Rare earth content determination method and system

Abstract

The invention discloses a method and a system for measuring the content of rare earth. The method comprises the following steps: S1, setting the injection amount of an injection pump, a solution ratio and automatic sampling time; and S2, within each sampling time, mixing the to-be-detected solution containing rare earth and a color developing reagent according to a preset proportion, injecting the mixture into a fiber optic spectrometer to measure the absorbance ABS at the wavelength of 572 nm, and converting the absorbance ABS into the concentration. By adopting the technical scheme provided by the invention, the total content of rare earth can be automatically and quickly detected.

Description

Technical Field

[0001] This invention belongs to the field of rare earth detection technology, and particularly relates to a method and system for determining rare earth content. Background Technology

[0002] Rare earth elements, as a core strategic resource for modern economic and technological development, are a key engine driving high-end manufacturing and green transformation. As essential raw materials for permanent magnets, battery materials, and precision devices, they support trillion-dollar industries such as new energy vehicles, wind power generation, and consumer electronics. Rare earth elements possess irreplaceable and unique properties in numerous fields: for example, neodymium iron boron permanent magnets are currently the strongest magnetic materials; lanthanum and cerium, as catalysts, can effectively improve petroleum cracking efficiency and automobile exhaust purification capabilities; furthermore, they play a central role in cutting-edge fields such as laser technology, high-temperature superconductivity, aerospace alloys, and quantum technology. For many years, China's rare earth metal industry has relied on its abundant resource reserves and relatively low production costs to continuously improve its preparation technology and product quality. Especially in recent years, with the surge in demand from downstream application markets, the industry has achieved rapid development and a rapid increase in output.

[0003] However, due to the high similarity in physicochemical properties among rare earth elements, their composition analysis has always been a technical challenge. Currently, rare earth detection technologies, based on differences in elemental characteristics and detection requirements, mainly include chemical analysis methods, inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray fluorescence spectrometry (XRF), and spectrophotometry. Chemical analysis methods quantify rare earth elements through chemical reactions, relying on standard solutions and indicators. The current national standard GB / T 14635-2020, "Chemical Analysis of Rare Earth Metals and Their Compounds," uses EDTA complexometric titration to determine the total rare earth content. ICP-OES has become the mainstream industrial detection technology due to its ability to simultaneously detect multiple elements, but its analysis speed and accuracy in determining the proportions of high-content major rare earth elements are insufficient to meet the stringent quality control requirements of the smelting process. XRF is suitable for rapid screening of solid samples, but its error is relatively large. Spectrophotometry utilizes the absorbance difference between rare earth ions and chromogenic reagents, with detection limits as low as 0.1 ppm; however, common spectrophotometric methods still require manual sampling, analysis, and data processing. In the rare earth industry's mining-smelting-processing industrial chain, the rare earth content needs to be tested at multiple stages, making the testing task extremely demanding. Therefore, there is an urgent need to develop rapid and automated analytical methods to solve this problem. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method and system for determining rare earth content.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for determining rare earth content, comprising:

[0007] Step S1: Set the injection volume of the syringe pump, the solution ratio, and the automatic sampling time;

[0008] Step S2: During each sampling period, the test solution containing rare earth elements is mixed with the colorimetric reagent in a preset ratio and injected into the fiber optic spectrometer to measure the absorbance ABS at a wavelength of 572 nm, and then converted into concentration.

[0009] As a preferred option, the colorimetric reagent is prepared as follows: In a 100mL volumetric flask, add 1-5 drops of 6M hydrochloric acid, 1-5mL of 10% sulfosalicylic acid, and 1-5mL of acetylacetone in sequence, then add 1-5 drops of xylenol orange indicator and 20% hexamethylenetetramine buffer solution, add water to 50mL, dilute to the mark with water, and shake well.

[0010] Preferably, the volume ratio of the test solution to the colorimetric reagent is 1:7 to 1:10.

[0011] Preferably, the automatic sampling interval is 5s-24h.

[0012] The present invention also provides a rare earth content determination system, comprising:

[0013] A high-precision micro-injection pump is used to set the injection volume, solution ratio, and automatic sampling time.

