Method for the analysis of silicon nitride-manganese alloys by glass fusion x-ray fluorescence

Abstract

The application discloses a method for analyzing silicon nitride manganese alloy by glass melting X-ray fluorescence spectrum, and comprises the following steps: step one, mixing a sample and an oxidizing agent and placing them in the middle of a platinum yellow crucible with a flux on the bottom; step two, placing the sample in an electric heating automatic melting furnace to prepare a to-be-detected glass disc by borate melting; step three, completely melting, automatically casting, cooling the sample disc, demolding and obtaining a glass disc for X fluorescence analysis; and step four, optimizing analysis parameters, establishing a working curve, performing sample analysis and obtaining the content of measured elements. The application relates to the technical field of metallurgical chemical analysis and detection, and particularly relates to a method for analyzing silicon nitride manganese alloy by glass melting X-ray fluorescence spectrum.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metallurgical chemical analysis and detection, in particular to a method for analyzing silicon nitride manganese alloy by glass melting X-ray fluorescence spectrum. BACKGROUND

[0002] Silicon nitride manganese alloy is a new type of steelmaking additive, which combines the special properties of silicon nitride and manganese nitride iron. Compared with traditional nitride alloys, it has strong micro-alloying effect and nitriding effect, and is increasingly widely used in the production of alloy steel, silicon steel, HRB400 above threaded steel and other fields.

[0003] The main substances in silicon nitride manganese are manganese nitride, silicon nitride and a small amount of harmful elements such as phosphorus, carbon and sulfur. The existing or reported methods for detecting silicon, manganese and phosphorus mainly include single element analysis, including gravimetric method, oxidation-reduction method, spectrophotometric method and ICP-OES method. The operation is relatively complicated, the pretreatment is difficult, and many chemical reagents are used, which is low in work efficiency and difficult to meet the requirements of batch rapid detection in actual production.

[0004] X-ray fluorescence spectrometry has the advantages of simplicity, rapidity and simultaneous determination of multiple elements. The melting sample preparation technique can effectively eliminate the mineral effect and particle size effect of the sample, and has good precision and uniformity of sample preparation. Artificially prepared calibration samples are considered to be the most accurate sample preparation method in X-ray fluorescence spectrometry. Therefore, the melting sample preparation-X-ray fluorescence spectrometry is widely used in the detection of steel metallurgy, refractory materials and other fields. There is no glass melting X-ray fluorescence spectrometry method for analyzing silicon nitride manganese alloy.

[0005] The method we established is to use sodium carbonate-boric acid mixed flux at a certain temperature to have a good oxidation-reduction effect on silicon nitride manganese. By laying a certain thickness of lithium tetraborate with a relatively high melting point than sodium carbonate-boric acid in the platinum yellow crucible (so that lithium tetraborate acts as a container), the sample is pre-oxidized by increasing the temperature from a relatively low temperature and maintaining a sufficient oxidation reaction time, removing the metal effect and reducing property of the sample, avoiding the problem of corrosion caused by the sample in its metal state and reducing state contacting the platinum yellow crucible. Then, the sample is reheated and melted, and cast into a suitable glass disc for X-ray fluorescence spectrometer measurement. The fluorescence X-ray intensity of the measured elements in the glass disc is measured. According to the calibration curve or equation, the content of the measured elements is obtained.

[0006] The X-ray fluorescence spectrum analysis of silicon, manganese and phosphorus in the silicon nitride manganese alloy is realized by selecting the best pre-oxidation condition, setting the typical sample by using multiple methods, selecting the similar alloy standard sample with suitable content, and setting the standard curve by mixing the standard sample and adding the standard solution, so that the linear range covers the analysis range of the conventional sample and the gradient is uniformly distributed. The test verification result is accurate and reliable, the comparison result with the chemical method is consistent, and the existing detection and analysis and quality control requirements of the silicon nitride manganese can be met. SUMMARY

[0007] The technical scheme adopted by the present application is as follows: the present application is a method for analyzing the silicon nitride manganese alloy by glass melting X-ray fluorescence spectrum, comprising the following steps:

