Determination method for organic carbon impurities in titanium tetrachloride

Abstract

The invention relates to the technical field of metallurgical engineering, and provides a method for determining organic carbon impurities in titanium tetrachloride, which comprises the following steps: filtering a titanium tetrachloride sample to remove inorganic carbon impurities; reacting the filtered sample with an oxidizing agent under pressurizing and heating conditions, so that organic carbon impurities in the sample are converted into a carbon-containing gas-phase product and solid-phase residues; collecting and measuring the carbon content in the carbon-containing gas-phase product to obtain the gas-phase carbon content; carrying out distillation separation on the reacted liquid, collecting residues, and measuring the carbon content in the residues to obtain the solid-phase carbon content; and adding the gas-phase carbon content and the solid-phase carbon content to obtain the content of the organic carbon impurity in the titanium tetrachloride. According to the scheme, high-precision and high-specificity quantitative analysis on the organic carbon impurities in the titanium tetrachloride is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metallurgical engineering, and particularly relates to a method for determining organic carbon impurities in titanium tetrachloride. BACKGROUND

[0002] Titanium tetrachloride is a key raw material for producing sponge titanium, titanium dioxide and titanium alloy for aerospace. The performance of the product is highly dependent on the purity of the raw material. Among them, the presence of organic carbon impurities is particularly critical. In the smelting process of titanium materials, it will form carbide inclusions, which will significantly reduce the mechanical properties and corrosion resistance of the material, and will adversely affect the electrical properties of semiconductor-grade titanium materials. Therefore, accurately determining the content of organic carbon impurities in titanium tetrachloride is a key link to ensure the quality of the final product.

[0003] At present, the detection of carbon impurities in titanium tetrachloride mainly relies on chemical titration method, infrared spectroscopy and gas chromatography. However, these existing methods have significant limitations. The chemical titration method needs to oxidize the organic matter for indirect determination, and the operation process is complicated, and it is easily disturbed by the hydrolysis products of titanium tetrachloride, affecting the accuracy of the results. Although the infrared spectroscopy method can be used to determine the total carbon, it cannot effectively distinguish between organic carbon and inorganic carbon (such as acyl chloride, carbon particles, etc.), resulting in deviation in the measurement results. Although the gas chromatography method can directly separate and detect specific organic impurities (such as chlorinated hydrocarbons), titanium tetrachloride itself has strong corrosiveness and high volatility, which will cause damage to the chromatographic column, and the detection limit of this method for low-boiling-point organic impurities is relatively high, which is difficult to meet the stringent requirements of high-purity titanium tetrachloride production.

[0004] Therefore, there is an urgent need for a method that can effectively distinguish between carbon forms, has strong anti-interference ability, is simple to operate, and is suitable for accurate determination of low-content organic carbon impurities. SUMMARY

[0005] In view of the obvious deficiencies in the detection accuracy and specificity of organic carbon impurities in titanium tetrachloride when dealing with multiple-component organic impurities in the complex matrix of titanium tetrachloride in the prior art, especially the lack of effective means for detecting trace amounts of alkanes, alkenes and other organic carbons, the present application proposes a method for determining organic carbon impurities in titanium tetrachloride, comprising: Step a, filtering titanium tetrachloride samples to remove inorganic carbon impurities; Step b, reacting the filtered sample with an oxidizing agent under pressurized and heated conditions to convert the organic carbon impurities in the sample into carbon-containing gas phase products and solid phase residues; Step c, collecting and determining the carbon content in the carbon-containing gas phase products to obtain the gas phase carbon content; Step d, distilling the liquid after the reaction, collecting the residues and determining the carbon content therein to obtain the solid phase carbon content; Step e, adding the gas phase carbon content and the solid phase carbon content to obtain the content of the organic carbon impurity in the titanium tetrachloride.

[0006] In some embodiments, the oxidant in step b comprises oxygen.

[0007] In some embodiments, the amount of the oxidant introduced is 10-20% of the volume of the sample after filtration.

[0008] In some embodiments, the reaction temperature in step b is 140-300℃, the reaction pressure is 0.1-1.5 MPa, and the reaction time is 0.5-6 hours.

[0009] In some embodiments, the carbon-containing gas phase product comprises carbon tetrachloride and carbon dioxide.

