Method for detecting 11 elements of ferrosilicon alloy by X fluorescence detection of direct oxidation fusion sample

Abstract

The application provides a composite flux and a method for detecting 11 elements in ferrosilicon alloy by X fluorescence detection of direct oxidation fusion sample, adopts 99.50% Li2B4O7-0.50% LiI, 99.0% Li2B4O7-1.0% LiBr and coarse-grained Li2B4O7 as the underlying composite flux, coarse-grained Li2B4O7 is in the uppermost layer, can dig out a hemispherical recess to hold the sample and oxidant, uses Li2CO3 and LiOH as the oxidant, designs the oxidation fusion temperature parameter curve, directly fuses and forms a sheet by oxidation, and meanwhile, the contact with and corrosion of the platinum yellow crucible are avoided. The application realizes the synchronous detection of 11 elements, i.e. Si, Fe, Mn, Cr, P, Al, Ca, Ti, V, Ni and Cu in the ferrosilicon alloy. By using the method, the detection time of a single sample is less than 120 minutes, the detection cost is lower than that of the national standard method, the detection process is simple, and the detection accuracy and precision are high.

Description

Technical Field

[0001] This invention belongs to the field of alloy detection, specifically relating to a composite flux and a method for X-ray fluorescence detection of 11 elements in ferrosilicon alloys using direct oxidation melting sample preparation. Background Technology

[0002] Ferrosilicon alloys are widely and extensively used in steelmaking, primarily for deoxidation and silicon supplementation. Silicon, as a major element and a crucial regulator of steel quality and performance, significantly improves steel's strength, hardness, and elasticity, increases its magnetic permeability, and reduces hysteresis losses in transformer steel. In GB2272-2020 "Ferrosilicon," ferrosilicon alloys are mainly classified into four categories: high-silicon ferrosilicon, ordinary ferrosilicon, low-aluminum ferrosilicon, and high-purity ferrosilicon. With increasing demands for ferrosilicon quality in steelmaking, high-purity ferrosilicon has been further subdivided into varieties such as low-carbon, low-titanium high-purity ferrosilicon.

[0003] With the rapid development of new energy sources, ferrosilicon alloys are playing a more diverse and specific role in increasing the variety of steel products and improving steel quality. This necessitates strict control over the internal components of ferrosilicon alloys, and the number of elements requiring testing is constantly increasing. Currently, the elements requiring testing include Si, Fe, Mn, Cr, C, P, S, Al, Ca, Ti, V, Ni, and Cu, totaling more than thirteen.

[0004] There are a total of eleven methods for detecting the content of elements in ferrosilicon alloys. For carbon and sulfur in ferrosilicon, the methods used are GB / T4333.10-2019 "Determination of Carbon Content in Ferrosilicon - Infrared Absorption Method" and GB / T4333.7-2019 "Determination of Sulfur Content in Ferrosilicon - Infrared Absorption Method and Chromatographic Separation Barium Sulfate Gravimetric Method". These two methods allow for simultaneous detection and are relatively convenient to use. For the other eleven elements, there is no single method that allows for simultaneous detection.

[0005] The existing detection method, GB / T24194-2009 "Determination of the Content of Ferrosilicon, Aluminum, Calcium, Manganese, Chromium, Titanium, Copper, Phosphorus and Nickel by Inductively Coupled Plasma Atomic Emission Spectrometry," can only detect trace amounts of these eight elements in ferrosilicon. It employs a quaternary acid solution system of nitric acid, hydrofluoric acid, hydrochloric acid, and perchloric acid, resulting in a complex procedure, with single-sample testing taking over 3 hours and low efficiency. Furthermore, it requires an expensive inductively coupled plasma atomic emission spectrometer (ICP-AES), with a single unit costing over 700,000 RMB for trace detection. The detection process necessitates argon excitation and cooling, the use of various chemical reagents and glassware for sample dissolution, the use of high-power hot plates for sample dissolution, and high-power fume hood ventilation. Therefore, the laboratory requirements are extensive, leading to high testing costs. The existing technology includes GB / T4333.5-2016, "Determination of Silicon, Manganese, Aluminum, Chromium and Iron Content by Wavelength Dispersive X-ray Fluorescence Spectrometry (Fused Glass Plate Method)," which can detect silicon and iron (two major elements) and manganese, aluminum, and chromium (three trace elements). However, it can only detect five elements, which is insufficient for detecting more than 11 elements. Furthermore, the preparation of the fused glass plate requires two steps: pre-oxidation of the sample and melting of the sample. The pre-oxidation process itself requires three steps: first, melting and forming a cup using lithium tetraborate; second, weighing and mixing the sample, followed by prolonged high-temperature oxidation; and third, weighing and adding potassium iodide after removing the pre-oxidized sample. The entire process is complex and fraught with difficulties; even a slight error can lead to experimental failure. During analysis, operators repeatedly perform tasks such as melting, forming cups, placing and removing samples, and clamping the platinum crucible at high temperatures, resulting in high labor intensity and potential discomfort due to the high temperatures.

[0006] In summary, existing detection methods can detect a total of twelve elements in ferrosilicon, but none of them cover vanadium. Analysts are persistently researching and inventing a method to simultaneously detect all elements except carbon and sulfur, in order to achieve high efficiency and low cost in detection.

[0007] For example, existing technologies such as the patent CN113960016A published on January 21, 2022, entitled "A method for rapidly determining the content of multiple elements in ferrosilicon", the patent CN115078339A published on September 20, 2022, entitled "A method for determining the content of manganese, phosphorus, aluminum, chromium, nickel, vanadium and titanium in high-purity ferrosilicon", and the patent CN111650231A published on September 11, 2020, entitled "A method for X-ray fluorescence spectroscopy analysis of the content of major elements in low-silicon ferrosilicon", have improved the quaternary acid dissolution system, but still have problems with multiple positions and environmental protection treatment of acid gas and acid liquid; some use the tablet pressing method for detection, and the accuracy and precision of the results cannot meet the high-quality control requirements; and some still cannot detect more than 11 elements.

[0008] The patent published on April 8, 2015, with publication number CN 104502169 A, entitled "Method for determining the element content in ferroalloys and the sample pretreatment method thereof", uses a pelleting method for detection. First, the ferroalloy is melted and pelletized using an alkaline mixed flux, followed by grinding, pelleting and detection. However, its operation process is relatively complicated and the detection accuracy cannot meet the requirements. Summary of the Invention

[0009] The purpose of this invention is to provide a composite flux that uses 99.50%Li₂B₄O₇-0.50%LiI, 99.0%Li₂B₄O₇-1.0%LiBr, and Li₂B₄O₇ as the base composite flux. First, 99.50%Li₂B₄O₇-0.50%LiI is laid as the bottom layer, followed by 99.0%Li₂B₄O₇-1.0%LiBr, and finally Li₂B₄O₇. Utilizing the large angle of repose of the last layer of Li₂B₄O₇, a hemispherical recess can be carved out to hold the sample and oxidant. Covering it with Li₂B₄O₇ allows for complete oxidation and melting of the sample, ensuring complete oxidization and participation in the melting process to form a glassy molten sheet, without affecting the accuracy of the detection results. Simultaneously, it avoids contact and corrosion with the platinum crucible.

