Method for detecting content of sodium chloride in chlorination process titanium dioxide primary product

Abstract

The invention relates to the technical field of titanium dioxide production, and discloses a method for detecting the content of sodium chloride in a chlorination process titanium dioxide primary product, which comprises the following steps: weighing the chlorination process titanium dioxide primary product, recording the mass M1, and baking the titanium dioxide primary product; weighing the baked titanium dioxide primary product, recording the mass M2, adding deionized water into the baked titanium dioxide primary product, and uniformly stirring to prepare mixed slurry; carrying out solid-liquid separation on the mixed slurry, washing again after separation to obtain a solid, baking the solid again, weighing and recording the mass M3; and calculating the content of sodium chloride in the titanium dioxide primary product based on M1, M2 and M3. Errors caused by complex chemical reactions and instrument signal interference in a traditional detection method are avoided, the method is simple and easy to operate, and an effective way is provided for accurately detecting the content of sodium chloride in titanium dioxide obtained through the chlorination process.

Description

Technical Field

[0001] The invention relates to the technical field of titanium dioxide production, in particular to a method for detecting the content of sodium chloride in a primary product of titanium dioxide produced by a chloride process. Background Art

[0002] The amount of sodium chloride added to titanium dioxide produced by the chloride process is not only related to the quality of the initial product but also affects the viscosity of the post-processing slurry. Therefore, the sodium chloride content in the initial titanium dioxide product is one of the important control parameters in the production of titanium dioxide produced by the chloride process. There are many methods for detecting sodium chloride, including titration, potentiometric titration, volumetric method, ion chromatography, spectrophotometry, atomic absorption, and capillary electrophoresis. Spectrophotometry and atomic absorption are widely used because of their high accuracy, simple operation, and safety. However, for titanium dioxide produced by the chloride process, the initial titanium dioxide product absorbs a large amount of chlorine, moisture, hydrogen chloride, etc. Therefore, the method of using quantitative anions to infer the sodium chloride content is inaccurate. If sodium ions are used to analyze the sodium chloride in the sample, the test results will be greatly different from the actual results due to the influence of titanium dioxide particles. The traditional sodium chloride detection method is not suitable for detecting the sodium chloride content in titanium dioxide produced by the chloride process.

[0003] Therefore, there is a need in the prior art for improving the method for detecting the sodium chloride content in the primary product of titanium dioxide produced by the chloride process. Summary of the invention

[0004] In view of this, the purpose of the embodiment of the present invention is to propose a method for detecting the sodium chloride content in a primary product of titanium dioxide produced by the chloride process. The method is simple and direct, avoids the errors caused by complex chemical reactions and instrument signal interference in traditional detection methods, is easier to operate and understand, and provides an effective way to accurately detect the sodium chloride content in titanium dioxide produced by the chloride process.

[0005] Based on the above purpose, the embodiment of the present invention provides a method for detecting the sodium chloride content in a primary product of titanium dioxide produced by the chloride process, comprising the following steps: S1 weighs the initial product of titanium dioxide produced by the chloride process and records the mass M1, and bakes the initial product of titanium dioxide; S2 weighs the baked titanium dioxide primary product and records the mass M2, adds deionized water to the baked titanium dioxide primary product and stirs evenly to form a mixed slurry; S3 performs solid-liquid separation on the mixed slurry, washes again after separation to obtain a solid, bakes the solid again, weighs it and records the mass M3; S4 calculates the content of sodium chloride in the primary titanium dioxide product based on M1, M2 and M3.

[0006] In some embodiments, in S1, the primary titanium dioxide product is placed in a crucible, the crucible is placed in a heating furnace, the temperature of the heating furnace is set from room temperature to 200° C. to 400° C., and the product is baked in the heating furnace for 1 h to 5 h.

[0007] In some embodiments, an air atmosphere is continuously introduced during baking.

[0008] In some embodiments, in S2, the amount of deionized water used is 9 to 10 times the quality of the initial titanium dioxide.

[0009] In some embodiments, in S3, deionized water is used for washing, and the amount of deionized water used is 40 to 60 times the quality of the initial titanium dioxide.

[0010] In some embodiments, in S3, a suction filtration funnel is used to separate the mixed slurry into solid and liquid.

[0011] In some embodiments, the suction filtration funnel is a Buchner funnel, and the solid-liquid separation includes maintaining the liquid level of the washing water in the Buchner funnel at 2 / 3 of the height of the funnel.

[0012] In some embodiments, in S3, the baking temperature is 200°C to 400°C, and the baking time in the heating furnace is 1 hour to 5 hours.

[0013] In some embodiments, in S4, the sodium chloride content = (M2 - M3) / M1 x 100%.

