Method for detecting content of barium sulfate

Abstract

The invention provides a method for detecting the content of barium sulfate, which comprises the following steps: providing a sample solution, providing a blank control solution and a standard solution, detecting the sample solution, the blank control solution and the standard solution by adopting ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometer), and obtaining the content of barium element in the sample solution by adopting a standard curve method, obtaining the content of the barium element in the sample by combining the content of the barium element in the sample solution with the weight of the sample and the weight of the sample solution; calculating the content of the barium element in the dry weight of the sample according to the content of the barium element in the sample and the dry weight ratio of the sample; calculating the content of BaSO4 in the dry weight of the sample according to the content of the barium element in the dry weight of the sample; the sample solution is quantified by digestion and weighing of the sample to provide the sample solution. The method for detecting the content of barium sulfate provided by the invention can accurately test a barium sulfate sample with the content of 0-100%, and is high in accuracy and good in repeatability.

Description

Technical Field

[0001] This invention relates to the field of inorganic analysis technology, and in particular to a method for detecting barium sulfate content. Background Technology

[0002] Barium sulfate (BaSO4) is a commonly used inorganic chemical raw material, widely used in industries such as plastics, rubber, inks, papermaking, and catalysts. Its quality directly affects the performance and application effects of downstream products. Currently, the national standard GB / T2899-2008 is commonly used in industry to detect its content. Although this method is accurate, it requires high-temperature treatment of the material, which is demanding, cumbersome, and has a long testing cycle, and is not suitable for rapid on-site analysis.

[0003] Patent CN106596517 A provides a method for detecting barium sulfate content in recycled lead powder using ICP-OES. The method involves weighing a certain amount of recycled lead powder, adding nitric acid, and slowly heating until the lead powder is completely dissolved. After cooling to room temperature, the filtrate is transferred to a volumetric flask and diluted to volume. A blank sample is treated in the same way as the test sample. The barium sulfate content in both the test sample and the blank sample is detected using an ICP detection device. The barium sulfate content in the test sample is calculated by substituting the values ​​into the standard barium sulfate solution curve equation.

[0004] While this method overcomes the drawbacks of high-temperature material treatment and long testing cycles in the GB / T 2899-2008 method, it has the following problems: a) The required range for barium sulfate content in the sample is narrow, resulting in low accuracy in barium testing. This is because barium sulfate has extremely low solubility and strong inertness at room temperature. If the barium sulfate content in the sample is slightly high, barium sulfate precipitate will form after digestion and cooling to room temperature. In this case, testing the barium sulfate content in the filtrate will lead to a large error in the measurement results. b) Significant matrix interference. The patent uses a volumetric flask dilution method for the filtrate, increasing the human influence factors introduced by the standard preparation and sample digestion and volume adjustment steps.

[0005] Therefore, there is an urgent need for a simple, accurate, and comprehensive method for detecting barium sulfate content. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for detecting barium sulfate content, so as to solve the problems in the prior art.

[0007] To achieve the above and other related objectives, the present invention is obtained through the following technical solution.

[0008] This invention provides a method for detecting barium sulfate content, the method comprising the following steps: A sample solution, a blank control solution, and a standard solution are provided. The sample solution, blank control solution, and standard solution are detected using ICP-OES. The content of barium in the sample solution is obtained by standard curve method. The content of barium in the sample is obtained by combining the content of barium in the sample solution with the sample weight and the sample solution weight; The content of barium in the dry weight of the sample is calculated based on the content of barium in the sample and the proportion of the sample's dry weight. The content of BaSO4 in the dry weight of the sample was calculated based on the content of barium in the dry weight of the sample. The sample solution is provided by digesting and weighing the sample.

