Method for detecting content of TiO2 in molten salt by using handheld X fluorescence

Abstract

The invention relates to the technical field of a molten salt chlorination method, and discloses a method for detecting the content of TiO2 in molten salt by using handheld X fluorescence, which comprises the following steps: S1, preparing a standard sample; s2, standard sample value determination: performing chemical titration on each standard sample for multiple times to obtain content data, screening the content data, and calculating an average value as a reference value of the TiO2 content of the standard sample; s3, establishing a fluorescence standard curve: pressing the standard sample into sheets, inputting the sheets into a handheld X luminoscope, detecting the fluorescence intensity, and generating a standard curve of the TiO2 content and the fluorescence intensity in combination with the reference value; and S4, detecting a sample to be detected: grinding and tabletting the fused salt sample to be detected, and determining the content of titanium dioxide by using a handheld X luminoscope in combination with the standard curve. According to the method, the detection time is short, the detection error is small, rapid and accurate detection of the TiO2 content in a complex molten salt system is achieved, the detection time of the TiO2 content in the molten salt is shortened to 10 minutes from 1.5 hours of a traditional chemical titration method, the detection error is smaller than or equal to 0.5%, and laboratory-level precision is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of molten salt chlorination method, and particularly to a method for detecting the TiO2 content in molten salt by using handheld X-ray fluorescence. Background Art

[0002] The production of titanium tetrachloride by chlorination method is an important link in the domestic production processes of titanium sponge and titanium dioxide chloride in recent years. Using titanium slag, petroleum coke and chlorine as the main raw materials, and industrial salts such as sodium chloride, potassium chloride, and magnesium chloride as auxiliary materials, the above materials are melted into chlorinated molten salt in a chlorination furnace at a certain temperature and pressure, and titanium tetrachloride is produced by reaction. Titanium tetrachloride is an important raw material for the production of titanium dioxide and titanium sponge. When producing titanium tetrachloride by molten salt chlorination method, chlorine is sprayed into the molten salt from the bottom of the molten salt chlorination furnace at a certain flow rate, which has a strong stirring effect on the molten salt and reaction materials, and is dispersed into many small bubbles and moves upward from the furnace bottom; the titanium slag and petroleum coke solid materials suspended in the molten salt adhere to the interface of the molten salt and chlorine bubbles under the action of surface tension, and a chlorination reaction occurs to generate titanium tetrachloride gas. The titanium slag and petroleum coke are dispersed in the whole melt with the flow of the molten salt and bubbles, creating good conditions for the chlorination reaction. The TiO2 content in the chlorinated molten salt is one of the key control indicators, which can reflect the reaction status of the materials in the furnace, and its content determines whether the chlorination furnace operates normally. The composition of the molten salt in the chlorination furnace is relatively complex. Using the chemical titration method, the sample dissolution is relatively complex, and the sample dissolution and analysis time is long (1.5 h), which cannot guide the production in time.

[0003] Therefore, there is a need to improve the detection method for TiO2 content in the prior art. Summary of the Invention

[0004] In view of this, the purpose of the embodiments of the present invention is to provide a method for detecting the TiO2 content in molten salt by using handheld X-ray fluorescence, which has a short detection time and a small detection error, and realizes the rapid and accurate detection of the TiO2 content in a complex molten salt system.

[0005] Based on the above purpose, the embodiments of the present invention provide a method for detecting the TiO2 content in molten salt by using handheld X-ray fluorescence, including: S1 Standard sample preparation: Select the molten salt of the chlorination furnace for sample preparation, and screen the chlorinated molten salt samples covering the limit range of TiO2 content in the molten salt chlorination furnace as the standard samples; S2 Standard sample value determination: Perform multiple chemical titrations on each standard sample to obtain content data, and calculate the average value as the reference value of the TiO2 content of the standard sample after screening and processing the content data; S3 Fluorescence standard curve establishment: Press the standard samples into tablets, input them into the handheld X-ray fluorescence spectrometer and detect the fluorescence intensity, and generate a standard curve of TiO2 content and fluorescence intensity in combination with the reference value; S4 Detection of the sample to be tested: After grinding and pressing the molten salt sample to be tested into tablets, use a handheld X-ray fluorescence spectrometer in combination with a standard curve to determine the titanium dioxide content.

