 g of toluene according to a liquid-solid mass ratio of 200:1 to obtain a mixed solution;

[0060] d) 0.2 g of tris(hydroxyl)aminomethane is added to the mixed solution in step c) according to a mixed solution to hydrophilic compound mass ratio of 500:1, and is stirred at reflux at 110°C for 10 h. The product is then cooled, and is filtered and dried after cooling to 35°C to obtain a solid fluorescence probe compound.

[0061] e) Take the solid fluorescent probe compound in step d) and dissolve in dimethyl sulfoxide to obtain a fluorescent probe detection reagent, with a liquid-solid mass ratio of 140:1.

[0062] In this example, the detection response time is 4.21 s.

[0063] Example 5

[0064] The method and workflow are the same as in Example 4, except that in the preparation of a detection reagent for high-purity lithium carbonate, step a) uses 2-phenylbenzoxazole as the substrate, and the substrate is dissolved in trifluoromethanesulfonic acid to obtain a mixed solution, with a liquid-solid mass ratio of 100:1.

[0065] In this example, the detection response time is 4.13 s.

[0066] Example 6

[0067] The method and workflow are the same as in Example 4, except that in the preparation of a detection reagent for high-purity lithium carbonate, step a) uses 2-(4-chlorophenyl)benzoxazole as the substrate, and the substrate is dissolved in trifluoromethanesulfonic acid to obtain a mixed solution, with a liquid-solid mass ratio of 100:1.

[0068] In this example, the detection response time is 9.78 s.

[0069] Example 7

[0070] The method and workflow are the same as in Example 4, except that in the preparation of a detection reagent for high-purity lithium carbonate, step c) takes 0.3 g of the solid compound in step b) and dissolves it in 60 g of ethyl acetate to obtain a mixed solution, with a liquid-solid mass ratio of 200:1.

[0071] In this example, the detection response time is 5.49 s.

[0072] Example 8

[0073] The method and workflow are the same as in Example 4, except that in the preparation of a detection reagent for high-purity lithium carbonate, step d) adds 0.2 g of glycerol to the mixed solution in step c), and the mass ratio of the mixed solution to the hydrophilic compound is 500:1, and the mixture is stirred and refluxed at 110°C for 10 h. Then, the product is cooled to 35°C, filtered, and dried to obtain a solid fluorescent probe compound.

[0074] In this example, the detection response time is 7.83 s.

[0075] Example 9

[0076] The method and workflow are the same as those in Embodiment 4, except that in the preparation step d) of the detection reagent of high-purity lithium carbonate, 0.2 g of ribose is added to the mixed solution in step c), and the mass ratio of the mixed solution to the hydrophilic compound is 500:1, and the mixture is stirred and refluxed at 110°C for 10 h, and then the product is cooled to 35°C, filtered and dried to obtain a solid fluorescent probe compound; in step e), the solid fluorescent probe compound in step d) is taken and dissolved in dimethylformamide at a liquid-solid mass ratio of 1400:1 to obtain a fluorescent probe detection reagent.

[0077] In the present embodiment, the detection response time is 4.43 s.

[0078] From the above embodiments, it can be seen that the detection response time of the trace magnesium in the high-purity lithium carbonate of the present application is 3-10 s, which can shorten the detection time of the high-purity lithium carbonate from the traditional minute or hour level to the level of seconds, which is superior to the detection methods such as chemical analysis, ion chromatography, inductively coupled plasma emission spectrometry, etc. The present application can greatly improve the quality inspection and production efficiency of lithium carbonate, meet the requirements of large quantities and rapid detection, and enable the lithium carbonate production process control to respond in time.

[0079] The above embodiments are preferred embodiments of the present application, but the embodiments of the present application are not limited by the above embodiments. For those skilled in the art, a number of variations and improvements can be made without departing from the principles of the present application, and all of them are included in the protection scope of the present application.