[0014] A low-noise miniature fiber optic spectrometer is used to mix a rare-earth-containing test solution with a colorimetric reagent in a preset ratio and inject the mixture into the fiber optic spectrometer to measure the absorbance (ABS) at a wavelength of 572 nm during each sampling time, and then convert the result into concentration.

[0015] As a preferred option, the colorimetric reagent is prepared as follows: In a 100mL volumetric flask, add 1-5 drops of 6M hydrochloric acid, 1-5mL of 10% sulfosalicylic acid, and 1-5mL of acetylacetone in sequence, then add 1-5 drops of xylenol orange indicator and 20% hexamethylenetetramine buffer solution, add water to 50mL, dilute to the mark with water, and shake well.

[0016] Preferably, the volume ratio of the test solution to the colorimetric reagent is 1:7 to 1:10.

[0017] Preferably, the automatic sampling interval is 5s-24h.

[0018] This invention enables automated and rapid detection of total rare earth content, solving the problem of rapid determination of rare earth content in actual production, improving work efficiency, and eliminating human error. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 This is a flowchart of the rare earth content determination method according to an embodiment of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Example 1:

[0024] like Figure 1 As shown, an embodiment of the present invention provides a method for determining rare earth content, comprising:

[0025] Step S1: Set the injection volume of the syringe pump, the solution ratio, and the automatic sampling time;

[0026] Step S2: During each sampling period, the test solution containing rare earth elements is mixed with the colorimetric reagent in a preset ratio and injected into a fiber optic spectrometer to measure the absorbance ABS at a wavelength of 572 nm (the maximum absorption wavelength after the reaction of rare earth ions with the colorimetric reagent is 572 nm), and then converted into concentration.

[0027] As one embodiment of the present invention, the colorimetric reagent is prepared as follows: In a 100mL volumetric flask, add 1-5 drops of 6M hydrochloric acid, 1-5mL of 10% sulfosalicylic acid, and 1-5mL of acetylacetone in sequence, add 1-5 drops of xylenol orange indicator and 20% hexamethylenetetramine buffer solution, add water to 50mL, dilute to the mark with water, and shake well.

[0028] As one embodiment of the present invention, the volume ratio of the test solution to the colorimetric reagent is 7 to 1:10.

[0029] As one embodiment of the present invention, the automatic sampling interval is 5s-24h.

[0030] Example 1: Plotting a standard curve

[0031] The total rare earth content of a rare earth solution was determined using the EDTA complexometric titration method according to GB / T 14635-2020. Standard solutions with total rare earth concentrations of 0.200, 0.400, 0.800, 1.600, 2.400, 3.600, 4.800, and 6.400 μg / mL were obtained through dilution. Sampling tubes were simultaneously inserted into the rare earth solution to be tested and deionized water. The automatic sampling time of the syringe pump was set to 5 min. First, 0.5 mL of the 0.200 μg / mL rare earth test solution and 4.5 mL of colorimetric reagent were mixed and injected into the fiber optic spectrometer. The absorbance (ABS) at 572 nm was measured. The tubing was then rinsed with deionized water, and the same procedure was performed on the rare earth test solutions of other concentrations. A standard curve was obtained, with concentration on the x-axis and ABS on the y-axis. The R-squared value of the standard curve was... 2 The value is 0.9971, indicating a good linear relationship between ABS and concentration, which meets the requirements for analytical detection.

[0032] Example 2: Real-time detection of rare earth content in rare earth extraction wastewater

[0033] The automatic sampling time of the syringe pump was set to 30 minutes. 0.5 mL of rare earth extraction wastewater from a specific process was automatically aspirated and mixed with 4.5 mL of colorimetric reagent, then injected into the fiber optic spectrometer. The absorbance (ABS) at 572 nm was measured. The ABS concentration was directly calculated from the standard curve using software and found to be 0.250 μg / mL. The total rare earth content was determined to be 0.248 μg / mL by ICP-OES. The relative error between the two measurements was 0.8%, which is relatively small, indicating reliable data.

[0034] Example 3: A rare earth solution with a total rare earth content of 182.6 μg / mL, determined by EDTA complexometric titration according to GB / T 14635-2020, was further analyzed by a spectrometer.

