Method for determining lithium in lithium ore bioleaching solution

Abstract

The invention discloses a method for determining lithium in a lithium ore bioleaching solution, and belongs to the technical field of biological metallurgy, the determination method comprises the following steps: preparing a lanthanum nitrate-strontium chloride composite matrix improver, sampling from the lithium ore bioleaching system leaching solution, centrifuging to remove solid impurities, filtering the solid impurities by using a 0.22 [mu] m filter membrane, and collecting the lithium in the lithium ore bioleaching system leaching solution; a sample is diluted for standby application, a lanthanum nitrate-strontium chloride composite matrix improver is added into the sample, the concentration ratio of lanthanum nitrate to strontium chloride in the lanthanum nitrate-strontium chloride composite matrix improver is 1: 2, and the sample is measured by adopting a flame atomic absorption spectrophotometer. The method is especially suitable for bioleaching solution analysis of lithium ore and efficient detection of lithium resources, the inhibition effect of coexisting ions on lithium atomization is avoided through the lanthanum nitrate-strontium chloride composite matrix improver, and the coexisting interfering ions are competitively complexed, background absorption is reduced, and a lithium signal is prevented from being covered, so that the determination accuracy is improved.

Description

Technical Field

[0001] This invention relates to the field of biometallurgy, and more specifically, to a method for determining lithium in bioleaching solutions of lithium ore. Background Technology

[0002] Lithium, as an important rare metal, possesses excellent electrochemical activity and exhibits significant advantages in redox potential and specific heat capacity. Therefore, it is considered a key strategic resource and is widely used in energy storage, electronic devices, and lithium batteries, especially in electric vehicles and renewable energy storage systems, where it holds irreplaceable strategic value. With the continuous increase in global demand for lithium resources, the development and utilization of lithium ore has become an important research direction in the mining industry. In the lithium extraction process, bioleaching technology, with its environmental friendliness and economic advantages, has gradually become an emerging method for lithium resource mining. Bioleaching solution refers to the liquid medium formed by the dissolution of lithium from ore into the liquid phase through microbial action. It is usually complex in composition, contains diverse impurities, and has fluctuating chemical properties, thus accurately determining the lithium concentration presents a significant technical challenge. To achieve efficient lithium extraction and optimize the leaching process, accurate measurement of the lithium concentration in the bioleaching solution is particularly important.

[0003] Currently, commonly used methods for determining lithium concentration in bioleaches include flame atomic absorption spectrometry (FAAS), inductively coupled plasma optical emission spectrometry (ICP-OES), and inductively coupled plasma mass spectrometry (ICP-MS). Although these methods generally possess high sensitivity and accuracy, FAAS remains widely used in complex matrix samples such as ores, slurries, and bioleaches due to its simple instrument structure, ease of operation, low cost, and ability to meet routine lithium concentration detection requirements. However, existing FAAS methods still have certain limitations in practical applications, including cumbersome sample pretreatment and significant matrix interference, which affect the accuracy and reliability of the detection results.

[0004] To address the above problems, this invention proposes a method for determining lithium in bioleaching solutions of lithium ore. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for determining lithium in lithium ore bioleaching solution, so as to achieve accurate determination of lithium concentration in lithium ore bioleaching solution and ensure the accuracy and reliability of data.

[0006] The technical solution adopted by this invention to solve its technical problem is: to provide a method for determining lithium in lithium ore bioleaching solution, comprising the following steps, S1: Lanthanum nitrate-strontium chloride composite matrix modifier was prepared. After sampling, the sample was centrifuged, filtered, and then the lanthanum nitrate-strontium chloride composite matrix modifier was added for determination. S2: Preparation of lithium standard solution; S3: Set up the flame atomic spectrophotometer; S4: Obtain the standard curve and determine the lithium concentration in the sample; The concentration ratio of lanthanum nitrate to strontium chloride in the lanthanum nitrate-strontium chloride composite matrix modifier is 1:2, and the lanthanum nitrate-strontium chloride composite matrix modifier is added according to the sample:modifier = 10:1.