[0014] In some embodiments, the primary titanium dioxide product includes carbon dioxide, titanium tetrachloride, titanium oxychloride and other impurities.

[0015] The present invention has at least the following beneficial technical effects: The method of the present invention can remove volatile impurities such as residual hydrogen chloride and unreacted titanium tetrachloride by baking, reduce interference with detection, and ensure the accuracy of the results. Secondly, after baking, the mixture is prepared and the solid-liquid separation is carried out, and then the solid is washed, which can improve the extraction efficiency of sodium chloride and make it more fully separated from the titanium dioxide particles. Finally, the sodium chloride content is calculated using the mass ratio before and after. The method is simple and direct, avoiding the errors caused by the complex chemical reaction and instrument signal interference in the traditional detection method, and is easier to operate and understand, providing an effective way to accurately detect the sodium chloride content in the chloride titanium dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is a schematic diagram of an embodiment of a method for detecting the sodium chloride content in a primary product of titanium dioxide produced by the chloride process provided by the present invention. DETAILED DESCRIPTION

[0018] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0019] The terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions; the terms "first", "second", etc. in the specification and claims of the present invention or the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order. "Multiple" means two or more, unless otherwise clearly and specifically defined.

[0020] In addition, reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0021] The method for producing titanium dioxide primary product by chlorination in the prior art comprises the following steps: Chlorination stage: High-purity titanium ore reacts with chlorine gas under the action of high temperature coke to produce titanium chloride, but at this time there are more impurities, which is crude titanium tetrachloride. Next, chemical treatment agents or distillation methods are used to remove other impurity ions from the crude titanium tetrachloride and transform it into refined titanium tetrachloride.

[0022] Oxidation stage: the newly obtained refined titanium tetrachloride, oxygen, nucleating agent and a series of reactants are added into the reactor for gas phase oxidation, and then a certain amount of coarse titanium dioxide is obtained through low-temperature circulating chlorine operation and dechlorination.

[0023] Post-processing section: Titanium dioxide can be obtained through grinding, grading, coating, washing, drying and crushing.

[0024] In the post-processing of titanium dioxide, sodium chloride may be added in the coating or dispersion steps to adjust the viscosity of the slurry. For example, in the coating process, when the surface of titanium dioxide is modified to improve its dispersibility and stability, adding an appropriate amount of sodium chloride can change the charge distribution and double layer structure on the particle surface. This helps to adjust the interaction force between particles, thereby controlling the viscosity of the slurry.

[0025] There are many methods for detecting sodium chloride in the prior art. For example, the operation requirements of the titration method are relatively strict. If the operation is unskilled or irregular, it is easy to produce large errors. And when using an indicator to judge the titration end point, the color change may be subjective. Different people have different sensitivities to color changes, which may lead to differences in endpoint judgment, thereby affecting the determination results of the sodium chloride content. The disadvantage of the spectrophotometric method is that, first, the linear range is relatively narrow. For samples with high or low sodium chloride content, pretreatments such as dilution or concentration may be required, otherwise the linear range of the method will be exceeded, resulting in inaccurate results. Second, there are many interference factors. Other substances in the sample may interfere with the determination of the spectrophotometric method and affect the accurate determination of sodium chloride. For example, factors such as the color and turbidity of the sample may affect the absorption of light, thereby causing deviations in the results. Third, the sensitivity is relatively low. Compared with some other analytical methods, the sensitivity of the spectrophotometric method is relatively low, and the detection of trace sodium chloride may not be accurate enough.

[0026] In general, the traditional sodium chloride detection method is not suitable for detecting the sodium chloride content in chloride process titanium dioxide. Therefore, the present invention provides a method for detecting the sodium chloride content in a primary product of chloride process titanium dioxide, comprising the following steps: S1 weighs the initial product of titanium dioxide produced by the chloride process and records the mass M1, and bakes the initial product of titanium dioxide; S2 weighs the baked titanium dioxide primary product and records the mass M2, adds deionized water to the baked titanium dioxide primary product and stirs evenly to form a mixed slurry; S3 performs solid-liquid separation on the mixed slurry, washes again after separation to obtain a solid, bakes the solid again, weighs it and records the mass M3; S4 calculates the content of sodium chloride in the primary titanium dioxide product based on M1, M2 and M3.

[0027] Further, in S1, the titanium dioxide primary product includes carbon dioxide, titanium tetrachloride, titanium oxychloride and other impurities. The titanium dioxide primary product is placed in a crucible, the crucible is placed in a heating furnace, the temperature of the heating furnace is set from room temperature to 200°C to 400°C, and the product is baked in the heating furnace for 1h to 5h. Air atmosphere is continuously introduced during the baking process.