[0006] In some embodiments, in S1, when preparing the sample, use a mortar made of agate or tungsten carbide to grind the molten salt sample from the chlorination furnace to a particle size not exceeding 0.016 mm, and the sample amount is not less than 20 g.

[0007] In some embodiments, in S1, use the physicochemical titration method to select the chlorinated molten salt sample covering the limit range of TiO2 content in the molten salt chlorination furnace as the standard sample.

[0008] In some embodiments, in S2, the number of chemical titrations is at least 11 times.

[0009] In some embodiments, in S2, the screening and processing of the content data include: removing the outliers in the content data by the Grubbs test method.

[0010] In some embodiments, in S3, weigh 10 g of the molten salt sample to be tested, and press the sample into a tablet with a thickness of not less than 1 cm.

[0011] In some embodiments, the pressure for pressing the standard sample tablet is 20 - 30 MPa, and the pressure holding time is 30 - 60 seconds.

[0012] In some embodiments, in S4, use a mortar made of agate or tungsten carbide to grind the molten salt sample from the chlorination furnace to a particle size not exceeding 0.016 mm for the molten salt sample to be tested, and press a 10 g sample into a tablet with a thickness of not less than 0.7 cm.

[0013] In some embodiments, in S3 and S4, the detection parameters of the handheld X-ray fluorescence spectrometer include: the X-ray tube voltage is 40 kV, the current is 100 μA, and the detection energy range is 4.5 - 5.5 keV.

[0014] In some embodiments, in S2, the thiocyanate spectrophotometry or hydrogen peroxide colorimetry is used to obtain the content data during chemical titration.

[0015] The present invention has at least the following beneficial technical effects: By preparing a special standard sample for molten salt covering the limit range and combining with the X-ray fluorescence rapid detection technology, the present invention not only solves the problems of complex sample dissolution, long sample dissolution and analysis time, and inability to guide production in a timely manner in the traditional chemical titration method, but also breaks through the technical bottleneck that there is no suitable standard sample in the traditional fluorescence detection method for complex molten salt systems. The detection time of TiO2 content in molten salt is shortened from 1.5 hours in the traditional chemical titration method to 10 minutes, and the detection error ≤ 0.5%, reaching the laboratory-level accuracy. Description of the Drawings

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other embodiments can be obtained based on these drawings.

[0017] Figure 1 It is a schematic diagram of an embodiment of a method for detecting the TiO2 content in molten salt using handheld X-ray fluorescence provided by the present invention. Specific embodiments

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the following will further elaborate on the embodiments of the present invention in detail with reference to specific embodiments and the accompanying drawings.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs; the terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For example, the terms "length", "width", "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or position based on the orientation or position shown in the accompanying drawings, which is only for convenience of description and cannot be construed as a limitation on the technical solution of the present invention.

[0020] The terms "comprising" and "having" and any variations thereof in the specification and claims of the present invention and the above accompanying drawing explanations are intended to cover non-exclusive inclusion; the terms "first", "second", etc. in the specification and claims of the present invention or the above accompanying drawings are used to distinguish different objects and not to describe a specific order. The meaning of "a plurality" is two or more, unless otherwise specifically defined.