[0010] Another objective of this invention is to provide a method for X-ray fluorescence detection of 11 elements in ferrosilicon alloys using direct oxidation-melting sample preparation. This method utilizes the aforementioned composite flux as the base flux and Li₂CO₃ and LiOH as oxidants. By designing oxidation-melting heating parameters, it enables direct oxidation-melting sample preparation, facilitating convenient and accurate detection using an X-ray fluorescence spectrometer. Furthermore, it achieves the detection of 11 elements (Si, Fe, Mn, Cr, P, Al, Ca, Ti, V, Ni, and Cu) in ferrosilicon alloys, providing a wide detection range for these 11 elements, from high to low concentrations, down to the ppm level and up to the constant level. Using this method, the detection time for a single sample is less than 120 minutes, the detection cost is lower than the national standard method, the detection process is simple, and the detection accuracy and precision are high.

[0011] The specific technical solution of this invention is as follows:

[0012] A composite flux comprising 99.50% Li₂B₄O₇-0.50% LiI, 99.0% Li₂B₄O₇-1.0% LiBr and Li₂B₄O₇;

[0013] The mass ratio of 99.50%Li₂B₄O₇-0.50%LiI, 99.0%Li₂B₄O₇-1.0%LiBr, and Li₂B₄O₇ is 4:1:3.

[0014] The 99.50%Li2B4O7-0.50%LiI is laid at the bottom of the crucible, followed by the 99.0%Li2B4O7-1.0%LiBr, and the top layer is Li2B4O7.

[0015] The 99.50%Li₂B₄O₇-0.50%LiI refers to a mixture of 99.50% Li₂B₄O₇ and 0.50% LiI by mass; its impurity content is ≤100ppm, it forms 0.5mm beads, and its angle of repose is 15°; the reagent does not pulverize or become damp in air, its water absorption rate is less than 0.1% after 2 hours, and its uniformity reaches 99.9% or higher. Uniformity indicates the evenness of the distribution of each element in the reagent. Because this reagent is a mixture of Li₂B₄O₇ and LiI, it is required that the mixing and pelletizing be very uniform. A certain amount of reagent is randomly weighed, and the I content is required to be approximately 99.9% similar.

[0016] The 99.0%Li₂B₄O₇-1.0%LiBr refers to a mixture of 99.0% Li₂B₄O₇ and 1.0% LiBr by mass, with an impurity content ≤100ppm, forming 0.5mm beads with an angle of repose of 15°. This reagent does not pulverize or become damp in air, has a water absorption rate of less than 0.1% after 2 hours, and a uniformity of over 99.9%. Uniformity indicates the evenness of the distribution of each element in the reagent. Because this reagent is a mixture of Li₂B₄O₇ and LiBr, very uniform mixing and pelletizing are required. Randomly weighed amounts of the reagent must have a Br content close to 99.9%.

[0017] The Li2B4O7 particles are of high quality and purity, with a particle size of 0.5 to 3.5 mm, and are irregular in shape with many edges and corners, and an angle of repose of 47°.

[0018] This invention provides a method for X-ray fluorescence detection of 11 elements in ferrosilicon alloys using direct oxidation melting sample preparation. The method utilizes the aforementioned composite flux and includes the following steps:

[0019] 1) In the center of the crucible, first lay 99.50%Li2B4O7-0.50%LiI at the bottom layer of the crucible, then lay 99.0%Li2B4O7-1.0%LiBr, and lay Li2B4O7 on the top layer. Use the top layer of Li2B4O7 to dig out a hemispherical depression, pour the sample and oxidant into the depression, and then cover it with Li2B4O7.

[0020] 2) Heat the platinum crucible to induce oxidation and melting;

[0021] 3) Prepare glass flakes and detect them using an X-ray fluorescence spectrometer.

[0022] In step 1), a hemispherical recess is carved out using the top layer of Li₂B₄O₇, ensuring that the center of the recess is aligned with the center of the crucible. The thickness of the recess walls is the same or nearly the same throughout, ensuring that the sample and oxidant within the recess are at roughly the same distance from the crucible surface. This guarantees the uniformity of the melting and oxidation process. The flux is in direct contact with the crucible, while the sample and oxidant are contained within the flux recess, avoiding direct contact with the crucible.

[0023] The crucible is selected from platinum yellow crucibles and has a composition of 95 wt% Pt + 5 wt% Au;

[0024] In step 1), the total mass of 99.50%Li2B4O7-0.50%LiI, 99.0%Li2B4O7-1.0%LiBr and Li2B4O7, the mass ratio of the sample and the oxidant is 45:1:6.

[0025] In step 1), the mass ratio of the topmost layer of Li2B4O7 to the covering layer of Li2B4O7 is 3:1;

[0026] In step 1), the sample is a silicon-iron alloy standard sample or a silicon-iron alloy sample to be tested;

[0027] In step 1), the oxidant refers to a mixture of lithium carbonate and lithium hydroxide;

[0028] The mass ratio of lithium carbonate to lithium hydroxide is 7:5;

[0029] In step 2), the platinum crucible is heated as follows: first, it is kept at 450℃ for 2.5 minutes, then the temperature is increased to 500℃ in 2 minutes, kept at 500℃ for 5 minutes, then increased to 850℃ in 50 minutes, kept at 850℃ for 5 minutes, then increased to 1050℃ in 5 minutes, and kept at 1050℃ for 5 minutes, with a swing angle of 20° during this process. Finally, it is kept at 1050℃ for 8 minutes, with a swing angle of 35° during this process. Initially, the swing angle is controlled at 20° because the sample and reagents have not yet completely melted into a viscous liquid state, and some loose flux remains. If the swing angle is too large, the reagents and sample will be thrown out. Then, the swing angle is controlled at 35° because the sample and reagents have completely melted into a viscous liquid state, and a larger swing angle allows for more uniform mixing.

[0030] In step 3), X-ray fluorescence spectrometry is used for detection. First, a standard silicon-iron alloy is used as the sample to obtain the working curves of each element, Si, Fe, Mn, Cr, P, Al, Ca, Ti, V, Ni, and Cu. Then, the silicon-iron alloy sample to be tested is tested, and the content of each element, Si, Fe, Mn, Cr, P, Al, Ca, Ti, V, Ni, and Cu in the silicon-iron alloy sample to be tested is obtained using the working curves of each element.

