Method and device for detecting inorganic carbon in titanium tetrachloride

Abstract

The invention discloses a method and device for detecting inorganic carbon in titanium tetrachloride, and the method comprises the following steps: S1, taking a titanium tetrachloride sample, carrying out rectification light component removal to separate organic carbon, and concentrating inorganic carbon to obtain a tower kettle concentrated solution; s2, weighing 0.1-1g of tower kettle concentrated solution, combusting in an oxygen-enriched environment at the temperature of 1300-1500 DEG C, and detecting CO2 by using an NDIR (Non-Dispersive Infra-Red) detector; and S3, calculating the inorganic carbon content in the tower kettle concentrated solution according to the carbon content standard curve, and converting the inorganic carbon content in the titanium tetrachloride sample by combining the concentration factor. Physical concentration of inorganic carbon is realized by evaporating the main solvent, the problem of detection of trace inorganic carbon is solved, efficient separation of organic carbon and inorganic carbon can be realized, and inorganic carbon is highly concentrated in a small amount of residual liquid by evaporating and separating most of titanium tetrachloride main body, so that carbon-sulfur analysis is coupled, and the detection accuracy is improved. Accurate and high-sensitivity detection of trace inorganic carbon is achieved, and the detection limit can reach the ppb level.

Description

Technical Field

[0001] This invention relates to the field of chemical analysis technology, and in particular to a method and apparatus for detecting inorganic carbon in titanium tetrachloride. Background Technology

[0002] Titanium tetrachloride (TiCl4) is a key precursor in the production of sponge titanium, titanium dioxide, and semiconductor thin film materials, and its purity directly affects the performance of the final product. Carbon is one of the common impurities in titanium tetrachloride, mainly existing in the form of organic carbon (such as CCl3COCl, COCl2, etc.) and inorganic carbon (such as fine carbon powder, certain carbon chlorides, etc.). Among them, inorganic carbon impurities are more difficult to remove in subsequent processes due to their chemical inertness and particulate characteristics, and have a greater negative impact on the electrical properties, uniformity, and yield of the product.

[0003] Currently, the detection of carbon content in titanium tetrachloride mainly focuses on total carbon or organic carbon.

[0004] For example, Chinese patent CN116046600A discloses a method for detecting the carbon content in titanium tetrachloride. The method involves hydrolyzing, neutralizing, and filtering a titanium tetrachloride sample to obtain a neutralized residue, and then using a carbon-sulfur analyzer to detect the carbon content in the neutralized residue in order to calculate the total organic matter content.

[0005] Although this method is relatively simple to operate, it has obvious shortcomings: 1) This method is designed to detect the total organic matter content and does not distinguish between organic carbon and inorganic carbon (such as toner, carbide, etc.). Inorganic carbon in titanium tetrachloride is more harmful to high-end applications such as semiconductors and needs to be monitored separately and accurately; 2) Hydrolysis and neutralization methods may result in the loss or transformation of some volatile or soluble inorganic carbon, affecting the accuracy of detection.

[0006] Chinese patent CN120685414A discloses a method for preparing and detecting the total carbon content test solution in titanium tetrachloride, which involves hydrolysis, evaporation, hydrofluoric acid dissolution, and ICP-MS / OES detection of the total carbon content.

[0007] This method also cannot distinguish between organic and inorganic carbon. In addition, its pretreatment process involves the use of hydrofluoric acid, which is highly dangerous, and the high-temperature evaporation and strong acid environment may lead to the loss or interference of some forms of inorganic carbon, making the process relatively complex.

[0008] Existing detection methods are significantly insufficient in accurately quantifying inorganic carbon content, making it difficult to provide timely and accurate data support for inorganic carbon impurities in the production process. The unstable control of carbon element in refined TiCl4 on the Panzhihua Iron and Steel Group's sponge titanium production line has become a key bottleneck restricting product quality improvement, making the development of a method for accurately detecting inorganic carbon content an urgent priority.

[0009] In view of this, improvements should be made to the existing technology. Summary of the Invention

[0010] The main objective of this invention is to provide a method for detecting inorganic carbon in titanium tetrachloride. By evaporating the main solvent, the inorganic carbon is physically concentrated, solving the problem of detecting trace inorganic carbon. This method enables efficient separation of organic and inorganic carbon. By evaporating and separating most of the titanium tetrachloride main solvent, the inorganic carbon is highly concentrated in a small amount of residual liquid, thereby coupling carbon and sulfur analysis to achieve accurate and highly sensitive detection of trace inorganic carbon, with a detection limit down to the ppb level.