[0007] In this embodiment, specifically, the process for preparing the lanthanum nitrate-strontium chloride composite matrix modifier in step S1 includes: adding strontium chloride to ultrapure water to prepare a 1000 μg / mL strontium single-element stock solution; adding strontium chloride to ultrapure water to prepare another 1000 μg / mL strontium single-element stock solution; mixing the strontium single-element stock solution and the strontium single-element stock solution at a volume ratio of 1:2; and then adding 1% nitric acid solution to obtain the lanthanum nitrate-strontium chloride composite matrix modifier. In this embodiment, specifically, step S1 includes: taking a sample from the leaching solution of the lithium ore bioleaching system; first, centrifuging to remove solid impurities; then filtering using a 0.22 μm filter membrane; and then diluting the sample 10 times.

[0008] In this embodiment, specifically, the method for preparing the lithium standard solution in step S2 is as follows: the concentration of the lithium standard solution is 1 mg / mL, and 0, 0.05, 0.1, 0.2, and 0.5 mL of lithium standard solution are respectively transferred by pipette and diluted to 100 mL in volumetric flasks to obtain lithium standard solutions with concentrations of 0, 0.5, 1, 2, and 5 mg / L.

[0009] In this embodiment, specifically, step S3 includes, S3.1: Select the hollow cathode lamp light source for lithium determination, install it on the instrument, and add the lithium element determination method in the method interface; S3.2: The characteristic absorption wavelength of lithium is selected as 670.8 nm; S3.3: The burner head is 100, and the instrument provides the maximum gas flow rate according to the set standard flow rate; S3.4: Set the zero point and standard calibration concentration on the standard calibration page; In S3.4, the zero point of calibration is set to 1 ppm, and the standard calibration is set to 5 ppm.

[0010] In this embodiment, specifically, in step S4, deionized water and 1% nitric acid solution are used for cleaning during the determination of lithium concentration in the sample.

[0011] In this embodiment, specifically, the flame atomic absorption spectrophotometer in step S4 is model NovAA800F.

[0012] In this embodiment, specifically, step S4 includes, S4.1: Prepare the sample, lithium standard solution, deionized water and nitric acid solution.

[0013] S4.2: Open the fume hood, open the main valve of the acetylene cylinder, turn on the air compressor, turn on the computer power, start the computer, turn on the instrument power, double-click the computer instrument icon, enter the start menu interface of the application software, and first click system check to enter the instrument initialization process; S4.3: Load the existing method, click on the method, click on the bottom left corner to open, and select the established lithium measurement method; S4.5: Establish the analysis sequence. In the analysis sequence menu, set the analysis sequence, click Add, click Calibration to draw the standard curve, click Accept, click Special Action, select Display Standard Curve, which will automatically pop up the standard curve after the standard solution is measured, click Accept, click Sample to set the sample quantity; S4.6: Ignition. Click the flame to enter the interface. Place the long cleaning tube above the liquid level in the cleaning bottle. The cleaning bottle contains 1% nitric acid solution. First, click to test the air and test the fuel gas. Observe whether the air and acetylene gas are normal. If both are normal, you can ignite. After ignition, you must immediately insert the long cleaning tube below the liquid level in the cleaning bottle. S4.7: Run the analysis sequence. Click the run icon in the analysis interface to start running the analysis sequence, perform standard curve and sample determination, and determine the lithium standard solution according to the concentration gradient from low to high. The standard curve will automatically pop up after the determination is completed.

[0014] In this embodiment, specifically, in step S4.2, the partial pressure of acetylene is 0.1 MPa, and the main pressure is greater than 0.4 MPa.

[0015] In this embodiment, specifically, the standard curve in S4.5 improves the R2 value through repeated measurements.

