A high efficiency pretreatment method for detecting elements in organic phase of extraction system

Abstract

The application discloses a kind of efficient pretreatment methods for detecting element in extraction system organic phase, it includes the following steps: pipette appropriate amount of measured organic phase to volumetric flask, add appropriate amount of back extraction acid, then add water to 1 / 3-2 / 3 of volumetric flask volume, cover bottle plug; Shake the back extraction of volumetric flask, and stand and separate, then use filter paper to draw and remove upper organic phase, after removing upper organic phase, the remaining aqueous phase is filtered using filter paper and the primary filtrate is discarded, and the filtrate is the sample to be detected, for element analysis detection.The method simplifies the operation process, is simple to operate, high in detection efficiency, and is not easy to contaminate;The organic phase volume used in the pretreatment operation of the method is small, compared with the existing back extraction method of separatory funnel, the amount of organic phase used is one tenth of the back extraction method of separatory funnel, or even less, reducing the waste of organic phase, at the same time, the amount of back extraction acid is reduced, and the amount and consumption of reagent are greatly reduced.

Description

Technical fields:

[0001] This invention relates to the field of detection technology, and in particular to an efficient pretreatment method for detecting elements in the organic phase of an extraction system. Background technology:

[0002] Solvent extraction utilizes the difference in partition coefficients between two immiscible (or slightly soluble) solvents to transfer elements (or compounds) from one solvent to the other. Through repeated extractions, the elements are separated or enriched. Solvent extraction is a very important and commonly used method in hydrometallurgy, offering advantages such as continuous operation, short production cycles, high enrichment efficiency, and high separation efficiency. It is widely used in the separation and purification of metallic elements, and the extraction and purification of rare and precious metals.

[0003] When using solvent extraction for elemental separation or enrichment, the extraction system consists of multiple stages including extraction, washing, and back-extraction. Due to differences in the extraction capabilities of different elements and varying separation factors between them, different extraction systems require different numbers of extraction stages. Furthermore, the complexity and variability of the raw material composition necessitate periodic concentration measurements of various elements in the aqueous and organic phases at different stages during production. For element detection in the aqueous phase, the solution can be directly transferred and appropriately diluted for determination. However, for element detection in the organic phase, back-extraction is required, followed by determining the dilution factor based on the concentration and back-extraction ratio, and then bringing the volume to a specific level for analysis.

[0004] Currently, the pretreatment of organic phases for elemental analysis generally uses a separatory funnel for back-extraction. A small amount of organic phase is taken into the separatory funnel based on the content of each element, and then back-extraction is performed using the concentration and volume of the back-extraction acid selected according to the back-extraction conditions. To ensure the efficiency of back-extraction, multiple back-extractions are performed. The organic entrainment is then washed away, and the back-extraction solution and washing solution are combined and diluted to volume. The dilution factor is calculated, and the solution is diluted and analyzed. This method is lengthy, cumbersome, complex, prone to contamination, and consumes a large amount of reagents. The pretreatment process requires a certain amount of time and is susceptible to leakage, incomplete phase separation, and other factors that can lead to a decrease in accuracy and precision. Summary of the Invention:

[0005] The purpose of this invention is to provide a pretreatment method for detecting elements in the organic phase of an extraction system that is simple to operate, has a short processing flow, and high detection efficiency, accuracy, and precision.

[0006] This invention is implemented by the following technical solution: an efficient pretreatment method for detecting elements in the organic phase of an extraction system, comprising the following steps:

[0007] (1) Micropipette: Using a micropipette / pipette, transfer an appropriate amount of the organic phase to be tested into a volumetric flask, add an appropriate amount of back-extraction acid, and then add water to 1 / 3-2 / 3 of the volume of the volumetric flask and stopper it.

[0008] (2) Mixed back extraction: After sealing the bottle, shake the volumetric flask. The element to be measured is back-extracted into the aqueous phase. The back extraction time is 5-10 min. The back extraction time is obtained based on experimental experience for different systems and different elements.