[0035] The automatic sampling time of the syringe pump was set to 2 minutes. 0.2 mL of rare earth solution was mixed with 1.8 mL of colorimetric reagent and injected into the fiber optic spectrometer. The absorbance of ABS at 572 nm was measured. The concentration of ABS was directly calculated from the standard curve using software, and was determined to be 182.9 μg / mL. The relative error between the two calculations was 0.2%, which is small, indicating relatively reliable data.

[0036] Example 2:

[0037] This invention also provides a rare earth content determination system, comprising:

[0038] A high-precision micro-injection pump is used to set the injection volume, solution ratio, and automatic sampling time.

[0039] A low-noise miniature fiber optic spectrometer is used to mix a rare-earth-containing test solution with a colorimetric reagent in a preset ratio and inject the mixture into the fiber optic spectrometer to measure the absorbance (ABS) at a wavelength of 572 nm during each sampling time, and then convert the result into concentration.

[0040] Furthermore, the high-precision micro-injection pump has the following characteristics: volume accuracy error ≤1%, volume precision repeatability error 0.3%-0.5%, injector 10mL, and linear velocity 0.005-30mm / s.

[0041] Low-noise miniature fiber optic spectrometer: includes fiber optic cable and attenuator. Spectral range 200-1100nm, spectral resolution 0.01-4nm, CMOS detector, signal-to-noise ratio >2000:1.

[0042] As one embodiment of the present invention, the colorimetric reagent is prepared as follows: In a 100mL volumetric flask, add 1-5 drops of 6M hydrochloric acid, 1-5mL of 10% sulfosalicylic acid, and 1-5mL of acetylacetone in sequence, add 1-5 drops of xylenol orange indicator and 20% hexamethylenetetramine buffer solution, add water to 50mL, dilute to the mark with water, and shake well.

[0043] As one embodiment of the present invention, the volume ratio of the test solution to the colorimetric reagent is 1:7 to 1:10.

[0044] As one embodiment of the present invention, the automatic sampling interval is 5s-24h.

[0045] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for determining rare earth content, characterized in that, include: Step S1: Set the injection volume of the syringe pump, the solution ratio, and the automatic sampling time; Step S2: During each sampling period, the test solution containing rare earth elements is mixed with the colorimetric reagent in a preset ratio and injected into the fiber optic spectrometer to measure the absorbance ABS at a wavelength of 572 nm, and then converted into concentration.

2. The method for determining rare earth content as described in claim 1, characterized in that, The colorimetric reagent is prepared as follows: In a 100mL volumetric flask, add 1-5 drops of 6M hydrochloric acid, 1-5mL of 10% sulfosalicylic acid, and 1-5mL of acetylacetone in sequence. Add 1-5 drops of xylenol orange indicator and 20% hexamethylenetetramine buffer solution. Add water to 50mL and dilute to the mark with water. Shake well.

3. The method for determining rare earth content as described in claim 2, characterized in that, The volume ratio of the test solution to the colorimetric reagent is 1:7 to 1:

10.

4. The method for determining rare earth content as described in claim 3, characterized in that, The automatic sampling interval is 5 seconds to 24 hours.

5. A rare earth content determination system, characterized in that, include: A high-precision micro-injection pump is used to set the injection volume, solution ratio, and automatic sampling time. A low-noise miniature fiber optic spectrometer is used to mix a rare-earth-containing test solution with a colorimetric reagent in a preset ratio and inject the mixture into the fiber optic spectrometer to measure the absorbance (ABS) at a wavelength of 572 nm during each sampling time, and then convert the result into concentration.

6. The rare earth content determination system as described in claim 5, characterized in that, The colorimetric reagent is prepared as follows: In a 100mL volumetric flask, add 1-5 drops of 6M hydrochloric acid, 1-5mL of 10% sulfosalicylic acid, and 1-5mL of acetylacetone in sequence. Add 1-5 drops of xylenol orange indicator and 20% hexamethylenetetramine buffer solution. Add water to 50mL and dilute to the mark with water. Shake well.

7. The rare earth content determination system as described in claim 6, characterized in that, The volume ratio of the test solution to the colorimetric reagent is 1:7 to 1:

10.

8. The rare earth content determination system as described in claim 7, characterized in that, The automatic sampling interval is 5 seconds to 24 hours.

Images