[0031] In step 3), X-ray fluorescence spectrometry is used for detection, and the parameters are set as follows:

[0032] Detection of Si element: voltage 40KV, current 70mA, PHD 5-115, channel angle 108.88, measurement time 40.00 seconds;

[0033] Fe element detection: voltage 40KV, current 70mA, PHD 5-145, channel angle 57.52, measurement time 40.00 seconds;

[0034] Mn element detection: voltage 40KV, current 70mA, PHD 15-125, channel angle 62.97, measurement time 40.00 seconds;

[0035] Cr element detection: voltage 40KV, current 70mA, PHD 20-155, channel angle 69.36, measurement time 40.00 seconds;

[0036] Detection of phosphorus (P) element: voltage 40 kV, current 70 mA, PHD 10-90, channel angle 141.03, measurement time 40.00 seconds;

[0037] Al element detection: voltage 40KV, current 70mA, PHD 10-105, channel angle 144.58, measurement time 40.00 seconds;

[0038] Ca element detection: voltage 40KV, current 70mA, PHD 30-140, channel angle 113.09, measurement time 40.00 seconds;

[0039] Ti element detection: voltage 40KV, current 70mA, PHD 10-130, channel angle 86.14, measurement time 40.00 seconds;

[0040] Detection of V element: voltage 40KV, current 70mA, PHD 20-120, channel angle 76.94, measurement time 40.00 seconds;

[0041] Ni element detection: voltage 40KV, current 70mA, PHD 15-100, channel angle 48.67°, measurement time 40.00 seconds;

[0042] Cu element detection: voltage 40KV, current 70mA, PHD 15-105, channel angle 45.03, measurement time 40.00 seconds.

[0043] The present invention provides a method for X-ray fluorescence detection of 11 elements in ferrosilicon alloys using direct oxidation melting sample preparation. This method is used to detect 11 elements: Si, Fe, Mn, Cr, P, Al, Ca, Ti, V, Ni, and Cu. The detection ranges are as follows: Si 45.0–80.0%, Fe 5.0–55.0%, Mn 0.010–0.70%, Cr 0.001–0.50%, P 0.003–0.10%, Al 0.02–3.0%, Ca 0.002–4.00%, Ti 0.005–0.300%, V 0.001–0.05%, Ni 0.002–0.50%, and Cu 0.005–0.40%.

[0044] Although there are various existing detection methods, such as X-ray fluorescence spectrometry and inductively coupled plasma atomic emission spectrometry for large-scale instrument detection, sample decomposition includes high-temperature melting and tetrabasic acid-based sample dissolution. However, these methods require a large number of reagents, resulting in low detection efficiency and high detection risks.

[0045] The design concept of this invention is as follows:

[0046] First, a direct oxidation melting system is constructed. This system encapsulates the oxidant and sample mixture in the center of the entire melt. Below is a composite flux base designed in this invention, and above is a Li2B4O7 flux cover. On the one hand, the designed composite flux and oxidant can achieve complete oxidation, and on the other hand, it avoids contact with the platinum crucible, thus preventing the corrosion of the platinum crucible by reducing elements.

[0047] In ferrosilicon alloys, elemental silicon and iron, especially elemental iron, readily form solid solutions with platinum and gold at high temperatures, leading to corrosion of the platinum crucible. A thick layer of composite flux is applied to the bottom of the platinum crucible. This serves two purposes: firstly, it prevents direct contact between the elemental metals in the alloy and the crucible; secondly, after the alloy oxidation is complete, it can participate in sample melting, forming a glassy molten sheet. The uppermost layer of this composite flux, Li₂B₄O₇, has a large angle of repose, allowing for the creation of hemispherical recesses. These recesses completely fill the mixture of sample and oxidant, achieving 100% oxidation of the elemental elements into oxides within the recesses. Furthermore, the hemispherical coating of the composite flux prevents contact and corrosion of the platinum crucible by the elemental metals. The pure Li₂B₄O₇ flux covering the sample and oxidant mixture prevents splashing during the oxidation process of the ferrosilicon alloy, ensuring no sample loss, and also prevents the splashed elemental metals from corroding the platinum crucible.

[0048] In this invention, to ensure the composite flux forms a hemispherical depression and to prevent it from slipping or sinking when being scraped from the center of the platinum crucible towards the outer perimeter, a sufficiently large static stacking angle is required. By measuring the angle of repose, the amount and stacking order of the initial composite flux were determined. 4 grams of bead-shaped 99.50% Li₂B₄O₇-0.50% LiI + 1 gram of 99.0% Li₂B₄O₇-1.0% LiBr were sequentially laid in the crucible. Then, 3 grams of Li₂B₄O₇ were weighed and laid on top. Because the top layer of Li₂B₄O₇ particles are large and irregularly shaped, they are less prone to slipping, making it easy to scrape out a downward-sloping hemispherical depression. Furthermore, considering that the 11 elements in silicon-based alloys are highly susceptible to X-ray fluorescence spectral interference caused by elements introduced by external reagents, this invention designs a unique composite flux with a ratio of "4 g 99.50% Li₂B₄O₇ - 0.50% LiI + 1 g 99.0% Li₂B₄O₇ - 1.0% LiBr + 3 g Li₂B₄O₇" to minimize the impact of introduced elements. Comparing blank tests with other single fluxes, considering the effects of various demolding elements on Ti and Al, as well as the cumulative effect of residual elements in the reagents on the detection results, only the composite flux with the specific ratio designed in this invention shows the best performance and the least interference.

[0049] The principle for determining the type and ratio of the sample and oxidant mixture in this invention is as follows:

[0050] Elemental silicon is a nonmetal, and it undergoes the following reaction in a strongly alkaline solution at room temperature:

[0051]

[0052] X-ray fluorescence detection involves melting the sample into a glass slide at high temperatures before detection. Since aqueous solutions are not permitted at these high temperatures, a low-melting-point strong base reagent must be selected. The reagent is melted into a liquid state by heating on a dry basis. In this liquid state, elemental silicon and iron fuse with the flowing ions to complete the oxidation. Based on the principle of X-ray fluorescence formation, using a strong base reagent with light elements can reduce spectral interference. Reagent properties confirmed that LiOH has a melting point of 462℃ and Li₂CO₃ has a melting point of 720℃. These two reagents were chosen for oxidation at high temperatures. The specific reaction formula is as follows:

[0053] ;

[0054] The direction of a chemical reaction is determined by the Gibbs free energy, which is given by the formula: ΔG = ΔH - TΔS, where ΔG is the reaction free energy. When it is negative, the reaction proceeds to the right, and when it is positive, the reaction proceeds to the left; ΔH is the enthalpy change, ΔS is the entropy change, and T is the reaction temperature.