[0008] Step one, the mixed sample and the oxidant are placed in the middle of the Pt95%-Au5% crucible with the flux on the bottom, a quantitative first melting flux is weighed and placed in the Pt95%-Au5% crucible, and the mixed sample and the melting oxidant are arranged in the form of a concave pit with a layer along the wall of the crucible, which is slightly higher than the center by 1mm-2mm, so that the mixed sample and the melting oxidant can be placed in the center concave pit, and the surface of the sample is leveled to be on the same horizontal plane;

[0009] A quantitative second mixed melting oxidant and a quantitative analysis sample are weighed and mixed uniformly, and then transferred into the Pt95%-Au5% crucible which is previously padded with the first melting flux and arranged in the form of a concave pit with a layer along the wall of the crucible, which is slightly higher than the center by 1mm-2mm, and the sample and the second mixed melting oxidant are placed in the center concave pit, avoiding the edge of 8-10mm, so as to prevent the sample and the second mixed melting oxidant from contacting the wall of the Pt95%-Au5% crucible, and the sample and the second mixed melting oxidant are leveled to be on the same horizontal plane with the surface of the first melting flux;

[0010] Step two, the borate glass round piece to be detected is prepared by placing it in the electric heating automatic melting furnace, setting the melting analysis conditions, and running the program to automatically melt, the crucible containing the sample, the oxidant and the flux is transferred to the automatic melting furnace, a quantitative release agent is added, and the melting program is set to automatically melt;

[0011] Step three, the glass round piece for X fluorescence analysis is obtained by complete automatic casting and cooling sample piece demolding, the whole oxidation and melting steps are completed under the specified temperature program and temperature, the automatic casting, cooling and manual demolding are performed, the label is attached, and the glass round piece for X fluorescence analysis is obtained for measurement;

[0012] Step four, optimize analysis parameters to establish working curve to perform sample analysis to obtain the content of measured elements, respectively, take the typical silicon nitride manganese sample whose value is determined by classical chemical wet method multiple determination, silicon, manganese, phosphorus known silicon manganese alloy, silicon calcium barium alloy and silicon nitride manganese mixed sample and silicon calcium alloy, silicon aluminum barium alloy standard sample with similar silicon, manganese, phosphorus content and silicon nitride manganese sample, so that the calibration sample is not less than 6, complete step one according to the same method of sample processing, before step two, add a certain amount of phosphorus standard solution to 2-3 samples, so that the content of each measured component can cover the sample analysis range and show uniform gradient distribution, then prepare glass disc according to steps two and three, cool down, and label; According to the special operation software provided by X fluorescence analyzer, the calibration curve of the measured elements is established by detecting the calibration sample, and the linear equation is obtained, and the linearity of the calibration curve is checked by the correlation coefficient r, which is required to be >0.999.

[0013] The glass disc of the sample to be tested is measured in sequence, and the analysis results of silicon, manganese and phosphorus elements are directly read out.

[0014] Further, in step one, the first melting agent is lithium tetraborate, and the X-ray fluorescence analysis uses superior pure, ≥99.50%, and the amount is 30-40 times the amount of the sample, and the amount of the sample is consistent with the amount used when preparing the glass disc for the calibration curve.

[0015] Further, in step one, the first melting agent is placed in a Pt95%-Au5% crucible, which is arranged as a concave pit with a layer along the crucible wall, which is slightly higher than the center 1mm-2mm, so that the mixed sample and the melting oxidant can be placed in the center pit, and the surface of the sample is leveled to the same level after spreading the sample.

[0016] Further, in step one, the second melting oxidant is sodium carbonate-boric acid mixed flux (Na2CO3-H3BO3): mixed according to 2:1, ground into 0.15mm-0.25mm powder, dried at 105±5℃, and sealed in a desiccator, sodium carbonate and boric acid are both analytical pure, the amount is 15-25 times the amount of the sample, and the amount of the sample is consistent with the amount used when preparing the glass disc for the calibration curve.

[0017] Further, in step one, the particle size of the analysis sample is required to be <0.125mm, and the sample is dried and mixed uniformly before weighing.

[0018] Further, in step one, the second mixed molten oxidizing agent and the quantitative analysis sample are mixed evenly in a 20 mL glass beaker, and then carefully transferred into the center pit of the Pt95%-Au5% crucible which is previously padded with the first flux for melting and arranged as a concave pit with a height of 1 mm-2 mm higher than the center, avoiding the edge of 8-10 mm, preventing the sample and the second mixed molten oxidizing agent from contacting the wall of the Pt95%-Au5% crucible, and flattening the sample and the second mixed molten oxidizing agent to be at the same level as the surface of the first flux for melting.

