Method for detecting titanium content in chromium-free passivation solution for electroplated tin steel plate

Abstract

The invention discloses a method for detecting the content of titanium in a chromium-free passivation solution for an electroplated tin steel plate. The method mainly solves the technical problems that the content of titanium in an existing chromium-free passivation solution for the electroplated tin steel plate cannot be accurately detected, and the detection efficiency is low. According to the technical scheme, the method for detecting the titanium content in the chromium-free passivation solution for the electroplated tin steel plate comprises the following steps: (1) preparing a to-be-detected sample solution, and taking 100mL of a chromium-free passivation solution stock solution for the electroplated tin steel plate to obtain a basic sample solution presenting a supernatant; transferring supernatant liquid of 2-10 mL of the basic sample solution into a beaker with the volume of 100 mL; dropwise adding 10-20mL of diluted hydrochloric acid solution into the beaker filled with the supernatant of the basic sample solution, and uniformly mixing until the color of the solution is changed from turbid to clear; 2) detecting the spectral intensity of the titanium element in the to-be-detected sample solution; and (3) calculating the mass content of titanium in the chromium-free passivation solution for the electroplated tin steel plate. The method is accurate and reliable in detection data and high in efficiency.

Description

Technical Field

[0001] The present invention relates to a method for detecting the components of a chromium-free passivation solution, and particularly to a method for detecting the titanium content in a chromium-free passivation solution for electroplated tin steel sheets, belonging to the technical fields of chemical analysis in iron and steel metallurgy and chemical analysis of cold-rolled raw and auxiliary materials. Background Art

[0002] The passivation solution for electroplated tin steel sheets is an essential raw material in cold-rolled electroplated tin production, which is used to passivate the coating after electroplating tin on cold-rolled electroplated tin steel sheets, and is beneficial to improving the corrosion resistance of tinplate.

[0003] With the increasing requirements of users for the product surface, in recent years, some manufacturers in the tin plating industry have gradually adopted chromium-free passivation solutions to replace chromium-containing passivation solutions for passivating the surface of tinplates, in order to produce greener tinplate products with higher environmental protection levels.

[0004] The components of the existing chromium-free passivation solution sold in the market are: zinc dihydrogen phosphate with a mass concentration of 5-20 g / L, sodium nitrate with a mass concentration of 1-5 g / L, OP-10 with a mass concentration of 0.2-2 g / L, ammonium hexafluorotitanate with a mass concentration of 1-10 g / L, and the balance is water; the pH value of the chromium-free passivation solution is 1.0-2.0; the pH value of the chromium-free passivation solution is adjusted with phosphoric acid; the use temperature of the chromium-free passivation solution is 30-50 °C.

[0005] The Chinese patent application document with the application publication number CN110551997A discloses a chromium-free passivation solution for electroplated tin steel sheets and its use method, which relates to the technical field of metal additives and only involves the component ratio of the chromium-free passivation solution, not the detection of the chromium-free passivation solution.

[0006] The Chinese patent application document with the application publication number CN110373661A discloses a passivation solution for tinplate and a passivation process, which relates to the technical field of metal additives and does not involve the detection of the chromium-free passivation solution.

[0007] The Chinese patent application document with the application publication number CN116626225A discloses a method for measuring the Zn 2+ content in a cobalt-containing trivalent chromium passivation solution, which relates to the technical field of metal additive detection. An EDTA disodium standard solution is added to completely react with zinc in the solution, an appropriate amount of eriochrome black T indicator is added to indicate the end point of the reaction, and a Zn standard solution is used for back titration to detect the Zn 2+ content in the solution, belonging to the traditional volumetric analysis method.

[0008] The Chinese patent application document with the publication number CN116297258A discloses a method for detecting the titanium dioxide content in titanium concentrate, which relates to the technical field of detecting chemical components in ores. After adding sodium peroxide alkaline flux to titanium concentrate and completely melting it at 650 - 850 °C, it is extracted with hot water, acidified with hydrochloric acid and made up to volume. Then a color-developing solution is added, and the titanium element content in the solution is detected by spectrophotometry, and then the titanium oxide content in the sample is calculated by multiplying by a conversion coefficient. This invention belongs to the detection method for solid powder samples and is not applicable to the detection of chromium-free passivation liquid samples.