[0016] The beneficial effects of this invention are as follows: The method for determining lithium in lithium ore bioleaching solution of this invention first prepares a lanthanum nitrate-strontium chloride composite matrix modifier. A sample is taken from the leaching solution of the lithium ore bioleaching system, centrifuged to remove solid impurities, filtered through a 0.22 μm filter membrane, and the sample is diluted for later use. The lanthanum nitrate-strontium chloride composite matrix modifier is then added to the sample, wherein the concentration ratio of lanthanum nitrate to strontium chloride in the lanthanum nitrate-strontium chloride composite matrix modifier is 1:2. The sample is measured using a flame atomic absorption spectrophotometer. This method is particularly suitable for the analysis of lithium ore bioleaching solution and the efficient detection of lithium resources. The lanthanum nitrate-strontium chloride composite matrix modifier avoids the inhibitory effect of coexisting ions on lithium atomization, competitively complexes coexisting interfering ions, reduces background absorption, and prevents the lithium signal from being masked, thereby improving the accuracy of the determination. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] In the picture: Figure 1 This is a standard curve of the concentration and absorbance of the lithium ion standard solution in Example 1; Figure 2 This is a graph showing the trend of lithium concentration in the leachate from Bacillus mucilage bioleaching in Example 1 over 20 days. Detailed Implementation

[0019] To make the technical problem to be solved, the technical solution, and the beneficial effects of this invention clearer, the invention will now be described in detail with reference to the accompanying drawings. This drawing is a simplified schematic diagram, illustrating only the basic aspects of the invention, and therefore only shows the components relevant to the invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0020] This invention provides a method for determining lithium in lithium ore bioleaching solutions, comprising the following steps: S1: Lanthanum nitrate-strontium chloride composite matrix modifier was prepared. After sampling, the sample was centrifuged, filtered, and then the lanthanum nitrate-strontium chloride composite matrix modifier was added for determination. S1.1: Weigh analytical grade lanthanum nitrate (La(NO3)3·6H2O) and strontium chloride (SrCl2·6H2O), dissolve and dilute with 1% nitric acid solution to obtain a lanthanum and strontium single-element stock solution with a concentration of 1000 μg / mL. Mix the single-element stock solution with lanthanum:strontium = 1:2 and dilute it with 1% nitric acid solution to a composite matrix modifier concentration of 50 μg / mL. Prepare and use immediately.

[0021] Preparation of lanthanum single-element stock solution: First, add 20 mL of 1% nitric acid solution to a 50 mL beaker. Accurately weigh 0.3117 g of lanthanum nitrate using an analytical balance and slowly add it to the beaker. Stir with a glass rod until completely dissolved (if dissolution is slow, gently heat to 30-40℃). After complete dissolution, transfer the solution along the glass rod to a 100 mL volumetric flask. Wash the beaker and glass rod several times with a small amount of 1% nitric acid solution. Pour all the washings into the volumetric flask. Finally, dilute to the mark with 1% nitric acid solution and mix well 10-15 times to obtain a lanthanum element stock solution with a concentration of 1000 μg / mL.

[0022] To prepare a strontium single-element stock solution, add approximately 20 mL of ultrapure water to a 50 mL beaker, accurately weigh 0.3043 g of strontium chloride and add it to the beaker. Stir until completely dissolved, transfer the solution to a 100 mL volumetric flask, wash the beaker and glass rod, and then dilute to the mark with ultrapure water. Mix and shake well to obtain a strontium single-element stock solution with a concentration of 1000 μg / mL.

[0023] Preparation of Lanthanum Nitrate-Strontium Chloride Composite Matrix Modifier: The total concentration of the target composite working solution is 50 μg / mL (lanthanum:strontium = 1:2). Using a 10 mL pipette, accurately transfer 1.67 mL of 1000 μg / mL lanthanum stock solution and 3.33 mL of 1000 μg / mL strontium stock solution, respectively. Add both to a 100 mL volumetric flask, add 1% nitric acid solution to the volumetric flask, and mix thoroughly to obtain the Lanthanum Nitrate-Strontium Chloride Composite Matrix Modifier.

[0024] Specifically, the blank sample and lithium standard solution must be consistent with the sample to be tested, that is, the composite matrix modifier is added to the blank sample and lithium standard solution at the same volume ratio (sample:modifier = 10:1).