[0021] In addition, the mention of "embodiment" herein means that a specific feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present invention. The occurrence of this phrase at various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0022] In the process of producing titanium tetrachloride by the chlorination method, detecting the content of titanium dioxide (TiO2) in the chlorination molten salt is crucial for process control. The abnormal TiO2 content directly reflects the reaction process: too high content indicates incomplete reaction (inadequate conversion of raw materials), insufficient chlorine supply, or low temperature; too low content may be due to unbalanced raw material ratio (such as insufficient TiO2 feeding) or excessive reaction (increased side reactions, such as the formation of lower-valent titanium chlorides). However, in the existing technology, the chemical titration method is used to determine the content of titanium dioxide. Due to the complex composition of the molten salt in the chlorination furnace, the sample dissolution is relatively complex, and the sample dissolution and analysis time are long (1.5 h), which cannot guide production in a timely manner and there are many problems.

[0023] Therefore, aiming at the problems of the existing technology, the present invention provides a method for detecting the TiO2 content in molten salt by using a handheld X-ray fluorescence, as Figure 1 shown, including the following steps: S1 Standard sample preparation: Select the molten salt of the chlorination furnace for sample preparation, and screen the chlorination molten salt samples covering the TiO2 content limit range in the molten salt chlorination furnace as the standard samples; S2 Standard sample value determination: Perform multiple chemical titrations on each standard sample to obtain content data, and calculate the average value as the reference value of the TiO2 content of the standard sample after screening and processing the content data; S3 Fluorescence standard curve establishment: Press the standard sample into a tablet, input it into the handheld X-ray fluorescence spectrometer and detect the fluorescence intensity, and generate a standard curve of TiO2 content and fluorescence intensity in combination with the reference value; S4 Detection of samples to be tested: After grinding and pressing the molten salt sample to be tested into a tablet, use the handheld X-ray fluorescence spectrometer to determine the titanium dioxide content in combination with the standard curve.

[0024] Further, in S1, during sample preparation, use a mortar made of agate or tungsten carbide to grind the molten salt sample of the chlorination furnace to a particle size not exceeding 0.016 mm, and the sample amount is not less than 20 g. The particle size ≤0.016 mm can eliminate the "particle effect" in X-ray fluorescence (XRF) detection, reduce signal fluctuations caused by uneven particles, and the agate / tungsten carbide material reduces the risk of sample contamination and ensures data authenticity.

[0025] Further, in S1, use the physicochemical titration method to select the chlorination molten salt samples covering the TiO2 content limit range in the molten salt chlorination furnace as the standard samples. The standard samples cover the extreme value range of the actual working conditions, avoid extrapolation errors caused by insufficient standard samples during XRF detection, adapt to different process parameters (such as fluctuations in raw material ratio), and the detection reliability is increased by 40%.

[0026] Further, in S2, the number of chemical titrations is at least 11 times. Specifically, perform ≥11 repeated chemical titrations on each standard sample and record each measured value. Evaluate the data discreteness through statistical analysis (such as calculating the average value and standard deviation).

[0027] Further, in S2, the screening and processing of the content data include: removing outliers in the content data through the Grubbs test method. Beneficial effects: Reducing the risk of misjudgment: Avoiding the influence of single abnormal data on the average value (such as a certain error causing the overall deviation to exceed 0.5%); Statistical reliability: Ensuring the scientific rigor of the certified reference material data through significance testing and meeting the requirements of ISO guidelines for the certification of reference materials.

[0028] Further, in S3, weigh 10 g of the molten salt sample to be measured and press the sample into a tablet with a thickness of not less than 1 cm. In some embodiments, the pressure for pressing the certified reference material tablet is 20 - 30 MPa, and the pressure holding time is 30 - 60 seconds. Specifically, weigh 10 g of the certified reference material, place it in a mold; apply a pressure of 20 - 30 MPa on a tablet press, release it after holding for 30 - 60 seconds, and obtain a tablet with a thickness ≥ 1 cm and a smooth surface.

[0029] In some embodiments, 20 - 30 MPa can ensure that the sample is fully dense, reduce internal pores (porosity < 2%), and avoid X-ray scattering; the deviation of the tablet density is ≤ 0.1 g / cm³, ensuring the linearity of the standard curve (R² ≥ 0.995).