[0011] According to one aspect of the present invention, a method for detecting inorganic carbon in titanium tetrachloride is provided, comprising the following steps: S1. Take a titanium tetrachloride sample and separate organic carbon by distillation to remove light carbon, and concentrate inorganic carbon to obtain the concentrate in the bottom of the column; S2. Weigh 0.1~1g of the concentrate in the bottom of the tower and burn it in an oxygen-enriched environment at 1300~1500℃. Use an NDIR detector to detect CO2. S3. Calculate the inorganic carbon content in the concentrate in the bottom of the column based on the carbon content standard curve, and then calculate the inorganic carbon content in the titanium tetrachloride sample by combining the concentration factor.

[0012] According to one embodiment of the present invention, the removal of light components by distillation is carried out through a distillation column for removing light components, which is a packed column.

[0013] According to one embodiment of the present invention, the packing inside the packed tower includes one or more of the following: 2-15mm stainless steel θ-ring packing, 2-15mm triangular spiral packing, 2-15mm quartz spring packing, and 2-15mm PFA packing.

[0014] According to one embodiment of the present invention, the inner wall of the distillation column for removing light pollutants is made of 316L stainless steel, and the lining material is titanium and / or Hastelloy and / or high-purity quartz glass.

[0015] According to one embodiment of the present invention, the theoretical number of plates in the distillation column for removing light components is 30 to 70.

[0016] According to one embodiment of the present invention, the temperature of the bottom of the distillation column for removing light components is controlled within the range of 120~150°C, and the temperature of the top of the column is controlled within the range of 60~120°C.

[0017] According to one embodiment of the present invention, the reflux ratio for distillation to remove light components is controlled within the range of 10 to 40.

[0018] According to one embodiment of the present invention, in step S3, a carbon content standard curve is established using a carbon-sulfur analyzer.

[0019] According to one embodiment of the present invention, the concentration factor is the ratio of the mass of titanium tetrachloride sample to the mass of the concentrate in the bottom of the column.

[0020] According to another aspect of the present invention, an apparatus for detecting inorganic carbon in titanium tetrachloride is provided, comprising a distillation column for removing light carbon, the distillation column having a distillation inlet, a distillation waste gas outlet and a distillation liquid outlet, the distillation waste gas outlet being located at the top of the distillation column and the distillation liquid outlet being located at the bottom of the distillation column.

[0021] According to an embodiment of the present invention, a method for detecting inorganic carbon in titanium tetrachloride achieves physical concentration of inorganic carbon by evaporating the main solvent, solving the problem of detecting trace inorganic carbon. It can achieve efficient separation of organic and inorganic carbon, and can highly concentrate inorganic carbon in a small amount of residual liquid by evaporating and separating most of the titanium tetrachloride main body, thereby coupling carbon and sulfur analysis to achieve accurate and highly sensitive detection of trace inorganic carbon, with a detection limit of up to ppb level. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some implementation examples of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A process flow diagram of a method for detecting inorganic carbon in titanium tetrachloride according to an exemplary embodiment of the present invention is shown. Figure 2 A schematic diagram of an apparatus for detecting inorganic carbon in titanium tetrachloride according to an exemplary embodiment of the present invention is shown. Detailed Implementation

[0024] The following detailed description of the embodiments is intended to exemplify the principles of the present invention, but should not be construed as limiting the scope of the invention. The present invention 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.

[0025] These embodiments are provided to make this disclosure thorough and complete, and to fully express the scope of the invention to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​set forth in these embodiments should be interpreted as merely exemplary and not as limiting.

[0026] It should be noted that, in the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationships, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0027] It should also be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention depending on the specific circumstances. When a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device.

[0028] All terms used in this invention have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0029] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0030] like Figure 1 As shown, this invention provides a method for detecting inorganic carbon in titanium tetrachloride, which includes the following steps: S1. Take a titanium tetrachloride sample and separate organic carbon by distillation to remove light carbon, and concentrate inorganic carbon to obtain the concentrate in the bottom of the column; S2. Weigh 0.1~1g of the concentrate in the bottom of the tower and burn it in an oxygen-enriched environment at 1300~1500℃. Use an NDIR detector (non-dispersive infrared detector) to detect CO2. S3. Calculate the inorganic carbon content in the concentrate in the bottom of the column based on the carbon content standard curve, and then calculate the inorganic carbon content in the titanium tetrachloride sample by combining the concentration factor.