[0010] In some embodiments, step c comprises: The concentration of carbon tetrachloride in the carbon-containing gas phase product is determined by gas chromatography-mass spectrometry, and the corresponding carbon content is calculated based on the conservation of carbon elements; The concentration of carbon dioxide in the carbon-containing gas phase product is determined by infrared gas analyzer, and the corresponding carbon content is calculated based on the conservation of carbon elements; The carbon contents of the above two are added to obtain the gas phase carbon content.

[0011] In some embodiments, the distillation method in step d is reduced pressure distillation.

[0012] In some embodiments, the vacuum degree of the reduced pressure distillation is 0.06-0.09 MPa, and the distillation temperature is 80-130℃.

[0013] In some embodiments, step d further comprises: determining the carbon content in the residue by high-frequency infrared carbon-sulfur analyzer.

[0014] In some embodiments, step a comprises: filtering the titanium tetrachloride sample by a 0.22-0.25 μm polytetrafluoroethylene filter membrane.

[0015] The determination method of the organic carbon impurities in the titanium tetrachloride realizes high-precision and high-specificity quantitative analysis of the organic carbon impurities in the titanium tetrachloride, and meanwhile ensures the anti-interference and operation feasibility of the method. The whole method process design effectively avoids the damage risk of the strong corrosiveness of the titanium tetrachloride to the precision analysis instrument, and the steps are clear and the operation is simple, which meets the harsh requirements of the low content and accurate determination of the organic carbon impurities in the production of high-purity titanium tetrachloride. Specifically, by filtering the sample, the inorganic carbon impurities are removed in advance, thereby avoiding the interference of acyl chloride, carbon particles and other inorganic carbon components on the subsequent determination from the source, directly solving the fundamental problem that traditional methods such as infrared spectroscopy cannot distinguish between organic carbon and inorganic carbon, and laying a solid foundation for the subsequent specific detection of organic carbon. The filtered sample is reacted with the oxidizing agent under the condition of pressurization and heating, which can efficiently and completely convert the complex organic carbon impurities into simple carbon-containing gas phase products and solid phase residues, overcoming the disadvantages of the chemical titration method such as complicated operation and being easily interfered by hydrolysis, and the strong reaction conditions ensure the complete conversion of various organic components (including difficult-to-decompose and low-boiling-point organic matters), solving the problems of insufficient detection limit of low-boiling-point organic matters and difficulty in dealing with complex components in the gas chromatography method. The carbon contents in the gas phase and the solid phase are determined independently, which can fully capture the carbon conversion products in different forms, ensuring the integrity and accuracy of the detection results and avoiding the possible omission of a single detection method. The total organic carbon content is obtained by adding the carbon contents in the gas phase and the solid phase, and the calculation method is logically rigorous, realizing the accurate quantification of the total amount of the organic carbon impurities in the sample. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other embodiments can also be obtained from these drawings without creative labor.

[0017] Figure 1 A flow chart of a determination method of organic carbon impurities in titanium tetrachloride is provided for an embodiment of the present application. DETAILED DESCRIPTION

[0018] The embodiments of the present disclosure will be further described in detail below in combination with the drawings and examples. The detailed description and drawings of the following embodiments are used to exemplarily illustrate the principles of the present disclosure, but cannot be used to limit the scope of the present disclosure, and the present disclosure can be implemented in many different forms, and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0019] The present disclosure provides these examples to make the disclosure thorough and complete, and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that: unless otherwise specified, the relative arrangement of components and steps, the composition of materials, numerical expressions and values set forth in these examples should be interpreted as merely exemplary, not as a limitation.

[0020] In addition, "first", "second" and similar words used in the present disclosure do not represent any order, quantity or importance, but are only used to distinguish different parts. "Include" or "contain" and similar words mean that the elements before the word cover the elements listed after the word, and do not exclude the possibility of also covering other elements.

[0021] All terms used in the present disclosure have the same meaning as understood by those skilled in the art to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted to have meanings consistent with their meanings in the context of the relevant art, and should not be interpreted in an idealized or excessively formalized sense, unless specifically defined here.

[0022] Techniques, methods and equipment known to those skilled in the relevant art may not be discussed in detail, but in appropriate cases, the techniques, methods and equipment should be considered as part of the specification.