[0019] Further, in step two, the release agent is lithium iodide (LiI) with a purity of ≥99.9%, prepared into a 200 g / L aqueous solution, and added in an amount of 8-12 drops, and the amount of the sample is consistent with that used for preparing the glass disc for the calibration curve, and the automatic melting program is set as: 500℃ into the furnace, 30℃ / min to 800℃, pre-oxidation for 15 min, 30℃ / min to 1050℃, static melting for 3 min, 10-15 min of melting while heating and shaking, and after the completion of the entire oxidation and melting steps at the set temperature, the automatic melting furnace executes the automatic casting, natural cooling, air cooling outside the furnace, and then the sample is manually demolded and taken out, and the quality of the glass disc is checked to meet the requirements of no unmelting material, cracks, bubbles or segregation defects.

[0020] Further, in step four, the silicon nitride manganese sample with a fixed value is a typical sample with reliable mass fraction of each measured element determined by multiple determinations by the chemical wet method and the ICP-OES method, and the standard phosphorus solution added when establishing the calibration curve is a 1000 ug / mL national standard solution of phosphorus, numbered GBW(E)080584 with a concentration of 1000 ug / mL and a medium of H2O.

[0021] Further, in step three, the silicon calcium, silicon calcium barium, silicon manganese and silicon aluminum barium alloy standard samples can be changed, as long as the content of the measured elements is similar to the content range of the sample analysis and the existing state of the silicon, manganese and phosphorus elements in the sample, and the spectral lines of the silicon, manganese and phosphorus elements are all Kɑ spectral lines.

[0022] The application has the following beneficial effects:

[0023] The application solves the problems of complicated chemical wet analysis process of silicon nitride manganese, multiple types of reagents required, and multiple sample dissolutions for single element determination, realizes X-ray fluorescence spectrum analysis of silicon, manganese and phosphorus in silicon nitride manganese alloy by one-time sample melting, and covers the linear range of 30-60% of silicon content, 0.20-20% of manganese and 0.010-0.25% of phosphorus in the silicon nitride manganese alloy sample, and the test verification result is accurate and reliable, consistent with the chemical determination result, and can meet the existing detection analysis and quality control requirements of silicon nitride manganese. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The step flow chart of the present application;

[0025] Figure 2 The silicon Kɑ spectrum calibration curve diagram of the embodiment of the present application;

[0026] Figure 3 The manganese Kɑ spectrum calibration curve diagram of the embodiment of the present application;

[0027] Figure 4 The phosphorus Kɑ spectrum calibration curve diagram of the embodiment of the present application;

[0028] Figure 5 The working curve of the ICP-OES method for determining phosphorus in the comparative example of the present application. DETAILED DESCRIPTION

[0029] As Figures 1-5 shown in the drawings, the present application is a method for analyzing silicon nitride manganese alloy by glass melting X-ray fluorescence spectrum,

[0030] In specific use: the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0031] Reagents:

[0032] a), the first melting flux: lithium tetraborate (Li2B4O7), X-ray fluorescence analysis with high purity, Luoyang special resistance experimental equipment Co., Ltd., ≥99.50%.

[0033] b), the second melting oxidant: sodium carbonate-boric acid mixed flux (Na2CO3-H3BO3): mixed and ground according to 2:1 to a particle size of 0.15mm-0.25mm powder, dried at 105±5℃, and sealed and stored in a desiccator. Sodium carbonate and boric acid are both analytical pure.

[0034] c), release agent: lithium iodide, high purity, ≥99.9%, prepared into a 200g / L solution.

[0035] d), standard solution: phosphorus standard solution 1000ug / mL, national standard solution number GBW(E)080584, medium H2O.

[0036] e), standard sample silicon calcium alloy: number GSB03-2197-2008, Jilin ferroalloy, Mn0.12%, Si60.30%, P0.030%.

[0037] f) Standard sample of silicon-manganese alloy: No. GSB (2011-1), Cixing Jinzhou Metal Co., Ltd., Mn 68.52%, Si 15.29%, P 0.100%.