[0025] S1.2: Take a sample from the leaching solution of the lithium ore bioleaching system, centrifuge to remove solid impurities, then filter it using a 0.22μm filter membrane, and dilute the sample 10 times to adapt to the detection specifications of the flame atomic absorption spectrophotometer.

[0026] S1.3: Take the lithium ore bioleaching solution sample to be tested after centrifugation and filtration, and shake it in a centrifuge tube for 30 seconds at a fixed volume ratio (sample:modifier = 10:1) to ensure that the modifier and interfering ions (Fe) in the sample are neutralized. 3+ Al 3+ (etc.) fully complexed, let stand for 5 minutes and then measure.

[0027] S2: Preparation of lithium standard solution; Lithium standard solutions with concentrations of 0, 0.5, 1, 2 and 5 mg / L were prepared. The lithium standard solution concentration used was 1 mg / mL. 0, 0.05, 0.1, 0.2 and 0.5 mL of lithium standard solution were respectively transferred by pipette and diluted to 100 mL in volumetric flasks to obtain lithium standard solutions with concentrations of 0, 0.5, 1, 2 and 5 mg / L.

[0028] S3: Set up the spectrophotometer; S3.1: The flame atomic absorption spectrophotometer is model NovAA800F. Select the hollow cathode lamp light source for lithium determination, install it on the instrument, and add the lithium element determination method in the method interface. S3.2: The characteristic absorption wavelength of lithium is selected as 670.8 nm; S3.3: The burner head is 100, and the instrument provides the maximum gas flow rate according to the set standard flow rate; Select the flow injection switch for sample transfer and disable the cleaning function. The flow injector precisely controls the flow rate into the instrument, ensuring a stable flow rate of sample into the flame zone via the sprayer, reducing measurement deviations caused by too much or too little sample. Disabling the cleaning function ensures that no cleaning operation is performed during sample transfer, saving time and reducing sample loss. Since the measurements are performed on lithium-containing solutions of varying concentrations, there is no possibility of cross-contamination between different samples.

[0029] S3.4: On the standard calibration page, set the calibration zero point and the standard calibration concentration. Set the calibration zero point to 1 ppm and the standard calibration to 5 ppm.

[0030] The zero point is set to 1 ppm, meaning that when the instrument is measuring a blank solution, the reference value is set to 1 ppm. This prevents the instrument from misinterpreting any signal as the absorbance signal of the sample, thus avoiding any signal interference and ensuring that the signal can be accurately corrected during the measurement process, resulting in more accurate measurement results. The standard calibration concentration is a standard solution concentration used to establish the relationship between concentration and absorbance. By measuring the absorbance of standard solutions at different concentrations, a corresponding standard curve can be plotted, and the lithium content in the sample can then be calculated. Setting the standard calibration concentration to 5 ppm ensures that the instrument operates within a relatively stable concentration range, as the instrument's linear response typically requires a certain concentration range to ensure its stability and accuracy. Simultaneously, the set standard calibration concentration also prevents excessively low concentrations from resulting in a weak signal or excessively high concentrations from causing absorbance saturation, thus ensuring the accuracy and reliability of the calibration results.