[0023] It should be understood that the embodiments of the present application shown in the exemplary embodiments are only illustrative. Although only a few embodiments are described in detail in the present application, those skilled in the art can easily appreciate that various modifications are possible without departing from the teachings of the present application subject matter. Accordingly, all such modifications should be included within the scope of the present application. Other substitutions, modifications, changes and omissions can be made to the design, operating conditions and parameters of the following exemplary embodiments without departing from the spirit of the present application.

[0024] Reference is made to Figure 1 , Figure 1 The flow chart of the method for determining organic carbon impurities in titanium tetrachloride provided by an embodiment of the present application is shown. The method for determining organic carbon impurities in titanium tetrachloride shown in this embodiment includes: Step a, take titanium tetrachloride sample for filtration to remove inorganic carbon impurities.

[0025] Specifically, for example, 200-500 mL of titanium tetrachloride sample is measured, and 0.22-0.25 μm polytetrafluoroethylene microporous filter membrane is used for suction filtration treatment, which can effectively remove inorganic carbon impurities such as carbon particles present in the sample. The filtered sample is collected in a brown glass bottle and sealed for light protection.

[0026] The step a removes inorganic carbon impurities in advance by filtering the sample, avoids the interference of acyl chloride, carbon particles and other inorganic carbon components on subsequent determination from the source, directly solves the fundamental problem that traditional methods such as infrared spectroscopy cannot distinguish between organic carbon and inorganic carbon, and lays a solid foundation for subsequent specific detection of organic carbon.

[0027] The step b is to react the filtered sample with an oxidizing agent under pressurized and heated conditions, so that the organic carbon impurities in the sample are converted into carbon-containing gas phase products and solid phase residues.

[0028] Specifically, for example, 100 mL of the filtered sample is injected into a Hastelloy material pressurized reactor, and then 10-20 mL of high-purity oxygen (purity ≥ 99.99%) is introduced as an oxidizing agent. After sealing the reactor, the temperature is raised to 140-300°C at a rate of 5°C / min, and the system pressure is maintained within the range of 0.1-1.5 MPa. Under this condition, the reaction is carried out for 0.5-6 hours, so that the organic carbon impurities in the sample are fully converted into carbon-containing gas phase products and solid phase residues.

[0029] The step b above can efficiently and completely convert complex organic carbon impurities into simple carbon-containing gas phase products and solid phase residues under pressurized and heated conditions, overcoming the disadvantages of chemical titration method such as complicated operation and susceptibility to hydrolysis interference. Moreover, the strong reaction conditions ensure the complete conversion of various organic components (including difficult-to-decompose and low-boiling organic substances), solving the problems of insufficient detection limit of low-boiling organic substances by gas chromatography and difficulty in dealing with complex components.

[0030] The step c is to collect and determine the carbon content in the carbon-containing gas phase products to obtain the gas phase carbon content.

[0031] Specifically, after the reaction is completed, the reactor is cooled to room temperature, and the generated gas products are quantitatively collected by a gas collection system. The concentration of carbon tetrachloride is analyzed by using a gas chromatography-mass spectrometry (GC-MS), and the corresponding carbon content is calculated according to the mass conservation of carbon element; at the same time, the concentration of carbon dioxide is measured by using an infrared gas analyzer and the carbon content is calculated. The carbon contents of carbon tetrachloride and carbon dioxide are added to obtain the gas phase carbon content C1.

[0032] The step d is to distill and separate the liquid after the reaction, collect the residues and determine the carbon content therein to obtain the solid phase carbon content.

[0033] Specifically, the remaining liquid after the reaction is transferred to a polytetrafluoroethylene material vacuum distillation device, and distillation is carried out under the conditions of a vacuum degree of 0.06-0.09 MPa and a temperature of 80-130 DEG C until no titanium tetrachloride fraction is produced. The remaining distillation residue is collected, and the total carbon content in the residue is determined by using a high-frequency infrared carbon-sulfur analyzer in an oxygen flow combustion mode to obtain a solid-phase carbon content C2.

[0034] The above steps c and d are independent determinations of the carbon content in the gas phase and the solid phase, respectively, which can comprehensively capture different forms of carbon conversion products, ensuring the integrity and accuracy of the detection results and avoiding possible omissions of a single detection method.

