A sample pretreatment method for detecting the carbon content of titanium tetrachloride by high-temperature calcination

Abstract

The present invention belongs to the technical field of chemical production, and specifically relates to a sample pretreatment method for detecting the carbon content of titanium tetrachloride by high-temperature calcination, which solves the defect in the prior art that all carbon-containing substances cannot be analyzed and added up by infrared spectroscopy and gas chromatography, resulting in the influence on the accuracy of total carbon determination; the technical solution includes: weighing a certain mass of titanium tetrachloride and a Lewis acid, adding the Lewis acid to the titanium tetrachloride, heating and refluxing to precipitate the residual carbon in the titanium tetrachloride, collecting the residual carbon precipitate through a filtering instrument, and cleaning the filtering instrument with a suitable reagent to ensure complete separation of the titanium tetrachloride and the residual carbon. Then, the residual carbon is completely dried and the mass is recorded, and after drying, it is calcined at high temperature until complete and the mass is recorded. The carbon content of the titanium tetrachloride is calculated according to the mass loss before and after calcination and the mass of the weighed titanium tetrachloride.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical production, and particularly relates to a sample pretreatment method for detecting the carbon content of titanium tetrachloride by high-temperature calcination. Background Art

[0002] The most popular method for titanium sponge production is the Kroll process. The core of the Kroll process is the magnesium reduction of high-purity titanium tetrachloride, and the chemical equation is 2Mg + TiCl4 = 2MgCl2 + Ti. From this equation, it can be seen that the impurity elements in titanium tetrachloride will be enriched in titanium sponge at a ratio of 4 times, affecting the quality of titanium sponge. Different impurities have different effects on titanium sponge, and among them, the three elements of carbon, oxygen, and nitrogen have the greatest impact on the hardness of titanium sponge.

[0003] Currently reported methods for determining the carbon content in titanium tetrachloride include infrared spectroscopy and gas chromatography. Infrared spectroscopy and gas chromatography can only directly determine the content of a certain carbon-containing substance in titanium tetrachloride or simultaneously determine the content of certain carbon-containing substances. For example, infrared is used to simultaneously determine the contents of carbon tetrachloride, trichloroacetyl chloride, dichloroacetyl chloride, monochloroacetyl chloride, carbon dioxide, carbon disulfide, and titanium oxychloride in titanium tetrachloride, and gas chromatography is used to analyze the contents of trace CS2 and CCl4 in TiCl4. If the total carbon result is to be obtained, it is necessary to first determine the contents of all carbon-containing substances and then sum them up to obtain the total carbon content. However, the types of carbon-containing substances in titanium tetrachloride are rich, and there is no way to verify whether infrared spectroscopy and gas chromatography have analyzed all carbon-containing substances, which will affect the accuracy of total carbon determination. Summary of the Invention

[0004] Currently, there is no method that can precipitate carbon compounds in titanium tetrachloride. In view of this, the purpose of the present invention is to provide a sample pretreatment method for detecting the carbon content of titanium tetrachloride by high-temperature calcination to determine the total carbon content in titanium tetrachloride.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A sample pretreatment method for detecting the carbon content of titanium tetrachloride by high-temperature calcination includes the following steps:

[0007] Step 1: Heat the titanium tetrachloride solution in the reaction vessel to 70 - 80 °C, turn on the stirring device, and slowly add a Lewis acid as a catalyst to the titanium tetrachloride solution until it is completely mixed evenly;

[0008] Step 2: Connect the reaction vessel to a condensation reflux device, turn on the heating device, heat the mixed solution to 136 °C - 140 °C, and the heating reflux time is 40 min - 60 min;

[0009] Step 3: Turn off the heating device and the stirring device. After cooling the reaction device to room temperature, pour the titanium tetrachloride solution in the reaction vessel into the filtering device to precipitate the black carbon compounds in the titanium tetrachloride solution, and wash and dry the precipitate.

[0010] Step 4: Re-add the filtered titanium tetrachloride solution to a new reaction vessel, and repeat Step 1 and Step 2. Observe whether black carbon compounds precipitate. If black carbon compounds precipitate, repeat Step 3 until no black carbon compounds precipitate.

[0011] Step 5: High-temperature calcine the dried black carbon compounds, and judge the carbon content in titanium tetrachloride according to the loss on ignition. The specific judgment principle is as follows:

[0012]

[0013] In the formula: w—the carbon content in titanium tetrachloride;

[0014] m1—the mass of the crucible and the sample;

[0015] m2—the mass of the crucible and the sample after drying;

[0016] m—the mass of titanium tetrachloride.

[0017] Adopting the above technical solution, the carbon-containing compounds in the titanium tetrachloride solution are precipitated by a Lewis acid, the precipitated precipitate is then high-temperature calcined, and finally the carbon content in the titanium tetrachloride is calculated according to the mass loss before and after calcination and the mass of the weighed titanium tetrachloride.

[0018] Preferably, the mixing ratio of the Lewis acid to titanium tetrachloride is between 1:60 and 1:70.