[0028] Furthermore, in S2, the amount of deionized water used is 9 to 10 times the quality of the initial titanium dioxide.

[0029] Further, in S3, deionized water is used for washing, and the amount of deionized water used is 40 to 60 times the quality of the initial titanium dioxide. A suction filtration funnel is used to separate the mixed slurry into solid and liquid. In some embodiments, the suction filtration funnel is a Buchner funnel, and the solid-liquid separation includes maintaining the liquid level of the washing water in the Buchner funnel at 2 / 3 of the funnel height.

[0030] Further, in S3, the baking temperature is 200°C to 400°C, and the baking time in the heating furnace is 1 hour to 5 hours.

[0031] Further, in S4, the sodium chloride content = (M2-M3) / M1×100%.

[0032] The method of the present invention has the following advantages: Less interference from impurities: In the production process of titanium dioxide powder by the chloride process, the primary titanium dioxide contains a variety of complex impurities. Through the baking step, some volatile impurities (such as residual hydrogen chloride, a small amount of unreacted titanium tetrachloride, etc.) can be volatilized. If these impurities exist, they may react with the detection reagents or interfere with the detection signal during the subsequent detection of sodium chloride content, thereby affecting the accuracy of the test results. After baking, the impurity components are reduced, making the subsequent detection of sodium chloride more accurate.

[0033] High sodium chloride extraction rate: After baking, the titanium dioxide primary product is made into a mixture and then separated into solid and liquid, which can make sodium chloride dissolve better in water. Due to the different solubility characteristics of titanium dioxide particles and sodium chloride in water, this method can make sodium chloride more effectively separated from titanium dioxide particles. In the process of washing the solid, the sodium chloride remaining on the surface of the solid is further removed, making the extraction of sodium chloride more complete.

[0034] More accurate calculation: After the above series of treatments, the solid mass obtained by baking again is mainly the mass of substances that are not easily soluble and volatile, such as titanium dioxide, and the mass of sodium chloride can be calculated more accurately through the difference between the mass before and after. This mass ratio calculation method is relatively simple and direct, avoiding the errors caused by complex chemical reactions and instrument signal interference in traditional detection methods.

[0035] The present invention will be further explained below in conjunction with specific embodiments.

[0036] Example 1 Weigh 9.00g of the first product of titanium dioxide produced by the chloride process, then put the weighed sample into a crucible, and then put the crucible into a heating furnace, raise the temperature from room temperature to 400℃, and bake it in the heating furnace for 1h while continuously passing air. Weigh the baked sample and record the mass of 8.91g, add the baked sample to a beaker containing 80.19g of deionized water, stir evenly, and make a slurry; pour the slurry into a suction flask funnel and wash it with 534.6g of deionized water; the solid in the obtained suction funnel is placed in a heating furnace for baking again, the baking temperature is 400℃, and the baking time in the heating furnace is 1h. When it drops to room temperature, the sample mass is weighed to be 8.63g; the sodium chloride content in the first product of titanium dioxide chloride is calculated as follows: (8.91-8.63) / 9.00×100%, that is, the percentage of sodium chloride in the first product of titanium dioxide is 3.11%.

[0037] Example 2 Weigh 100.00g of the first product of titanium dioxide produced by the chloride process, then put the weighed sample into a crucible, and then put the crucible into a heating furnace, raise the temperature from room temperature to 300℃, and bake it in the heating furnace for 3h while continuously passing air. Weigh the baked sample and record the mass of 99.1g, add the baked sample to a beaker containing 891.9g of deionized water, stir evenly, and make a slurry; pour the slurry into a suction flask funnel and wash it with 3964g of deionized water; the solid in the obtained suction funnel is placed in a heating furnace for baking again, the baking temperature is 400℃, and the baking time in the heating furnace is 1h. When it drops to room temperature, the sample mass is weighed to be 96.62g; the sodium chloride content in the first product of titanium dioxide chloride is calculated as follows: (99.1-96.62) / 100.00×100%, that is, the percentage of sodium chloride in the first product of titanium dioxide is 2.49%.

[0038] Example 3 Weigh 50.00g of the first product of titanium dioxide produced by the chloride process, then put the weighed sample into a crucible, and then put the crucible into a heating furnace, raise the temperature from room temperature to 200℃, and bake it in the heating furnace for 5h while continuously passing air. Weigh the baked sample and record the mass of 49.58g, add the baked sample to a beaker containing 446.22g of deionized water, stir evenly, and make a slurry; pour the slurry into a suction flask funnel and wash it with 2479g of deionized water; the solid in the obtained suction funnel is placed in a heating furnace for baking again, the baking temperature is 400℃, and the baking time in the heating furnace is 1h. When it drops to room temperature, the sample mass is weighed to be 48.16g; the sodium chloride content in the first product of titanium dioxide chloride is calculated as follows: (49.58-48.16) / 50.00×100%, that is, the percentage of sodium chloride in the first product of titanium dioxide is 2.84%.