[0009] This application employs a gravimetric method to quantify the sample solution (i.e., to determine the weight of the sample solution to be tested), thus replacing the volumetric method commonly used in existing technologies for quantifying sample solutions. This effectively avoids experimental errors caused by visual errors in the "meniscus" reading, inherent deviations of the volumetric flask, sample solution adhesion to the walls, and thermal expansion of the liquid when using the volumetric method for sample solution quantification. Furthermore, the gravimetric method in this application uses an electronic balance for sample solution quantification. The introduction of the electronic balance makes the measurement results more accurate, to three decimal places; it also fundamentally avoids the adverse effects of solution adhesion to the walls and thermal expansion and contraction of the solution volume. The gravimetric method for quantifying sample solutions in this application not only minimizes experimental errors but also simplifies the rinsing steps involved in the volumetric method, making the experiment efficient and accurate.

[0010] Preferably, the sample is a powder or slurry containing barium sulfate. For example, it can be one or more of lead powder, coated paper slurry, nano-barium sulfate aqueous slurry, and precipitated barium sulfate.

[0011] Preferably, during the digestion process, the sample is pre-wetted in water, and then an excess of aqua regia is added for a first reaction. The aqua regia is a mixture of concentrated HCl and concentrated HNO3 in a volume ratio of 3:1. More specifically, the concentration of the concentrated HCl is 36-38%, and it is of analytical grade; the concentration of the concentrated HNO3 is 65-68%, and it is of analytical grade.

[0012] Preferably, the temperature of the first reaction is 95~130℃.

[0013] Preferably, the volume ratio of the aqua regia to the weight ratio of the sample is 800~3200:1, mL / g. For example, it can be 1800~2500:1, mL / g, or 1987~2176:1, mL / g.

[0014] In this application, the amount of aqua regia used is a crucial parameter and is not arbitrarily set. If too much aqua regia is used, without evaporating or diluting the excess acid, the high acid concentration will cause severe matrix effects during testing (such as a sharp drop in atomization / transmission efficiency and ionization equilibrium interference), significantly affecting the accuracy of the detection. If the excess acid is evaporated or diluted, the experiment will be prolonged, efficiency reduced, and emissions of hydrogen chloride and nitrogen oxides will increase, causing unnecessary waste and pollution. If too little aqua regia is used, the acidity will be too low due to volatilization and decomposition, leading to incomplete sample digestion. Only the dosage specified in this application achieves both experimental efficiency and complete sample digestion.

[0015] Preferably, after 30-60 seconds of the first reaction, when the yellow gas is at its most concentrated, a digestion aid is added to initiate the second reaction, yielding the sample digest. The reaction time can be 30-45 seconds or 45-60 seconds.

[0016] Preferably, the digestion aid includes one or more of hydrofluoric acid, perchloric acid, hydrochloric acid, nitric acid, phosphoric acid, and hydrogen peroxide. More preferably, it is hydrofluoric acid.

[0017] Preferably, the temperature of the second reaction is 95~130℃.

[0018] The timing of adding the digestion aid is a crucial technical aspect. Only when added at the specific temperature (95-130°C) described in this application and after a specific reaction time following the addition of aqua regia can the synergistic effect of dissolving barium sulfate with aqua regia, as described in this application, be achieved. Specifically, if the digestion aid is added too early, or simultaneously with aqua regia, it will react first with the glass or other reaction vessels, leading to corrosion of these vessels. Furthermore, the volatilization of the digestion aid will increase its usage, resulting in unnecessary waste. If the digestion aid is added too late, the acidity of the sample solution will be too low, hindering the dissolution of barium sulfate. Only when the digestion aid is added under the conditions provided in this application can it synergistically work with aqua regia to completely dissolve barium sulfate in the shortest possible time, while minimizing the amount of digestion aid used.

[0019] Preferably, the second reaction is completed when the sample is completely digested and the volume of the sample digest has evaporated to the same level as the pre-wetting volume. The time for the second reaction is 20-40 minutes. For example, it can be 20 minutes, 30 minutes, or 40 minutes.

[0020] Preferably, the volume ratio of the digestion aid to aqua regia is 1:800~3200. For example, it can be 1:800~1500 or 1:1500~3200.