[0035] Step e: adding the gas-phase carbon content and the solid-phase carbon content to obtain the content of the organic carbon impurity in the titanium tetrachloride.

[0036] Specifically, the measured gas-phase carbon content C1 and the solid-phase carbon content C2 are added to obtain the total mass of the organic carbon in the sample. Then, the mass of the titanium tetrachloride sample taken is divided by the mass to obtain the content of the organic carbon impurity in the titanium tetrachloride, which is expressed in mass fraction (ppm).

[0037] In some embodiments, step e includes adding the gas-phase carbon content and the solid-phase carbon content to obtain the content of the organic carbon impurity in the titanium tetrachloride. Specifically, the gas-phase carbon content C1 and the solid-phase carbon content C2 are added to obtain the total carbon content, and then the total mass of the titanium tetrachloride sample is divided by the mass to obtain the content of the organic carbon impurity in the titanium tetrachloride, which is expressed in ppm (mg / kg).

[0038] The above step e adds the gas-phase carbon content and the solid-phase carbon content to obtain the total organic carbon content, and the calculation method is logically rigorous and realizes accurate quantification of the total amount of the organic carbon impurity in the sample.

[0039] The above method for determining the organic carbon impurity in titanium tetrachloride realizes high-precision and high-specificity quantitative analysis of the organic carbon impurity in titanium tetrachloride, while ensuring the anti-interference and operation feasibility of the method. The entire method flow design effectively avoids the damage risk of the strong corrosiveness of titanium tetrachloride to the precision analysis instrument, and the steps are clear and the operation is simple, which meets the stringent requirements of accurate determination of the low content of the organic carbon impurity in high-purity titanium tetrachloride production.

[0040] According to some embodiments of the present application, the oxidizing agent in step b includes oxygen.

[0041] According to some embodiments of the present application, the amount of the oxidizing agent introduced is 10-20% of the volume of the filtered sample.

[0042] According to some embodiments of the present application, the reaction temperature in step b is 140-300℃, the reaction pressure is 0.1-1.5 MPa, and the reaction time is 0.5-6 hours.

[0043] According to some embodiments of the present application, the carbon-containing gas phase product includes carbon dioxide and carbon tetrachloride.

[0044] As a specific embodiment, in step b, the filtered sample is reacted with an oxidizing agent under pressurized and heated conditions. Specifically, 100 mL of the filtered sample is injected into a Hastelloy pressurized reactor, 10-20 mL of oxygen with a purity of not less than 99.99% is added as the oxidizing agent, and after sealing, the temperature is raised to 140-300℃, the pressure is maintained at 0.1-1.5 MPa, and the reaction is carried out for 0.5-6 hours, so that the organic carbon impurities in the sample are completely converted into a carbon-containing gas phase product and a solid phase residue.

[0045] According to some embodiments of the present application, step c includes: using a gas chromatograph-mass spectrometer to determine the concentration of carbon tetrachloride in the carbon-containing gas phase product, and calculating the corresponding carbon content based on the conservation of carbon elements; using an infrared gas analyzer to determine the concentration of carbon dioxide in the carbon-containing gas phase product, and calculating the corresponding carbon content based on the conservation of carbon elements; and adding the carbon contents of the above two to obtain the gas phase carbon content.

[0046] For example, after the reaction is completed, the system is cooled to room temperature, the gas product is discharged, the concentration of carbon tetrachloride in the gas product is determined using a gas chromatograph-mass spectrometer, and the corresponding carbon content is calculated based on the conservation of carbon elements; at the same time, the concentration of carbon dioxide is determined using an infrared gas analyzer, and the corresponding carbon content is calculated based on the conservation of carbon elements; and the carbon contents of the above two are added to obtain the gas phase carbon content.

[0047] According to some embodiments of the present application, the distillation method in step d is vacuum distillation.

[0048] According to some embodiments of the present application, the vacuum degree of the vacuum distillation is 0.06-0.09 MPa, and the distillation temperature is 80-130℃.

[0049] According to some embodiments of the present application, step d further includes: using a high-frequency infrared carbon-sulfur analyzer to determine the carbon content in the residue.