[0038] g) Standard sample of silicon-manganese alloy: No. GSB03-2600-2010, Jilin Ferroalloy, Mn 67.96%, Si 25.03%, P 0.065%.

[0039] h) Standard sample of silicon-aluminum-barium alloy: No. YSB14607-2001, Jilin Ferroalloy, Mn 0.14%, Si 24.12%, P 0.015%.

[0040] i) Standard sample of silicon-calcium-barium alloy: No. GBW01434, Jilin Ferroalloy, Mn 0.067%, Si 59.24%, P 0.024%.

[0041] j) Argon-methane gas: 90% Ar + 10% CH4, used for X-ray fluorescence spectrometer gas proportional counter.

[0042] Instrument and equipment:

[0043] X-ray fluorescence spectrometer, the basic principle of working is that the primary X-rays emitted by the X-ray tube excite the atoms in the sample, the generated fluorescent X-rays are spectrally dispersed by a crystal and measured by a detector, and the qualitative and quantitative analysis of elements is carried out according to the wavelength and intensity of the characteristic X-ray spectrum of various elements.

[0044] Technical performance includes precision, stability, X-ray count rate, and detector meeting the requirements of Class A in JJG810 and the provisions and requirements of GB / T16597.

[0045] Detector energy resolution: expressed in terms of half-width of pulse height distribution and percentage of average pulse height, should meet SC: R≤60% PC: R≤40%

[0046] Test instrument: Japan RIGAKU ZSX Primus IV type X-ray fluorescence spectrometer analyzer, maximum continuous output power 4.0 kW, voltage (positive voltage) 20-60 kV, current 2-150 mA, end window type Rh target X-ray tube, ZSX software, instrument measurement conditions are shown in Table 1.

[0047] Table 1 Instrument measurement conditions

[0048] Spectrum Crystal Collimator Detector 2 theta Measurement time Voltage Current Pulse height distribution Si-K alpha PETH S4 PC 109.080︒ 40s 30 KV 100 mA 100- 320 P-K alpha GeH S4 PC 141.108︒ 40S 30 KV 100 mA 150-280 Mn-K alpha LiF (200) S2 SC 62.962︒ 20S 50 KV 60 mA 50-500

[0049] Electronic balance: sensitivity 0.1 mg.

[0050] O / R 6 automatic electric heating sample melting machine: Beijing Yuxing Technology full-automatic sample melting machine, which can maintain a temperature of 1100°C, can realize different temperature and heating rate settings, has pre-oxidation, swinging during melting process, automatic mold making and other functions.

[0051] METTLER-TOLEDO AX204 electronic balance: precision 0.1 mg, maximum weighing 200 g.

[0052] Platinum-gold (Pt95%-Au5%) crucible and matching mold, suitable for fluorescent fusion sheet preparation, volume not less than 25 mL, suitable for automatic electric heating melting equipment.

[0053] The rest: sample weighing tools and other commonly used tools for chemical wet experiments.

[0054] In the following examples, silicon nitride manganese is prepared into an analysis sample with a particle size of <0.125 mm according to the method of "GB / T4010-2015 Iron alloy chemical analysis sample taking and preparation" in advance, and is fully mixed. Example one

[0055] Step one, mix the sample and oxidizing agent and place it in the middle of the platinum-yellow crucible with flux at the bottom: accurately weigh 7.0000 g (accurate to 0.0005 g) of Li2B4O7 flux and place it in a Pt95%-Au5% crucible, arrange it into a layer along the crucible wall with a concave pit about 1-2 mm higher than the center, so that the mixed sample and the molten oxidizing agent can be placed in the center concave pit, and the surface of the sample is leveled to the same level after spreading, respectively weigh 2.0000 g (accurate to 0.0005 g) of sodium carbonate-boric acid mixed oxidizing flux and 0.2000 g (accurate to 0.0001 g) of analysis sample into a small beaker, mix well, and carefully transfer it into the previously placed Li2B4O7 flux in the middle concave pit (the sample should avoid the Pt95%-Au5% crucible edge position 8-10 mm to prevent the sample from not being completely pre-oxidized and contacting the Pt95%-Au5% crucible causing corrosion);