[0021] In this application, the addition of a digestion aid is a crucial technical measure, and the selection of its type is specific. Specifically, barium sulfate has very low solubility in water. Generally, for barium sulfate to dissolve in acid and react with it, the acid needs to provide sufficiently strong protons or other reactive particles to disrupt the crystal structure of barium sulfate. Although aqua regia can dissolve many sparingly soluble substances, its dissolving effect on barium sulfate is limited because barium sulfate has extremely weak reducing and coordinating abilities, and aqua regia lacks effective coordinating ability.

[0022] The addition of a digestion aid with strong coordination ability (such as hydrofluoric acid) provides a single-level ligand, allowing the partially dissolved Ba to... 2+ (aq) and SO4 2- The reaction proceeds, thereby causing Ba in the solution to... 2+ and SO4 2- As the concentration of barium sulfate continues to decrease, the dissolution equilibrium continues to shift to the right. Therefore, with the synergistic effect of aqua regia and the digestion aid, barium sulfate is eventually completely dissolved.

[0023] Preferably, after the second reaction is completed, the sample digestion solution is cooled to 30~80℃, transferred to a clean container, diluted with water, weighed and quantified to obtain the sample solution.

[0024] Preferably, the temperature during the transfer process is 30~80°C. More preferably, it is 40~60°C. The transfer is rapid to prevent a sudden drop in temperature.

[0025] Preferably, a standard solution is provided by digesting, transferring, and weighing a standard sample with a known barium concentration.

[0026] Preferably, the concentration range of barium in the standard solution is: 80% of the estimated concentration of barium in the sample to 120% of the estimated concentration of barium in the sample.

[0027] Preferably, a blank control solution is provided by quantifying the water through digestion, transfer, and weighing.

[0028] Preferably, the conditions for performing ICP-OES testing include one or more of the following characteristics: The detection temperature is 30~80℃; The detection wavelength is 230~500nm.

[0029] The detection wavelength can be 230.424nm~493.409nm, 230.424nm~233.527nm, or 455.403nm~493.409nm; more preferably, it is 230.424nm. The detection temperature can be 30~45℃ or 45~80℃.

[0030] Preferably, the dry weight ratio of the sample is obtained in accordance with GB / T 5211.3-2020.

[0031] Preferably, the dry weight ratio of the sample is obtained by drying the sample until constant weight.

[0032] More preferably, the sample to be tested by ICP-OES or the sample of equal weight to be tested by ICP-OES is placed in a constant temperature environment of (105±2)℃ and dried until constant weight is obtained. The dry weight ratio of the sample is obtained by dividing the constant weight of the sample by the initial weight of the sample.

[0033] Preferably, the content of barium in the dry weight of the sample is calculated using Formula I, which is: ; Where P is the content of barium in the dry weight of the sample, %, C is the content of barium in the sample solution, μg / g, m1 is the mass of the sample solution, g, m0 is the mass of the sample, g, W is the dry weight ratio of the sample.

[0034] Preferably, the content of BaSO4 in the dry weight of the sample is calculated using Formula II, where Formula II is: A = P × (M BaSO4 / M Ba ), in units of %; where A is the content of BaSO4 in the dry weight of the sample, %, P is the content of barium element in the dry weight of the sample, %, M BaSO4 M is the relative molecular mass of barium sulfate. Ba is the relative molecular mass of barium.

[0035] The beneficial effects of this invention are: 1) The method described in this application uses aqua regia combined with a digestion aid during sample digestion, thereby ensuring complete sample digestion and eliminating the need for post-digestion filtration and rinsing. This avoids errors caused by incomplete sample digestion and guarantees the consistency between the sample solution and the standard solution.

[0036] 2) In the preparation of the sample solution and the ICP-OES test, the temperature of this application is kept at no less than 30°C, thereby avoiding the re-precipitation of barium sulfate in the digested sample solution. This ensures that the barium sulfate content can be accurately tested within the range of 0-100% (preferably 0.5-80%), further ensuring the accuracy of the test structure.

