Sample pretreatment method and measurement analysis method for measuring organic components in titanium tetrachloride

Abstract

The invention discloses a sample pretreatment method for measuring organic components in titanium tetrachloride and a measurement and analysis method, and belongs to the technical field of detection and analysis of the organic components in inorganic materials. The sample pretreatment method and the measurement analysis method comprise the following steps: carrying out liquid-liquid extraction on a titanium tetrachloride sample to be detected by adopting a combined reagent, fully reacting, standing for layering to obtain a clear, transparent, non-emulsified and clear-interface two-phase system, separating and collecting a subnatant liquid phase to obtain a solution to be detected for detecting and analyzing the organic components in titanium tetrachloride; and sending the solution to be detected to an organic analysis instrument for organic component detection and analysis by adopting a direct sample injection mode. The method provided by the invention can effectively solve the influence of deposition blockage, matrix effect, highly corrosive volatile gas of HCl and the like caused by high-concentration inorganic components such as Ti < 4 + >, Cl <->, H < + > and the like in TiCl4 on a detection instrument and a determination result.

Description

Technical Field

[0001] The present invention belongs to the technical field of detection and analysis of organic components in inorganic materials, and relates to a sample pretreatment method and a measurement and analysis method for measuring organic components in titanium tetrachloride. In particular, the present invention relates to a composition formula of a liquid-liquid separation and extraction combination reagent for detecting organic components in titanium tetrachloride, a method for preparing a sample test solution, and a detection and analysis method for determining the organic components. Background Art

[0002] my country's titanium sponge industry has achieved rapid development in recent years, but the production capacity of high-quality titanium sponge is low and still mainly relies on imports. The main reason is that it is difficult to stably control the level of impurities in the product. At present, the mainstream production process of titanium metal uses high-titanium slag to produce crude titanium tetrachloride (TiCl4) through a chlorination process. The crude TiCl4 is refined to obtain refined TiCl4. The refined TiCl4 is reduced with active metal magnesium to prepare titanium sponge, which is then used to manufacture various titanium metals or titanium alloy materials. After the refined TiCl4 is reduced to titanium sponge, the impurities contained in it are difficult to remove, and the impurities in the refined TiCl4 are transferred to the titanium sponge with a 4-fold enrichment relationship. Therefore, the quality of the refined TiCl4 determines the quality of the titanium sponge product.

[0003] The primary raw material for my country's titanium industry comes from Panxi vanadium-titanium magnetite. Due to the complex co-existing elements in this resource, impurities such as vanadium and silicon introduced into crude TiCl₄ (TiCl₄) can remain in the refined TiCl₄ during distillation and rectification, resulting in large amounts of impurities with a separation coefficient close to 1. This significantly impacts the quality of the end-product, titanium sponge. Therefore, appropriate impurity removal processes must be implemented to remove these impurities from the crude TiCl₄. Currently, the development of mineral oil-based impurity removal technology for producing high-quality refined TiCl₄ is a hot topic of research both domestically and internationally. The key to this technology lies in addressing the problem of excessive carbon content in titanium sponge due to residual carbon-containing organic impurities in TiCl₄. Existing research indicates that residual carbon-containing organic impurities in refined TiCl₄ are the primary cause of excessive total carbon content in subsequent titanium sponge products. Therefore, in order to effectively monitor TiCl₄ quality and guide the removal of these organic impurities, it is necessary to master detection and analysis techniques for the organic impurity components in TiCl₄.

[0004] Currently, the detection and analysis technology for organic impurities in TiCl4 is still in the exploratory stage both domestically and internationally. Existing analyses primarily rely on infrared spectroscopy, gas chromatography, and gas chromatography-mass spectrometry to detect specific components, such as carbon tetrachloride (CCl4) and carbon dioxide (CO2), or through headspace extraction / gas chromatography-mass spectrometry analysis of carbon disulfide (CS2) and CCl4, and gas chromatography electron capture (ECD) analysis of CCl4. Gas chromatography-mass spectrometry is an important tool for the qualitative and quantitative analysis of complex organic mixtures. However, due to the matrix effect of high concentrations of titanium and chlorine in TiCl4, as well as the influence of highly corrosive volatile HCl gases, conventional gas chromatography-mass spectrometry instruments cannot be used for analysis using direct injection. Using conventional chemical reactions to remove HCl or separate the titanium matrix can easily lead to the loss of volatile organic components or the precipitation of titanium-based organic components, which can be encapsulated and adsorbed.