[0055] ΔH=1216.04 + 2×484.93 - 1649.33- 2×598.93 - 2×110.54 - 241.84=92.23;

[0056] ΔS=80.33 + 2×37.91 + 2×197.90 + 188.74 - 18.83 - 2×90.17 - 2×42.80=455.92;

[0057] ΔG = ΔH - TΔS = 92.23-298.15×0.45592 = -43.7;

[0058] Calculations show that the reaction proceeds to the right at room temperature. Since there are few negative values, the reaction rate is slow. When the temperature is raised to the point where LiOH begins to melt, the reaction rate increases and elemental silicon can be gradually oxidized into lithium silicate.

[0059] LiOH and Li₂CO₃ are low-melting-point reagents. Li₂CO₃ acts as an oxidant to oxidize elemental silicon and iron, while LiOH, being a strong base, neutralizes silicic acid. This invention determines the initial temperature of the oxidation reaction based on the Gibbs free energy formula. Furthermore, to accelerate the reaction rate, the molar number of reactants must be greater than that of the reactants. After conditional experiments, the final ratio of the sample to the oxidant mixture was determined to be: 0.7000 g lithium carbonate + 0.5000 g lithium hydroxide + 0.2000 g sample. At this ratio, the oxidation effect is optimal, and the molten glass is clear, without spots or impurities.

[0060] NO3 must not be used for the oxidation of ferrosilicon alloys. - High-temperature oxidation of salts and BaO-like substances is extremely dangerous. Due to the violent oxidation reaction, the alloy is prone to splashing, resulting in sample loss and damage to the platinum crucible.

[0061] This invention utilizes a direct oxidation melting temperature program curve based on the properties of oxidants. X-ray fluorescence diffraction analysis of the uniformity of elemental components in the glass molten sheet, along with a temperature program set according to the melting and boiling points of each oxidizing agent, achieves complete oxidation of the elemental components, resulting in uniform distribution within the glass sheet. Verification using standard materials and different national standard methods shows that the ranges for silicon and iron are 0.51% and 0.21%, respectively, lower than the error of wet method detection. Because the elemental components are completely oxidized, the damage rate of the platinum crucible due to chemical corrosion is reduced to zero.

[0062] Furthermore, high concentrations of the I and Br dual release agent can interfere with Ti and Al elements. However, if it sublimates to a concentration that is too low, the glass melt cannot be cast, and even if it is cast, it is prone to cracking during the cooling stage. The method designed in this invention, involving a constant temperature of 1050℃ for 5 minutes (oscillation angle 20°) followed by a constant temperature of 1050℃ for 8 minutes (oscillation angle 35°), results in an I and Br dual release agent concentration of approximately 10 ppm. The impact on Ti and Al blanks is 0.015% and 0.02%, respectively. This impact can be eliminated through blank correction, and the glass melt casting success rate reaches over 99%.

[0063] Compared with existing technologies, this invention, through the design of the composite flux and its proportions, can create a hemispherical recess to hold the reagents and oxidant, and can reduce the influence of the flux on element detection. By selecting the oxidant and setting the heating parameters and swing angle, a one-step direct oxidation melting method for glass slide preparation can be achieved, resulting in a method for X-ray fluorescence detection of 11 elements in ferrosilicon alloys using direct oxidation melting sample preparation. The process is short, simple to operate, cost-effective, and more environmentally friendly. Attached Figure Description

[0064] Figure 1 The working curve for silicon;

[0065] Figure 2 Working curve for iron;

[0066] Figure 3 Working curve for manganese;

[0067] Figure 4 Working curve for chromium;

[0068] Figure 5 Working curve for phosphorus;

[0069] Figure 6 Working curve for aluminum;

[0070] Figure 7 Working curve for calcium element;

[0071] Figure 8 Working curve for titanium;

[0072] Figure 9 Working curve for vanadium;

[0073] Figure 10 Working curve for nickel;

[0074] Figure 11 Working curve for copper;

[0075] Figure 12 Comparison of experimental spectra at different melting temperatures;

[0076] Figure 13Comparison of experimental spectra at different melting times. Detailed Implementation

[0077] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0078] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.

[0079] Unless otherwise specified in the embodiments, the techniques or conditions described in the literature in this field or in accordance with the product manual may be followed.

[0080] The reagents used in this invention are as follows:

[0081] 99.50%Li₂B₄O₇-0.50%LiI, with impurity content ≤100ppm, in the form of 0.5mm beads, with an angle of repose of 15°; the reagent does not pulverize or become damp in air, with a water absorption rate of less than 0.1% after 2 hours, and a uniformity of over 99.9%.

[0082] 99%Li₂B₄O₇-1%LiBr, impurity content ≤100ppm, in the form of 0.5mm beads, with an angle of repose of 15°; this reagent does not pulverize or become damp in air, has a water absorption rate of less than 0.1% after 2 hours, and a uniformity of over 99.9%.

[0083] Li2B4O7, fine particles, impurity content ≤100ppm, bead-like particles, particle size ≤0.5mm;

[0084] Li2B4O7, coarse particles, high quality and purity, with a particle size of 0.5-3.5 mm, and an irregular shape with many edges and corners, and an angle of repose of 47°.

[0085] KI, Luoyang Tenai, high-quality pure;

[0086] Li2CO3, Luoyang Tenai, high-quality and pure;

[0087] LiOH, Xilong Chemical, analytical grade.

[0088] The equipment used in this invention:

[0089] Platinum crucible: Composition Au 5wt% + Pt 95 wt%, volume 30mL, abbreviated as "platinum crucible";

[0090] Electronic balance: Model AB204-S, Mettler Toledo, Switzerland;

[0091] Fully automatic electric melting furnace: Model FE0000-2D, CLAISSE, Canada;

[0092] Field emission scanning electron microscope: Model Sigma 300, Zeiss, Germany;

[0093] X-ray fluorescence spectrometer: Model MXF-2400, Shimadzu Corporation, Japan, power 3600W, 75µm beryllium window X-ray tube, tube voltage 40kV, tube current 70mA.

[0094] The present invention will be further illustrated by the following embodiments and comparative examples:

[0095] Example 1

[0096] A composite flux comprising 99.50% Li₂B₄O₇-0.50% LiI, 99.0% Li₂B₄O₇-1.0% LiBr and Li₂B₄O₇;

[0097] The mass ratio of 99.50%Li₂B₄O₇-0.50%LiI, 99.0%Li₂B₄O₇-1.0%LiBr, and Li₂B₄O₇ is 4:1:3.

[0098] The 99.50%Li2B4O7-0.50%LiI is laid at the bottom of the crucible, followed by the 99.0%Li2B4O7-1.0%LiBr, and the top layer is Li2B4O7.

[0099] The 99.50%Li2B4O7-0.50%LiI refers to a mixture of 99.50% Li2B4O7 and 0.50% LiI by mass; its impurity content is ≤100ppm, it is in the form of 0.5mm beads, and its angle of repose is 15°; the reagent does not pulverize or become damp in the air, its water absorption rate is less than 0.1% after 2 hours, and its uniformity reaches 99.9% or higher.

