Precise analysis method for rare earth phase in bottom slag of zinc-aluminum-magnesium production line based on phase structure

Abstract

The invention relates to a phase structure-based accurate analysis method for a rare earth phase in bottom slag of a zinc-aluminum-magnesium production line, which comprises the following steps of: sampling, roughly grinding, finely grinding, polishing and corroding, putting a polished sample into a corrosive agent for corroding for 1-2 seconds, then washing with alcohol, and blow-drying; then observing by a scanning electron microscope and determining components of phases by an energy disperse spectroscopy; a corrosive agent used for corrosion is prepared from an HF aqueous solution with the mass concentration of 0.01-0.05%, a nitric acid alcohol solution with the mass concentration of 0.1-0.5% and 1-3 ml of a picric acid aqueous solution saturated at room temperature. According to the method, the phase structure, morphology, size and distribution of the rare earth phase in the bottom slag can be displayed and observed simply and rapidly at low cost, components of the rare earth phase in the bottom slag and the atomic ratio of all elements can be accurately determined through the energy disperse spectroscopy, and the method has the advantages of being low in detection cost, rapid, simple and accurate.

Description

Technical Field

[0001] The present invention belongs to the technical field of metallographic analysis and detection, and particularly relates to an accurate analysis method for rare earth phases in the bottom slag of a zinc-aluminum-magnesium production line based on phase structure. Background Art

[0002] Bottom slag is generated during the production of zinc-aluminum-magnesium. The bottom slag contains certain amounts of valuable metals such as rare earths, zinc, aluminum, and magnesium. Rare earth elements have important economic value. Detecting the content of rare earth elements in the bottom slag helps to evaluate the recycling value of rare earth elements in the bottom slag, provides a basis for the recycling and utilization of resources, realizes the circular utilization of resources, and improves economic benefits. Abnormal changes in the content of rare earth elements in the bottom slag can reflect quality problems or equipment failures during the production process. By detecting rare earth elements in the bottom slag, problems can be discovered in a timely manner and corresponding measures can be taken to solve them, ensuring the stability of product quality.

[0003] However, the amount of rare earth elements in the bottom slag is very small and unevenly distributed. Through current conventional chemical analysis methods and direct detection using a scanning electron microscope combined with an energy spectrometer, the rare earth elements in the bottom slag cannot be detected. Due to the uneven distribution and small content of rare earth elements in the bottom slag, when using chemical analysis methods, rare earth elements do not dissolve into the solution or are interfered by similar elements, resulting in the inability to detect rare earth elements in the bottom slag by chemical methods. Similarly, when using the direct energy spectrometry method, since energy spectrometry analysis is a micro-area analysis and the distribution of rare earth elements is uneven, the direct energy spectrometry method often cannot detect rare earth elements in the bottom slag. Therefore, there is an urgent need to create a new detection method that can clearly display the phase structure, morphology, size, and distribution of rare earth phases in the bottom slag, and can accurately determine the composition of rare earth phases in the bottom slag and the atomic ratio of each element through an energy spectrometer, with the characteristics of low detection cost, fast speed, simplicity, and accuracy. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an accurate analysis method for rare earth phases in the bottom slag of a zinc-aluminum-magnesium production line based on phase structure. This method can clearly display the phase structure, morphology, size, and distribution of rare earth phases in the bottom slag, and can accurately determine the composition of rare earth phases in the bottom slag and the atomic ratio of each element through an energy spectrometer, with the characteristics of low detection cost, fast speed, simplicity, and accuracy.

[0005] To solve the above technical problem, the technical solution adopted by the present invention is: An accurate analysis method for rare earth phases in the bottom slag of a zinc-aluminum-magnesium production line based on phase structure, including sampling, rough grinding, fine grinding, polishing, and etching. The polished specimen is placed in an etching agent for etching, and the etching time is 1 - 2 seconds, and then it is rinsed clean with alcohol and dried; Then, observe with a scanning electron microscope and determine the composition of the phase with an energy spectrometer; The etchant used for etching is prepared from an HF aqueous solution with a mass concentration of 0.01 - 0.05%, a nitric acid alcohol solution with a mass concentration of 0.1 - 0.5%, and 1 - 3 ml of a saturated picric acid aqueous solution at room temperature.

