A method for detecting barium sulfate content

Abstract

The application 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 ICP-OES, obtaining the content of barium element in the sample solution by a standard curve method, obtaining the content of barium element in the sample by the content of barium element in the sample solution in combination with the weight of the sample and the weight of the sample solution, calculating the content of barium element in the dry sample according to the content of barium element in the sample in combination with the dry weight proportion of the sample, calculating the content of BaSO4 in the dry sample according to the content of barium element in the dry sample, and providing the sample solution by digesting the sample and quantifying by weighing. The method for detecting the content of barium sulfate provided by the application can accurately test the barium sulfate sample with a content of 0-100%, and has high accuracy and good repeatability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of inorganic analysis, in particular to a method for detecting the content of barium sulfate. BACKGROUND

[0002] Barium sulfate (BaSO4) is a commonly used inorganic chemical raw material, widely used in plastic, rubber, ink, papermaking, catalyst and other industries, and its quality directly affects the performance and application effect of downstream products. At present, GB / T 2899-2008 national standard is often used in industry to detect its content. Although this method is accurate, it needs to treat the material at high temperature, the treatment condition is harsh, the operation is complicated, the detection period is long, and it is not suitable for on-site rapid analysis.

[0003] Patent CN106596517 A provides a method for detecting the content of barium sulfate in recycled lead powder by ICP-OES. The method is as follows: a certain amount of recycled lead powder is weighed, nitric acid is added and slowly heated until the recycled lead powder is completely dissolved, after cooling to room temperature, the filtrate is transferred to a volumetric flask for constant volume, the blank sample and the sample are treated in the same way, and the content of barium sulfate in the sample and the blank sample is detected by ICP detection equipment, and the content of barium sulfate in the sample is calculated by substituting the standard barium sulfate solution curve equation.

[0004] Although this method solves the problems of high temperature treatment of material and long detection period in GB / T 2899-2008 method, it still has the following problems: a. The content range of barium sulfate in the sample to be tested is narrow, and the accuracy of barium test is low. Because barium sulfate has very low solubility and strong inertness at room temperature, if the content of barium sulfate in the sample to be tested is slightly high, barium sulfate will precipitate when it is cooled to room temperature after digestion, which will cause large error in the measurement result of barium sulfate content in the filtrate. b. Large matrix interference. In this patent, the filtrate is diluted by constant volume in a volumetric flask, which increases the human factors caused by the preparation of standard and sample digestion constant volume.

[0005] Therefore, there is an urgent need for a detection method for barium sulfate content which is simple in operation, high in precision and accuracy, and can cover a wide range of barium sulfate content. SUMMARY

[0006] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a method for detecting the content of barium sulfate, which solves the problems in the prior art.

[0007] To achieve the above-mentioned purposes and other related purposes, the present application is obtained by the following technical solutions.

[0008] The present application provides a method for detecting the content of barium sulfate, which comprises the following steps:

[0009] The sample solution is provided, the blank control solution and the standard solution are provided, the sample solution, the blank control solution and the standard solution are detected by ICP-OES, and the content of the barium element in the sample solution is obtained by a standard curve method;

[0010] The content of the barium element in the sample is obtained 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.

[0011] The content of the barium element in the sample is obtained by combining the content of the barium element in the sample with the weight of the sample and the weight of the sample solution.

[0012] The content of the barium element in the sample is obtained by combining the content of the barium element in the sample with the weight of the sample and the weight of the sample solution.

[0013] The sample is digested and weighed to provide the sample solution.

[0014] In the present application, the weighing method is used to quantify the sample solution (i.e., to determine the weight of the sample solution to be detected), thereby replacing the constant volume method commonly used in the prior art for quantifying the sample solution. Thus, the experimental errors caused by the visual errors of the operator in reading the meniscus, the self-bias of the volumetric flask, the sample solution hanging wall, and the temperature expansion liquid, etc. are effectively avoided. The weighing method in the present application uses an electronic balance to quantify the sample solution. The introduction of the electronic balance makes the measurement result more accurate, which can be accurate to three decimal places. At the same time, the adverse effects caused by the solution hanging wall and the thermal expansion and contraction of the solution volume are fundamentally avoided. The technical means of the weighing method in the present application for quantifying the sample solution not only can minimize the experimental error, but also can simplify the steps such as rinsing in the constant volume method, making the experiment efficient and accurate.

[0015] Preferably, the sample is a powder or slurry containing barium sulfate. For example, it can be one or more of lead powder, copper plate paper coating slurry, nano barium sulfate aqueous slurry, and precipitated barium sulfate.