[0009] The Chinese patent application document with the publication number CN116676593A discloses a chromium-free passivation agent for aluminum alloy surfaces containing organic acid chromium and its preparation method, which relates to the technical field of metal additives. By adding a repair agent and organic acid salts, the self-repair function of the protective film is synergistically enhanced, and it does not involve the detection of titanium elements in chromium-free passivation liquid.

[0010] National standard "Determination of titanium content in iron and steel and alloys - Diantipyrylmethane spectrophotometric method GB / T 223.84 - 2009". This standard dissolves the sample with hydrochloric acid and nitric acid, smokes with sulfuric acid, filters the solution, burns the filter paper and residue at low temperature to remove carbon, volatilizes silicon with sulfuric acid and hydrofluoric acid, dissolves the residue with potassium bisulfate and combines it with the previously reserved filtrate. Using diantipyrylmethane as the color-developing solution, the titanium element in the solution is detected by the traditional spectrophotometry, and then the mass content of titanium element in the iron and steel sample is further calculated. This standard is applicable to the determination of titanium content with a mass content of 0.002% - 0.80% in iron and steel.

[0011] The prior art has disclosed methods for detecting titanium content, and there are mainly the following problems: (1) The sample matrix is complex or the matrix element content is much higher than the content of the element to be detected, and matrix interference cannot be completely eliminated; (2) When using spectrophotometry for detection, the types of reagents added are numerous and the operation steps are cumbersome; (3) When using ICP emission spectrometry for multi-element joint determination, spectral interference of the analyzed elements is likely to occur, affecting the detection accuracy and precision.

[0012] Currently, the traditional volumetric analysis method in the prior art for detecting passivation liquid has low detection efficiency, long time consumption and great operation difficulty. The spectrophotometry in the prior art for detecting titanium in steel samples has a narrow linear detection range and is not applicable to the detection of various types of samples in industrial production. Summary of the Invention

[0013] The purpose of the present invention is to provide a method for detecting the titanium content in chromium-free passivation liquid for electroplated tin steel sheets, mainly solving the technical problems of inaccurate detection of the titanium content in the existing chromium-free passivation liquid for electroplated tin steel sheets and low detection efficiency.

[0014] The method of the present invention is applicable to the detection of titanium in a chromium-free passivation solution for tin plating with a titanium mass content of 10 to 1000 g / L, meeting the accurate and rapid detection of titanium content in the chromium-free passivation solution for raw materials in cold-rolled tin plating production.

[0015] The technical idea of the method of the present invention is to add dilute hydrochloric acid to the chromium-free passivation solution to eliminate the interference of organic substances and suspended particles in the solution on the detection, prepare a test solution, measure the spectral intensity of titanium in the solution with an ICP-AES inductively coupled plasma emission spectrometer, and calculate the mass content of titanium in the sample.

[0016] The technical solution adopted by the present invention is a method for detecting the titanium content in a chromium-free passivation solution for electroplated tin steel sheets, including the following steps:

[0017] 1) Prepare a test sample solution. Take 100 mL of the original solution of the chromium-free passivation solution for electroplated tin steel sheets, stand for 7 - 9 hours to obtain a basic sample solution with a supernatant. Transfer 2 - 10 mL of the supernatant of the basic sample solution to a 100 mL beaker. Then, add 10 - 20 mL of dilute hydrochloric acid solution dropwise to the beaker containing the supernatant of the basic sample solution and mix well until the solution color changes from turbid to clear. Transfer the solution in the beaker to a 100 mL volumetric flask and make up the volume to 100 mL with deionized water to obtain a test sample solution. The volume ratio of concentrated hydrochloric acid to deionized water in the dilute hydrochloric acid solution is 1:1 - 1:2;

[0018] 2) Detect the spectral intensity of titanium element in the test sample solution, and use an inductively coupled plasma emission spectrometer to detect the spectral intensity I of titanium element in the test sample solution Ti ;

