Method for the digestion of rma material and determination of the zirconia content therein

Abstract

The application belongs to the technical field of RMA material analysis and detection, and discloses a digestion method of RMA material and a determination method of zirconia content in the RMA material. The digestion method is as follows: the RMA material is calcined to remove organic matter, and then is added into a mixed digestion solution composed of ammonium nitrate, sulfuric acid and hydrochloric acid to perform microwave digestion, so as to obtain a digestion solution. The determination method of the zirconia content is as follows: the digestion solution is diluted with nitric acid and an internal standard substance is added, and the volume is adjusted to obtain a sample to be measured; a standard series solution with different zirconium (Zr) concentrations is prepared, and then an inductively coupled plasma emission spectrometer is used to perform scanning and draw a standard working curve; meanwhile, the sample to be measured is tested, and the zirconia content in the sample to be measured is calculated according to the standard curve. The method can completely digest the RMA material without adding hydrofluoric acid, and has a good guiding significance for studying the influence of the zirconia (ZrO2) content in the RMA material on the performance improvement of the material.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of RMA material analysis and detection, and particularly relates to a digestion method of RMA material and determination of zirconium oxide content in the RMA material. BACKGROUND

[0002] The main components of RMA powder and target material are zinc oxide, praseodymium oxide, indium oxide and zirconium oxide. The conventional digestion method of zirconium oxide mainly uses hydrofluoric acid for digestion. However, hydrofluoric acid is highly toxic and corrosive, and the experiment is highly dangerous. After digestion is completed, a large amount of time is needed to chase the acid, and a hydrofluoric acid-resistant system needs to be replaced when analyzing the sample, which causes the digestion and detection time to be too long and affects the test efficiency.

[0003] Patent CN 102721688 A discloses a method for determining the content of indium and tin in ITO target material. The determination steps are as follows: after the sample is dissolved by acid, the test solution is taken and potassium nitrate is added. Excessive EDTA is used to complex with indium and tin, ammonia water is used to adjust the pH value, and heating is performed until boiling. Then, the solution is cooled to room temperature. Then, hexamethylenetetramine is added to adjust the pH value, an indicator dimethyl phenol orange is added, and the solution is titrated with zinc standard solution until the color changes from yellow to red. The total content of indium and tin in the sample is calculated by the volume of the consumed zinc standard solution. Ammonium fluoride is added to mask tin. After the ammonium fluoride is completely dissolved, the solution is heated to the required temperature and then cooled to room temperature. At this time, the solution is yellow. The red color is the titration end point. The content of indium oxide in the sample is calculated by the volume of the consumed zinc standard solution. The acid used to dissolve the sample in the patent technology is a mixed acid of one or more acids selected from hydrochloric acid, nitric acid, sulfuric acid and hydrofluoric acid. The chemical titration method used in the patent technology has the problems of long time consumption and low accuracy.

[0004] Patent CN 107589108 A discloses a method for determining the content of metal oxides in rubber. The determination steps are as follows: one of hydrochloric acid or nitric acid or a mixed acid including the two is used to dissolve the test material in a microwave digestion instrument. A beaker is used on an electric heating plate, and a mixed acid including sulfuric acid and phosphoric acid is added to heat and boil the solution until the solution is clear. Then, the content of the measured metal is determined by an inductively coupled plasma atomic emission spectrometer. The patent technology mainly discloses a digestion method of rubber matrix material and a method for determining the content of metal oxides in the rubber matrix material. However, there are significant differences in the matrix interference of RMA powder and target material and rubber material. The existing technology discloses a method for determining the content of zirconium oxide in RMA powder and target material. SUMMARY

[0005] In view of the shortcomings and deficiencies of the prior art, the primary purpose of the present application is to provide a digestion method of RMA material. The digestion method of the present application can completely digest the RMA powder or target material mixture without adding hydrofluoric acid, reduces the experimental operation steps, improves the work efficiency, and further improves the safety of the experiment.

[0006] Another object of the present application is to provide a method for determining the content of zirconia in RMA materials.

[0007] The object of the present application is achieved by the following technical solutions.

[0008] A digestion method of RMA materials comprises the following steps:

[0009] (1) calcining the RMA materials at 900-1000℃ to remove organic matter;

[0010] (2) adding the RMA materials treated in step (1) into a mixed digestion solution composed of ammonium nitrate, sulfuric acid and hydrochloric acid, mixing thoroughly, then reacting at normal temperature for 10-15 min, and then performing microwave digestion at 200-210℃ for 50-60 min to obtain a completely digested RMA solution.