[0031] In the method for detecting inorganic carbon in titanium tetrachloride according to an embodiment of the present invention, the inorganic carbon is physically concentrated by evaporating the main solvent, which solves the problem of detecting trace inorganic carbon. It can achieve efficient separation of organic carbon and inorganic carbon. By evaporating and separating most of the titanium tetrachloride main body, the inorganic carbon is highly concentrated in a small amount of residual liquid, thereby coupling carbon and sulfur analysis to achieve accurate and highly sensitive detection of trace inorganic carbon, with a detection limit of up to ppb level.

[0032] In some embodiments, the amount of concentrate taken from the bottom of the column is 0.5g.

[0033] Step S1 utilizes the significant differences in volatility and boiling point between organic carbon impurities (such as CHCl3, COCl3, etc., which are mostly light components) and inorganic carbon impurities (such as carbon powder, high-boiling-point carboxylates, etc., which are mostly heavy components) in titanium tetrachloride. Through a precisely controlled distillation process to remove light components, organic carbon impurities with boiling points lower than titanium tetrachloride are removed from the top of the column, thereby concentrating and enriching inorganic carbon in the bottom product.

[0034] In some specific embodiments, the distillation column for removing light components is a packed column.

[0035] Based on the above embodiments, the packing material inside the packed tower includes one or more of the following: 2-15 mm stainless steel θ-ring packing, 2-15 mm triangular spiral packing, 2-15 mm quartz spring packing, and 2-15 mm PFA packing. These packing materials can provide a large specific surface area to ensure efficient gas-liquid mass transfer.

[0036] In some embodiments, the inner wall of the distillation column for removing light pollutants is made of 316L stainless steel, and the lining material is titanium and / or Hastelloy and / or high-purity quartz glass to ensure resistance to titanium tetrachloride corrosion.

[0037] In some specific embodiments, the theoretical plate number of the distillation column for removing light components is 30 to 70. A higher theoretical plate number ensures sufficient separation efficiency, effectively separating organic light components with similar boiling points from titanium tetrachloride.

[0038] Based on the above embodiments, the temperature of the distillation column for removing light pollutants is controlled within the range of 120~150℃. This temperature not only ensures the vaporization of titanium tetrachloride, but also maintains a high evaporation rate, so that most of the titanium tetrachloride is collected from the distillation vapor outlet as the top product of the column, rather than being completely refluxed.

[0039] The temperature at the top of the column is controlled within the range of 60~120℃ to condense and separate light organic components with boiling points below this temperature.

[0040] In some specific embodiments, the reflux ratio for distillation and removal of light components is controlled within the range of 10 to 40. While ensuring separation efficiency, by controlling the appropriate reflux ratio and withdrawal rate, only a small amount (5% to 20% of the initial feed) of titanium tetrachloride can be retained in the bottoms as the final concentrate. During this process, poorly volatile inorganic carbon impurities are continuously retained in the bottoms liquid phase. As most of the titanium tetrachloride is distilled off, its concentration is significantly increased, with enrichment factors reaching 5 to 20 times or even higher.

[0041] Based on the above embodiments, in step S3, a carbon-sulfur analyzer is used to establish a carbon content standard curve. The carbon-sulfur analyzer allows for precise quantification of inorganic carbon.

[0042] Because inorganic carbon has been enriched, its signal intensity is greatly enhanced under the same sample weight.

[0043] In some specific embodiments, the concentration factor is the ratio of the mass of the titanium tetrachloride sample to the mass of the concentrate in the bottom of the column.

[0044] The detection method provided by this invention is precise for inorganic carbon and can reduce the effective detection limit to below 10 ppm. It has the advantages of relatively safe operation, low detection limit, good repeatability and strong specialization. It can be directly applied to the quality control and process research and development departments of titanium tetrachloride production enterprises.

[0045] The implementation of this technology can provide key technical support for the precise control of inorganic carbon content in the production process, and for stabilizing and improving the quality of refined TiCl4, directly supporting the goal of improving the grade rate of the new production line.

[0046] The successful application of the technology in this invention will be an urgent and necessary technical guarantee for breaking through the current quality bottleneck and realizing the strategy of improving the quality and reducing the cost of sponge titanium. It has broad prospects for promotion in the field of high value-added utilization of vanadium and titanium resources.