[0019] Preferably, the Lewis acid is anhydrous aluminum chloride, ferric chloride or boron trifluoride.

[0020] Preferably, the pore diameter of the filter screen in the filtering device is 6 - 8 μm.

[0021] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0022] The disadvantages of using infrared spectroscopy to measure the organic content of titanium tetrachloride in the prior art are as follows: 1. Titanium tetrachloride will produce corrosive acid mist when it encounters water in the air, which requires high sealing requirements for the sample cell; 2. If the sample cell is not cleaned thoroughly, it will have a great impact on the analysis result error. The sample cell is difficult to clean and needs to be dried each time, resulting in a long sample analysis time. 3. The equipment is of high value and there is a risk of leakage and corrosion during sample measurement; The defects of using gas chromatography for analysis in the prior art are: 1. Titanium tetrachloride corrodes the micro syringe used for gas chromatography feeding, and the hydrolyzate will block the syringe needle, and the syringe can only be used for one injection. 2. The separation effect of gas chromatography is poor and the results fluctuate greatly; 3. Titanium tetrachloride samples may block the chromatographic column and corrode the metal structure inside the instrument, including the detector.

[0023] The sample pretreatment method for detecting the carbon content of titanium tetrachloride by high-temperature calcination provided by the present invention precipitates the carbon-containing compounds in the titanium tetrachloride solution through a Lewis acid, filters out the solid carbon compounds, and finally judges the carbon content in titanium tetrachloride according to the loss on ignition. Using high-temperature calcination to detect the carbon content of titanium tetrachloride avoids the above problems, has low sample measurement input and cost, is easy to operate, has high result accuracy, and has a wide promotion range. Specific embodiments

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Apparently, the described embodiments are only some of the embodiments of the present application, rather than all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0025] The present invention will be described in detail below.

[0026] Example 1:

[0027] A sample pretreatment method for detecting the carbon content of titanium tetrachloride by high-temperature calcination provided in Example 1 of the present application includes the following steps:

[0028] Step 1: Heat the titanium tetrachloride solution in the reaction vessel to 70 °C, turn on the stirring device, and slowly add the Lewis acid as a catalyst to the titanium tetrachloride solution at a mass ratio of 1:60 until it is completely mixed evenly. Under the catalysis of the Lewis acid, activate the organic functional groups and promote the formation of compounds with carbon-carbon and carbon-hetero bonds;

[0029] Step 2: Connect the reaction vessel to a condensation reflux device, turn on the heating device, heat the mixed solution to 136 °C, and the heating reflux time is 40 min;

[0030] Step 3: Turn off the heating device and the stirring device. After cooling the reaction device to room temperature, pour the titanium tetrachloride solution in the reaction vessel into the filtering device to precipitate the black carbon compound in the titanium tetrachloride solution, press-filter the black carbon compound into a filter cake, and wash and dry the filter cake.

[0031] Step 4: Re-add the filtered titanium tetrachloride precipitation solution to a new reaction vessel, repeat Step 1 and Step 2, observe whether there is a black carbon compound precipitated. If there is a black carbon compound precipitated, repeat Step 3 until no black carbon compound is precipitated.

[0032] Step 5: High-temperature burn the dried black carbon compound, and judge the carbon content in titanium tetrachloride according to the loss on ignition. The specific judgment principle is as follows:

[0033]

[0034] In the formula: w—the carbon content in titanium tetrachloride;

[0035] m1—the mass of the crucible and the sample;

[0036] m2—the mass of the crucible and the sample after drying;

[0037] m—the mass of titanium tetrachloride.

[0038] In this embodiment, the Lewis acid is anhydrous aluminum chloride, ferric chloride or boron trifluoride.

[0039] In this embodiment, the pore size of the filter screen in the filtering device is 6 - 8 μm.

[0040] Example Two:

[0041] The following is a sample pretreatment method for detecting the carbon content in titanium tetrachloride by high-temperature burning provided in Embodiment 1 of the present application, which includes steps:

[0042] Step 1: Heat the titanium tetrachloride solution in the reaction vessel to 80°C, turn on the stirring device, and slowly add the Lewis acid as a catalyst and the titanium tetrachloride solution in a mass ratio of 1:70 until completely mixed evenly. Under the catalysis of the Lewis acid, activate the organic functional groups to promote the formation of compounds with carbon-carbon and carbon-hetero bonds;

[0043] Step 2: Connect the reaction vessel to a condensation reflux device, turn on the heating device, heat the mixed solution to 140°C, and the heating reflux time is 60 min.