[0019] 3) Calculate the mass content of titanium in the chromium-free passivation solution for electroplated tin steel sheets. The titanium content in the chromium-free passivation solution for electroplated tin steel sheets is calculated according to Formula 1. In Formula 1, C Ti is the titanium content in the chromium-free passivation solution for electroplated tin steel sheets, with the unit of g / L; a is the background equivalent concentration, with the unit of μg; b is the conversion of the spectral intensity of titanium to mass, with the unit of μg / cps; I Ti$I$ is the spectral intensity of titanium in the sample solution to be tested, with the unit of cps; $V$ is the volume of the supernatant of the basic sample solution taken, with the unit of mL; in Formula 1, the background equivalent concentration $a$ and the mass conversion $b$ of the spectral intensity of titanium are determined by the working curve equation of the relationship between the mass of titanium in the titanium standard solution and the spectral intensity of titanium. Specifically: respectively take 0 mL, 1.00 mL, 4.00 mL, 7.00 mL, and 10.00 mL of titanium standard solutions with a mass-volume concentration of 1000 μg / mL and place them in 5 corresponding quartz volumetric flasks with a volume of 100 mL; add 5 mL of dilute hydrochloric acid solution to each of the 5 volumetric flasks. In the dilute hydrochloric acid solution, make up the volume to 100 mL with deionized water and shake well; make up the volume to 100 mL with deionized water and shake well; the volume concentration ratio of concentrated hydrochloric acid to deionized water in the dilute hydrochloric acid is 1:1 to 1:2; use an inductively coupled plasma emission spectrometer to measure the spectral intensity $I$ of the titanium standard solution Ti标液 , and calculate the unary linear regression equation $m = a + b×I$ of the working curve of the relationship between the mass of titanium in the titanium standard solution and the spectral intensity of titanium Ti标液 Determine the values of $a$ and $b$ according to Formula 2; in Formula 2, $m$ is the mass of titanium in the titanium standard solution, with the unit of μg; $a$ is the background equivalent concentration, with the unit of μg; $b$ is the mass conversion of the titanium spectral intensity, with the unit of μg / cps; $I$ Ti标液 is the spectral intensity of titanium element in the titanium standard solution, with the unit of cps.

[0020] Furthermore, in step 2), use an inductively coupled plasma emission spectrometer to measure the spectral intensity of titanium element in the sample solution to be tested. The power of the radio frequency generator of the inductively coupled plasma emission spectrometer is 1100 - 1150 W, the nebulizer flow rate is 0.4 - 0.6 L / min, the peristaltic pump flushing speed is 50 - 75 r / min, the peristaltic pump stabilization time is 5 - 10 s, the integration time is 15 - 20 s, and the measurement wavelength is 333.749 nm or 412.323 nm.

[0021] Furthermore, the beaker is a polyvinyl chloride beaker.

[0022] The titanium content in the chromium-free passivation solution for electroplated tin steel sheets is 10 - 1000 g / L.

[0023] Based on the following research of the applicant, in a certain volume of the test solution and the addition amount of dilute hydrochloric acid, the suspended matter in the solution is dissolved in the acidic environment, and the solution changes from turbid to clear, ensuring that the test solution can be fully atomized by the inductively coupled plasma emission spectrometer, improving the atomization efficiency of the solution, solving the problem of interference in the detection of organic components and suspended matter in the chromium-free passivation solution for electroplated tin steel sheets, and after selecting appropriate analysis spectral lines and optimizing the instrument conditions, use an ICP - AES inductively coupled plasma emission spectrometer to measure the titanium content in the chromium-free passivation solution for electroplated tin steel sheets.

[0024] During the research process, the applicant found that adding a dilute hydrochloric acid solution with a volume ratio of 1:1 or 1:2 (concentrated hydrochloric acid to deionized water) to the sample can eliminate the influence of suspended organic matter in the sample on the test results.

[0025] This method is applicable to the detection of the mass content of titanium in the chromium-free passivation solution for electroplated tin steel sheets.

[0026] The present invention has the following positive effects compared with the prior art: 1. The present invention realizes the rapid and accurate determination of the titanium content in the chromium-free passivation solution for electroplated tin steel sheets, has a wide linear range, and can accurately detect the chromium-free passivation solution for electroplated tin steel sheets with a titanium content range of 10 - 1000 g / L. 2. By selecting the best sample-dissolving acid and its addition amount, and the sample-dissolving temperature, the chromium-free passivation solution for electroplated tin steel sheets is fully acidified under the best conditions, and the measured values are accurate and reliable with excellent precision. 3. The method of the present invention is applicable to the detection of the mass content of titanium in the chromium-free passivation solution for electroplated tin steel sheets, with fast detection speed, high detection precision, and low detection cost. Specific embodiments

[0027] The present invention will be further described below in conjunction with embodiments.