[0031] S4: Determine the lithium concentration in the sample; S4.1: Prepare the prepared lithium standard solution, the treated bioleaching sample, deionized water, and 1% nitric acid solution for cleaning; S4.2: Open the fume hood, open the main valve of the acetylene cylinder. The cylinder valve opens counterclockwise and closes clockwise. The partial pressure of acetylene is 0.1MPa, and the main pressure is greater than 0.4MPa. Turn on the air compressor, turn on the computer power, start the computer, turn on the instrument power, double-click the computer instrument icon to enter the start menu interface of the application software, and first click System Check to enter the instrument initialization process. S4.3: Load the existing method, click on the method, click on the bottom left corner to open, and select the established lithium measurement method; S4.4: Spectrometer. Click on Spectrometer, select Load Lithium in Data Source, and under the Energy menu, first click Adjust under Lamp Adjustment to automatically adjust the lamp position (align the optical path), then click Automatic Gain Control to close and exit Spectrometer. S4.5: Establish the analysis sequence. In the analysis sequence menu, set the analysis sequence, click Add, click Calibration to draw the standard curve, click Accept, click Special Action, select Display Standard Curve, which will automatically pop up the standard curve after the standard solution is measured, click Accept, click Sample to set the sample quantity; S4.6: Ignition. Click the flame to enter the interface. Place the long cleaning tube above the liquid level in the cleaning bottle. The cleaning bottle contains 1% nitric acid solution. First, click to test the air and test the fuel gas. Observe whether the air and acetylene gas are normal. If both are normal, you can ignite. After ignition, you must immediately insert the long cleaning tube below the liquid level in the cleaning bottle. S4.7: Run the analysis sequence. Click the run icon in the analysis interface to start running the analysis sequence, perform standard curve and sample determination, and determine the lithium standard solution according to the concentration gradient from low to high. The standard curve will automatically pop up after the determination is completed. The accuracy of the standard solution can be judged by the R2 value of the standard curve. When R... 2 A value ≥0.99 is sufficient for sample determination. 2 A higher value indicates a more linear standard curve and more accurate and reliable detection of lithium concentration in the sample. For the determination of the leachate sample, simply follow the on-screen instructions.

[0032] Example 1: 1. Lanthanum nitrate-strontium chloride composite matrix modifier was prepared. After sampling, the sample was centrifuged, filtered, and then the lanthanum nitrate-strontium chloride composite matrix modifier was added for determination. The concentration ratio of lanthanum nitrate to strontium chloride in the lanthanum nitrate-strontium chloride composite matrix modifier is 1:2, and the lanthanum nitrate-strontium chloride composite matrix modifier is added according to the sample:modifier = 10:1.

[0033] The sample is a bioleaching solution from the process of Bacillus mucilaginosus leaching lepidolite. The components of the silicate leaching medium include: 5.0 g / L sucrose, Na... 2 HPO 4 2.0 g / L, MgSO 4 ·7H 2 The concentrations were 0.5 g / L O, 0.005 g / L FeCl3, 0.1 g / L CaCO3, and pH 7.0 - 7.5. Samples were taken every 2 days and centrifuged and filtered.

[0034] 2. Construct a standard curve and measure the samples: Using lithium standard solutions of different concentration gradients (0, 0.5, 1, 2, and 5 mg / L), measurements were sequentially performed using a flame atomic absorption spectrophotometer to generate a standard curve between lithium concentration and absorbance. Then, the samples were measured sequentially according to the on-screen instructions. Figure 2 As shown.

[0035] The data show that the concentration range is consistent with the expected range. This example demonstrates, through repeated measurements, that the method has good repeatability and stability, and is suitable for the quantitative analysis of lithium content in lithium ore bioleaching solutions.

[0036] The beneficial effects of the method for determining lithium in lithium ore bioleaching solution of the present invention are as follows: This invention is particularly suitable for the analysis of bioleaching solutions from lithium ore and the efficient detection of lithium resources. By using a lanthanum nitrate-strontium chloride composite matrix modifier, it avoids the inhibitory effect of coexisting ions on lithium atomization. Through competitive complexation of coexisting interfering ions and reduction of background absorption, it prevents the lithium signal from being masked, thereby improving the accuracy of the determination. It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0037] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0038] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the scope of the present invention. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for determining lithium in a lithium ore bioleaching solution, characterized by, It comprises the following steps, S1: preparing lanthanum nitrate-strontium chloride composite matrix modifier, taking sample, centrifuging and filtering the sample, adding the lanthanum nitrate-strontium chloride composite matrix modifier, and determining; S2: preparing lithium standard solution; S3: setting up a flame atomic spectrophotometer; S4: obtaining a standard curve and determining the lithium concentration in the sample; The concentration ratio of lanthanum nitrate to strontium chloride in the lanthanum nitrate-strontium chloride composite matrix modifier is 1:2, and the lanthanum nitrate-strontium chloride composite matrix modifier is added according to the sample: modifier = 10:

1.