[0011] Further, the RMA materials in step (1) refer to RMA powders or RMA target materials.

[0012] Further, the mass concentration (relative to water as solvent) of each substance in the mixed digestion solution in step (2) is as follows: ammonium nitrate 21%-22%, sulfuric acid 95%-98%, and hydrochloric acid 36%-38%.

[0013] A method for determining the content of zirconia in RMA materials comprises the following steps:

[0014] 1) diluting the RMA materials to be measured after digestion according to the above digestion method with nitric acid solution, adding an internal standard substance, then using ultrapure water to make up the volume to obtain a sample to be measured;

[0015] 2) placing zinc oxide reference material, praseodymium oxide reference material and indium reference material in a digestion tube, adding a mixed digestion solution composed of ammonium nitrate, sulfuric acid and hydrochloric acid to heat and digest, then adding a zirconium (Zr) standard solution (national liquid standard sample: raw material is metallic zirconium, medium is HNO3 and HF) to a volumetric flask, using nitric acid solution to make up to the scale, shaking well, diluting the obtained solution with nitric acid solution, then adding an internal standard substance, and then using ultrapure water to make up the volume to prepare a standard series solution with different zirconium concentrations, then using an inductively coupled plasma emission spectrometer to scan the standard series solution to draw a standard working curve;

[0016] 3) using an inductively coupled plasma emission spectrometer to test the sample to be measured in step 1), and calculating the content of zirconia in the sample to be measured according to the standard curve in step 2).

[0017] Further, the internal standard substance in steps 1) and 2) is selected as Y (yttrium) element (national liquid standard sample: raw material is yttrium oxide, medium is HNO3).

[0018] Further, the specific preparation steps of the sample to be tested in step 1) are as follows: after the solution of the RMA material after calcination treatment is digested is cooled to room temperature, it is transferred to a 100ml volumetric flask, the digestion tube is rinsed with 1% nitric acid solution for 3 times, the volume is adjusted to the scale with 1% nitric acid solution, and 1ml is taken to another 100ml volumetric flask, 5ml of nitric acid and 0.30ml of Y standard solution with a concentration of 1000ug / ml are added, and the volume is adjusted to the scale with ultrapure water, and the solution is shaken uniformly, which is the sample to be tested.

[0019] Further, the specific preparation steps of the standard series solution with different zirconium concentrations in step 2) are as follows: 0.0788g (accurate to 0.0001g) of zinc oxide reference material, 0.013g (accurate to 0.0001g) of praseodymium oxide reference material and 0.4032g (accurate to 0.0001g) of indium oxide reference material are weighed respectively and placed in a 50ml digestion tube, 4ml of ammonium nitrate, 6ml of hydrochloric acid and 5ml of sulfuric acid are added, and after being shaken uniformly, the tube is placed in a graphite digestion instrument and heated to 100℃ until the solid is completely dissolved, and then the solution is cooled to room temperature and transferred to a 100ml volumetric flask, the digestion tube is rinsed with 1% nitric acid solution for 3 times, 5.0ml of zirconium (Zr) standard solution (national liquid standard sample: raw material is metal zirconium, medium is HNO3 and HF) with a concentration of 1000ug / ml is added to the volumetric flask, and the volume is adjusted to the scale with 1% nitric acid solution, and the solution is shaken uniformly, which is recorded as "solution 1"; at this time, the concentration of zinc oxide in the solution is 0.788g / L, the concentration of praseodymium oxide is 0.13g / L, the concentration of indium oxide is 4.032g / L, and the concentration of zirconium is 50ug / ml; 0ml, 0.5ml, 1ml, 1.5ml and 2ml of "solution 1" are added to five 100ml volumetric flasks respectively, 5ml of nitric acid and 0.30ml of yttrium (Y) standard solution with a concentration of 1000ug / ml are added, and the volume is adjusted to the scale with ultrapure water, and the solution is shaken uniformly, thereby obtaining standard series solutions with zirconium concentrations of 0ug / ml, 0.25ug / ml, 0.50ug / ml, 0.75ug / ml and 1.0ug / ml respectively.