[0016] Preferably, when the digestion is performed, the sample is pre-wetted in water, and then an excess of aqua regia is added for the first reaction. The aqua regia is a mixed acid of concentrated HCl and concentrated HNO3 in a volume ratio of 3:1. More specifically, the concentration of the concentrated HCl is 36-38%, which is a high-purity concentrated HCl; and the concentration of the concentrated HNO3 is 65-68%, which is a high-purity concentrated HNO3.

[0017] Preferably, the temperature of the first reaction is 95-130°C.

[0018] Preferably, the volume to weight ratio of the aqua regia to the sample is 800~3200:1, mL / g. It can be 1800~2500:1, mL / g, and can be 1987~2176:1, mL / g.

[0019] In the present application, the amount of aqua regia is a very critical parameter, not randomly set. If the amount of aqua regia is too much, without evaporating or diluting the excess acid, due to the excessive concentration of acid, serious matrix effect (such as sudden drop in atomization / transmission efficiency, ionization balance interference, etc.) will occur during testing, which will greatly affect the accuracy of the test. If the aqua regia is evaporated or the excess acid is diluted, it will lead to longer experimental time, lower efficiency, and also increase the emission of hydrogen chloride and nitrogen oxides in the environment, causing unnecessary waste and pollution. If the amount of aqua regia is too small, due to acid volatilization, decomposition, etc., the acidity is too low, resulting in incomplete sample digestion. Only under the amount described in the present application, both experimental efficiency and complete sample digestion can be achieved.

[0020] Preferably, after the first reaction for 30s~60s, when the yellow gas is the most concentrated, the auxiliary digestion reagent is added for the second reaction to obtain the sample digestion solution. The reaction time can be 30~45s, 45~60s.

[0021] Preferably, the auxiliary digestion reagent includes one or more of hydrofluoric acid, perchloric acid, hydrochloric acid, nitric acid, phosphoric acid, and hydrogen peroxide. More preferably, it is hydrofluoric acid.

[0022] Preferably, the temperature of the second reaction is 95~130℃.

[0023] The timing of adding the auxiliary digestion reagent is a very important technical means. Only under the specific temperature (95~130℃) and after a specific time of adding aqua regia, the auxiliary digestion reagent can be added to achieve the technical effect of dissolving barium sulfate together with aqua regia. Specifically, if the auxiliary digestion reagent is added too early, or added into the sample at the same time as aqua regia, the auxiliary digestion reagent will first react with the reaction container such as glass, resulting in corrosion of the beaker and other reaction containers. At the same time, the volatilization of the auxiliary digestion reagent will also increase its amount, leading to an increase in the amount of reagent, causing unnecessary waste. If the auxiliary digestion reagent is added too late, the acidity in the sample solution will be too low, which is not conducive to the dissolution of barium sulfate. Only under the conditions of the technical scheme provided in the present application, the auxiliary digestion reagent can be added to work together with aqua regia to completely dissolve barium sulfate in the shortest time, while reducing the amount of auxiliary digestion reagent used.

[0024] Preferably, the second reaction is completed until the sample is completely digested, and the volume of the sample digestion solution is volatilized to the same volume as the pre-wetting volume, and the time of the second reaction is 20-40 min. Such as 20 min, 30 min, 40 min.

[0025] Preferably, the volume ratio of the digestion aid reagent to aqua regia is 1:800-3200. Such as 1:800-1500, and 1:1500-3200.

[0026] In this application, the addition of the digestion aid reagent is a very important technical means, and the selection of its type is also specific. Specifically, the solubility of barium sulfate in water is very small. In general, in order to make barium sulfate dissolve in acid and react with acid, it is necessary to provide enough strong protons or other active particles to destroy the crystal structure of barium sulfate. Although aqua regia can dissolve many insoluble substances, because the reducing property and coordination ability of barium sulfate are very weak, and aqua regia lacks effective coordination ability, the dissolution effect of aqua regia on barium sulfate is also limited.

[0027] And the addition of the digestion aid reagent with strong coordination ability (such as hydrofluoric acid) provides a single-stage ligand, so that part of the dissolved Ba 2+ (aq) and SO4 2- react, and further reduce the concentration of Ba 2+ and SO4 2- in the solution, and the dissolution equilibrium continues to proceed to the right, so that under the synergistic action of aqua regia and the digestion aid reagent, barium sulfate is finally completely dissolved.