[0047] like Figure 2 As shown, this application also provides a device for detecting inorganic carbon in titanium tetrachloride, which includes a distillation column for removing light carbon. The distillation column for removing light carbon has a distillation inlet, a distillation waste gas outlet and a distillation liquid outlet. The distillation inlet is used to receive titanium tetrachloride samples, the distillation waste gas outlet is located at the top of the distillation column for removing light carbon, and the distillation liquid outlet is located at the bottom of the distillation column for removing light carbon.

[0048] The distillation waste gas outlet is for light components and titanium tetrachloride, while the distillation liquid outlet is for the enriched product.

[0049] The present application will be further described below through specific embodiments.

[0050] Example 1 S1. A distillation column with 50 theoretical plates for removing light components was used, filled with 3mm stainless steel θ-ring packing, and the column body was made of 316L stainless steel. 2000g of the titanium tetrachloride sample to be tested was added to the column reboiler. Heating was started, and the reboiler temperature was controlled at 140℃, while the top temperature was stabilized at 120℃. The reflux ratio was set to 30. Under these conditions, the distilled titanium tetrachloride product was continuously collected from the top of the column. When the remaining material in the reboiler was approximately 200g (i.e., concentrated 10 times), operation was stopped, and the concentrate in the reboiler was collected.

[0051] S2. Using a carbon-sulfur analyzer, establish a carbon content standard curve (R²>0.999), accurately weigh 0.1000g of the concentrate sample from the bottom of the tower for analysis, and set the combustion temperature to 1350℃ and the oxygen flow rate to 1.5L / min.

[0052] S3. The instrument shows that the carbon content of this concentrated sample is 320 ppm. Original sample inorganic carbon content = concentrated solution carbon content / concentration factor = 320 ppm / 10 = 32 ppm.

[0053] Using the same batch of titanium tetrachloride to be tested, three complete distillation-concentration-detection processes were performed in parallel. The inorganic carbon content of the original samples measured in the three tests was 30, 34, and 31 ppm, respectively.

[0054] The mean value was 31.7 ppm, the relative standard deviation (RSD) was 6.6%, and the standard deviation was 2.08.

[0055] According to IUPAC standards, the detection limit is calculated based on 3 times the standard deviation. The detection limit (LoD) for the original sample is 3 × standard deviation = 6.24 ppm.

[0056] Example 2 Using the same batch of titanium tetrachloride samples, the same distillation column, packing and operating parameters as in Example 1 were employed (bottom temperature 140°C, top temperature 120°C, reflux ratio 30).

[0057] Change the concentration endpoint. Stop the operation when the remaining material in the column is 250g (concentrated 8 times) and 150g (concentrated about 13.3 times), respectively, and collect the concentrate.

[0058] Carbon and sulfur analysis was performed on the two concentrated solutions, and the inorganic carbon content of the original samples was calculated back.

[0059] When concentrated 8 times, the tested carbon content was 250 ppm, and the calculated carbon content of the original sample was 31 ppm.

[0060] When concentrated 13.3 times, the tested carbon content was 420 ppm, and the calculated carbon content of the original sample was 32 ppm.

[0061] The calculated inorganic carbon content of the original samples was highly consistent, fluctuating slightly around 32 ppm. This demonstrates that the method of this invention is insensitive to changes in the concentration endpoint within a reasonable range, exhibiting good robustness and further ensuring the accuracy of the detection results.

[0062] Comparative Example 1 A 0.1g sample of the same batch of raw titanium tetrachloride was taken directly and analyzed under the same conditions (1350℃, 1.5L / min) using the same carbon-sulfur analyzer without any pretreatment. Due to the low absolute content of inorganic carbon and the interference of organic carbon, the detection signal was weak and unstable. The total carbon values ​​measured three times were 50, 60, and 40 ppm, respectively, but it was impossible to distinguish between organic and inorganic carbon. Furthermore, the results of multiple measurements showed large dispersion and could not be used for accurate quantification.

[0063] Through the above examples and comparisons, it is fully demonstrated that the detection method based on distillation to remove light carbon and evaporation concentration provided by this invention successfully solves the technical problem that direct detection methods cannot accurately quantify trace inorganic carbon in titanium tetrachloride. This method utilizes actual process parameters (50 theoretical plates, 3mm θ-ring packing, bottom / top temperatures of 140 / 120℃, reflux ratio of 30, and a 10-fold concentration) to achieve efficient enrichment and high-precision detection of inorganic carbon (RSD = 5.8%), demonstrating outstanding industrial application value and reliability.