[0028] In the embodiment, a polyvinyl chloride beaker is used, and the spectral intensity of titanium element in the sample solution to be tested is measured by an inductively coupled plasma emission spectrometer. The power of the radio frequency generator of the inductively coupled plasma emission spectrometer is 1100 W, the atomizer flow rate is 0.5 L / min, the peristaltic pump flushing speed is 50 r / min, the peristaltic pump stabilization time is 7.5 s, the integration time is 15 s, and the measurement wavelength is 333.749 nm.

[0029] A method for detecting the titanium content in a chromium-free passivation solution for electroplated tin steel sheets includes the following steps:

[0030] 1) Prepare the sample solution to be tested. Take 100 mL of the original chromium-free passivation solution for electroplated tin steel sheets and let it stand for 8 hours to obtain a basic sample solution with a supernatant. Transfer 2 mL of the supernatant of the basic sample solution to a beaker with a volume of 100 mL. Then, add 20 mL of dilute hydrochloric acid solution to the beaker containing the supernatant of the basic sample solution and mix well until the solution color changes from turbid to clear. Transfer the solution in the beaker to a 100 mL volumetric flask and make up to 100 mL with deionized water to obtain the sample solution to be tested; the volume ratio of concentrated hydrochloric acid to deionized water in the dilute hydrochloric acid solution is 1:1;

[0031] 2) Detect the spectral intensity of titanium element in the sample solution to be tested, and use an inductively coupled plasma emission spectrometer to detect the spectral intensity I of titanium element in the sample solution to be tested Ti ;

[0032] 3) Calculate the mass content of titanium in the chromium-free passivation solution for electroplated tin steel sheets. The titanium content in the chromium-free passivation solution for electroplated tin steel sheets is calculated according to Formula 1. In Formula 1, C Ti is the titanium content in the chromium-free passivation solution for electroplated tin steel sheets, with the unit of g / L; a is the background equivalent concentration, with the unit of μg; b is the conversion of the spectral intensity of titanium to mass, with the unit of μg / cps; I Ti is the spectral intensity of titanium in the sample solution to be tested, with the unit of cps; V is the volume of the supernatant of the basic sample solution taken, with the unit of mL; in Formula 1, the background equivalent concentration a and the conversion of the spectral intensity of titanium to mass b are determined by the working curve equation of the relationship between the mass of titanium and the spectral intensity in the titanium standard solution. Specifically: respectively take 0 mL, 1.00 mL, 4.00 mL, 7.00 mL, and 10.00 mL of titanium standard solutions with a mass-volume concentration of 1000 μg / mL and place them in 5 corresponding quartz volumetric flasks with a volume of 100 mL; add 5 mL of dilute hydrochloric acid solution to each of the 5 volumetric flasks. In the dilute hydrochloric acid solution, make up to 100 mL with deionized water and shake well; make up to 100 mL with deionized water and shake well; the volume concentration ratio of concentrated hydrochloric acid to deionized water in the dilute hydrochloric acid is 1:1; use an inductively coupled plasma emission spectrometer to measure the spectral intensity I Ti标液 of the titanium standard solution, and calculate the unary linear regression equation m = a + b×I of the working curve of the relationship between the mass of titanium and the spectral intensity in the titanium standard solution Ti标液 Determine the values of a and b according to Formula 2; in Formula 2, m is the mass of titanium in the titanium standard solution, with the unit of μg; a is the background equivalent concentration, with the unit of μg; b is the conversion of the titanium spectral intensity to mass, with the unit of μg / cps; I Ti标液 is the spectral intensity of titanium element in the titanium standard solution, with the unit of cps.

[0033] The precision and accuracy of the method of the present invention are confirmed through the precision and spike recovery experiments of the samples.

[0034] Precision experiment: Conduct 11 precision tests on the titanium content in 3 chromium-free passivation solutions for electroplated tin steel sheets respectively. The test results are shown in Table 1.

[0035] Table 1 Precision test of the samples

[0036]

[0037] Spike recovery experiment: Add a certain amount of titanium standard solution to 3 chromium-free passivation solutions for electroplated tin steel sheets, and conduct experiments according to the method of the present invention. The test results are shown in Table 2.

[0038] Table 2 Spike recovery test of the samples

[0039] Specimen number Titanium addition amount / μg Recycled titanium amount / μg Recovery rate / % 1# 100 101 101.0 2# 200 198 99.0 3# 300 296 98.7

[0040] As shown in Tables 1 and 2, the precision RSD of the test data of the samples is less than 0.09%, with good precision and good spiked recovery rate. The present invention has been applied in daily testing, providing accurate and reliable test data for cold rolling production. The method of the present invention solves the technical problems of inaccurate detection and low detection efficiency of titanium content in the chromium-free passivation solution for electroplated tin steel sheets.