Claims

1. A test reagent for high-purity lithium carbonate, characterized by comprising: The following preparation steps are taken: a. The solid-state benzoxazole heterocyclic compound is dissolved in a solution to obtain a mixed solution; the solid-state benzoxazole heterocyclic compound in step a is any one of 2-phenylbenzoxazole, 2-(4-chlorophenyl)benzoxazole, and 2-(2-hydroxyphenyl)benzoxazole; the solution is any one of trifluoroacetic acid and triflic acid; the liquid-solid mass ratio of the solution to the substrate in step a is (20-100):1; b. The solid hexamethylenetetramine is dissolved in the mixed solution of step a, stirred while using a condenser to reflux, then the product is cooled, and then water is added to filter and wash to obtain a solid compound; the liquid-solid mass ratio of the solid hexamethylenetetramine to the mixed solution of step a in step b is (6-33):1; c. The solid compound of step b is dissolved in an organic solvent to obtain a mixed solution; d. The hydrophilic compound is added to the mixed solution of step c, stirred and refluxed using a condenser, then the product is cooled, and then filtered and dried to obtain a solid fluorescent probe compound; the hydrophilic compound in step d is any one of glycerol, tris(hydroxyl)aminomethane, and ribose; the mass ratio of the mixed solution of step c to the hydrophilic compound is (75-500):1; e. The solid fluorescent probe compound of step d is dissolved in a water-miscible organic solvent to obtain a fluorescent probe detection reagent, which is a detection reagent for high-purity lithium carbonate, to detect magnesium in an aqueous solution; the liquid-solid mass ratio of the water-miscible organic solvent to the solid fluorescent probe compound of step d in step e is (140-1400):1; the water-miscible organic solvent is any one of dimethyl sulfoxide and dimethyl formamide.

2. The detection reagent for high-purity lithium carbonate according to claim 1, characterized by: In step b, the stirring temperature is 60-95°C, the condensation reflux time is 3-7 h, and the product is filtered and washed after being cooled to 15-35°C.

3. The detection reagent of high-purity lithium carbonate according to claim 1, characterized by: In step c, the liquid-solid mass ratio of the organic solvent to the solid compound of step b is (50-200):1, and the organic solvent is any one of toluene and ethyl acetate.

4. The detection reagent of high-purity lithium carbonate according to claim 1, characterized by: In step d, the stirring temperature is 90-110°C, the condensation reflux time is 6-10 h, and the product is filtered and dried after being cooled to 15-35°C.

5. A method for rapid detection of high purity lithium carbonate, characterized by, The detection reagent of any one of claims 1-4 is used, specifically including the following steps: a) A high-purity lithium carbonate solid phase is placed in deionized water to prepare a lithium carbonate suspension, and the amount of high-purity lithium carbonate solid phase and deionized water is recorded; b) The upper liquid phase of the lithium carbonate suspension of step a) is taken and injected into a cuvette of a fluorescence spectrophotometer; c) The fluorescent probe detection reagent is added to the cuvette, and the fluorescence spectrum of the liquid phase in the cuvette is measured at an excitation wavelength of 380-440 nm using the fluorescence spectrophotometer. The time taken for the fluorescence intensity of the fluorescence spectrum to change is the detection response time; d) According to the fluorescence intensity value at the emission peak of the fluorescence spectrum of the liquid phase in the cuvette in step c), the corresponding magnesium concentration value is read on the working curve of fluorescence intensity and magnesium concentration. This value is the magnesium ion concentration in the liquid phase. e) The content of impurity magnesium in the high-purity lithium carbonate solid phase is obtained according to the calculation method of . 6.The method for rapid detection of high-purity lithium carbonate according to claim 5, characterized in that: The high-purity lithium carbonate in step a) is prepared from old brine of a salt lake, and the liquid-solid mass ratio of deionized water to the high-purity lithium carbonate in solid phase is (10-3000):1; the upper liquid phase of the lithium carbonate suspension liquid in step b) is sucked using a needle filter or a pipette after the lithium carbonate suspension liquid is left to stand and settle; the amount of the fluorescent probe detection reagent in step c) is 1 / 300-1 / 50 of the volume of the upper liquid phase sucked in step b).

7. The method for rapid detection of high-purity lithium carbonate according to claim 5, characterized in that: The working curve in step d) refers to a relationship curve between the concentration of the fluorescent probe detection reagent used and the detected magnesium ion concentration, which is drawn according to the fluorescence spectrum measurement results of a suspension liquid of a mixture of lithium carbonate and magnesium chloride in a known proportion, and the ordinate of the relationship curve is the fluorescence intensity at the fluorescence emission peak when the fluorescent probe detection reagent responds to magnesium ions, and the abscissa is the magnesium concentration value. 8.The method for rapid detection of high-purity lithium carbonate according to claim 7, characterized in that: The high-purity lithium carbonate in step a) is prepared from old brine of a salt lake after potassium is extracted from magnesium sulfate subtype brine of the salt lake.

Images