[0050] As a feasible embodiment, the liquid after the reaction is subjected to distillation separation, the residue is collected, and the carbon content therein is determined. Specifically, a vacuum distillation method can be used, and the distillation is carried out under the conditions of a vacuum degree of 0.06-0.09 MPa and a temperature of 80-130℃, and after all titanium tetrachloride is distilled out, a distillation residue is obtained. For example, a high-frequency infrared carbon-sulfur analyzer can be used to directly determine the carbon content in the distillation residue, and the solid phase carbon content is obtained.

[0051] According to several embodiments of the present application, step a comprises filtering the titanium tetrachloride sample using a 0.22-0.25 μm polytetrafluoroethylene filter.

[0052] As a feasible embodiment, a titanium tetrachloride sample is filtered to remove inorganic carbon impurities. For example, a 200-500 mL titanium tetrachloride sample can be filtered using a 0.22 μm polytetrafluoroethylene filter to remove mechanical impurities including carbon particles, and the filtered sample is stored in a brown sealed bottle in the dark. As a feasible embodiment, in step a, a titanium tetrachloride sample is filtered to remove inorganic carbon impurities. For example, a 200-500 mL titanium tetrachloride sample can be filtered using a 0.22 μm polytetrafluoroethylene filter to remove mechanical impurities including carbon particles, and the filtered sample is stored in a brown sealed bottle in the dark.

[0053] In summary, the method for determining organic carbon impurities in titanium tetrachloride according to the present application realizes high-precision and high-specificity quantitative analysis of organic carbon impurities in titanium tetrachloride, while ensuring the anti-interference and operational feasibility of the method. The entire method flow design effectively avoids the risk of damage to precision analytical instruments caused by the strong corrosiveness of titanium tetrachloride, and the steps are clear and easy to operate, meeting the stringent requirements for low content and accurate determination of organic carbon impurities in high-purity titanium tetrachloride production.

[0054] In order to further understand the method for determining organic carbon impurities in titanium tetrachloride provided by the present application, the following is further elaborated in specific embodiments.

[0055] Example 1 A 200 mL titanium tetrachloride sample was filtered through a 0.22 μm polytetrafluoroethylene filter to remove inorganic carbon impurities. 100 mL of the filtered sample was accurately transferred to a 500 mL Hastelloy material pressurized reaction kettle. 8 mL of high-purity oxygen (purity ≥ 99.99%) was introduced as an oxidizing agent, and the reaction kettle was sealed. The reaction system was programmed to heat to 300°C at a rate of 5°C / min, and the system pressure was maintained at 0.1 MPa during the process. After reaching the set temperature, the reaction was continued for 2 h to ensure that the organic carbon impurities in the sample were fully converted into carbon-containing gas phase products and solid residues.

[0056] After the reaction was completed, the system was cooled to room temperature, and all the gas products were quantitatively collected. Gas chromatography-mass spectrometry (GC-MS) was used to analyze the gas components, and the carbon tetrachloride (CCl4) concentration was measured to be 6.5 μg / L (equivalent to 0.08 ppm in terms of carbon); at the same time, an infrared gas analyzer was used to determine the carbon dioxide (CO2) concentration to be 229.3 μg / L (equivalent to 28.7 ppm in terms of carbon). According to the principle of carbon element conservation, the total carbon content C1 of the gas phase was obtained by adding the carbon contents of the above two, i.e. C1 = 0.08 + 28.7 = 28.78 ppm.

[0057] The remaining liquid after the reaction was transferred to a polytetrafluoroethylene material vacuum distillation device, and distillation was carried out under the conditions of a vacuum degree of 0.085 MPa and a temperature of 90°C until no titanium tetrachloride fraction was distilled out. The total carbon content in the residue was determined by a high-frequency infrared carbon-sulfur analyzer, and the solid-phase carbon content C2 was 9.2 ppm.

[0058] The total organic carbon content in the titanium tetrachloride sample was calculated as Ctotal = C1 + C2 = 28.78 + 9.2 = 37.98 ppm. A standard sample with a carbon content of 50.0 ppm was used for method verification, and the measured result was 50.2 ppm, with a relative error of 0.4%, indicating that the method has high accuracy.