[0006] Further, the volume ratio of the HF aqueous solution with a mass concentration of 0.01 - 0.05%, the nitric acid alcohol solution with a mass concentration of 0.1 - 0.5%, and the saturated picric acid aqueous solution is 10 - 20:10 - 20:1 - 3.

[0007] Further, the specific operations of sampling and rough grinding in the present invention are as follows: 1) Sampling: Take the bottom slag on the zinc - aluminum - magnesium production line, cut a sample with a metallographic cutting machine, and the size is 8 - 15 mm × 8 - 15 mm; Place the cut sample face - down, hot - inlay for 5 minutes, and after taking it out, grind it flat with a grinding machine.

[0008] Further, the specific operation of fine grinding is as follows: Hold the roughly ground sample, gently press the sample with a force of 10 - 15 N, use 600# sandpaper on a fully automatic grinding and polishing machine, at a speed of 900 - 1400 revolutions per minute, grind for 10 - 50 seconds until the scratches from rough grinding disappear.

[0009] Further, the specific operation of polishing is as follows: Hold the finely ground sample, gently press the sample with a force of 10 - 15 N, spray a polishing agent of 0.5 - 2.5 microns on a 250 - mm twill cloth polishing cloth, polish at a rotation speed of 900 - 1400 revolutions per minute, sprinkle water while polishing, and polish for 1 - 2 minutes until the surface is bright and free of scratches.

[0010] Further, the polishing agent is a polycrystalline diamond spray grinding and polishing agent. Shake it well before use, and spray twice every 5 - 20 seconds during polishing.

[0011] Further, for observing with a scanning electron microscope and determining the composition of the phase by an energy spectrometer, place the prepared sample under the scanning electron microscope for observation. The electron microscope voltage is 15 - 20 KV, the dead time of the energy spectrometer is set to 20% - 30%, and the counting rate is 1000 - 5000 CPS.

[0012] The method provided by the present invention can clearly display the phase structure, morphology, size, and distribution of rare - earth phases in the bottom slag after grinding, polishing, etching, and under a scanning electron microscope. The composition of the rare - earth phases in the bottom slag and the atomic ratio of each element can be accurately determined by an energy spectrometer. It has the characteristics of low detection cost, rapidity, simplicity, and accuracy. The beneficial effects produced by adopting the above - mentioned technical solution are as follows: The present invention provides a simple, rapid, and low - cost method for displaying and observing the phase structure, morphology, size, and distribution of rare - earth phases in the bottom slag. The composition of the rare - earth phases in the bottom slag and the atomic ratio of each element can be accurately determined by an energy spectrometer. It has the characteristics of low detection cost, rapidity, simplicity, and accuracy.

[0013] The etchant used in the method provided by the present invention is prepared from 0.01-0.05% HF, 0.1-0.5% nitric acid alcohol, and saturated picric acid aqueous solution at room temperature. This etchant has low cost, is safe and non-toxic, and is convenient to prepare. It can clearly and completely display the phase structure, morphology, size, and distribution of rare earth phases in the bottom slag.

[0014] The method provided by the present invention has the characteristics of low detection cost, rapidity, simplicity, and accuracy. Description of the Drawings

[0015] Figure 1 It is the phase structure diagram of rare earth phases in the bottom slag in Example 1; Figure 2 It is the energy spectrum detection result diagram of rare earth phases in the bottom slag in Example 1; Figure 3 It is the bottom slag component diagram measured by the chemical method in Comparative Example 1; Figure 4-1 It is the electron microscope scanning diagram directly measured by the scanning electron microscope energy spectrometer in Comparative Example 2; Figure 4-2 It is the energy spectrum detection result diagram directly measured by the scanning electron microscope energy spectrometer in Comparative Example 2; Figure 5 It is the phase structure diagram of rare earth phases in the bottom slag in Example 2; Figure 6 It is the energy spectrum detection result diagram of rare earth phases in the bottom slag in Example 2; Figure 7 It is the phase structure diagram of rare earth phases in the bottom slag in Example 3; Figure 8 It is the energy spectrum detection result diagram of rare earth phases in the bottom slag in Example 3. Detailed Embodiments