[0056] Step two, place the borate glass round piece to be tested in the electric automatic melting furnace, set the melting analysis conditions and run the program automatically, transfer the crucible containing the sample, oxidizing agent and flux to the automatic melting furnace support, add 10 drops of release agent lithium iodide solution (200 g / L), set the melting program as follows: 500°C into the furnace, 30°C / min to 800°C, pre-oxidation and melting for 15 min, 30°C / min to 1050°C, static melting for 3 min, heating and shaking for 12 min, start the program to begin automatic melting;

[0057] Step three, melt completely automatic casting cooling sample demoulding obtains X fluorescence analysis glass round piece, completes all pre-oxidation, melting step under the above set temperature program and temperature, automatic casting, cooling, checks sample state requirement to meet no unmelting, crack, bubble or segregation and other defects, pastes label on the qualified sample upper surface, manual demoulding takes out qualified sample, obtains X fluorescence analysis diameter 32±2mm glass round piece to be measured;

[0058] Step four, optimization analysis parameter establishes working curve executes sample analysis to obtain measured element content, weighs 2 typical silicon nitride manganese samples, silicon calcium standard sample 1, silicon aluminum barium standard sample 1, and unequal amount of silicon manganese, silicon calcium barium alloy standard sample and typical silicon nitride manganese mixed standard sample 4 listed in table 2, establishes working curve with 8 calibration samples, each measured component content is seen in table 3, completes step 1 according to the same sample processing method, before step 2, 200, 200, 400ug of phosphorus standard solution is added to the third, fourth, sixth calibration samples respectively, and then the glass round piece is prepared according to steps 2, 3, cooled, and pasted with a label.

[0059] The special operation software provided with the X fluorescence machine analyzer is used according to the instruction to detect the calibration sample, obtain a linear equation, establish the calibration curve of the measured element, check the linearity of the calibration curve through the linear correlation of the calibration curve, and the correlation coefficient r is required to be >0.999, the linear equation of each measured element and the correlation coefficient r are seen in table 4.

[0060] The glass round piece of the sample to be detected is measured in turn, and the analysis results of silicon, manganese and phosphorus elements are directly read out.

[0061] Table 2 calibration curve preparation table (%)

[0062]

[0063] Table 3 content range of each element in calibration sample (%)

[0064] Element Si Mn P Content range 24.12-60.30 0.12-19.70 0.015-0.230

[0065] Table 4 regression equation and correlation coefficient of calibration curve

[0066] Element Regression equation Correlation coefficient Si w Si = 0.590116 Si -1.02031 0.9996 Mn w Mn = 0.100329 Mn -0.0719577]]> 0.9998 P w P = 0.218025 P - 0.0290817 0.9997

[0067] The glass round piece of the sample to be detected is measured in turn, and the analysis results of silicon, manganese and phosphorus elements are directly read out.

[0068] Table 5 X fluorescence method determination results of example sample (%)

[0069] Sample No. Si Mn P Manganese silicon nitride HY00230 30 60 140 45.83 11.26 0.046 Manganese silicon nitride HY00230 30 60 246 40.64 12.35 0.051 Manganese silicon nitride HY00230 30 60 488 44.39 13.42 0.059 Manganese silicon nitride HY00240 20 41 287 41.96 11.56 0.027

[0070] Working principle of the present application:

[0071] The powder sample is mixed with a sodium carbonate-boric acid mixed flux with a lower melting point than lithium tetraborate (melting point of sodium carbonate 851℃, melting point of boric acid 722℃, melting point of mixed flux about 800℃), and is placed in the center of a platinum-gold crucible padded with a certain thickness of lithium tetraborate with a melting point of 930℃, so that the lithium tetraborate acts as a container. The temperature is raised from 500℃ to 800℃ and maintained, at which time the sodium carbonate-boric acid completes the oxidation of the metal components in the sample, removes the metal effect and reducing property of the sample, and avoids corrosion of the platinum-gold crucible during direct melting. The temperature is then raised to 1050℃ to complete the melting in an automatic melting furnace, and the glass disc is cast into a suitable glass disc for X-ray fluorescence spectrometer measurement. The fluorescence X-ray intensity of the measured elements in the glass disc is measured. According to the calibration curve or equation, the content of the measured element is obtained.