[0059] Example 2 A 500 mL titanium tetrachloride sample was filtered through a 0.25 μm polytetrafluoroethylene filter membrane to remove inorganic carbon impurities. 200 mL of the filtered sample was accurately transferred to a 1 L Hastelloy material pressurized reaction kettle. 10 mL of high-purity oxygen (purity ≥ 99.99%) was introduced as an oxidizing agent, and the reaction kettle was sealed. The reaction system was programmed to heat to 200°C at a rate of 5°C / min, and the system pressure was maintained at 0.5 MPa during the process. After reaching the set temperature, the reaction was continued for 3 h to fully convert the organic carbon impurities in the sample.

[0060] After the reaction was completed, the system was cooled to room temperature, and all the gas products were quantitatively collected. GC-MS analysis showed that the carbon content corresponding to carbon tetrachloride was 0.5 ppm; an infrared gas analyzer was used to determine the carbon content corresponding to carbon dioxide, which was 2.7 ppm. According to the principle of carbon element conservation, the total gas-phase carbon content C1 was calculated as C1 = 0.5 + 2.7 = 3.2 ppm.

[0061] The remaining liquid after the reaction was subjected to vacuum distillation (vacuum degree 0.07 MPa, temperature 100°C), and after all the titanium tetrachloride was distilled out, the distillation residue was collected. A high-frequency infrared carbon-sulfur analyzer was used to determine the total carbon content in the residue, and the solid-phase carbon content C2 was 1.7 ppm.

[0062] The total organic carbon content in the titanium tetrachloride sample was calculated as Ctotal = C1 + C2 = 3.2 + 1.7 = 4.9 ppm. A standard sample with a carbon content of 5.0 ppm was used for method verification, and the relative error was 2.0%, indicating that the method still has good accuracy in the low concentration range.

[0063] Example 3 Take 300 mL of titanium tetrachloride sample, filter through a 0.22 μm polytetrafluoroethylene filter to remove inorganic carbon impurities. Accurately transfer 150 mL of the filtered sample into a 500 mL Hastelloy material pressurized reactor. According to the proportion of 10% of the volume of the filtered sample, 15 mL of high-purity oxygen (purity ≥ 99.99%) is introduced as an oxidizing agent, and the reactor is sealed. The reaction system is programmed to heat to 140°C at a rate of 5°C / min, and the system pressure is maintained at 1.5 MPa during the process. After reaching the set temperature, the reaction is continued for 0.5 hours to allow the organic carbon impurities in the sample to be fully converted into carbon-containing gas phase products and solid phase residues.

[0064] After the reaction is completed, the system is cooled to room temperature, and all the gas products are quantitatively collected. Gas chromatography-mass spectrometry (GC-MS) is used to analyze the gas components, and the carbon content corresponding to carbon tetrachloride (CCl4) is measured to be 0.8 ppm; at the same time, an infrared gas analyzer is used to determine the carbon content corresponding to carbon dioxide (CO2) to be 15.2 ppm. According to the principle of carbon element conservation, the total carbon content C1 of the gas phase is obtained by adding the carbon contents of the above two, i.e. C1 = 0.8 + 15.2 = 16.0 ppm.

[0065] The remaining liquid after the reaction is transferred to a polytetrafluoroethylene material vacuum distillation device, and distilled at a vacuum degree of 0.06 MPa and a temperature of 130°C until no titanium tetrachloride fraction is distilled out. The total carbon content in the distilled residue is determined by a high-frequency infrared carbon and sulfur analyzer, and the solid phase carbon content C2 is obtained as 4.5 ppm.

[0066] The total organic carbon content in the titanium tetrachloride sample is calculated as Ctotal = C1 + C2 = 16.0 + 4.5 = 20.5 ppm. A standard sample with a carbon content of 20.0 ppm is used for method verification, and the relative error is 2.5%, indicating that the method still has good accuracy under the parameter range endpoint conditions.

[0067] Example 4 Take 400 mL of titanium tetrachloride sample, filter through a 0.22 μm polytetrafluoroethylene filter to remove inorganic carbon impurities. Accurately transfer 200 mL of the filtered sample into a 1 L Hastelloy material pressurized reactor. According to the proportion of 20% of the volume of the filtered sample, 40 mL of high-purity oxygen (purity ≥ 99.99%) is introduced as an oxidizing agent, and the reactor is sealed. The reaction system is programmed to heat to 300°C at a rate of 5°C / min, and the system pressure is maintained at 0.1 MPa during the process. After reaching the set temperature, the reaction is continued for 6 hours to allow the organic carbon impurities in the sample to be fully converted.