[0009] (3) Volume adjustment: After back extraction, the solution is adjusted to the mark of the volumetric flask with pure water, then shaken and allowed to stand for phase separation. Then, pure water is added to adjust the volume to the mark of the volumetric flask and shaken.

[0010] (4) Remove organic phase: After the aqueous phase is brought to a certain volume, let it stand for 10-15 minutes to separate the phases. Then use filter paper to remove the upper organic phase. After removing the upper organic phase, filter the remaining aqueous phase with filter paper and discard the initial filtrate. The filtrate is the sample to be tested.

[0011] (5) Analysis and detection: Take the sample to be tested obtained in step (4) for elemental analysis and detection.

[0012] Furthermore, in step (1), the volume of the organic phase to be tested transferred is 10-1000 μL. The dilution factor is calculated based on the approximate concentration of the analyte in the organic phase and the sensitivity of the detection instrument to determine the volume of the organic phase transferred; preferably, the volume of the organic phase to be tested transferred is 10-500 μL. Compared with the existing separatory funnel back-extraction method, the amount of organic phase used is one-tenth, or even less, of that used in the separatory funnel back-extraction method, reducing the waste of organic phase.

[0013] Furthermore, in step (1), the volumetric flask has a volume of 50-1000 mL.

[0014] Furthermore, if the aqueous phase remains emulsified and turbid after the removal of the organic phase, step (4) further promotes phase separation by using an oscillator or ultrasonic cleaner before allowing the phases to stand.

[0015] Furthermore, the detection method in step (5) shall be implemented in accordance with the corresponding professional field detection standards or enterprise standards, such as: using inductively coupled plasma atomic emission spectrometry, atomic absorption spectrometry or spectrophotometry.

[0016] Furthermore, the back-extraction acid is hydrochloric acid, nitric acid, or sulfuric acid.

[0017] Furthermore, the back-extraction acid is hydrochloric acid or nitric acid. Since other elements are present in the system during instrument detection, hydrochloric acid or nitric acid does not readily form precipitates with these elements.

[0018] Furthermore, the amount of back-extraction acid added in step (1) is 2-50 mL. The amount of back-extraction acid added is determined in conjunction with the back-extraction conditions of the element to be measured and the acidity requirements of the instrument during measurement.

[0019] Furthermore, the amount of back-extraction acid added in step (1) is 5-25 mL.

[0020] Furthermore, the element to be measured is an easily back-extractable element, such as rare earth, nickel, cobalt, manganese, copper, magnesium, calcium, etc. extracted by the P507 or P204 system, titanium extracted by the primary amine system, boron extracted by the primary alcohol system, lithium extracted by the ketone system, etc.

[0021] Advantages of this invention:

[0022] (1) The method of the present invention simplifies the operation process, is simple to operate, has high detection efficiency, and is not easily contaminated: The method of the present invention only needs to perform one back-extraction operation to ensure the efficiency of back-extraction, and the amount of organic entrainment is very small, which has little impact on the detection accuracy. Therefore, it is not necessary to wash the organic phase after back-extraction to remove the organic entrainment, thus simplifying the operation process. At the same time, the method of the present invention realizes the back-extraction and dilution operations in one container, that is, the back-extraction and dilution steps are combined and completed in one step, further simplifying the operation process.

[0023] (2) The organic phase used in the pretreatment operation of the present invention is smaller in volume. Compared with the existing separatory funnel back-extraction method, the amount of organic phase used is one-tenth or even less than that of the separatory funnel back-extraction method, which reduces the waste of organic phase. At the same time, the amount of back-extraction acid used is reduced, and the amount and consumption of reagents are greatly reduced.

[0024] (3) The method of the present invention solves the problems of leakage and incomplete phase separation that exist in the pretreatment operation using the separatory funnel method, and improves the accuracy and precision of detection. Detailed implementation method:

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1: Determination of lithium concentration at different grades in lithium salt extraction line from old salt lake brine.