[0030] Further, in S4, for the molten salt sample to be measured, grind the molten salt sample of the chlorination furnace with a mortar made of agate or tungsten carbide to a particle size not exceeding 0.016 mm, and press a 10 g sample into a tablet with a thickness of not less than 0.7 cm.

[0031] Further, in S3 and S4, the detection parameters of the handheld X-ray fluorescence spectrometer include: the X-ray tube voltage is 40 kV, the current is 100 μA, and the detection energy range is 4.5 - 5.5 keV.

[0032] Further, in S2, the thiocyanate spectrophotometry or hydrogen peroxide colorimetry is used to obtain the content data during chemical titration.

[0033] The following further explains the present invention with specific embodiments.

[0034] Taking the molten salt of the chlorination furnace as an example, the specific operation of the present invention is as follows: (1) Take about 20 g of chlorinated molten salt and grind it in an agate mortar to pass through a 0.016 mm standard sieve.

[0035] (2) Weigh 0.5 g of the sample and detect the TiO2 content therein by chemical titration method. Select the sample concentration gradient according to an increment of 1%, and the highest value covers the highest value of the molten salt of the chlorination furnace.

[0036] (3)Measure the selected samples 11 times respectively. For the 11 measurement results of each sample, after discarding the outliers by Grubbs’ Test, calculate the average value as the reference value for the TiO2 content of the selected standard sample.

[0037] (4)Take 10 g of the sieved sample and press it into a sheet with a smooth surface and a thickness of 1 cm.

[0038] (5)Number each molten chloride salt sample in ascending order, input the corresponding reference value of TiO2 content into the instrument, detect the fluorescence intensity of the samples respectively, and select instrument parameters such as the measurement crystal, analysis line, and background subtraction position of Ti element according to the intensity and interference situation to establish a standard curve.

[0039] (6)For the sample to be measured, use an agate or tungsten carbide mortar to grind the molten salt sample from the chlorination furnace until the particle size does not exceed 0.016 mm. For a 10 g sample, press it into a sheet with a thickness of not less than 0.7 cm and a smooth surface, and use a handheld X-ray fluorescence detector for detection. The instrument directly outputs the measurement result of TiO2 (wt%).

[0040] The detection result of parallel samples of the present invention is ≤0.3%, and the deviation from the chemical titration method is <0.4%. The measurement time for the whole process does not exceed 10 minutes.

[0041] The present invention prepares a molten salt standard sample covering the limit range by chemical titration method, and uses Grubbs’ Test to ensure the statistical reliability of the standard sample data, solving the industry problem of no suitable standard sample for complex molten salt systems. Traditional XRF relies on general standard samples and cannot match the interference environment of high Cl and multiple elements in molten salts. However, this method realizes the homologous matching of the standard sample and the sample to be measured through the closed-loop process of "titration calibration → XRF detection".

[0042] The beneficial effects of the present invention include: (1)The detection time is shortened from 1.5 hours (chemical titration) to 10 minutes, meeting the real-time regulation requirements of continuous production of molten salt chlorination furnace.

[0043] (2)The detection error of parallel samples is ≤0.5%, reaching the same level of accuracy as the chemical titration method (the error of traditional XRF in molten salts is usually >1%). (3)On-site detection with a handheld XRF instrument, no laboratory equipment is required, reducing the detection cost; (4)Agate / tungsten carbide mortar is corrosion-resistant and suitable for the high-temperature characteristics of molten salts.

[0044] The above are the exemplary embodiments disclosed by the present invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments disclosed by the present invention as defined by the claims. The functions, steps, and / or actions of the method claims according to the disclosed embodiments herein need not be performed in any particular order. In addition, although the elements disclosed by the embodiments of the present invention may be described or claimed in individual form, they may also be understood as plural unless explicitly limited to the singular form.

[0045] It should be understood that, as used herein, unless the context clearly supports exceptions, the singular form "a" is also intended to include the plural form. It should also be understood that the "and / or" used herein refers to any and all possible combinations of one or more of the related listed items.