[0016] The technical solution of the present invention will be further described in detail below with reference to the drawings and specific embodiments. Embodiment

[0017] An accurate analysis method for rare earth phases in the bottom slag of a zinc-aluminum-magnesium production line based on phase structure includes sampling, rough grinding, fine grinding, polishing, etching, scanning electron microscope observation, and energy spectrometer to determine the composition of the phase; specifically: (1) Sampling: Take the bottom slag on the zinc-aluminum-magnesium production line, cut the sample with a metallographic cutting machine, and the size is 8mm×8mm; place the cut sample with the plane facing down, hot inlay for 5 minutes, and then grind it flat with a grinding machine after taking it out.

[0018] (2) The specific operation of the fine grinding described in the present invention is: Hold the sample after rough grinding, gently press the sample with a force of 10N, use 600# sandpaper on the full-automatic grinding and polishing machine, and grind at a speed of 900 revolutions per minute for 50 seconds until the scratches of the rough grinding disappear.

[0019] (3) The specific operation of the polishing in the present invention is as follows: Hold the finely ground specimen by hand, gently press the specimen with a force of 10 N, spray 0.5-micron polycrystalline diamond spray grinding and polishing agent on a 250-mm twill cloth polishing cloth, polish at a rotational speed of 900 revolutions per minute, sprinkle water while polishing, and polish for 2 minutes until the surface is bright and free of scratches.

[0020] (4) The etchant used for the etching in the present invention is prepared by mixing 1 part (10 ml) of 0.05% HF, 1 part (10 ml) of 0.5% nitric acid alcohol, and 1 part (1 ml) of saturated picric acid aqueous solution at room temperature. The etching time is 2 seconds, and then it is rinsed clean with alcohol and dried.

[0021] (5) For the scanning electron microscope observation and energy dispersive spectrometer to determine the composition of the phase in the present invention, place the prepared specimen under the scanning electron microscope for observation. The voltage of the electron microscope is 15 KV, which can clearly show the morphology, size, and distribution of rare earth elements in the bottom slag. The results are shown in Figure 1 , set the dead time of the energy dispersive spectrometer to 20% and the counting rate to 1000 CPS, and qualitatively determine the rare earth elements lanthanum and cerium in the bottom slag precisely. The results are shown in Figure 2 and Table 1.

[0022] Table 1 Atomic ratios of each element in the rare earth element phase in Example 1

[0023] Comparative Example 1: Chemical method Weigh 0.8519 g of the bottom slag sample, digest it by acid dissolution method, make the volume up to 50 ml, turn on the ICP spectrometer, after preheating, set the test parameters, prepare the standard solution, and use the ICP spectrometer to measure. The results show that the composition of rare earth elements in the bottom slag cannot be measured. The results are shown in Table 2.

[0024] Table 2 Composition of bottom slag measured by chemical method

[0025] Comparative Example 2: Scanning electron microscope observation + energy dispersive spectrometer directly determine the composition of the bottom slag Use the scanning electron microscope observation + energy dispersive spectrometer to directly determine the composition of the bottom slag. The steps are as follows: (1) Protect the bottom slag sample with plastic wrap to prevent contamination.

[0026] (2) Cut a sample of 8 - 10 mm using a metallographic cutting machine.

[0027] (3) Take it out after cleaning the surface clean by ultrasonic cleaning for 5 minutes, and dry it with a hair dryer.

[0028] (4) Observe under a scanning electron microscope, and use an energy spectrometer to select positions to qualitatively analyze the composition of the bottom slag. Since energy spectrometry is micro-area analysis and the composition of the bottom slag is uneven, direct scanning electron microscope + energy spectrometer analysis cannot identify different phase structures and has no characteristic morphology. Direct energy spectrometer detection cannot detect rare earth elements. The results are shown in Figure 4, and Table 3 shows the results of direct scanning electron microscope + energy spectrometer.