[0027] Take 50 mL of each of the loaded organic phases from different grades (grades 1-15) of the salt lake brine extraction production line, transfer 100 μL of each to 15 corresponding 100 mL volumetric flasks, add 10 mL of 6 mol / L hydrochloric acid to each volumetric flask, then add about 50 mL of pure water, stopper the flasks, mix and shake the volumetric flasks for back-extraction, the back-extraction time is 5-10 min, in this example the back-extraction time is 7 min, dilute with pure water to the mark of the volumetric flask, and shake well.

[0028] Let the phases separate for 10-15 minutes. In this embodiment, the standing time is 6 minutes. After the phases separate, dilute with pure water to the mark on the volumetric flask and shake well.

[0029] The phases were allowed to stand for 10-15 minutes. In this embodiment, the standing time was 10 minutes. Then, the upper organic phase was removed by using filter paper. The remaining aqueous phase after removing the upper organic phase was filtered with filter paper and the initial filtrate was discarded. The filtrate was the sample to be tested.

[0030] The lithium concentration in the sample was detected using an atomic absorption spectrometer, and then the lithium concentration in the organic phase was calculated based on the dilution factor.

[0031] Place 50 mL of the loaded organic phase in a 200 mL separatory funnel, and back-extract the organic phase three times using 50 mL of 6 mol / L hydrochloric acid. Combine the back-extracts into a 100 mL volumetric flask and make up to volume. Then, dilute the solution 500 times for detection.

[0032] The comparison of detection data from the two methods is shown in Table 1:

[0033] Table 1: Test Results of Example 1

[0034]

[0035]

[0036] The extraction line is divided into an extraction section, a back-extraction section, and a washing section. Extraction is completed in the extraction section, and the concentration of lithium in the loaded organic phase increases continuously within a certain number of stages. Then, the concentration decreases continuously in the back-extraction section and the washing section, until a low-concentration organic phase or a blank organic phase is obtained.

[0037] By comparing the detection results of the two methods, the organic phase volume used in the pretreatment operation of the present invention is smaller. Compared with the existing separatory funnel back-extraction method, the amount of organic phase used is one-five-hundredth of that used in the separatory funnel back-extraction method, which reduces the waste of organic phase. At the same time, the amount of back-extraction acid used is reduced accordingly, and the amount and consumption of reagents are greatly reduced.

[0038] Meanwhile, the results from the two methods show minimal deviation, which is sufficient to meet the daily production quality control requirements of the workshop.

[0039] Example 2: Determination of cobalt and nickel concentrations at different grades using a cobalt-nickel extraction separation line.

[0040] Take 50 mL of the loaded organic phase from each stage (stages 1-15) of the cobalt-nickel separation extraction line, and transfer 50 μL of each phase into 15 100 mL volumetric flasks. Add 10 mL of 8 mol / L sulfuric acid to each volumetric flask, then add about 50 mL of pure water, stopper the flasks, mix and shake to perform back-extraction. The back-extraction time is 5-10 min. In this example, the back-extraction time is 6 min. Dilute to the mark with pure water and shake well.

[0041] Let the phases separate for 10-15 minutes. In this embodiment, the standing time is 10 minutes. After the phases separate, dilute with pure water to the mark of the volumetric flask and shake well.

[0042] After adjusting the volumetric volume, the flask was placed in an ultrasonic cleaner with an ultrasonic frequency of 42kHz and sonicated for 5 minutes. It was then allowed to stand for 10-15 minutes for phase separation. In this embodiment, it was allowed to stand for 10 minutes for phase separation. Then, the upper organic phase was removed by using filter paper. The remaining aqueous phase after removing the upper organic phase was filtered with filter paper and the initial filtrate was discarded. The filtrate was the sample to be tested.

[0043] The concentrations of cobalt and nickel in the sample were detected using atomic absorption spectrometry, and then the concentrations of cobalt and nickel in the organic phase were calculated based on the amount transferred and the dilution factor.

[0044] Place 50 mL of the loaded organic phase in a 200 mL separatory funnel, and back-extract the organic phase three times using 50 mL of 8 mol / L sulfuric acid. Combine the back-extracts into a 100 mL volumetric flask and make up to volume. Then, continue to dilute 1000 times for detection.