[0039] Example 4 Weigh 70.00g of the first product of titanium dioxide produced by the chloride process, then put the weighed sample into a crucible, and then put the crucible into a heating furnace, raise the temperature from room temperature to 400℃, and bake it in the heating furnace for 3h while continuously passing air. Weigh the baked sample and record the mass of 69.51g, add the baked sample to a beaker containing 625.59g of deionized water, stir evenly, and make a slurry; pour the slurry into a suction flask funnel and wash it with 2780.4g of deionized water; the solid in the obtained suction funnel is placed in a heating furnace for baking again, the baking temperature is 300℃, and the baking time in the heating furnace is 2h. When it drops to room temperature, the sample mass is weighed to be 67.66g; the sodium chloride content in the first product of titanium dioxide chloride is calculated as follows: (69.51-67.66) / 70.00×100%, that is, the percentage of sodium chloride in the first product of titanium dioxide is 2.64%.

[0040] The above are exemplary embodiments disclosed in the present invention, but it should be noted that various changes and modifications may be made without departing from the scope disclosed in the embodiments of the present invention as defined in the claims. The functions, steps and / or actions of the method claims according to the disclosed embodiments described herein do not need to be performed in any particular order. In addition, although the elements disclosed in the embodiments of the present invention may be described or required in individual form, they may also be understood as multiple unless explicitly limited to the singular.

[0041] It should be understood that, as used herein, the singular forms "a", "an" are intended to include the plural forms as well, unless the context clearly supports an exception. It should also be understood that, as used herein, "and / or" refers to any and all possible combinations including one or more of the associated listed items.

[0042] The serial numbers of the embodiments disclosed in the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0043] A person skilled in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the above embodiments of the present invention, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the embodiments of the present invention.

Claims

1. A method for detecting the sodium chloride content in a primary product of titanium dioxide produced by the chloride process, characterized in that: include: S1 weighs a chloride process titanium dioxide primary product and records the mass M1, and bakes the titanium dioxide primary product; S2 weighs the baked titanium dioxide primary product and records the mass M2, adds deionized water to the baked titanium dioxide primary product and stirs evenly to form a mixed slurry; S3 performs solid-liquid separation on the mixed slurry, washes again after separation to obtain a solid, bakes the solid again, weighs it and records the mass M3; S4 calculates the content of sodium chloride in the titanium dioxide primary product based on M1, M2 and M3.

2. The method for detecting sodium chloride content in a primary product of titanium dioxide produced by the chloride process according to claim 1, characterized in that: In S1, the titanium dioxide primary product is put into a crucible, the crucible is placed in a heating furnace, the temperature of the heating furnace is set from room temperature to 200° C. to 400° C., and the product is baked in the heating furnace for 1 hour to 5 hours.

3. The method for detecting sodium chloride content in the primary product of chloride process titanium dioxide according to claim 2, characterized in that: Air is continuously introduced during the baking process.

4. The method for detecting sodium chloride content in a primary product of titanium dioxide produced by the chloride process according to claim 1, characterized in that: In S2, the amount of deionized water used is 9 to 10 times the quality of the initial titanium dioxide.

5. The method for detecting sodium chloride content in a primary product of titanium dioxide produced by the chloride process according to claim 1, characterized in that: In S3, deionized water is used for washing, and the amount of deionized water used is 40 to 60 times the quality of the initial titanium dioxide.

6. The method for detecting sodium chloride content in a primary product of titanium dioxide produced by the chloride process according to claim 1, characterized in that: In S3, a suction filtration funnel is used to separate the mixed slurry into solid and liquid.

7. The method for detecting sodium chloride content in a primary product of titanium dioxide produced by the chloride process according to claim 6, characterized in that: The suction filtration funnel is a Buchner funnel, and the solid-liquid separation includes maintaining the liquid level of the washing water in the Buchner funnel at 2 / 3 of the funnel height.

8. The method for detecting sodium chloride content in primary product of chloride process titanium dioxide according to claim 1, characterized in that: In S3, the baking temperature is 200°C to 400°C, and the baking time in the heating furnace is 1 hour to 5 hours.

9. The method for detecting sodium chloride content in a primary product of titanium dioxide produced by the chloride process according to claim 1, characterized in that: In S4, sodium chloride content = (M2-M3) / M1×100%.

10. The method for detecting sodium chloride content in primary product of chloride process titanium dioxide according to claim 1, characterized in that: The titanium dioxide primary product includes carbon dioxide, titanium tetrachloride, titanium oxychloride and other impurities.

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