[0100] The 99.0%Li2B4O7-1.0%LiBr refers to a mixture of 99.0% Li2B4O7 and 1.0% LiBr by mass, with an impurity content ≤100ppm, forming 0.5mm beads with an angle of repose of 15°. This reagent does not pulverize or become damp in air, has a water absorption rate of less than 0.1% after 2 hours, and a uniformity of over 99.9%.

[0101] The Li2B4O7 is coarse-grained, of high quality and purity, with a particle size of 0.5–3.5 mm, and is irregular in shape with many sharp edges and corners, and has an angle of repose of 47°.

[0102] Example 2

[0103] A method for X-ray fluorescence detection of 11 elements in ferrosilicon alloys using direct oxidation melting sample preparation, employing the composite flux described in Example 1 above, includes the following steps:

[0104] 1) In the center of a 30mL platinum crucible, first weigh 4g of 99.50%Li₂B₄O₇-0.50%LiI and place it at the bottom layer. Then weigh 1g of 99.0%Li₂B₄O₇-1.0%LiBr and place it at the middle layer. Finally, weigh 3g of high-purity Li₂B₄O₇ and place it at the top layer. Use the top layer of Li₂B₄O₇ to carve out a hemispherical depression. Take another 100mL glass and accurately weigh in 0.7000g of Li₂CO₃ and 0.5000g of LiOH, then weigh in 0.2000g of the sample. Stir well with a glass rod and slowly pour it into the depression in the platinum crucible. Then weigh in 1g of high-purity Li₂B₄O₇ and cover it on the mixture of sample and oxidant.

[0105] In step 1), when digging out a hemispherical recess, the digging should ideally use only the top layer of pure Li₂B₄O₇. 4 grams of 99.50%Li₂B₄O₇-0.50%LiI should be placed at the bottom layer, and 1 gram of 99.0%Li₂B₄O₇-1.0%LiBr should be placed in the middle layer. Since these are bead-like particles, they are easy to roll, and if touched during digging, they will not affect the test results. Do not dig to the point of exposing the crucible to avoid corrosion. The diameter of the hemispherical recess is 25 mm, and the depth is 20 mm. Therefore, tanα = 25 ÷ 2 ÷ 20 = 0.625. Looking up the arctangent function, the angle α is 32°. Theoretically, reaching 32° is sufficient to dig out a hemispherical recess. Using the above-mentioned composite flux, the angle of repose for digging out a hemispherical recess is 36°, thus meeting the requirements for creating a hemispherical recess.

[0106] 2) Heat the platinum crucible for oxidation melting. Specifically, place the platinum crucible into a fully automatic electric melting furnace with a pre-programmed "oxidation melting temperature rise curve". The specific temperature rise curve is as follows: 450℃ for 2.5 minutes → 2 minutes to 500℃ → 500℃ for 5 minutes → 50 minutes to 850℃ → 850℃ for 5 minutes → 5 minutes to 1050℃ → 1050℃ for 5 minutes (oscillation angle 20°) → 1050℃ for 8 minutes (oscillation angle 35°).

[0107] 3) Prepare glass slides and perform X-ray fluorescence spectrometry (XRF) analysis. Specifically, select 15 types of ferrosilicon alloy standards from Table 1, prepare molten glass slides under the determined fusion conditions, and analyze the sample glass slides using the XRF parameters determined in Table 2. The working curves for 11 elements are shown in the figure. Figures 1-11 .

[0108] Working curves for each element:

[0109] Si Cs i =1.343262 Is i +3.349853, R=1.0000;

[0110] Fe C Fe =0.093162 I Fe +0.276461, R=1.0000;

[0111] Mn C Mn =0.242528 I Mn -0.196580, R=0.9990;

[0112] Cr C Cr =0.381123 I Cr -0.207739, R=0.9988;

[0113] PC P =0.474716 I P -0.019685, R=0.9987;

[0114] Al C Al =1.816258 I Al -0.302500, R=0.9998;

[0115] Ca C Ca =0.572386I Ca -0.173503, R=0.9999;

[0116] Ti C Ti =0.300195 I Ti -0.268099, R=0.9980;

[0117] VC V =0.237989 I V -0.209158, R=0.9973;

[0118] Ni C Ni =0.071869 I Ni -0.452069, R=0.9981;

[0119] Cu C Cu =0.064273 I Cu -0.514199, R=0.9986;

[0120] Cs i Concentration of Si element ， Is i The value represents the fluorescence intensity of Si; the values ​​for other elements are calculated similarly.

[0121] Table 1. Elemental composition of 15 types of silicon-iron alloys

[0122]

[0123] Table 2 X-ray fluorescence spectrometer detection parameters

[0124]

[0125] The spectral lines for each element are shown in Table 3 below.

[0126] Table 3. Energy of each spectral line and spectroscopic crystal.

[0127]

[0128] Using the working curves of the 11 elements that have been plotted, two other standard samples and six samples were randomly selected and tested according to the same method as in Example 2. The test results are shown in Table 4. From the comparative analysis of the tests, it can be seen that the results fully meet the allowable error range specified by the national testing standards for ferrosilicon alloys.

[0129] Table 4 Comparison of detection results using X-ray fluorescence method in Example 2

[0130]

[0131] The X-ray fluorescence detection method for 11 elements in Example 2 was successfully used in January 2024 and has been applied in routine testing. Eight samples were randomly selected on March 12, 2024. According to the comparative data analysis in Table 3, the results of the X-ray fluorescence method (range of eight samples) provided by this invention and the national standard method (X-ray fluorescence + ICP) are all within the allowable error range.

[0132] Note: The Ni and Ti values ​​for standard sample GT-07 do not have a specified range; this data is not included in the range calculation.

[0133] Comparative Example 1

[0134] To compare the interference of different fluxes on the test results, a blank test was conducted. The specific procedure was as follows: accurately weigh composite fluxes with different raw material compositions, add 0.7000 g of lithium carbonate and 0.5000 g of lithium hydroxide, stir evenly with a glass rod in a 100 ml glass beaker, and slowly pour into a platinum crucible; melt in an alloy melting furnace at 1050℃ for 25 minutes, and mold into a glass sheet. This glass sheet was used to detect 11 elements.

[0135] The specific selection of composite fluxes composed of different raw materials is as follows:

[0136] I. Blank test of high-quality coarse-grained pure Li₂B₄O₇ with a particle size of 0.5–3.5 mm, irregular shape, many edges and corners, and an angle of repose of 47°: Since pure Li₂B₄O₇ cannot be demolded after melting, the selected weighing ratio is 9 g of superior pure Li₂B₄O₇ + 1 g of KI mixed and melted. Six portions of the same flux ratio were weighed. Glass flakes were prepared under the determined experimental procedure. X-ray fluorescence spectrometry was used to detect the contents of the 11 elements under the experimental parameters specified in Tables 2 and 3. The content range of the 11 elements is shown in Table 5.