[0037] 3) In addition, this technical solution uses the weighing method for quantification instead of the volumetric method in the existing technology, which greatly reduces the human influence factors in the preparation of standard solutions and sample solutions, and further improves the precision, accuracy and reliability of the method. Attached Figure Description

[0038] Figure 1 The curve shown is the standard operating curve in this embodiment of the invention. Detailed Implementation

[0039] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0040] Before further describing specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the respective manufacturers.

[0041] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. In addition to the specific methods, apparatus, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description of this invention, any prior art methods, apparatus, and materials similar to or equivalent to those described, apparatus, and materials in the embodiments of this invention may be used to implement the present invention.

[0042] In this application, the standard curve method includes the following steps: 1) Prepare standard solutions of barium element with different concentrations, perform ICP-OES detection respectively, obtain the linear relationship between various barium element concentrations and the corresponding spectral intensities at each concentration, plot the corresponding standard working curves, and calculate the regression equation of the standard working curves of barium element concentration and the corresponding spectral intensities at each concentration. 2) Perform ICP-OES detection on the sample solution containing barium sulfate. Substitute the obtained corresponding spectral intensities into the regression equation of the standard working curve of barium ion concentration and corresponding spectral intensity at that concentration in step 1) to calculate the content of barium element in the sample.

[0043] Preferably, in the standard working curve, the concentration of barium element (barium ion) is used as the abscissa (X-axis), and the corresponding spectral intensity of barium element is used as the ordinate (Y-axis).

[0044] In the following embodiments of this application, the standard working curve used in the standard curve method is obtained by the following method: a) Accurately weigh a certain amount of standard samples with barium content of 80% and 95% respectively. According to the method of GB / T 5211.3, determine the dry weight ratio of the standard samples respectively. After completion, place the standard samples in a clean 250mL tall glass beaker, add deionized water to pre-wet the standard samples, and rinse the inner wall of the beaker with a small amount of deionized water, leaving all the water in the beaker so that the volume after pre-wetting is 10mL.

[0045] b) Heat the solution to 100°C on a hot plate until it boils, add 32 mL of aqua regia (the volume ratio of concentrated HCl to concentrated HNO3 is 3:1). The first reaction takes 45 seconds. When the yellow gas is most concentrated, add 10 μL of hydrofluoric acid. The second reaction takes 40 minutes until the volume of the standard digest solution evaporates to 10 mL. Remove the solution from the hot plate and cool it to 45°C.

[0046] c) Keep the standard digestion solution at 45°C and quickly transfer it to a clean volumetric flask of known weight. Dilute the standard digestion solution with deionized water and weigh it to 100g to obtain standard solutions of different concentrations.

[0047] d) The standard solutions with different barium concentrations were subjected to ICP-OES detection under the following conditions: detection wavelength 230.424 nm, detection temperature 45 °C. After the instrument stabilized, the standard solutions of different concentrations were sequentially sprayed into the ICP light source, and the spectral intensities corresponding to different concentrations of barium were measured. The standard working curve was then fitted.

[0048] The barium element and its corresponding spectral intensities are shown in Table 1 below, and the standard working curve is attached. Figure 1 .

[0049] Table 1

[0050] It should be noted that the blank control solution in this application is prepared in exactly the same way as the standard solution, except that the standard sample is replaced with an equal amount of deionized water.

[0051] In this application, the method of GB / T 5211.3 is specifically as follows: the sample to be tested by ICP-OES is placed in a constant temperature environment of (105±2)℃ and dried until constant weight. The dry weight ratio of the sample is obtained by dividing the constant weight of the sample by the initial weight of the sample.

[0052] Comparative Example 1 Analytical grade reagent with a barium sulfate content of 98.5% was used; the barium content in the sample was tested using the national standard method GB / T 2899-2008, and the barium content in the sample was found to be 58%, and the corresponding barium sulfate content in the dry weight of the sample was calculated to be 98.56%.

[0053] This embodiment provides a specific method for detecting barium sulfate content, including the following steps: 1) Weigh out 6 samples of barium sulfate of different weights, the same as those in Comparative Example 1. Then, determine the dry weight ratio of the samples according to the method of GB / T 5211.3. After completion, place the samples in clean 250mL tall glass beakers, add deionized water to pre-wet them, rinse the inner wall of the beaker with a small amount of deionized water and retain all the water in the beaker so that the volume after pre-wetting is 10mL.