[0029] Table 3 Results of direct scanning electron microscope + energy spectrometer for Comparative Example 2

[0030] Example 2 An accurate analysis method for rare earth phases in the bottom slag of a zinc-aluminum-magnesium production line based on phase structure, including sampling, rough grinding, fine grinding, polishing, etching, scanning electron microscope observation, and energy spectrometer determination of the phase composition; specifically: (1) Sampling: Take the bottom slag on the zinc-aluminum-magnesium production line, cut the sample with a metallographic cutting machine, and the size is 10mm×10mm; place the cut sample with the plane facing down, heat-inlay for 5 minutes, and then grind it flat with a grinding machine after taking it out.

[0031] (2) The specific operation of the fine grinding in the present invention is: Hold the sample after rough grinding, gently press the sample with a force of 15N, use 600# sandpaper on a full-automatic grinding and polishing machine, and grind at a speed of 1400 revolutions per minute for 10 seconds until the scratches of the rough grinding disappear.

[0032] (3) The specific operation of the polishing in the present invention is: Hold the sample after fine grinding, gently press the sample with a force of 15N, spray 2.5-micron polycrystalline diamond spray grinding and polishing agent on a 250mm twill cloth polishing cloth, polish at a speed of 1400 revolutions per minute, sprinkle water while polishing, and polish for 1 minute until the surface is bright and free of scratches.

[0033] (4) The etching agent used in the etching of the present invention is prepared from 1 part (20ml) of 0.01% HF, 1 part (20ml) of 0.1% nitric acid alcohol, and 1 part (3ml) of saturated picric acid aqueous solution at room temperature. The etching time is 2 seconds, and then it is rinsed clean with alcohol and dried.

[0034] (5) For the scanning electron microscope observation and energy spectrometer determination of the phase composition in the present invention, place the prepared sample under the scanning electron microscope for observation. The electron microscope voltage is 20KV, which can clearly show the morphology, size, and distribution of rare earth elements in the bottom slag. The results are shown in Figure 5 , set the dead time of the energy spectrometer to 30%, the counting rate to 3000CPS, and qualitatively determine the rare earth elements lanthanum and cerium in the bottom slag accurately. The energy spectrum diagram is shown in Figure 6 , and the energy spectrum qualitative results are shown in Table 4.

[0035] Table 4 Atomic ratios of each element in the rare earth element phase in Example 2

[0036] Example 3 An accurate analysis method for rare earth phases in the bottom slag of a zinc-aluminum-magnesium production line based on phase structure, including sampling, rough grinding, fine grinding, polishing, etching, scanning electron microscope observation, and energy spectrometer to determine the composition of the phases; specifically: (1) Sampling: Take the bottom slag on the zinc-aluminum-magnesium production line, cut the specimen with a metallographic cutting machine, with the size of 15mm×15mm; place the cut specimen with the plane facing down, hot inlay for 5 minutes, and after taking it out, grind it flat with a grinding machine.

[0037] (2) The specific operation of the fine grinding in the present invention is: Hold the specimen after rough grinding, gently press the specimen with a force of 13N, use 600# sandpaper on a full-automatic grinding and polishing machine, at a speed of 1400 revolutions per minute, grind for 30 seconds until the scratches of the rough grinding disappear.

[0038] (3) The specific operation of the polishing in the present invention is: Hold the specimen after fine grinding, gently press the specimen with a force of 10N, spray 1.0 micron polycrystalline diamond spray grinding and polishing agent on a 250mm twill cloth polishing cloth, polish at a speed of 900 revolutions per minute, sprinkle water while polishing, polish for 2 minutes until the surface is bright and without scratches.

[0039] (4) The etching agent used in the etching of the present invention is prepared from 1 part (20ml) of 0.03% HF, 1 part (10ml) of 0.3% nitric acid alcohol, and 1 part (1ml) of saturated picric acid aqueous solution at room temperature. The etching time is 2 seconds, then rinse it with alcohol and dry it.