[0137] Table 5. Blank test data of 9g superior pure Li₂B₄O₇ + 1g KI mixed melting.

[0138]

[0139] As can be seen from Table 3, among the 11 elements, 7 elements such as Mn, Cr, P, Al, V, Ni, and Cu had zero blanks, indicating good results. However, there were blanks for Si, Fe, Ca, and Ti. The content of Si and Fe is about 80% and 20% respectively, so the impact of the blanks is not significant. However, the content of Ca and Ti is about 0.10%, especially for Ti, where the blank detection value is more than 5 times the sample content. Therefore, it is not suitable to analyze all 11 elements.

[0140] II. Blank test of fine-particle superior-grade pure Li2B4O7: Since pure Li2B4O7 cannot be demolded after melting, the selected weighing ratio is 9 grams of Li2B4O7 + 1 gram of KI mixed and melted. Six portions of the same reagent ratio were weighed and glass flakes were prepared under the determined experimental procedure. X-ray fluorescence spectrometry was used for detection under the same parameters. The analysis results of 11 elements are shown in Table 6.

[0141] Table 6. Blank test data of 9g Li2B4O7 + 1g KI mixture.

[0142]

[0143] As can be seen from Table 6, for the 11 elements, the blank values ​​of the fine-particle Li2B4O7 used in this study were smaller than those of the coarse-particle Li2B4O7 mentioned above. The blank values ​​for 8 elements, namely Mn, Cr, P, Al, Ca, V, Ni, and Cu, were zero, which is a good result. However, there were still blank values ​​for Si, Fe, and Ti. The contents of Si and Fe are about 80% and 20% respectively, so the blank values ​​have little impact. However, the contents of Ti are about 0.10%, and the blank detection value is still more than 5 times that of the sample content. Therefore, it is still not suitable for the analysis of 11 elements.

[0144] III. Impurity content ≤100ppm, in the form of 0.5mm beads, with an angle of repose of 15°; the reagent does not pulverize or become damp in air, with a water absorption rate of less than 0.1% after 2 hours, and a uniformity of 99.9% or higher. Blank test of 99.50%Li2B4O7-0.50%LiI flux: Since this reagent is a mixed flux and contains LiI release agent, no other release agent is needed. 10 grams are directly weighed and melted to obtain a glass flake. X-ray fluorescence spectrometry is used for detection under the same parameters. The analysis results of 11 elements are shown in Table 7.

[0145] Table 7. Blank test data of 99.50%Li₂B₄O₇-0.50%LiI

[0146]

[0147] As can be seen from Table 7, among the 11 elements, the 99.50%Li2B4O7-0.50%LiI mixed flux performed better than the Li2B4O7+KI combined flux. Although the blanks of 10 elements, including Si, Mn, Cr, P, Al, Ca, Ti, V, Ni, and Cu, were all detected, the results were generally low. In particular, the blank content of Ti decreased significantly, accounting for only about 10% of the sample content. However, due to the significant increase in Ni and Cu content, reaching 5 to 10 times the sample content, and the large fluctuations in the blank detection results of elements such as Al and Ca, it is still not suitable for the analysis of 11 elements in ferrosilicon alloys.

[0148] IV. Impurity content ≤100ppm, in the form of 0.5mm beads, with an angle of repose of 15°; the reagent does not pulverize or become damp in air, with a water absorption rate of less than 0.1% after 2 hours, and a uniformity of over 99.9%. Blank test of 99.0%Li2B4O7-1.0%LiBr: Since this reagent is also a mixed flux and contains LiBr as a release agent, no other release agent needs to be added. Simply weigh 10g and melt it to obtain a glass flake. Detect it using an X-ray fluorescence spectrometer under the same parameters. The analysis results of 11 elements are shown in Table 8.

[0149] Table 8. Blank test data of 99.0%Li₂B₄O₇-1.0%LiBr

[0150]

[0151] As can be seen from Table 8, the blank detection results of the 11 elements show that the 99.0%Li2B4O7-1.0%LiBr mixed flux has a unique characteristic: the detection value of Ti is zero. The contents of the other 10 elements such as Si and Fe are detected. The results of 9 elements are low, while the result of Al is high, with an average value of 1.0972%, which is more than 10 times the content of the sample. Therefore, a single flux is not suitable for the analysis of 11 elements.

[0152] Comparing the four single or mixed fluxes, the most obvious characteristic is that if the flux contains iodine release agent, the blank detection value of Ti element is high, and it increases with the increase of I element content; if the flux contains Br element release agent, the blank detection value of Al element is high, and it increases with the increase of Br element content.

[0153] V. Blank test of the above-mentioned 99.50%Li2B4O7-0.50%LiI+99.0%Li2B4O7-1.0%LiBr+coarse-particle Li2B4O7 composite flux: Based on the blank effect caused by various reagents, this invention provides a unique I and Br dual-demolding composite flux. The specific ratio is 4g of 99.50%Li2B4O7-0.50%LiI+1g of 99.0%Li2B4O7-1.0%LiBr+3g of coarse-particle Li2B4O7. Six parts of the composite flux were weighed and melted to obtain glass flakes. X-ray fluorescence spectrometry was used for detection under the same parameters. The analysis of 11 elements is shown in Table 9.

[0154] Table 9. Blank test data of the composite flux formulation of the present invention.

[0155]

[0156] As shown in Table 9, the detection results of the 11 elements in the blank test using the I / Br dual-release composite flux formulated according to the present invention are generally low. Although the data for Si, Fe, Ni, and Cu are slightly higher, their content proportions in the control sample are relatively low. From the precision analysis of the blank values, the range values ​​of the 11 elements are all below 0.03, fully meeting the requirements for sample detection baseline. Furthermore, the composite flux itself contains an ultra-low content of I / Br dual-release agent, eliminating the need for additional release agent and avoiding the influence of incompletely sublimated release agent on elements such as Al, Ti, Cr, and Ni. The composite flux provided by the present invention, combining the characteristics of each element, results in relatively low blank detection values ​​for the 11 elements, enabling simultaneous detection of all 11 elements.

[0157] Comparative Example 2

[0158] To prevent the unoxidized ferrosilicon alloy from contacting the platinum crucible, the sample mixed with oxidant needs to be encased in a composite flux. This invention designs a hemispherical recess carved into the composite flux. The thickness of the recess walls is uniform or nearly uniform throughout, ensuring that the sample and oxidant within the recess are at roughly the same distance from the crucible surface. This guarantees the uniformity of the melting and oxidation process. The flux is in direct contact with the crucible, while the sample and oxidant are contained within the flux recess, avoiding direct contact with the crucible. The uniformly stirred mixture of oxidant and sample is poured into the recess, where oxidation is completed. Subsequent shaking and melting will not damage the platinum crucible.