[0044] Step 3: Turn off the heating device and the stirring device. After cooling the reaction device to room temperature, pour the titanium tetrachloride solution in the reaction vessel into the filtering device to precipitate the black carbon compound in the titanium tetrachloride solution, press-filter the black carbon compound into a filter cake, and wash and dry the filter cake;

[0045] Step 4: Re-add the filtered titanium tetrachloride precipitation solution to a new reaction vessel, repeat Step 1 and Step 2, observe whether there is a black carbon compound precipitated. If there is a black carbon compound precipitated, repeat Step 3 until no black carbon compound is precipitated;

[0046] Step 5: Conduct high-temperature calcination on the dried black carbon compound under the conditions of calcining at 700 °C for 60 minutes. Finally, judge the carbon content in titanium tetrachloride according to the loss on ignition. The specific judgment principle is as follows:

[0047]

[0048] In the formula: w—the carbon content in titanium tetrachloride;

[0049] m1—the mass of the crucible and the sample;

[0050] m2—the mass of the crucible and the sample after drying;

[0051] m—the mass of titanium tetrachloride.

[0052] In this embodiment, the Lewis acid is anhydrous aluminum chloride, ferric chloride or boron trifluoride.

[0053] In this embodiment, the aperture of the filter screen in the filtering device is 6 - 8 μm.

[0054] For the above two embodiments, further, the present invention also provides a specific experimental process, and the specific steps are as follows:

[0055] S1. Weigh m = 200.0000 g of titanium tetrachloride in a fume hood and pour it into a three-necked flask, heat it to 80 °C, turn on the stirring device, and slowly add 3.0000 g of aluminum chloride to the three-necked flask;

[0056] S2. Connect the condenser to the flask mouth and fix the condenser. Place the flask in a heating mantle in the fume hood and heat it to 136 °C, slowly reflux for 60 min, and cool the three-necked flask in the fume hood until it can be safely handled;

[0057] S3. In the fume hood, place the prepared corundum filtering crucible on the suction filtering bottle mouth, connect the vacuum suction filtering device, and filter the precipitated residual carbon. Turn on the switch of the vacuum suction filtering device, slowly pour the sample into the crucible, filter out the residual carbon, and separately load the filtrate into a new three-neck flask. Slowly wash the filtering crucible with 1:1 hydrochloric acid, and also wash the flask with 1:1 hydrochloric acid. Pour the washing liquid into the filtering crucible for suction filtration, and repeat boiling the flask for washing until all the precipitates are transferred to the crucible;

[0058] S4. Reheat the titanium tetrachloride filtered in step 3 to 80 °C, turn on the stirring device, and slowly add 3.0000 g of aluminum chloride to this three-neck flask;

[0059] S5. Connect the condenser to the flask mouth and fix the condenser. In the fume hood, place the flask in a heating mantle and heat it to 136 °C, slowly reflux for 60 min, and cool the three-neck flask in the fume hood. Observe whether there is any black carbide precipitated. If there is, filter and collect it according to the washing method. Finally, it is found that there is no black carbon compound precipitated, and stop the sample pretreatment;

[0060] S5. Collect the black carbon compound twice, wash it with deionized water for filtration, transfer it into a crucible of constant weight. The weight of the crucible is 23.5471 g, and dry the carbide to obtain 6.2547 g; and conduct high-temperature calcination, and judge the carbon content in titanium tetrachloride according to the loss on ignition;

[0061] S6. Put the black carbide into a muffle furnace at 700 °C and calcine it for 60 minutes, then take it out and place it in a drying dish for three times of constant weight at room temperature, and finally obtain 29.6007 g;

[0062] S7. Calculate:

[0063]

[0064] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes falling within the meaning and scope of the same elements of the claims in the present invention..

[0065] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A sample pretreatment method for detecting the carbon content of titanium tetrachloride by high-temperature calcination, characterized in that, It includes the following steps: Step 1: Heat the titanium tetrachloride solution in the reaction vessel to 70 - 80 °C, turn on the stirring device, and slowly add the Lewis acid as a catalyst to the titanium tetrachloride solution until it is completely mixed evenly; Step 2: Connect the reaction vessel to the condensation reflux device, turn on the heating device, heat the mixed solution to 136 °C - 140 °C, and the heating reflux time is 40 min - 60 min; Step 3: Turn off the heating device and the stirring device. After cooling the reaction device to room temperature, pour the titanium tetrachloride solution in the reaction vessel into the filtering device to precipitate the black carbon compound in the titanium tetrachloride solution, and wash and dry the precipitate; Step 4: Re-add the filtered titanium tetrachloride solution to a new reaction vessel, repeat Step 1 and Step 2, observe whether there is a black carbon compound precipitated. If there is a black carbon compound precipitated, repeat Step 3 until no black carbon compound is precipitated; Step 5: High-temperature calcine the dried black carbon compound, and judge the carbon content in titanium tetrachloride according to the loss on ignition. The specific judgment principle is as follows: W = (m1 - m2) / m * 100% In the formula: w—the carbon content in titanium tetrachloride; m1—the mass of the crucible and the sample; m2—the mass of the crucible and the sample after drying; m—the mass of titanium tetrachloride; The mixing ratio of the Lewis acid to titanium tetrachloride is between 1:60 and 1:70; The Lewis acid is anhydrous aluminum chloride, ferric chloride or boron trifluoride; The pore size of the filter screen in the filtering device is 6 - 8 μm.

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