[0005] Therefore, existing methods mostly use headspace sampling and other methods. However, not only can non-volatile organic components not enter the instrument for effective detection, but HCl will still volatilize and corrode the instrument. Therefore, the instrument needs to have special anti-corrosion devices to eliminate the influence of HCl. In addition, it can only analyze a small number of volatile organic compounds and cannot meet the needs of detecting and analyzing all components of organic impurities in TiCl4. Summary of the Invention

[0006] The technical problem to be solved by the present invention is that the existing method for detecting organic components in titanium tetrachloride is difficult to meet the demand for comprehensive analysis of organic impurities in all components of TiCl4.

[0007] To achieve the above application objectives, the technical solutions adopted in this application are as follows:

[0008] In a first aspect, the present invention provides a sample pretreatment method for measuring organic components in titanium tetrachloride, comprising: performing liquid-liquid extraction on a titanium tetrachloride sample to be tested using a combined reagent; allowing the sample to stand for stratification after sufficient reaction to obtain a clear, transparent, non-emulsified two-phase system with a distinct interface; separating and collecting the lower liquid phase to obtain a solution to be tested for detection and analysis of organic components in titanium tetrachloride; wherein the combined reagent comprises an organic component extractant and an inorganic component solubilizer, the organic component extractant is carbon tetrachloride, and the inorganic component solubilizer is ethanol and water; in the two-phase system, the upper layer is an ethanol-water phase containing inorganic components, and the lower layer is a carbon tetrachloride phase enriched in organic components.

[0009] In the liquid-liquid extraction process, the volume ratio of the titanium tetrachloride sample to be tested to the organic component extractant is 1:1 to 5:1, that is, the organic components / impurities in the titanium tetrachloride are enriched by 1 to 5 times.

[0010] In the above-mentioned combined reagent, the volume ratio of the organic component extractant to the inorganic component dissolving agent is 1:5 to 1:20.

[0011] In the above-mentioned inorganic component dissolving agent, the volume ratio of ethanol to water is 1:4 to 1:9.

[0012] In the above-mentioned combined reagent, carbon tetrachloride is of chromatographic grade or above, and ethanol is anhydrous ethanol with a purity of not less than 99.7%.

[0013] First, the present invention provides a combination reagent formula for separating and extracting organic components in TiCl4. The combination reagent is composed of three substances, CCl4, ethanol, and water, in proportion. Among them, CCl4 serves as an organic component extraction agent and can effectively extract and separate the organic components in titanium tetrachloride based on the principle of like dissolves like. At the same time, ethanol and water serve as solubilizers for inorganic matrix components such as titanium and chlorine. Ethanol and titanium ions are complexed to form titanium alcoholate, and the high solubility of titanium alcoholate in water is utilized to promote the rapid and complete dissolution of high-concentration titanium ions and the titanium precipitate produced by their hydrolysis in an ethanolic aqueous solution. In addition, since the solubility of the organic matter in TiCl4 in CCl4 is much greater than its solubility in an ethanolic aqueous solution, and CCl4 is completely immiscible with TiCl4 and the ethanolic aqueous solution, when the combination reagent is used for liquid-liquid extraction, a clear and transparent two-phase solution with a clear stratification interface and no emulsification can be obtained.

[0014] When the liquid-liquid extraction is carried out in an inert atmosphere and / or a closed environment, the titanium tetrachloride sample to be tested and the combined reagent are added to the extraction device simultaneously or in any order.

[0015] When the liquid-liquid extraction is carried out in an air atmosphere and / or an open environment, the titanium tetrachloride sample to be tested is first added to the extraction device, then the organic component extractant is immediately added, and finally the inorganic component dissolving agent is added.