[0054] 2) Heat the solution to 100°C on a hot plate until it boils, add 32 mL of aqua regia (the volume ratio of concentrated HCl to concentrated HNO3 is 3:1). The first reaction takes 45 seconds. When the yellow gas is most concentrated, add 10 μL of hydrofluoric acid. The second reaction takes 40 minutes until the volume of the sample digestion solution evaporates to 10 mL. Remove the solution from the hot plate and cool it to 45°C.

[0055] 3) Keep the sample digestion solution at 45°C and quickly transfer it to a clean volumetric flask of known weight. Dilute the sample digestion solution with deionized water and weigh and quantify it to obtain the sample solution.

[0056] 4) Perform ICP-OES detection on the above sample solutions under the following conditions: detection wavelength 230.424 nm, detection temperature 45℃. After the instrument stabilizes, spray different sample solutions into the ICP light source in sequence, and measure the spectral intensity corresponding to different concentrations of barium. Then, input the results into the standard working curve and combine them with the sample weight and the weight of the sample solution to obtain the content of barium in the corresponding sample.

[0057] 5) Through formula I: The content of barium in the dry weight of the sample was calculated, where P is the content of barium in the dry weight of the sample, %; C is the content of barium in the sample solution, μg / g; m1 is the mass of the sample solution, g; m0 is the mass of the sample, g; and W is the dry weight ratio of the sample.

[0058] 6) Using formula II: A = P × (M) BaSO4 / M Ba The content of BaSO4 in the dry weight of the sample was calculated, where A is the content of BaSO4 in the dry weight of the sample (%), P is the content of barium in the dry weight of the sample (%), and M is the content of barium in the dry weight of the sample (%). BaSO4 The relative molecular mass of barium sulfate is (233.39); M Ba The relative molecular mass of barium is 137.33.

[0059] The specific results are shown in Table 2.

[0060] Table 2

[0061] As shown in Table 2, Examples 1-6 of this application tested the same sample, and the results showed that the barium content in the sample was 57.12%-57.99%, corresponding to a barium sulfate content of 97.07%-98.55% in the dry weight of the sample. The experimental results of these six parallel experiments showed extremely small errors, which were within a negligible range, indicating that the barium sulfate content detection method provided by this application has good stability, high accuracy of detection results, and good repeatability.

[0062] Comparative Examples 2-4 Weigh out three portions of barium sulfate samples of different weights, the same as those in Examples 1-3, and follow the same steps as in Example 1.

[0063] The sample digestion process was exactly the same as in Example 1.

[0064] 3) Except for replacing weighing to quantify the sample solution with volume adjustment to quantify the sample solution, the sample solution is obtained exactly the same as in Example 1.

[0065] 4) The above sample solution was subjected to ICP-OES detection. The test conditions and calculation process were exactly the same as in Example 1.

[0066] The specific results are shown in Table 3.

[0067] Table 3

[0068] As shown in Tables 3 and 2, compared with Examples 1-3, in Comparative Examples 2-4, when the sample solution was quantified using the volumetric method, the experimental results obtained from different batches showed significant differences, poor parallelism, and poor stability. This indicates that the detection results of the technical solution in this application are more accurate and have better repeatability.

[0069] Examples 7-13 Aqueous slurry samples with barium sulfate contents of 0.5%, 1.5%, 5%, 10%, 30%, 50% and 80% by dry weight were prepared. The slurry formulations are shown in Table 4 below.

[0070] The calculated barium content in the dry weight of the samples is: 0.29%, 0.88%, 2.94%, 5.88%, 17.65%, 29.42%, and 47.07%.

[0071] Table 4

[0072] Aqueous slurry samples from formulations 1 to 7 were taken respectively, and the barium sulfate content in the samples was detected using the detection method provided in this application. The specific steps were exactly the same as in Example 1, and the specific results are shown in Table 5.