[0159] The composite flux used in this invention to create hemispherical recesses requires accumulating a 35mm diameter from the inner and outer circumference of the crucible towards the center. 。 The slope described above is higher at the outer perimeter and lower at the center. The angle formed by the static stacking of reagents is called the angle of repose, which is the maximum angle at which bulk materials can maintain natural stability when stacked.

[0160] Angle of repose tests were performed on each flux, and the results are shown in Table 10 below:

[0161] Table 10 Comparison of Angles of Repose for Four Types of Fluids

[0162]

[0163] As can be seen from Table 10, the three types of fluxes, Li₂B₄O₇-0.50%LiI, Li₂B₄O₇-1.0%LiBr, and fine-particle Li₂B₄O₇, are particularly prone to sliding due to their 0.5mm bead-like structure, with an angle of repose of 15°. 。 The coarse-grained Li₂B₄O₇ particles range in size from 0.5 to 3.5 mm, are irregular in shape, have many sharp edges, and an angle of repose of 47°. 。 Therefore, the ternary composite flux system of Li2B4O7 (coarse particles) + Li2B4O7-0.50%LiI + Li2B4O7-1.0%LiBr designed in this invention can achieve an angle of repose of 35°. 。 The above measures not only meet the requirements for sample preparation but also reduce sample melting costs.

[0164] Comparative Example 3

[0165] The procedure was followed as in Example 2, except that the highest isothermal temperature in step 2) was changed from 1050°C in Example 2 to two different isothermal temperatures: 950°C and 1000°C. The molten glass slide was subjected to field emission scanning electron microscopy for microscopic analysis of the sample oxidation and flux melting state. For details, see [link to analysis]. Figure 12The highest constant temperatures from left to right are 950℃, 1000℃, and 1050℃. Analysis of the microscopic spectra magnified 50x shows that the amount of unmelted foreign matter gradually decreases, reaching a relatively good melting effect at 1050℃.

[0166] Comparative Example 4

[0167] The process was carried out according to Example 2, except that the isothermal time of 35° oscillation in step 2) was changed. The melting effect was compared at 3, 5, and 8 minutes, and the comparative analysis results are shown below. Figure 13 .

[0168] from Figure 13 The comparison charts show that in Example 2 of this invention, the molten sheet quality meets the requirements for X-ray fluorescence analysis when the swaying melting is completed for 8 minutes, but not at other times. Furthermore, 35° is the maximum swaying angle of this invention; any larger angle results in molten reagent being ejected, and molten material was found sticking to the periphery of the platinum crucible.

[0169] Comparative Example 5

[0170] The experiment was conducted according to Example 2, except that the composite flux formulation was changed, as follows:

[0171] Weigh 6.5000g of 99.5% fine-grained Li₂B₄O₇ + 0.5% LiI and spread it in the crucible. Then weigh 1.0000g of coarse-grained Li₂B₄O₇ and spread it as a base flux in the platinum crucible. Dig a hemispherical indentation in the 1g coarse-grained Li₂B₄O₇ flux. Inevitably, you will dig down to the underlying 99.5% fine-grained Li₂B₄O₇ + 0.5% LiI layer. Dig out a certain depth... The temperature should be just right, but the platinum crucible should not be touched, otherwise it will be easily corroded; weigh 0.7000 g of lithium carbonate, 0.5000 g of lithium hydroxide, and 0.2000 g of sample into a glass beaker, mix them with a glass rod, and then slowly pour them into the hemispherical recess of the platinum crucible; weigh 1.5000 g of 99.5% fine-grained Li₂B₄O₇ + 0.5% LiI to cover the sample; select two standard samples and four samples for comparison using different methods, and the results are shown in Table 11.

[0172] Table 11 Detection results of Comparative Example 5

[0173]

[0174] As can be seen from Table 11, when the composite flux of fine-particle 99.50% Li2B4O7-0.50% LiI + coarse-particle Li2B4O7 is used as the base, the analytical results of titanium are basically close to the standard values. However, the fluctuation of titanium content ≤0.020% is far beyond the national standard range. In addition, some glass flakes show crystallization.

[0175] Comparative Example 6

[0176] The experiment was conducted according to Example 2, except that the composite flux formulation was changed, as follows:

[0177] Weigh 5.000 g of 99.5% Li₂B₄O + 0.5% LiI, 2.0000 g of 99% Li₂B₄O + 1% LiBr, and 1.0000 g of coarse-grained Li₂B₄O. Dig a hemispherical cavity using the same method as in Example 2 and set aside. Weigh 0.7000 g of lithium carbonate, 0.5000 g of lithium hydroxide, and 0.2000 g of the sample into a glass beaker, mix well with a glass rod, and slowly pour into the hemispherical cavity. Weigh 1.0000 g of coarse-grained 100% Li₂B₄O to cover the sample. Continue to select one standard sample and five samples for comparison using different methods. The results are shown in Table 12.

[0178] Table 12 Detection results of Comparative Example 6

[0179]

[0180] As can be seen from Table 12, the addition of 2 grams of 99.0%Li2B4O7-1.0%LiBr improved the detection results of low-content Ti elements, which were close to the results of the two methods in Example 2; however, the results of aluminum elements fluctuated greatly, and the results of the two methods showed a large difference; in addition, some glass flakes showed cracks.

[0181] Through comparative experiments with two different formulations of the base-forming composite flux (Comparative Examples 5 and 6), the superior performance of the base-forming composite flux provided by this invention was further demonstrated. A comparison of Example 2 with Comparative Examples 5 and 6 shows that, under the same melting conditions and X-ray fluorescence spectrometry analysis, the accuracy and precision of the results obtained using different formulations of the base-forming composite flux do not meet the national standard requirements.

[0182] Compared with the prior art, the present invention has the following outstanding effects:

[0183] I. This invention employs a designed composite flux for direct oxidation melting, increasing detection speed by 45.45%. Previously, for ferrosilicon alloys, Si, Fe, and P were detected using X-ray fluorescence spectrometry, taking 120 minutes per sample. The remaining eight elements were detected using acid dissolution followed by inductively coupled plasma (ICP) spectroscopy, taking 100 minutes per sample. The direct oxidation melting X-ray fluorescence detection provided by this invention can simultaneously detect all 11 elements, eliminating the need for ICP spectroscopy after acid dissolution, reducing detection time by 100 minutes and increasing speed by 45.45%.