[0016] Secondly, the present invention provides a sample pretreatment method for measuring organic components in TiCl4, which is applicable to different environmental conditions, including inert gas / closed environment and air atmosphere / open environment. Since TiCl4 is highly hydrolyzed, even if it encounters moisture in the air during the extraction process, a hydrolysis reaction may occur, generating sediment and a large amount of hydrogen chloride gas. Therefore, during the liquid-liquid extraction process, if the entire process is carried out in an inert gas or closed environment, the contact of TiCl4 with moisture in the air can be effectively avoided, preventing the occurrence of hydrolysis reaction. At the same time, it can also prevent the volatile organic components in TiCl4 from escaping with HCl gas during the hydrolysis process, thereby ensuring the integrity of the components to be measured. If liquid-liquid extraction is carried out in an air atmosphere / open environment, the components need to be added in a specific order, specifically: first add TiCl4 to the separatory funnel, then add CCl4 to cover the TiCl4 or soak the resulting precipitate, and finally add a larger volume of a mixed solution of ethanol and water prepared in proportion to ensure that it completely covers the first two solutions. After manual or mechanical shaking to fully extract the solution, the mixture will be clear and transparent, free of emulsification, and with a distinct interface. The ethanol-water solution containing the inorganic components will reside in the upper layer, while the carbon tetrachloride solution containing the organic components will sink to the lower layer. By opening the stopcock of the separatory funnel, the sample solution in the lower layer can be easily and accurately collected for subsequent analysis of the organic components.

[0017] In a second aspect, the present invention provides a method for measuring and analyzing organic components in titanium tetrachloride, wherein the sample pretreatment method is used to obtain a test solution, and the test solution is directly injected into an organic analysis instrument for organic component detection and analysis.

[0018] The above-mentioned organic analysis instrument is any one of a gas chromatography-mass spectrometer, a gas chromatograph, a liquid chromatograph, a liquid chromatography-mass spectrometer, and an infrared spectrometer.

[0019] Finally, the present invention provides a method for measuring and analyzing organic components in titanium tetrachloride. By combining reagents and sample pretreatment methods, the organic components in TiCl4 are enriched in a pure organic phase of carbon tetrachloride and completely separated from the inorganic components of TiCl4 dissolved in an ethanol aqueous solution. This completely eliminates the influence of the sample matrix coexisting medium on the detection results and the analytical instrument. The prepared test solution contains only the carbon tetrachloride matrix and the extracted trace organic components. Therefore, a direct injection method can be used to directly inject the prepared test solution manually or automatically into any organic analytical instrument such as gas chromatography-mass spectrometry, gas chromatography, liquid chromatography, liquid chromatography-mass spectrometry, infrared spectroscopy, etc. to perform organic component detection and analysis.

[0020] Among them, due to its good separation ability and international standard spectral library for retrieval and comparison, gas chromatography-mass spectrometry (GC-MS) is one of the mainstream detection and analysis methods for identifying mixed unknown organic substances. The present invention preferably uses a gas chromatography-mass spectrometer to detect and analyze the organic components in the test solution; the detection parameters are: inlet temperature 250~350℃; column box temperature: 50~80℃ holding time 3~5min, heating rate 10~20℃ / min to 250~350℃, holding 10~15min; carrier gas He: pressure 11.583psi, total flow rate 14mL / min, split ratio 1:1~1:10; ion source temperature 200~250℃; transmission line temperature 180~220℃; injection volume 0.5~3.0μL.

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

[0022] The present invention has developed a liquid-liquid separation combination agent for extracting organic components from TiCl4 and a sample pretreatment method thereof. Through the liquid-liquid separation extraction reaction mode, all organic impurities in TiCl4 are extracted and enriched in a pure organic medium liquid phase, and the coexisting inorganic matrix components such as titanium base and HCl are completely separated and dissolved into another liquid phase dominated by inorganic medium. The two phases are completely and clearly separated, achieving the goal of completely separating and enriching trace organic components from TiCl4 with characteristics such as easy hydrolysis and strong acidity, and completely solving the problem of high concentration of Ti in TiCl4. 4+ 、Cl - 、H + The influence of deposition blockage, matrix effect, strong corrosive volatile gas of HCl, etc. caused by inorganic components on the detection instrument and measurement results is eliminated, meeting the needs of detecting mixed organic impurity components in TiCl4 by conventional direct injection method / gas chromatography-mass spectrometry. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the total ion chromatogram (TIC) of GC-MS of Example 1 (Sample 1#) of the present invention;