[0020] Further, the inductively coupled plasma optical emission spectrometer used in steps 2) and 3) is Thermo 7400 ICP-oes; the scanning wavelength is 327.305nm, 339.198nm or 343.823nm; more preferably, it is 339.198nm or 343.823nm, the spectral line intensity at 339.198nm or 343.823nm is obviously stronger than that at other wavelengths, and the interference of impurity elements on the determination of the content of zirconium (Zr) element can be ignored.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] The application establishes a digestion method for RMA materials, such as RMA powder and target material: a sulfuric acid-ammonium nitrate-hydrochloric acid digestion system is used, and an ICP-OES measurement method for measuring ZrO2 in the RMA powder and target material is established. The method can completely digest the RMA material without adding hydrofluoric acid, reduces the experimental operation steps under the premise of ensuring the accuracy of the data, improves the safety of the experiment, can be used for laboratory batch analysis and detection, and has a good guiding significance for studying the improvement of the ZrO2 content in the RMA powder and target material on the performance of the material. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figures 1-3 respectively, the scanning test result graphs of the recommended wavelengths Zr-327.305nm, Zr-339.198nm and Zr-343.823nm in the embodiment are shown.

[0024] Figure 4 The standard working curve graph of the standard series solution under the condition of the Zr-339.198nm wavelength in the embodiment by using the internal standard method is shown. DETAILED DESCRIPTION

[0025] The application will be further described in detail below in combination with the embodiments and drawings, but the embodiments of the application are not limited thereto.

[0026] The instruments and reagents required in the following embodiments are as follows:

[0027] Instruments: CEM Mar6 microwave digestion instrument, Thermo 7400 ICP-oes; muffle furnace.

[0028] Experimental reagents: hydrochloric acid UP grade (mass concentration: 36-38%); sulfuric acid UP grade (mass concentration: 95-98%); ammonium nitrate solution GR grade (mass concentration: 21-22%); praseodymium oxide reference material (purity ≥ 99.95%); indium oxide reference material (purity ≥ 99.95%); zinc oxide reference material (purity ≥ 99.95%); zirconium (Zr) standard solution (national liquid standard sample: raw material is metallic zirconium, medium is HNO3 and HF, Zr concentration is 1000 μg / ml); yttrium (Y) standard solution (national liquid standard sample: raw material is yttrium oxide, medium is HNO3, Y concentration is 1000 μg / ml); ultrapure water.

[0029] Example 1

[0030] 1. Sample digestion

[0031] (1) Take 20g of RMA powder and place it in a muffle furnace at 900-1000℃ for 2h to completely burn the organic matter in the powder.

[0032] (2) Take 0.5 g of RMA powder and pour it into a digestion tank. Add 4 ml of ammonium nitrate, 5 ml of sulfuric acid, and 6 ml of hydrochloric acid in sequence. Shake well and react at room temperature for 10 min. Set the temperature of CEM Mar 6 microwave digestion instrument to 200-210°C and perform microwave digestion for 50 min.

[0033] (3) After digestion is completed, the sample is completely digested, and the solution is light transparent yellow-green. After cooling to room temperature, transfer it to a 100 ml volumetric flask. Rinse the digestion tube with 1% nitric acid solution for 3 times. Use 1% nitric acid solution to dilute to the calibration mark. Shake well and transfer 1 ml to another 100 ml volumetric flask. Add 5 ml of nitric acid and 0.30 ml of yttrium (Y) standard solution (concentration 1000 pg / ml). Dilute to the calibration mark with ultrapure water. Shake well. This is the sample to be tested.

[0034] 2. Preparation of series of standard solutions

[0035] (1) Take 0.0788 g (accurate to 0.0001 g) of zinc oxide reference material, 0.013 g (accurate to 0.0001 g) of praseodymium oxide reference material, and 0.4032 g (accurate to 0.0001 g) of indium oxide reference material, respectively, and place them in a 50 ml digestion tube. Add 4 ml of ammonium nitrate, 6 ml of hydrochloric acid, and 5 ml of sulfuric acid. Shake well and place in a graphite digestion instrument at 100°C until the solid is completely dissolved. Cool to room temperature and transfer to a 100 ml volumetric flask. Rinse the digestion tube with 1% nitric acid solution for 3 times. Add 5.0 ml of Zr standard solution (concentration 1000 pg / ml) to the volumetric flask. Dilute to the calibration mark with 1% nitric acid solution. Shake well. This solution is referred to as "Solution 1". At this time, the concentration of zinc oxide in the solution is 0.788 g / L, the concentration of praseodymium oxide is 0.13 g / L, the concentration of indium oxide is 4.032 g / L, and the concentration of zirconium is 50 pg / ml.