[0040] (5) For the scanning electron microscope observation and energy spectrometer to determine the composition of the phases in the present invention, place the prepared specimen under the scanning electron microscope for observation. The electron microscope voltage is 15KV, which can clearly show the morphology, size, and distribution of rare earth elements in the bottom slag. The results are shown in Figure 7 , set the dead time of the energy spectrometer to 25%, the counting rate to 1000CPS, accurately determine the rare earth elements lanthanum and cerium in the bottom slag, and the spectrogram is shown in Figure 8 , and the results are shown in Table 5.

[0041] Table 5 Atomic ratios of each element in the rare earth element phases in Example 3

[0042] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the scope protected by the present invention.

Claims

1. An accurate analysis method for rare earth phases in the bottom slag of a zinc-aluminum-magnesium production line based on phase structure, characterized in that, It includes sampling, rough grinding, fine grinding, polishing and etching. The polished specimen is placed in the etchant for etching. The etching time is 1 - 2 seconds, and then it is rinsed with alcohol and dried; Then, it is observed by scanning electron microscope and the composition of the phase is determined by energy dispersive spectrometer; The etchant used for etching is prepared from an HF aqueous solution with a mass concentration of 0.01 - 0.05%, a nitric acid alcohol solution with a mass concentration of 0.1 - 0.5% and 1 - 3 ml of a saturated picric acid aqueous solution at room temperature.

2. The precise analysis method for rare earth phases in the bottom slag of a zinc-aluminum-magnesium production line based on phase structure according to claim 1, wherein, The volume ratio of the HF aqueous solution with a mass concentration of 0.01 - 0.05%, the nitric acid alcohol solution with a mass concentration of 0.1 - 0.5% and the saturated picric acid aqueous solution is 10 - 20:10 - 20:1 - 3.

3. The precise analysis method of rare earth phases in the bottom slag of a zinc-aluminum-magnesium production line based on phase structure according to claim 1, wherein The specific operations of sampling and rough grinding in the present invention are as follows: 1) Sampling: Take the bottom slag on the zinc - aluminum - magnesium production line, cut the specimen with a metallographic cutting machine, and the size is 8 - 15 mm×8 - 15 mm; Place the cut specimen with the plane facing down, hot - inlay it for 5 minutes, and after taking it out, grind it flat with a grinding machine.

4. The precise analysis method of rare earth phases in the bottom slag of a zinc-aluminum-magnesium production line based on phase structure according to claim 1, wherein, The specific operation of fine grinding is as follows: Hold the specimen after rough grinding, gently press the specimen with a force of 10 - 15 N, use 600# sandpaper on a fully automatic grinding and polishing machine, and grind at a speed of 900 - 1400 revolutions per minute for 10 - 50 seconds until the scratches of rough grinding disappear.

5. The precise analysis method of rare earth phases in the bottom slag of a zinc-aluminum-magnesium production line based on phase structure according to claim 1, characterized in that The specific operation of polishing is as follows: Hold the specimen after fine grinding, gently press the specimen with a force of 10 - 15 N, spray a polishing agent of 0.5 - 2.5 microns on a 250 - mm twill cloth polishing cloth, polish at a rotation speed of 900 - 1400 revolutions per minute, sprinkle water while polishing, and polish for 1 - 2 minutes until the surface is bright and free of scratches.

6. The precise analysis method of rare earth phases in the bottom slag of a zinc-aluminum-magnesium production line based on phase structure according to claim 5, characterized in that The polishing agent is a polycrystalline diamond spray grinding and polishing agent. Shake it well before use and spray twice every 5 - 20 seconds during polishing.

7. The precise analysis method for rare earth phases in the bottom slag of a zinc-aluminum-magnesium production line based on phase structure according to claim 1, characterized in that, For observing by scanning electron microscope and determining the composition of the phase by energy dispersive spectrometer, place the prepared specimen under the scanning electron microscope for observation. The electron microscope voltage is 15 - 20 KV, the dead time of the energy dispersive spectrometer is set at 20% - 30%, and the counting rate is 1000 - 5000 CPS.

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