[0068] After the reaction, the system was cooled to room temperature, and all the gas products were quantitatively collected. The carbon content corresponding to carbon tetrachloride was 2.1 ppm, which was measured by GC-MS analysis; the carbon content corresponding to carbon dioxide was 45.3 ppm, which was measured by an infrared gas analyzer. According to the principle of carbon element conservation, the total carbon content of the gas phase C1 = 2.1 + 45.3 = 47.4 ppm was obtained by adding the carbon contents of the above two.

[0069] The remaining liquid after the reaction was subjected to vacuum distillation (vacuum degree 0.09 Pa, temperature 80°C), and after all the titanium tetrachloride was distilled out, the distillation residue was collected. The total carbon content in the residue was measured by a high-frequency infrared carbon-sulfur analyzer, and the solid-phase carbon content C2 = 12.6 ppm was obtained.

[0070] The total organic carbon content in the titanium tetrachloride sample was calculated: Ctotal = C1 + C2 = 47.4 + 12.6 = 60.0 ppm. A standard sample with a carbon content of 60.5 ppm was used for method verification, and the relative error was 0.8%, indicating that the method also performs excellent accuracy and reliability under the conditions of another set of parameter range endpoints.

[0071] So far, the embodiments of the present disclosure have been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein according to the above description.

[0072] Although some specific embodiments of the present disclosure have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration, not for limiting the scope of the present disclosure. Those skilled in the art should understand that the above embodiments can be modified or some technical features can be replaced equivalently without departing from the scope and spirit of the present disclosure. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way.

Claims

1. A method for determining organic carbon impurities in titanium tetrachloride, characterized in that, include: Step a: Take a titanium tetrachloride sample and filter it to remove inorganic carbon impurities; Step b: The filtered sample is reacted with an oxidant under pressure and heating conditions to convert organic carbon impurities in the sample into carbon-containing gaseous products and solid residues. Step c: Collect and determine the carbon content in the carbon-containing gaseous products to obtain the gaseous carbon content; Step d: Distill the liquid after the reaction, collect the residue and determine the carbon content to obtain the solid phase carbon content; Step e: Add the gas phase carbon content to the solid phase carbon content to obtain the content of organic carbon impurities in the titanium tetrachloride.

2. The method for determining organic carbon impurities in titanium tetrachloride according to claim 1, characterized in that, The oxidant in step b includes oxygen.

3. The method for determining organic carbon impurities in titanium tetrachloride according to claim 2, characterized in that, The amount of oxidant introduced is 10-20% of the volume of the filtered sample.

4. The method for determining organic carbon impurities in titanium tetrachloride according to claim 1, characterized in that, The reaction temperature in step b is 140-300℃, the reaction pressure is 0.1-1.5MPa, and the reaction time is 0.5-6 hours.

5. The method for determining organic carbon impurities in titanium tetrachloride according to claim 1, characterized in that, The carbon-containing gaseous products include carbon dioxide and carbon tetrachloride.

6. The method for determining organic carbon impurities in titanium tetrachloride according to claim 5, characterized in that, Step c includes: The concentration of carbon tetrachloride in the carbon-containing gaseous product was determined by gas chromatography-mass spectrometry, and the corresponding carbon content was calculated based on the carbon element conservation law. The concentration of carbon dioxide in the carbon-containing gaseous products was determined using an infrared gas analyzer, and the corresponding carbon content was calculated based on the carbon element conservation law. The carbon content of the gas phase is obtained by adding the carbon content of the two above.

7. The method for determining organic carbon impurities in titanium tetrachloride according to claim 1, characterized in that, The distillation method in step d is vacuum distillation.

8. The method for determining organic carbon impurities in titanium tetrachloride according to claim 7, characterized in that, The vacuum degree of the vacuum distillation is 0.06-0.09 MPa, and the distillation temperature is 80-130℃.

9. The method for determining organic carbon impurities in titanium tetrachloride according to claim 1, characterized in that, Step d further includes: determining the carbon content in the residue using a high-frequency infrared carbon-sulfur analyzer.

10. The method for determining organic carbon impurities in titanium tetrachloride according to claim 1, characterized in that, Step a includes filtering the titanium tetrachloride sample using a 0.22-0.25 μm polytetrafluoroethylene filter membrane.

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