[0036] (2) Add 0 ml, 0.5 ml, 1 ml, 1.5 ml, and 2 ml of "Solution 1" to 5 100 ml volumetric flasks, respectively. Add 5 ml of nitric acid and 0.30 ml of Y standard solution (concentration 1000 pg / ml). Dilute to the calibration mark with ultrapure water. Shake well. At this time, the concentration of Zr in the standard series solution is 0, 0.25, 0.50, 0.75, and 1.0 pg / ml, respectively.

[0037] 3. Selection of spectral lines:

[0038] The recommended wavelengths given by Thermo 7400 ICP-oes are: Zr-327.305 nm, Zr-339.198 nm, and Zr-343.823 nm. By querying the parameters together, and using each wavelength to scan test the standard series solution and wavelength test solution, the peak values and background interference of the spectral lines at the above wavelengths are observed. The results are as follows:Figure 1 , Figure 2 and Figure 3 as shown (L0 is a standard blank curve, L1, L2, L3, L4 are standard series solution curves). By observing the spectrum and processing the data, it is known that the linear correlation coefficients obtained by measuring the standard series solution at the three wavelengths recommended by the instrument are all above 0.999, which meets the requirements, but the spectral line intensity at Zr-339.198 nm and Zr-343.823 nm is obviously stronger than that at other wavelengths. After comprehensive consideration, the optimal wavelength Zr-339.198 nm recommended by the equipment is selected as the analysis line for this experiment.

[0039] 4. Exclusion of matrix interference

[0040] The indium oxide, zinc oxide, praseodymium oxide, and zirconium oxide mixture has very high contents of indium, zinc, praseodymium, and zirconium, and the contents of other impurity elements such as calcium, magnesium, sodium, and iron are all less than 0.01%. Through analysis and selection of wavelengths, the interference of impurity elements on the determination of zirconium (Zr) element content can be ignored.

[0041] 5. Selection of internal standard element

[0042] The yttrium (Y) element has little spectral interference, and the indium oxide, zinc oxide, praseodymium oxide, and zirconium oxide mixture does not contain Y element. After comprehensive consideration, Y element is selected as the internal standard element with a concentration of 3 μg / ml.

[0043] 6. Drawing of standard working curve

[0044] The standard series solution is used to draw the standard working curve at Zr-339.198 nm by the internal standard method, and the results are shown in Figure 4 . The correlation coefficient is 0.999, and the linearity is good, which can be used for quantitative analysis of Zr element content.

[0045] 7. Reproducibility test of the method

[0046] Ten portions of the RMA powder after ignition are taken, and the ZrO2 content is determined according to the above method. The results are shown in Table 1.

[0047] Table 1

[0048]

[0049] As can be seen from Table 1, the average value of the test results of 10 times is 0.9611%, which is close to the theoretical value of 0.95%. The SD of the test results is 0.65%, and the RSD is 0.67%, indicating that the reproducibility of the experiment is good, and the experimental data is reliable.

[0050] 8. Test of the recovery rate of the method

[0051] According to the above experimental method, different concentrations of Zr standard solution (concentration 1000 ug / ml) were added to the sample respectively, and the standard addition recovery verification experiment was carried out, and the results are shown in Table 2.

[0052] Table 2

[0053]

[0054] From Table 2, the experimental standard addition recovery rate is between 98.95% and 101.93%, indicating that the experimental method has high reliability and can meet the daily testing requirements. By comparing and verifying the test results of the hydrofluoric acid-hydrochloric acid digestion system, the ZrO2 content is 0.9632%, which is basically consistent with the digestion system used in the experiment (the average value of 10 times test results of the sulfuric acid-ammonium nitrate-hydrochloric acid digestion system is 0.9611%), further verifying the reliability of the method.

[0055] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application are equivalent replacement methods and are included in the protection scope of the present application.

Claims

1. A method for digesting RMA materials, characterized in that: The steps include: (1) calcining the RMA material at 900-1000°C to remove organic matter; (2) adding the RMA material treated in step (1) to a mixed digestion solution consisting of ammonium nitrate, sulfuric acid, and hydrochloric acid, mixing thoroughly, reacting at room temperature for 10 to 15 minutes, and then performing microwave digestion at a temperature of 200 to 210° C. for 50 to 60 minutes to obtain a completely digested RMA solution.