[0045] The comparison of detection data from the two methods is shown in Table 2:

[0046] Table 2: Test Results of Example 2

[0047]

[0048]

[0049] During cobalt-nickel separation, the extractant has a greater extraction capacity for cobalt than for nickel, so cobalt is the reverse liquid product and nickel is the residual liquid product.

[0050] By comparing the detection results of the two methods, the organic phase volume used in the pretreatment operation of the present invention is smaller. Compared with the existing separatory funnel back-extraction method, the amount of organic phase used is one-thousandth of that used in the separatory funnel back-extraction method, which reduces the waste of organic phase. At the same time, the amount of back-extraction acid used is reduced accordingly, and the amount and consumption of reagents are greatly reduced.

[0051] Meanwhile, the results from the two methods show minimal deviation, which is sufficient to meet the daily production quality control requirements of the workshop.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A highly efficient pretreatment method for detecting elements in the organic phase of an extraction system, characterized in that, It includes the following steps: (1) micropipette; (2) mixed back-extraction; (3) volume adjustment; (4) removal of organic phase; (5) analysis and detection; wherein, (1) Micropipette: Transfer an appropriate amount of the organic phase to be tested into a volumetric flask, add an appropriate amount of back-extraction acid, and then add water to 1 / 3-2 / 3 of the volume of the volumetric flask and stopper it. (2) Mixed back extraction: After sealing the bottle, shake the volumetric flask. The element to be measured is back-extracted into the aqueous phase. The back extraction time is 5-10 min. (3) Volume adjustment: After back extraction, the solution is adjusted to the mark of the volumetric flask with pure water, then shaken and allowed to stand for phase separation. Then, pure water is added to adjust the volume to the mark of the volumetric flask and shaken. (4) Remove organic phase: After the aqueous phase is brought to a certain volume, let it stand for 10-15 minutes to separate the phases. Then use filter paper to remove the upper organic phase. After removing the upper organic phase, filter the remaining aqueous phase with filter paper and discard the initial filtrate. The filtrate is the sample to be tested. (5) Analysis and detection: Take the sample to be tested obtained in step (4) for elemental analysis and detection.

2. The efficient pretreatment method for detecting elements in the organic phase of an extraction system according to claim 1, characterized in that, In step (1), the volume of the organic phase to be tested is 10-1000 μL.

3. The efficient pretreatment method for detecting elements in the organic phase of an extraction system according to claim 1, characterized in that, In step (1), the volumetric flask has a volume of 50-1000 mL.

4. The efficient pretreatment method for detecting elements in the organic phase of an extraction system according to claim 1, characterized in that, Step (4) further promotes phase separation by using an oscillator or ultrasonic cleaner before allowing the phases to stand.

5. The efficient pretreatment method for detecting elements in the organic phase of an extraction system according to claim 1, characterized in that, The testing method in step (5) shall be implemented in accordance with the relevant professional field testing standards or enterprise standards.

6. The efficient pretreatment method for detecting elements in the organic phase of an extraction system according to claim 1, characterized in that, The back-extraction acid is hydrochloric acid, nitric acid, or sulfuric acid.

7. The efficient pretreatment method for detecting elements in the organic phase of an extraction system according to claim 6, characterized in that, The back-extraction acid is hydrochloric acid or nitric acid.

8. The efficient pretreatment method for detecting elements in the organic phase of an extraction system according to claim 1, characterized in that, The amount of back-extraction acid added in step (1) is 2-50 mL.

9. The efficient pretreatment method for detecting elements in the organic phase of an extraction system according to claim 8, characterized in that, The amount of back-extraction acid added in step (1) is 5-25 mL.

10. The efficient pretreatment method for detecting elements in the organic phase of an extraction system according to claim 1, characterized in that, The element to be tested is an easily stripped element; the easily stripped element is rare earth, nickel, cobalt, manganese, copper, magnesium, calcium, titanium, boron or lithium.

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