[0073] Table 5

[0074] As shown in Table 5, the results of barium sulfate content in the dry weight of samples obtained using the technical solution provided in this application are highly accurate and precise, with the content accurate to three decimal places. Furthermore, this indicates that the detection method provided in this application has a wide testing range for barium sulfate content in the dry weight of samples, covering samples containing at least 0.5% to 80% barium sulfate.

[0075] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for detecting barium sulfate content, characterized in that, The method includes the following steps: A sample solution, a blank control solution, and a standard solution are provided. The sample solution, blank control solution, and standard solution are detected using ICP-OES. The content of barium in the sample solution is obtained by standard curve method. The content of barium in the sample is obtained by combining the content of barium in the sample solution with the sample weight and the sample solution weight. The content of barium in the dry weight of the sample is calculated based on the content of barium in the sample and the proportion of the sample's dry weight. The content of BaSO4 in the dry weight of the sample was calculated based on the content of barium in the dry weight of the sample. The sample solution is provided by digestion and gravimetric analysis.

2. The method according to claim 1, characterized in that, The sample is a powder or slurry containing barium sulfate; And / or, during the digestion process, the sample is pre-wetted in water, and then an excess of aqua regia is added to carry out the first reaction, wherein the aqua regia is a mixture of concentrated HCl and concentrated HNO3 in a volume ratio of 3:

1.

3. The method according to claim 2, characterized in that, The temperature of the first reaction is 95~130℃; And / or, the volume ratio of the aqua regia to the weight ratio of the sample is 800~3200:1, mL / g; And / or, after the first reaction for 30 to 60 seconds, when the yellow gas is at its most concentrated, add a digestion aid to carry out the second reaction, and obtain the sample digest solution.

4. The method according to claim 3, characterized in that, The digestion aids include one or more of hydrofluoric acid, perchloric acid, hydrochloric acid, nitric acid, phosphoric acid, and hydrogen peroxide; And / or, the temperature of the second reaction is 95~130℃; And / or, until the sample is completely digested and the volume of the sample digest has evaporated to the same volume as the pre-wetting volume, the second reaction is completed, and the time for the second reaction is 20~40 min; And / or, the volume ratio of the digestion aid to aqua regia is 1:800~3200; And / or, after the second reaction is completed, wait for the sample digestion solution to cool to 30~80℃, transfer it to a clean container, dilute it with water, weigh it to obtain the sample solution.

5. The method according to claim 4, characterized in that, The temperature during the transfer process is 30~80℃.

6. The method according to claim 1, characterized in that, A standard solution is provided by digesting, transferring, and quantifying a standard sample with a known barium concentration using a gravimetric method. And / or, a blank control solution may be provided by quantifying water through digestion, transfer, and gravimetric analysis; And / or, obtain the dry weight ratio of the sample by drying the sample to constant weight.

7. The method according to claim 6, characterized in that, The concentration range of barium in the standard solution is: 80% of the estimated concentration of barium in the sample to 120% of the estimated concentration of barium in the sample.

8. The method according to claim 1, characterized in that, The conditions for performing ICP-OES testing include one or more of the following characteristics: The detection temperature is 30~80℃; The detection wavelength is 230~500nm.

9. The method according to claim 1, characterized in that, The content of barium in the dry weight of the sample is calculated using Formula I, which is: ； Where P is the content of barium in the dry weight of the sample, %, C is the content of barium in the sample solution, μg / g, m1 is the mass of the sample solution, g, m0 is the mass of the sample, g, W is the dry weight ratio of the sample.

10. The method according to claim 1, characterized in that, The content of BaSO4 in the dry weight of the sample was calculated using Formula II, which is: A = P × (M BaSO4 / M Ba ),unit%; Where A is the content of BaSO4 in the dry weight of the sample (%), P is the content of barium in the dry weight of the sample (%), and M is the content of barium in the dry weight of the sample (%). BaSO4 M is the relative molecular mass of barium sulfate. Ba is the relative molecular mass of barium.

Images