[0028] Preferably, after the completion of the second reaction, the sample digestion solution is transferred to a clean container after cooling to 30-80°C, diluted with water, and weighed to obtain a sample solution.

[0029] Preferably, the temperature during the transfer process is 30-80°C. More preferably, it is 40-60°C. The process is quickly transferred to prevent a sharp drop in temperature.

[0030] Preferably, a standard solution is provided by digesting, transferring, and weighing a standard sample with a known concentration of barium element.

[0031] Preferably, the concentration of barium element in the standard solution is in the range of: the estimated concentration of barium element in the sample × 80%-the estimated concentration of barium element in the sample × 120%.

[0032] Preferably, a blank control solution is provided by digesting, transferring, and weighing water.

[0033] Preferably, the conditions for ICP-OES detection include one or more of the following characteristics:

[0034] The detection temperature is 30-80℃;

[0035] The detection wavelength is 230-500nm.

[0036] The detection wavelength can be 230.424nm-493.409nm, 230.424nm-233.527nm, 455.403nm-493.409nm, and more preferably 230.424nm. The detection temperature can be 30-45℃, 45-80℃.

[0037] Preferably, the dry weight ratio of the sample is obtained by referring to GB / T 5211.3-2020.

[0038] Preferably, the dry weight ratio of the sample is obtained by drying the sample until the constant weight.

[0039] More preferably, the sample to be tested by ICP-OES or an equivalent amount of sample is placed in a constant temperature environment of (105±2)℃, dried until the constant weight, and the dry weight ratio of the sample is obtained by dividing the constant weight of the sample by the initial weight of the sample.

[0040] Preferably, the content of barium element in the dry weight of the sample is obtained by formula I, and the formula I is:

[0041] ;

[0042] Wherein, P is the content of barium element in the dry weight of the sample, %, C is the content of barium element 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, %.

[0043] Preferably, the content of BaSO4 in the dry weight of the sample is obtained by formula II, and the formula II is: A = P×(M BaSO4 / M Ba ), unit %; wherein 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 is the relative molecular mass of barium sulfate; and M Ba is the relative molecular mass of barium element.

[0044] The beneficial effects of the present application are:

[0045] 1) When the sample is digested according to the scheme, aqua regia is combined with an auxiliary digestion agent, so that the sample can be completely digested without the need for filtering and washing after digestion. The error caused by incomplete digestion of the sample is avoided, and the consistency of the sample solution and the standard solution is ensured.

[0046] 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.

[0047] 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

[0048] Figure 1 The curve shown is the standard operating curve in this embodiment of the invention. Detailed Implementation

[0049] 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.

[0050] 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.

[0051] 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.

[0052] In this application, the standard curve method includes the following steps:

[0053] 1) Prepare standard solutions of different concentrations of barium element, respectively, and detect by ICP-OES to obtain the linear relationship between the concentration of barium element and the corresponding spectral intensity at this concentration, draw the corresponding standard working curve, and calculate the regression equation of the standard working curve of the concentration of barium element and the corresponding spectral intensity at this concentration;

[0054] 2) Detect the sample solution containing barium sulfate by ICP-OES, and substitute the obtained corresponding spectral intensity into the regression equation of the standard working curve of the concentration of barium ion and the corresponding spectral intensity at this concentration in step 1) to calculate the content of barium element in the sample.

[0055] Preferably, in the standard working curve, the concentration of barium element (barium ion) is taken as the abscissa (X axis), and the corresponding spectral intensity of barium element is taken as the ordinate (Y axis).

[0056] In the following examples of the present application, the standard working curve used in the standard curve method is obtained by the following method:

[0057] a) Accurately weigh a certain amount of barium element content of 80% and 95% standard sample respectively, and measure the dry weight ratio of the standard sample according to the method of GB / T 5211.3, and then place the standard sample in a clean 250mL high form glass beaker, add deionized water to pre-wet the standard sample, and wash the inner wall of the beaker with a small amount of deionized water and keep all the water in the beaker, so that the volume of the pre-wetted sample is 10mL.

[0058] b) Heat to 100℃ on the electric heating plate until the solution boils, add 32 mL of aqua regia (volume ratio of concentrated HCl and concentrated HNO3 is 3:1), first reaction for 45s, when the yellow gas is the most concentrated, add 10μL of hydrofluoric acid, second reaction for 40min, until the volume of the standard sample digestion solution volatilizes to 10mL, remove from the electric heating plate, and cool to 45℃.