[0072] Precision experiment:

[0073] The typical silicon nitride manganese sample is independently measured according to the present scheme for 6 times to obtain SD and RSD, and the data are shown in Table 6 below.

[0074] Table 6 Precision test data (%)

[0075]

[0076] The data show that the precision of the method meets the precision expectation value requirements of the measured substance in the content range in GB / T 32465-2015 Chemical Analysis Method Verification Confirmation and Internal Quality Control (target component content 100%, RSD expectation value <1.3%, target component content 10%, RSD expectation value <1.9%, target component content 1%, RSD expectation value <2.7%, target component content 0.010%, RSD expectation value <3.70).

[0077] Accuracy experiment:

[0078] a), Select a typical sample and measure according to the present method and compare with the measurement results of chemical wet method and ICP-OES method. The data groups measured by the two methods are in good agreement, as shown in Table 7 below.

[0079] Table 7 Test data of different methods (%)

[0080]

[0081] The above describes one embodiment of the present application in detail, but the content described is only a preferred embodiment of the present application and cannot be considered as limiting the scope of the present application. Any equivalent changes and improvements made within the scope of the present application should still be included in the patent coverage of the present application.

[0082] Comparative Example 1

[0083] This comparative example is to analyze silicon, manganese and phosphorus in silicon nitride manganese (No. HY002404058071) by chemical wet method and ICP-OES method, which consists of the following steps:

[0084] Step one, determination of silicon content in silicon nitride manganese (reference CSM04141401-2001 Manganese-silicon alloy-determination of silicon content-perchloric acid dehydration gravimetric method):

[0085] Accurately weigh about 0.5g of silicon nitride manganese analysis sample with particle size less than 0.125mm, put the sample into an iron crucible containing 5g of sodium peroxide, mix well, and cover with 1g of sodium perchlorate. Low temperature dissolution at 400℃, heat to 700℃ in a high temperature furnace for 15min, and take out slightly cool. Put the crucible into a beaker containing 100mL of hot water for leaching, and wash the crucible. Add 20mL of hydrochloric acid to the beaker, after the salt is dissolved, add 30-50mL of perchloric acid, heat and evaporate for 10-15min until the perchloric acid smoke is generated. Take out slightly cool, add 10mL of hydrochloric acid and 80ml of hot water, heat to dissolve the salt, and drop a few drops of hydrogen peroxide to reduce the solution to clear.

[0086] Filter the above sample solution while hot with medium speed filter paper, retain the filtrate, and wash the beaker with a rubber head scrubber and hot hydrochloric acid (5+95), wash the filter paper with hot hydrochloric acid (5+95) until there is no yellow color of iron salt, and finally wash the precipitate with hot water until there is no chlorine ion, and check with silver nitrate solution (10g / L). Place the beaker containing the filtrate and washings on the hot plate and evaporate to about 200mL of solution volume. Add 10mL of perchloric acid and follow the same operation as above for the second dehydration and filtration to recover the silicon in the filtrate.

[0087] Put the secondary precipitate together with the filter paper into a platinum crucible, low temperature ashing in a muffle furnace at 1000℃ for 30min, take out slightly cool, place in a desiccator and cool to room temperature, and weigh. Re-calcine to constant weight (m1).

[0088] Add a few drops of sulfuric acid (1+1) and about 5mL of hydrofluoric acid to the platinum crucible, heat and evaporate to dryness, add 2mL of hydrofluoric acid, low temperature heat and evaporate until white smoke of sulfur trioxide is generated, and place in a muffle furnace and calcine for 15-20min. Take out slightly cool, place in a desiccator and cool to room temperature, weigh, and calcine to constant weight (m2). Simultaneously determine the blank to obtain (m3)=(m 01 )-(m 02 ).

[0089] Calculate the silicon content in mass fraction according to the following formula:

[0090]

[0091] In the formula: m1 - the mass of the impure silicon dioxide and platinum crucible before volatilization, g; m2 - the mass of the residue and platinum crucible after volatilization, g; m3 - the mass of the silicon used for the blank test with the test sample, g; m - the mass of the test sample, g; 0.4674 - the coefficient for converting silicon dioxide into silicon.