[0024] Figure 2 Partial mass spectrum library search result 1 of Example 1 (Sample 1#) of the present invention;

[0025] Figure 3 Partial mass spectrum library search result 2 of Example 1 (Sample 1#) of the present invention;

[0026] Figure 4 This is the total ion chromatogram (TIC) of GC-MS of Example 2 (Sample 2#) of the present invention;

[0027] Figure 5 Partial mass spectrum library search result 1 of Example 2 (Sample 2#) of the present invention;

[0028] Figure 6 This is the partial mass spectrum library search result 2 of Example 2 (Sample 2#) of the present invention. DETAILED DESCRIPTION

[0029] In order to make the technical problems, technical solutions and beneficial effects to be solved in the present application clearer, the present application will be further described in detail below in conjunction with the embodiments. It will be understood by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Unless otherwise defined, all scientific and technological terms used herein have the same meanings understood by those of ordinary skill in the art.

[0030] A sample pretreatment method for measuring organic components in titanium tetrachloride and a method for measuring and analyzing organic components in titanium tetrachloride include: using a combined reagent to perform liquid-liquid extraction on a titanium tetrachloride sample to be measured; after sufficient reaction, the sample is allowed to stand and separate to obtain a clear, transparent, non-emulsified two-phase system with a distinct interface; the lower liquid phase is separated and collected to obtain a solution to be measured for detecting and analyzing organic components in titanium tetrachloride; and the solution to be measured is fed to an organic analyzer for detecting and analyzing organic components by direct injection.

[0031] In one embodiment of the present invention, during the liquid-liquid extraction process, the volume ratio of the titanium tetrachloride sample to be tested to the organic component extractant is 1:1 to 5:1. As a non-limiting example, the volume ratio of the titanium tetrachloride sample to be tested to the organic component extractant can be 1:1, 2:1, 3:1, 4:1, 5:1, or any ratio therebetween.

[0032] In one embodiment of the present invention, in the above-mentioned combination reagent, the volume ratio of the organic component extractant to the inorganic component solubilizer is 1:5 to 1:20. As a non-limiting example, the volume ratio of the organic component extractant to the inorganic component solubilizer can be 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, 1:20, or any ratio therebetween.

[0033] In one embodiment of the present invention, the volume ratio of ethanol to water in the inorganic component dissolving agent is 1:4 to 1:9. As a non-limiting example, the volume ratio of ethanol to water can be 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, or any ratio therebetween.

[0034] In one embodiment of the present invention, the analysis and detection of the organic components are carried out using any one of the following instruments: gas chromatography-mass spectrometry (GC-MS), gas chromatograph (GC), liquid chromatograph (LC), liquid chromatography-mass spectrometry (LC-MS) or infrared spectrometer (FTIR), etc.; preferably GC-MS.

[0035] In one embodiment of the present invention, the GC-MS detection parameters are: injection port temperature 250-350°C; column oven temperature program: 50-80°C for 3-5 minutes, heating at 10-20°C / min to 250-350°C and then holding for 10-15 minutes; carrier gas (He) parameters: pressure 11.583 psi, total flow rate 14 mL / min, split ratio 1:1-1:10; ion source temperature 200-250°C; transfer line temperature 180-220°C; injection volume 0.5-3.0 μL. As a non-limiting example, the injection port temperature can be 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, or within a range consisting of any two of the above values. In the column oven temperature program, the initial temperature can be 50°C, 60°C, 70°C, 80°C, or within a range between any two of the above values; the hold time can be 3 min, 4 min, 5 min, or any value therebetween; the heating rate can be 10°C / min, 12°C / min, 14°C / min, 16°C / min, 18°C / min, 20°C / min, or any value therebetween; the final temperature can be 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, or within a range between any two of the above values; the hold time can be 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, or any value therebetween; the carrier gas split ratio can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, or any ratio therebetween. The ion source temperature can be 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, or a range between any two of the above values. The transfer line temperature can be 180°C, 190°C, 200°C, 210°C, 220°C, or a range between any two of the above values. The injection volume can be 0.5 μL, 1.0 μL, 1.5 μL, 2.0 μL, 2.5 μL, 3.0 μL, or a range between any two of the above values.