[0064] The beneficial effects of this invention are: 1) The core innovation lies in first achieving efficient separation and enrichment of organic and inorganic carbon through distillation technology, and specifically pre-treating the inorganic carbon that is difficult to remove, thus solving the problem that existing technologies cannot distinguish and detect them. 2) The distillation conditions are mild, avoiding the use of strong acids and highly corrosive reagents, reducing the risk of carbon loss, and making the operation safer; 3) The subsequent coupling of mature carbon and sulfur analysis methods is specifically designed for the detection of enriched inorganic carbon. It has a low detection limit (≤10ppm) and good precision (RSD<20%), providing a precise and dedicated detection method for the titanium tetrachloride production process, especially for the control of inorganic carbon impurities.

[0065] The method for detecting inorganic carbon content in titanium tetrachloride provided by this invention enables precise quantification of inorganic carbon, a key impurity in refined TiCl4, with a detection limit ≤10ppm and an RSD better than 20%. The application of this method will directly improve the quality control level and the targeted nature of process adjustments in Panzhihua Iron & Steel Group's sponge titanium production line, helping to increase the 0-grade yield of the new line and improve economic efficiency.

[0066] The above are exemplary embodiments disclosed in this invention. The order of the disclosed embodiments is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. However, it should be noted that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the disclosed embodiments of this invention (including the claims) is limited to these examples. Various changes and modifications can be made without departing from the scope defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular.

[0067] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of the different aspects of the invention as described above exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A method for detecting inorganic carbon in titanium tetrachloride, characterized in that, Includes the following steps: S1. Take a titanium tetrachloride sample and separate organic carbon by distillation to remove light carbon and concentrate inorganic carbon to obtain the concentrate in the bottom of the column; S2. Sample the concentrate from the bottom of the tower and use a carbon-sulfur analyzer to accurately quantify the inorganic carbon.

2. The method for detecting inorganic carbon in titanium tetrachloride according to claim 1, characterized in that, The light-light removal process is carried out through a light-light removal column, which is a packed column.

3. The method for detecting inorganic carbon in titanium tetrachloride according to claim 2, characterized in that, The packing material inside the packed tower includes one or more of the following: stainless steel θ-ring packing with an outer dimension of 2-15 mm, triangular spiral packing with an outer dimension of 2-15 mm, quartz spring packing with an outer dimension of 2-15 mm, and PFA packing with an outer dimension of 2-15 mm.

4. The method for detecting inorganic carbon in titanium tetrachloride according to claim 2, characterized in that, The inner wall material of the distillation column for removing light pollutants includes at least one of the following: 316L stainless steel, titanium, Hastelloy, and quartz glass.

5. The method for detecting inorganic carbon in titanium tetrachloride according to claim 2, characterized in that, The theoretical number of plates in the distillation column for removing light components is 30 to 70.

6. The method for detecting inorganic carbon in titanium tetrachloride according to claim 1, characterized in that, The temperature of the bottom of the distillation column for removing light pollutants is controlled within the range of 120~150℃, and the temperature of the top of the column is controlled within the range of 60~120℃.

7. The method for detecting inorganic carbon in titanium tetrachloride according to claim 1, characterized in that, The controlled reflux ratio for distillation and light component removal is in the range of 10 to 40.

8. The method for detecting inorganic carbon in titanium tetrachloride according to claim 1, characterized in that, Step S2 includes: A carbon content standard curve was established using the aforementioned carbon-sulfur analyzer. Weigh 0.1~1g of the concentrate from the bottom of the column and burn it in an oxygen-enriched environment at 1300~1500℃. Detect the CO2 concentration using the NDIR detector of the carbon-sulfur analyzer. The inorganic carbon content in the concentrate at the bottom of the column is calculated based on the carbon content standard curve and the CO2 concentration detected by the NDIR detector. Then, the inorganic carbon content in the titanium tetrachloride sample is calculated by combining the concentration factor.

9. The method for detecting inorganic carbon in titanium tetrachloride according to claim 1, characterized in that, The concentration factor is the ratio of the mass of the titanium tetrachloride sample to the mass of the concentrate in the bottom of the column.

10. A device for detecting inorganic carbon in titanium tetrachloride, characterized in that, For performing the detection method as described in any one of claims 1-9, the detection device includes a distillation column for removing light pollutants and a carbon and sulfur analyzer. The distillation column for removing light pollutants is provided with a distillation inlet, a distillation waste gas outlet, and a distillation liquid outlet. The distillation waste gas outlet is located at the top of the distillation column for removing light pollutants, and the distillation liquid outlet is located at the bottom of the distillation column for removing light pollutants.

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