[0059] c) Keep the standard sample digestion solution at 45℃, quickly transfer it to a clean volumetric flask of known weight, dilute the standard sample digestion solution with deionized water respectively, and weigh and quantitatively add to 100g to obtain standard solutions of different concentrations.

[0060] d) Detect the above standard solutions of different concentrations of barium element by ICP-OES, the conditions are: detection wavelength 230.424nm, detection temperature 45℃, after the instrument is stable, different concentrations of standard solutions are sprayed into the ICP light source in turn, and the corresponding spectral intensity of different concentrations of barium element is tested respectively, and the standard working curve is fitted.

[0061] Among them, the barium element and its corresponding spectral intensity are shown in Table 1 below, and the standard working curve is shown in the attached Figure 1 .

[0062] Table 1

[0063]

[0064] It should be noted that the preparation method of the blank control solution and the standard solution in the present application is exactly the same, only the standard sample is replaced by an equal amount of deionized water.

[0065] In the present 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) °C, and is dried until the constant weight, and the dry weight ratio of the sample is obtained by dividing the constant weight of the sample by the initial weight of the sample.

[0066] Comparative Example 1

[0067] An analytical reagent with a barium sulfate content of 98.5% was taken; using the GB / T 2899-2008 national standard method, the barium content in the sample was obtained as 58%, and the corresponding barium sulfate content in the dry weight of the sample was calculated as 98.56%.

[0068] The present embodiment provides a specific method for detecting the content of barium sulfate, comprising the following steps:

[0069] 1) Six portions of the same barium sulfate sample as in Comparative Example 1 were weighed, and then the dry weight ratio of the sample was determined according to the method of GB / T 5211.3, after which the sample was placed in a clean 250 mL high-form glass beaker, deionized water was added for pre-wetting, and a small amount of deionized water was used to rinse the inner wall of the beaker and all the water was retained in the beaker, so that the volume of the pre-wetted sample was 10 mL.

[0070] 2) Heat to 100°C on a hot plate until the solution boils, add 32 mL of aqua regia (volume ratio of concentrated HCl and concentrated HNO3 is 3:1), first reaction for 45s, when the yellow gas is most concentrated, add 10 μL of hydrofluoric acid, second reaction for 40 min, until the volume of the sample digestion solution is volatilized to 10 mL, remove from the hot plate and cool to 45°C.

[0071] 3) Keep the sample digestion solution at 45°C, quickly transfer it to a clean volumetric flask of known weight, dilute the sample digestion solution with deionized water, and weigh and quantify to obtain a sample solution.

[0072] 4) The sample solution is subjected to ICP-OES detection, and the conditions are: detection wavelength 230.424 nm, detection temperature 45℃, after the instrument is stabilized, different sample solutions are sprayed into the ICP light source in turn, and the spectral intensity corresponding to different concentrations of barium elements is respectively tested, and the standard working curve is brought in, combined with the weight of the sample and the weight of the sample solution, to obtain the content of barium elements in the corresponding sample.

[0073] 5) The content of barium elements in the dry weight of the sample is calculated by formula I: , wherein P is the content of barium elements in the dry weight of the sample, %, C is the content of barium elements 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, %.

[0074] 6) The content of BaSO4 in the dry weight of the sample is calculated by formula II: A = P x (M BaSO4 / M Ba ), wherein A is the content of BaSO4 in the dry weight of the sample, %, P is the content of barium elements in the dry weight of the sample, %, M BaSO4 is the relative molecular mass of barium sulfate (233.39); and M Ba is the relative molecular mass of barium element (137.33).

[0075] The specific results are shown in Table 2.

[0076] Table 2

[0077]

[0078] As shown in Table 2, the same sample is detected by Examples 1-6, and the detection results show that the content of barium elements in the sample is 57.12-57.99%, and the content of barium sulfate in the dry weight of the sample is 97.07-98.55%. The experimental results of the six parallel experiments have very small errors, which are in the negligible range, indicating that the barium sulfate content detection method provided by the application has good stability, high detection result preparation degree, and good repeatability.

[0079] Comparative Examples 2-4

[0080] Three portions of barium sulfate samples with different weights are weighed, which are the same as in Examples 1-3, and the remaining steps are the same as in Example 1.

[0081] The sample digestion process is the same as in Example 1.

[0082] 3) Except that the sample solution is quantitatively replaced by constant volume, which is the same as in Example 1, to obtain the sample solution.

[0083] 4) The sample solution is subjected to ICP-OES detection, and the test conditions and calculation process are completely the same as those in Example 1.

[0084] The specific results are shown in Table 3.