2. The digestion method of RMA material according to claim 1, characterized in that: The RMA material in step (1) refers to RMA powder or RMA target.

3. The digestion method of RMA material according to claim 1, characterized in that, The mass concentrations of the substances in the mixed digestion solution in step (2) are: ammonium nitrate 21% to 22%, sulfuric acid 95% to 98%, and hydrochloric acid 36% to 38%.

4. A method for determining the content of zirconium oxide in RMA material, characterized in that: The steps include: 1) digesting the RMA material to be tested according to the digestion method according to any one of claims 1 to 3, diluting it with a nitric acid solution, adding an internal standard substance, and then calibrating the volume with ultrapure water to obtain a sample to be tested; 2) placing a zinc oxide reference substance, a praseodymium oxide reference substance, and an indium oxide reference substance in a digestion tube, adding them to a mixed digestion solution consisting of ammonium nitrate, sulfuric acid, and hydrochloric acid, and heating and digesting them; then adding a zirconium standard solution to a volumetric flask, and then calibrating the volume to the mark with nitric acid solution, shaking well, diluting the resulting solution with nitric acid solution, adding an internal standard substance, and then calibrating the volume with ultrapure water to prepare a standard series of solutions with different zirconium concentrations; then scanning the standard series of solutions using an inductively coupled plasma optical emission spectrometer to draw a standard working curve; 3) The sample to be tested in step 1) is tested using an inductively coupled plasma optical emission spectrometer, and the zirconium oxide content in the sample to be tested is calculated based on the standard curve in step 2).

5. The method for determining the zirconium oxide content in RMA material according to claim 4, characterized in that: In steps 1) and 2), the internal standard substance is selected as yttrium element.

6. The method for determining the zirconium oxide content in RMA material according to claim 4, characterized in that: The specific preparation steps of the sample to be tested in step 1) are as follows: the solution after digestion of 0.5 g of calcined RMA material is cooled to room temperature and transferred to a 100 ml volumetric flask, the digestion tube is rinsed three times with 1% nitric acid solution, the volume is adjusted to the scale with 1% nitric acid solution, shaken and 1 ml is transferred to another 100 ml volumetric flask, 5 ml of nitric acid and 0.30 ml of 1000 μg / ml yttrium standard solution are added, the volume is adjusted to the scale with ultrapure water, and shaken. This is the sample to be tested.

7. The method for determining the zirconium oxide content in RMA material according to claim 4, characterized in that: The specific preparation steps of the standard series solutions with different zirconium concentrations in step 2) are as follows: 0.0788 g of zinc oxide standard substance, 0.013 g of praseodymium oxide standard substance, and 0.4032 g of indium oxide standard substance are weighed respectively and placed in a 50 ml digestion tube, 4 ml of ammonium nitrate, 6 ml of hydrochloric acid, and 5 ml of sulfuric acid are added and shaken thoroughly, and then placed in a graphite digester at 100 ° C. and heated until the solid is completely dissolved. After cooling to room temperature, the solution is transferred to a 100 ml volumetric flask, and the digestion tube is rinsed 3 times with 1% nitric acid solution, and 5.0 ml of a zirconium standard solution with a concentration of 1000 μg / ml is added to the volumetric flask, and the volume is adjusted to the scale with 1% nitric acid solution, and shaken. This solution is recorded. Prepare "Solution 1"; at this point, the solution contains 0.788 g / L zinc oxide, 0.13 g / L praseodymium oxide, 4.032 g / L indium oxide, and 50 μg / ml zirconium. Add 0 ml, 0.5 ml, 1 ml, 1.5 ml, and 2 ml of "Solution 1" to five 100 ml volumetric flasks, respectively. Add 5 ml of concentrated nitric acid and 0.30 ml of a 1000 μg / ml yttrium standard solution. Dose to volume with ultrapure water and shake well to obtain a series of standard solutions with zirconium concentrations of 0 μg / ml, 0.25 μg / ml, 0.50 μg / ml, 0.75 μg / ml, and 1.0 μg / ml, respectively.

8. The method for determining the zirconium oxide content in RMA material according to claim 4, wherein: The inductively coupled plasma optical emission spectrometer in steps 2) and 3) is a Thermo Fisher 7400 ICP-oes; the scanning wavelength is 327.305 nm, 339.198 nm or 343.823 nm.

9. The method for determining the zirconium oxide content in RMA material according to claim 8, characterized in that: The scanning wavelength is selected to be 339.198 nm or 343.823 nm.

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