[0092] Step two, determination of the manganese content in the silicon nitride manganese (refer to CSM 04 14 25 02-2001 Manganese-silicon alloy - Determination of manganese content - Ammonium persulfate oxidation volumetric method):

[0093] About 0.40 g of the silicon nitride manganese analysis sample with a particle size of less than 0.125 mm is accurately weighed in a 500 mL conical flask, 20 mL of nitric acid (1+1), 1 mL of hydrofluoric acid are added, and dissolution is performed on a hot plate, 30 mL of sulfuric acid (1+1) is added, 20 mL of phosphoric acid is added, heating is performed until smoke is generated, and then the sample is removed, slightly cooled, 200 mL of water is added, and salts are dissolved, 10 mL of silver nitrate solution (10 g / L) is added, 40 mL of ammonium persulfate solution (200 g / L) is added, heating and boiling are performed for 10 min, and then the sample is removed and cooled. Titration is performed with a 0.10 mol / L ferrous ammonium sulfate standard titration solution until a light red color is obtained, 3 drops of N-phenyl-p-aminobenzoic acid indicator (2 g / L) is added, and titration is continued until a bright green color is obtained, which is the end point. 0.1 g of a silicon manganese alloy standard sample (number GSB03-2600-2010, Jilin Ferroalloy, Mn 67.96%) is simultaneously weighed and dissolved and titrated according to the sample method, and the manganese content is calculated according to the following formula, expressed as a mass fraction:

[0094]

[0095] In the formula: Cs - the manganese content in the silicon manganese standard sample, %; Vi - the volume of the ferrous ammonium sulfate standard titration solution consumed in the titration of the analysis sample, mL; Vs - the volume of the ferrous ammonium sulfate standard titration solution consumed in the titration of the standard sample, mL; ms - the mass of the standard sample, g; m i - the mass of the test sample, g.

[0096] Step three, determination of the phosphorus content in the silicon nitride manganese (ICP-OES method)

[0097] About 0.5 g of the silicon nitride manganese analysis sample with a particle size of less than 0.125 mm is accurately weighed, the test sample is placed in an iron crucible containing 5 g of sodium peroxide, mixed, and covered with 1 g of sodium perchlorate. Low-temperature dissolution is performed at 400°C, and the temperature is increased to 700°C for high-temperature melting in the furnace for 15 min, and then the sample is removed and slightly cooled. The crucible is placed in a beaker containing 100 mL of hot water for leaching, and a small amount of 1+1 hydrochloric acid is used to wash the crucible. 50 mL of 1+1 hydrochloric acid is added to the beaker, and heating is performed to dissolve the salts and residues until the solution is clear, and then the solution is cooled and transferred into a 200 mL volumetric flask, and mixed. 20 mL is taken and diluted to the mark in a 100 mL volumetric flask, and mixed for testing. A blank solution is simultaneously prepared.

[0098] Preparation of working curve: 5 portions of 20 mL blank solution were taken in 100 mL volumetric flask, and 0, 5, 25, 32, 62 ug of phosphorus standard solution was added, corresponding to the P content of 0.00%, 0.010%, 0.050%, 0.064%, 0.124% of 0.5000 g sample in turn, diluted to the mark, and shaken well as the calibration solution. The ICP spectrometer was started and stabilized, and the special operation software equipped with the inductively coupled plasma emission spectrometer (ICP-OES) was used to select multiple analysis lines, and the phosphorus (P) element analysis line spectral intensity of the calibration curve solution was measured on the inductively coupled plasma emission spectrometer in turn, and the phosphorus content and phosphorus element intensity first equation was obtained, and the best analysis line and analysis parameter (power: 1150W; pump speed: 35r / min; auxiliary gas flow: 0.5L / min; plasma observation height: 12cm; integration time: short wave 15s; cooling gas flow: 12L / min; atomizer gas flow: 0.7L / min; sample flushing time: 30s; atomizer: 1.5mm high salt; phosphorus analysis line: P178.284nm) were selected by observing the spectral peak, background and interference, and the calibration solution was analyzed in turn, and the calibration curve was drawn, and the correlation coefficient of the calibration curve was checked to be >0.999, and the calibration curve was established, and the calibration curve was established. Figure 5 The blank solution and sample solution were introduced for determination, and the phosphorus element content % was directly read.