[0184] II. The direct oxidation-fusion method employed in this invention reduces reagent testing costs by 30%. Previously, the three elements Si, Fe, and P in ferrosilicon alloys were all detected using reagent oxidation-fusion, with a single-element price of 3.46 yuan. The remaining eight elements were detected using ICP spectrometry, with a single-element price of 2.89 yuan. Using the direct oxidation-fusion X-ray fluorescence detection method of this invention, while the use of high-quality reagents in the base composite flux increases the cost per sample fusion, the fact that 11 elements can be analyzed simultaneously in a single fusion reduces the cost per element to 2.14 yuan, resulting in a total cost reduction of approximately 30%. If the composite flux is mass-produced in the future, the testing cost will further decrease.

[0185] Third, the direct oxidation-fusion method of this invention improves detection efficiency by 50%. Previously, two methods and two detection stations were required to detect 11 elements. Now, only one method and one detection station are needed, improving detection efficiency by more than 50%.

[0186] IV. The direct oxidation-fusion method employed in this invention completely solves the environmental pollution problems of waste acid gas and waste acid water. X-ray fluorescence detection is a high-temperature fusion glass slide method that does not require any acid or alkali reagents. It also completely solidifies the carbon in the reagents and samples, eliminating emissions and meeting carbon reduction requirements. After discontinuing the use of acid dissolution ICP spectroscopy, the large amounts of HF, HCl, HNO3, and HClO4 used in acid dissolution, as well as the acid gas and waste acid water generated during sample dissolution, have achieved zero emissions.

[0187] V. This invention employs a direct oxidation-fusion method, which improves the safety of the detection method. Since there is no need to use HClO4 for sample dissolution, the possibility of HClO4 volatilizing at high temperatures, remaining, accumulating, and potentially exploding with organic matter upon reheating is completely eliminated.

[0188] VI. This invention can accurately detect 11 elements, and the detection range of each element is shown in Table 13.

[0189] Table 13 Detection content range of the 11 elements in this invention

[0190]

[0191] This invention enables direct oxidation and melting to form slides, and X-ray fluorescence spectrometry can conveniently and accurately detect 11 elements in ferrosilicon alloys, with a detection cost lower than the national standard method.

[0192] The above description of the embodiments is intended to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A composite flux, characterized in that, The composite flux comprises 99.50%Li₂B₄O₇-0.50%LiI, 99.0%Li₂B₄O₇-1.0%LiBr and Li₂B₄O₇; The mass ratio of 99.50%Li₂B₄O₇-0.50%LiI, 99.0%Li₂B₄O₇-1.0%LiBr, and Li₂B₄O₇ is 4:1:

3. The 99.50%Li2B4O7-0.50%LiI refers to a mixture of 99.50% Li2B4O7 and 0.50% LiI by mass. The 99.0%Li2B4O7-1.0%LiBr refers to a mixture of 99.0% Li2B4O7 and 1.0% LiBr by mass. 99.50%Li2B4O7-0.50%LiI was laid at the bottom of the crucible, followed by 99.0%Li2B4O7-1.0%LiBr, and the top layer was Li2B4O7. The Li2B4O7 has high-quality coarse particles with a particle size of 0.5–3.5 mm and an irregular shape, and an angle of repose of 47°.

2. A method for X-ray fluorescence detection of 11 elements in ferrosilicon alloys using direct oxidation fusion sample preparation, characterized in that... The method uses the composite flux according to claim 1, and the specific method includes the following steps: 1) In the center of the crucible, first lay 99.50%Li2B4O7-0.50%LiI at the bottom layer of the crucible, then lay 99.0%Li2B4O7-1.0%LiBr, and lay Li2B4O7 on the top layer. Use the top layer of Li2B4O7 to dig out a hemispherical depression, pour the sample and oxidant into the depression, and then cover it with Li2B4O7. 2) Heat the platinum crucible to induce oxidation and melting; 3) Prepare glass flakes and detect them using an X-ray fluorescence spectrometer.

3. The method according to claim 2, characterized in that, The total mass of 99.50%Li₂B₄O₇-0.50%LiI, 99.0%Li₂B₄O₇-1.0%LiBr, and Li₂B₄O₇, the mass ratio of the sample to the oxidant is 45:1:6; the mass ratio of the top layer of Li₂B₄O₇ to the covering Li₂B₄O₇ is 3:

1.

4. The method according to claim 2 or 3, characterized in that, In step 1), the oxidant refers to a mixture of lithium carbonate and lithium hydroxide.

5. The method according to claim 4, characterized in that, The mass ratio of lithium carbonate to lithium hydroxide is 7:

5.

6. The method according to claim 2, characterized in that, In step 2), the platinum crucible is heated as follows: first, it is kept at 450°C for 2.5 minutes, then the temperature is increased to 500°C in 2 minutes, kept at 500°C for 5 minutes, then the temperature is increased to 850°C in 50 minutes, kept at 850°C for 5 minutes, then the temperature is increased to 1050°C in 5 minutes, and kept at 1050°C for 5 minutes. During this process, the swing angle is 20°, and finally the temperature is kept at 1050°C for 8 minutes. During this process, the swing angle is 35°.

7. The method according to claim 2, characterized in that, X-ray fluorescence spectrometry was used for detection. First, a standard silicon-iron alloy was used as the sample to obtain working curves for each element, Si, Fe, Mn, Cr, P, Al, Ca, Ti, V, Ni, and Cu. The concentrations of each element, Si, Fe, Mn, Cr, P, Al, Ca, Ti, V, Ni, and Cu, in the silicon-iron alloy sample to be tested were obtained using the working curves.

8. The method according to claim 2, characterized in that, X-ray fluorescence spectrometry was used for detection, with the following parameter settings: Detection of Si element: voltage 40KV, current 70mA, PHD 5-115, channel angle 108.88, measurement time 40.00 seconds; Fe element detection: voltage 40KV, current 70mA, PHD 5-145, channel angle 57.52, measurement time 40.00 seconds; Mn element detection: voltage 40KV, current 70mA, PHD 15-125, channel angle 62.97, measurement time 40.00 seconds; Cr element detection: voltage 40KV, current 70mA, PHD 20-155, channel angle 69.36, measurement time 40.00 seconds; Detection of phosphorus (P) element: voltage 40 kV, current 70 mA, PHD 10-90, channel angle 141.03, measurement time 40.00 seconds; Al element detection: voltage 40KV, current 70mA, PHD 10-105, channel angle 144.58, measurement time 40.00 seconds; Ca element detection: voltage 40KV, current 70mA, PHD 30-140, channel angle 113.09, measurement time 40.00 seconds; Ti element detection: voltage 40KV, current 70mA, PHD 10-130, channel angle 86.14, measurement time 40.00 seconds; Detection of V element: voltage 40KV, current 70mA, PHD 20-120, channel angle 76.94, measurement time 40.00 seconds; Ni element detection: voltage 40KV, current 70mA, PHD 15-100, channel angle 48.67°, measurement time 40.00 seconds; Cu element detection: voltage 40KV, current 70mA, PHD 15-105, channel angle 45.03, measurement time 40.00 seconds.

Images