[0046] The serial numbers of the above-disclosed embodiments of the present invention are only for description and do not represent the superiority or inferiority of the embodiments.

[0047] Those of ordinary skill in the art should understand that: the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the embodiments disclosed by the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features between the above embodiments or different embodiments can also be combined, and there are many other variations in different aspects of the above embodiments of the present invention, which are not provided in detail for the sake of brevity. Therefore, any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiments of the present invention shall be included in the protection scope of the embodiments of the present invention.

Claims

1. A method for detecting the TiO2 content in molten salt using handheld X-ray fluorescence, characterized in that, Including: S1 Standard sample preparation: Select the molten salt from the chlorination furnace for sample preparation, and screen the chlorinated molten salt samples covering the TiO2 content limit range in the molten salt chlorination furnace as the standard samples; S2 Standard sample value determination: Perform multiple chemical titrations on each of the standard samples to obtain content data, and calculate the average value as the reference value of the TiO2 content of the standard sample after screening and processing the content data; S3 Fluorescence standard curve establishment: Press the standard sample into a tablet, input it into a handheld X-ray fluorescence spectrometer and detect the fluorescence intensity, and generate a standard curve of TiO2 content and fluorescence intensity in combination with the reference value; S4 Detection of samples to be tested: After grinding and pressing the molten salt sample to be tested into a tablet, use a handheld X-ray fluorescence spectrometer to determine the titanium dioxide content in combination with the standard curve.

2. The method for detecting the TiO2 content in molten salt by using handheld X-ray fluorescence according to claim 1, wherein In S1, during sample preparation, use a mortar made of agate or tungsten carbide to grind the molten salt sample from the chlorination furnace to a particle size not exceeding 0.016 mm, and the sample amount is not less than 20 g.

3. The method for detecting the TiO2 content in molten salt by using handheld X-ray fluorescence according to claim 1, wherein In S1, use the physicochemical titration method to select the chlorinated molten salt samples covering the TiO2 content limit range in the molten salt chlorination furnace as the standard samples.

4. The method for detecting the TiO2 content in molten salt by using handheld X-ray fluorescence according to claim 1, wherein In S2, the number of times of the chemical titration is at least 11 times.

5. The method for detecting the TiO2 content in molten salt by using handheld X-ray fluorescence according to claim 1, characterized in that, In S2, the screening and processing of the content data includes: removing the outliers in the content data by the Grubbs test method.

6. The method for detecting the TiO2 content in molten salt by using handheld X-ray fluorescence according to claim 1, wherein In S3, weigh 10 g of the molten salt sample to be tested, and press the sample into a tablet with a thickness not less than 1 cm.

7. The method for detecting the TiO2 content in molten salt by using handheld X-ray fluorescence according to claim 6, characterized in that, The pressure for pressing the standard sample tablet is 20 - 30 MPa, and the pressure holding time is 30 - 60 seconds.

8. The method for detecting the TiO2 content in molten salt by using handheld X-ray fluorescence according to claim 1, characterized in that, In S4, for the molten salt sample to be tested, use a mortar made of agate or tungsten carbide to grind the molten salt sample from the chlorination furnace to a particle size not exceeding 0.016 mm, and press a 10 g sample into a tablet with a thickness not less than 0.7 cm.

9. The method for detecting the TiO2 content in molten salt by using handheld X-ray fluorescence according to claim 1, wherein, In S3 and S4, the detection parameters of the handheld X-ray fluorescence spectrometer include: the X-ray tube voltage is 40 kV, the current is 100 μA, and the detection energy range is 4.5 - 5.5 keV.

10. The method for detecting the TiO2 content in molten salt by using handheld X-ray fluorescence according to claim 1, characterized in that, In S2, the thiocyanate spectrophotometry or hydrogen peroxide colorimetry is used to obtain the content data during chemical titration.

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