[0041] In addition to the above embodiments, the present invention may have other embodiments. All technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the present invention.

Claims

1. A method for detecting the titanium content in a chromium-free passivation solution for electroplated tinplate, characterized in that, The method includes the following steps: 1) Prepare the sample solution to be tested. Take 100 mL of the original chromium-free passivation solution for electroplated tin steel sheets, let it stand for 7 - 9 hours to obtain a basic sample solution with a supernatant. Transfer 2 - 10 mL of the supernatant of the basic sample solution to a 100 mL beaker. Then, add 10 - 20 mL of dilute hydrochloric acid solution to the beaker containing the supernatant of the basic sample solution and mix well until the solution color changes from turbid to clear. Transfer the solution in the beaker to a 100 mL volumetric flask and make up to 100 mL with deionized water to obtain the sample solution to be tested. The volume ratio of concentrated hydrochloric acid to deionized water in the dilute hydrochloric acid solution is 1:1 - 1:2; 2) Detect the spectral intensity of titanium element in the test sample solution, and use an inductively coupled plasma emission spectrometer to detect the spectral intensity I of titanium element in the test sample solution Ti ; 3) Calculate the mass content of titanium in the chromium-free passivation solution for electroplated tinplate. The titanium content in the chromium-free passivation solution for electroplated tinplate is calculated according to Formula 1. Formula 1, in Formula 1, C Ti is the titanium content in the chromium-free passivation solution for electroplated tinplate, with the unit of g / L; a is the background equivalent concentration, with the unit of μg; b is the conversion of the spectral intensity of titanium to mass, with the unit of μg / cps; I Ti is the spectral intensity of titanium in the test sample solution to be tested, with the unit of cps; V is the volume of the supernatant of the basic sample solution taken, with the unit of mL; in Formula 1, the background equivalent concentration a and the conversion of the spectral intensity of titanium to mass b are determined by the working curve equation of the relationship between the mass of titanium and the spectral intensity in the titanium standard solution. Specifically: respectively take 0 mL, 1.00 mL, 4.00 mL, 7.00 mL, and 10.00 mL of titanium standard solutions with a mass-volume concentration of 1000 μg / mL and place them in 5 corresponding quartz volumetric flasks with a volume of 100 mL; add 5 mL of dilute hydrochloric acid solution to each of the 5 volumetric flasks. In the dilute hydrochloric acid solution, make up to 100 mL with deionized water and shake well; make up to 100 mL with deionized water and shake well; the volume concentration ratio of concentrated hydrochloric acid to deionized water in the dilute hydrochloric acid is 1:1 to 1:2; use an inductively coupled plasma emission spectrometer to measure the spectral intensity I Ti标液 of the titanium standard solution, and calculate the unary linear regression equation m = a + b×I of the working curve of the relationship between the mass of titanium and the spectral intensity in the titanium standard solution Ti标液 Determine the values of a and b according to Formula 2; in Formula 2, m is the mass of titanium in the titanium standard solution, with the unit of μg; a is the background equivalent concentration, with the unit of μg; b is the conversion of the titanium spectral intensity to mass, with the unit of μg / cps; I Ti标液 is the spectral intensity of titanium element in the titanium standard solution, with the unit of cps.

2. The detection method of titanium content in the chromium-free passivation solution for electroplated tin steel sheets according to claim 1, characterized in that, Detect the spectral intensity of titanium element in the sample solution to be tested using an inductively coupled plasma emission spectrometer. The power of the radio frequency generator of the inductively coupled plasma emission spectrometer is 1100 - 1150 W, the nebulizer flow rate is 0.4 - 0.6 L / min, the peristaltic pump flushing speed is 50 - 75 r / min, the peristaltic pump stabilization time is 5 - 10 s, the integration time is 15 - 20 s, and the measurement wavelength is 333.749 nm or 412.323 nm.

3. The method for detecting the titanium content in the chromium-free passivation solution for electroplated tin steel sheets according to claim 1, characterized in that, The beaker used is a polyvinyl chloride beaker.

4. The method for detecting the titanium content in the chromium-free passivation solution for electroplated tin steel sheets according to claim 1, characterized in that, The titanium content in the chromium-free passivation solution for electroplated tin steel sheets is 10 - 1000 g / L.

Images