[0036] Example 1

[0037] A 5.0 mL portion of the TiCl₄ sample solution (Sample #1) was placed in a separatory funnel. 5.0 mL of chromatographically pure or higher carbon tetrachloride was immediately added, followed by 50 mL of an ethanol-water solution (1 part anhydrous ethanol, no less than 99.7% pure, mixed evenly with 9 parts water) in a volume ratio of 1:9. After thorough vortexing to complete the extraction reaction, the solution was allowed to separate into layers, and the lower layer was used as the test sample. The test solution was directly injected into the GC-MS inlet for analysis. The injection volume was 0.5 μL. The inlet temperature was 250°C. The column oven temperature was 50°C for 3 minutes, then ramped at a rate of 10°C / min to 250°C, held for 10 minutes. The carrier gas was He at a pressure of 11.583 psi, a total flow rate of 14 mL / min, and a split ratio of 1:10. The ion source temperature was 200°C, and the transfer line temperature was 180°C.

[0038] The total ion chromatogram (TIC) of GC-MS of sample 1# is as follows: Figure 1 As shown; some mass spectrum library search results are shown Figure 2 、 Figure 3 As shown. Figures 1 to 3 It can be seen that the organic groups to be tested were separated from the inorganic phase of titanium tetrachloride and enriched in the pure organic phase of carbon tetrachloride. GC-MS can clearly separate and detect the organic components and obtain mass spectrometry search results with a high degree of matching.

[0039] Example 2

[0040] 20.0 mL of the TiCl₄ sample solution (Sample #2) was placed in a separatory funnel. 4.0 mL of carbon tetrachloride solution was immediately added, followed by 80 mL of an ethanol-water solution (1 part anhydrous ethanol mixed with 4 parts water) in a volume ratio of 1:4 ethanol:water. The mixture was shaken and extracted, and the layers were allowed to stand for stratification. The lower layer was directly injected into the GC-MS for analysis. The injection volume was 3.0 μL; the injection port temperature was 350°C; the column oven temperature was 80°C for 5 minutes, then ramped at a rate of 20°C / min to 350°C and held for 15 minutes; the carrier gas was He at a pressure of 11.583 psi, a total flow rate of 14 mL / min, and a split ratio of 1:1. The ion source temperature was 250°C; and the transfer line temperature was 220°C.

[0041] The total ion chromatogram (TIC) of GC-MS of sample 2# is as follows: Figure 4 As shown; some mass spectrum library search results are shown Figure 5 、 Figure 6 As shown. Figures 4 to 6 It can be seen that the organic groups to be tested were separated from the inorganic phase of titanium tetrachloride and enriched in the pure organic phase of carbon tetrachloride. GC-MS can clearly separate and detect the organic components and obtain mass spectrometry search results with a high degree of matching.

[0042] Example 3

[0043] In order to verify the extraction and separation effect of the sample pretreatment method, a titanium tetrachloride matrix component separation effect verification test was carried out, as follows.

[0044] First round of test: 10.0 mL of TiCl4 sample solution (sample 3#) was taken into a separatory funnel, and 10.0 mL of carbon tetrachloride solution was immediately added, followed by 50 mL of ethanol-water solution with a volume ratio of ethanol to water = 1:6.

[0045] Second round of test: 10.0 mL of TiCl4 sample solution (sample 4#) was taken into a separatory funnel, and 10.0 mL of carbon tetrachloride solution was immediately added, followed by 100 mL of ethanol-water solution with a volume ratio of ethanol to water = 1:6.

[0046] The extraction was performed by shaking, and the layers were separated by standing. The contents of titanium ions and chloride ions in the upper ethanol aqueous solution liquid phase were detected. The results are shown in Table 1.