[0085] Table 3

[0086]

[0087] As can be seen from Table 3 and Table 2, compared with Examples 1-3, in Comparative Examples 2-4, when the sample solution is quantified by the constant volume method, the experimental results obtained by testing different batches have large differences, poor parallelism, and poor stability of test results. It is shown that the detection results of the technical scheme of the present application are more accurate and have good repeatability.

[0088] Examples 7-13

[0089] An aqueous slurry sample with a barium sulfate content of 0.5%, 1.5%, 5%, 10%, 30%, 50%, and 80% in dry weight is prepared, and the slurry formula is shown in Table 4 below.

[0090] The corresponding barium content in the dry weight of the sample is calculated as: 0.29%, 0.88%, 2.94%, 5.88%, 17.65%, 29.42%, and 47.07%.

[0091] Table 4

[0092]

[0093] The aqueous slurry samples in the above Formulas 1-7 are taken respectively, and the barium sulfate content in the samples is detected by using the detection method provided by the present application, and the specific steps are completely the same as those in Example 1, and the specific results are shown in Table 5.

[0094] Table 5

[0095]

[0096] As can be seen from Table 5, the results of the barium sulfate content in the dry weight of the sample obtained by using the technical scheme provided by the present application are accurate and have high precision, and the content can be accurately to three decimal places. At the same time, it is shown that the detection method provided by the present application has a wide test range for the barium sulfate content in the dry weight of the sample, and can at least cover samples containing 0.5%-80% barium sulfate.

[0097] The above embodiments are only illustrative of the principles of the present application and its efficacy, and are not intended to limit the present application. Any modification or change made by any person skilled in the art without departing from the spirit and scope of the present application shall be covered by the claims of the present application.

Claims

1. A method for detecting the content of barium sulfate, characterized by, The method 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 ICP-OES, and obtaining the content of barium in the sample solution by a standard curve method; obtaining the content of barium in the sample by combining the content of barium in the sample solution with the weight of the sample and the weight of the sample solution; calculating the content of barium in the dry sample according to the content of barium in the sample and the dry weight proportion of the sample; calculating the content of BaSO4 in the dry sample according to the content of barium in the dry sample; providing the sample solution by digesting and quantifying the sample by weighing; when the digestion is performed, the sample is pre-wetted in water, and then an excess of aqua regia is added for a first reaction, the aqua regia being a mixed acid of concentrated HCl and concentrated HNO3 in a volume ratio of 3:1; the temperature of the first reaction is 95-130℃; the volume ratio of the aqua regia to the weight of the sample is 800-3200:1, mL / g; after the first reaction for 30s-60s, when the yellow gas is the most concentrated, a digestion aid reagent is added for a second reaction to obtain a sample digestion solution; the digestion aid reagent comprises one or more of hydrofluoric acid, perchloric acid, hydrochloric acid, nitric acid, phosphoric acid and hydrogen peroxide; the temperature of the second reaction is 95-130℃; the second reaction is completed until the sample is completely digested and the volume of the sample digestion solution is volatilized to the same volume as the pre-wetting volume, and the time of the second reaction is 20-40min; the volume ratio of the digestion aid reagent to the aqua regia is 1:800-3200.

2. The method of claim 1, wherein, The sample is a powder or slurry containing barium sulfate.

3. The method of claim 1, wherein, After the second reaction is completed, the sample digestion solution is transferred to a clean container after cooling to 30-80℃, diluted with water and weighed to obtain the sample solution.

4. The method of claim 3, wherein, The temperature during the transfer process is 30-80℃.

5. The method of claim 1, wherein, The standard solution is provided by digesting, transferring and quantifying a standard sample with a known barium concentration by weighing; and / or, the blank control solution is provided by digesting, transferring and quantifying water by weighing; and / or, the dry weight proportion of the sample is obtained by drying the sample to a constant weight.

6. The method of claim 5, wherein, The concentration range of barium in the standard solution is: the estimated concentration of barium in the sample × (80-120%).

7. The method of claim 1, wherein, The conditions for ICP-OES detection include one or more of the following characteristics: the detection temperature is 30-80℃; the detection wavelength is 230-500nm.

8. The method of claim 1, wherein, The content of barium element in the dry weight of the sample is calculated by formula I: ; wherein, P is the content of barium element in the dry weight of the sample, %, C is the content of barium element 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 proportion of the sample, %.

9. The method of claim 1, wherein, The content of BaSO4 in the dry weight of the sample was calculated using Formula II, which 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.

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