2. The method of claim 1, wherein the method is characterized by, The process of preparing the lanthanum nitrate-strontium chloride composite matrix modifier in step S1 specifically comprises taking strontium chloride to prepare a 1000 μg / mL single-element strontium stock solution in ultrapure water, taking strontium chloride to prepare a 1000 μg / mL single-element strontium stock solution in ultrapure water, mixing the two single-element strontium stock solutions in a volume ratio of 1:2, and adding 1% nitric acid solution to obtain the lanthanum nitrate-strontium chloride composite matrix modifier.

3. The method of claim 1, wherein the method is characterized by, The step S1 specifically comprises taking a sample from the leaching solution of the lithium ore bioleaching system, removing solid impurities by centrifugation, filtering with a 0.22 μm filter, and then diluting the sample by 10 times.

4. The method of claim 1, wherein the method is characterized by, The preparation method of the lithium standard solution in the step S2 is that the concentration of the lithium standard solution used is 1 mg / mL, 0, 0.05, 0.1, 0.2, and 0.5 mL of lithium standard solution are respectively taken with a pipette gun, and the volume is set to 100 mL in a volumetric flask to obtain lithium standard solutions with concentrations of 0, 0.5, 1, 2, and 5 mg / L.

5. The method of claim 1, wherein the method is characterized by, The step S3 specifically comprises, S3.1: selecting a hollow cathode lamp light source for determining lithium and installing it on the instrument and adding a lithium element determination method in the method interface; S3.2: selecting the characteristic absorption wavelength of lithium as 670.8 nm; S3.3: the combustion head is 100, and the instrument provides the maximum gas flow according to the set standard flow; S3.4: setting the correction zero point and the concentration of the standard correction on the standard correction page; The correction zero point in the S3.4 is set to 1 ppm, and the standard correction is set to 5 ppm.

6. The method of claim 1, wherein the method is characterized by, Deionized water and 1% nitric acid solution are used for cleaning during the determination of the lithium concentration in the step S4.

7. The method of claim 1, wherein the method is characterized by, The flame atomic absorption spectrophotometer in the step S4 is a NovAA800F.

8. The method of claim 1, wherein the method is characterized by, The step S4 specifically comprises, S4.1: preparing the sample, lithium standard solution, deionized water, and nitric acid solution. S4.2: opening the fume hood, opening the total valve of the acetylene gas cylinder, opening the air compressor, turning on the computer power supply, starting the computer, turning on the instrument power supply, double-clicking to open the computer instrument icon, entering the start menu interface of the application software, and first clicking the system check to enter the instrument initialization process; S4.3: loading the established method, clicking the method, clicking the lower left corner to open, and selecting the established lithium determination method; S4.5: establishing an analysis sequence, setting the analysis sequence in the analysis sequence menu, clicking add, clicking correction to draw a standard curve, clicking accept, clicking special action, selecting display standard curve, which will automatically pop up a standard curve graph after the standard solution is determined, clicking accept, and setting the number of samples. S4.6: Ignition, click the flame into the interface, take the long cleaning tube above the liquid surface of the cleaning bottle, the cleaning bottle is 1% nitric acid solution, first click to test air and test gas, observe whether the air and acetylene gas are normal, if both are normal, ignition can be performed, after ignition, the long cleaning tube must be inserted below the liquid surface of the cleaning bottle immediately; S4.7: Run the analysis sequence, click the run icon under the analysis interface to start running the analysis sequence, and determine the standard curve and the sample, and determine the lithium standard solution in the concentration gradient from low to high, and the standard curve will automatically pop up after the determination is completed.

9. A method for determining lithium in a lithium ore bioleaching solution according to claim 8, characterized by, In the step S4.2, the acetylene partial pressure is 0.1 MPa, and the main pressure is greater than 0.4 MPa.

10. The method of claim 8, wherein the method is characterized by, The standard curve in S4.5 improves R by multiple replicates 2 values.

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