[0099] Table 8 Test data in the present comparative example

[0100]

[0101] In summary, the sodium carbonate-boric acid mixed flux has a good oxidation-reduction effect on the silicon nitride manganese at a certain temperature, the platinum yellow crucible is padded with a certain thickness of lithium tetraborate with a relatively high melting point relative to sodium carbonate-boric acid (so that lithium tetraborate plays a role similar to a container), the silicon nitride manganese sample is pre-oxidized by increasing the temperature from a relatively low temperature and maintaining a sufficient oxidation reaction time, the metal effect and reducing property of the sample are removed, the problem of corrosion caused by the contact of the sample in the metal state and the reducing state to the platinum yellow crucible is avoided, and then the temperature is increased for melting and casting into a suitable glass disc for X-ray fluorescence spectrometer measurement, and the fluorescence X-ray intensity of the measured elements in the glass disc is measured. According to the calibration curve or equation, the content of the measured element is obtained.

[0102] The linear range covers the analysis range of the conventional sample and is uniformly distributed in the form of gradient, which can be applied to the analysis of silicon 30-60%, manganese 0.20-20%, silicon 0.010-0.25% silicon nitride manganese alloy sample. The test verification results are accurate and reliable, consistent with the chemical method, and can meet the detection analysis and quality control requirements of different specifications of silicon nitride manganese samples.

[0103] Although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A method for the glass fusion X-ray fluorescence spectroscopic analysis of silicon nitride manganese alloys, characterized in that, It comprises the following steps: Step one, weigh the flux for quantitative melting and place it in a platinum yellow crucible, arrange it into a concave shape along the wall of the crucible, which is slightly lower than the surrounding 1mm-2mm, so that the mixed sample and the melting oxidant can be placed in the central concave part, and the sample and the mixed melting oxidant are leveled to be at the same level with the surface of the flux for melting, the flux for melting is lithium tetraborate, and the amount is 30-40 times of the sample amount; the melting oxidant is a mixed flux of sodium carbonate-boric acid, which is ground and sieved into a particle size of 0.15mm-0.25mm powder, dried at 105±5℃, and sealed and stored in a desiccator, and sodium carbonate and boric acid are both analytically pure, and the amount is 15-25 times of the sample amount; Step two, transfer the crucible containing the sample, the melting oxidant and the flux for melting to the automatic melting furnace, add a certain amount of release agent, set the melting program to perform automatic melting, the release agent is lithium iodide, which is of superior purity and ≥99.9%, and is prepared into a 200g / L aqueous solution, and the amount added is 8-12 drops, and the set automatic melting program is 500℃ into the furnace, 30℃ / min to 800℃, 15min of pre-oxidation melting, 30℃ / min to 1050℃, 3min of static melting, 10-15min of melting while heating and shaking, and after the completion of the entire oxidation and melting steps at the set temperature, the automatic melting furnace performs automatic casting outside the furnace, natural cooling, air cooling, labeling on the upper surface, manual demolding to take out the sample piece, and checking the glass disc quality requirements to meet the no unmelting material, crack, bubble or segregation defects, and obtaining the glass disc for X-ray fluorescence analysis; Step three, weigh the silicon manganese nitride calibration samples with determined values determined by classical chemical wet method and ICP-OES method respectively, so that the calibration samples are not less than 6, complete step one according to the same sample treatment method, add a certain amount of phosphorus standard solution to 2-3 samples before step two, so that the content of each measured component can cover the sample analysis range and show uniform gradient distribution, then prepare the glass disc according to step two, cool and label; detect the calibration sample by referring to the special operation software provided with the X-ray fluorescence analyzer, establish the calibration curve of the measured element, check the linearity of the calibration curve through the linear correlation of the calibration curve, and the correlation coefficient r is required to be >0.999; Determine the glass disc of the sample to be tested in turn, and directly read out the analysis results of silicon, manganese and phosphorus elements.

2. The method of glass fusion X-ray fluorescence spectroscopic analysis of silicon nitride manganese alloy according to claim 1, characterized in that: The sample particle size in step one is required to be <0.125mm, and the sample is dried and mixed uniformly before weighing.

3. The method for the glass fusion X-ray fluorescence spectrometric analysis of silicon nitride manganese alloys according to claim 2, characterized in that: The melting oxidant and the sample in step one are fully mixed and uniform in a 20mL glass beaker.

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