[0047] Table 1 Cl entering the upper liquid phase - and TiO2 content (g / L)

[0048]

[0049] The test results showed that the titanium and chlorine contents in the ethanol-water solution were consistent with theoretical values, indicating that matrix components such as titanium and chlorine in the titanium tetrachloride sample solution, which interfere with GC-MS analysis, were completely separated into the inorganic phase, thereby completely separating them from the organic components to be measured that entered the organic phase. In this example, the amount of ethanol-water solution used as the solvent for the inorganic components in the second round of experiments was twice that of the first round. Therefore, the theoretical concentrations of titanium and chlorine in the upper liquid phase of the second round of experiments should be half of that in the second round of experiments.

Claims

1. A sample pretreatment method for measuring organic components in titanium tetrachloride, characterized in that: Liquid-liquid extraction is performed on the titanium tetrachloride sample to be tested using a combined reagent. After sufficient reaction, the sample is allowed to stand for separation to obtain a clear, transparent, non-emulsified two-phase system with a distinct interface. The lower liquid phase is separated and collected to obtain a test solution for detection and analysis of organic components in titanium tetrachloride. The combined reagent comprises an organic component extractant and an inorganic component solubilizer, the organic component extractant is carbon tetrachloride, and the inorganic component solubilizer is ethanol and water; in the two-phase system, the upper layer is an ethanol-water phase containing inorganic components, and the lower layer is a carbon tetrachloride phase enriched with organic components.

2. The sample pretreatment method for measuring organic components in titanium tetrachloride according to claim 1, wherein: During the liquid-liquid extraction process, the volume ratio of the titanium tetrachloride sample to be tested to the organic component extractant is 1:1 to 5:

1.

3. The sample pretreatment method for measuring organic components in titanium tetrachloride according to claim 1, characterized in that: In the combined reagent, the volume ratio of the organic component extractant to the inorganic component dissolving agent is 1:5 to 1:

20.

4. The sample pretreatment method for measuring organic components in titanium tetrachloride according to claim 1, wherein: In the inorganic component dissolving agent, the volume ratio of ethanol to water is 1:4 to 1:

9.

5. The sample pretreatment method for measuring organic components in titanium tetrachloride according to claim 1, wherein: In the combined reagent, the carbon tetrachloride is of chromatographic grade or higher, and the ethanol is anhydrous ethanol with a purity of not less than 99.7%.

6. The sample pretreatment method for measuring organic components in titanium tetrachloride according to claim 1, characterized in that: When the liquid-liquid extraction is carried out in an inert atmosphere and / or a closed environment, the titanium tetrachloride sample to be tested and the combined reagent are added to the extraction device simultaneously or in any order.

7. The sample pretreatment method for measuring organic components in titanium tetrachloride according to claim 1, characterized in that: When the liquid-liquid extraction is carried out in an air atmosphere and / or an open environment, the titanium tetrachloride sample to be tested is first added to the extraction device, then the organic component extractant is immediately added, and finally the inorganic component dissolving agent is added.

8. A method for measuring and analyzing organic components in titanium tetrachloride, characterized in that: The sample pretreatment method according to any one of claims 1 to 7 is used to obtain a test solution, and the test solution is sent to an organic analysis instrument for organic component detection and analysis by direct sampling.

9. The method for measuring and analyzing organic components in titanium tetrachloride according to claim 8, wherein: The organic analysis instrument is any one of a gas chromatography-mass spectrometer, a gas chromatograph, a liquid chromatograph, a liquid chromatography-mass spectrometer, and an infrared spectrometer.

10. The method for measuring and analyzing organic components in titanium tetrachloride according to claim 9, characterized in that: Gas chromatography-mass spectrometry is used to detect and analyze the organic components in the test solution; The detection parameters are as follows: injection port temperature 250-350°C; column oven temperature: 50-80°C holding time 3-5 min, heating rate 10-20°C / min to 250-350°C, holding time 10-15 min; carrier gas He: pressure 11.583 psi, total flow rate 14 mL / min, split ratio 1:1-1:10; ion source temperature 200-250°C; transfer line temperature 180-220°C; injection volume 0.5-3.0 μL.

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