CN-121978085-A - Method for measuring content of calcium fluoride in desulfurizing agent

Abstract

The invention discloses a method for measuring the content of calcium fluoride in a desulfurizing agent, and belongs to the technical field of analytical chemistry and metallurgical detection. The method comprises the steps of grinding a desulfurizing agent sample, sieving and drying to obtain a sample, weighing the sample, adding a calcium-containing acetic acid solution, standing at normal temperature, intermittently stirring, selectively dissolving calcium oxide while calcium fluoride is basically insoluble, adding perchloric acid, heating until dense white smoke is emitted, removing fluorine ions in the solution, acidifying, heating to dissolve salts, cooling, transferring to a volumetric flask for constant volume, measuring the spectral intensity of the test solution under a characteristic spectral line of calcium element by using ICP-OES, calculating the calcium content according to a pre-drawn working curve of the calcium element, and converting the calcium content into a mass fraction of the calcium fluoride. The invention effectively eliminates the transmission interference and spectral line interference of fluorine ions to the ICP-OES calcium measurement by the pretreatment process of normal temperature selective dissolution of calcium-containing acetic acid and fluorine removal of perchloric acid, and is suitable for the wide-range measurement of the calcium fluoride content in the desulfurizing agent.

Inventors

• WANG SHAOCUI
• GUO WEI
• YU HE
• ZHU YING
• CHEN KE
• ZENG ZHIWEN
• JIANG FEI
• LI LINLIN

Assignees

• 重庆钢铁股份有限公司

Dates

Publication Date

20260505

Application Date

20260209

Claims (9)

1. 1. The method for measuring the content of calcium fluoride in the desulfurizing agent is characterized by comprising the following steps of: a) Grinding a desulfurizing agent sample to pass through a 240-mesh sieve, and drying at 105+/-1 ℃ to obtain a sample; b) Weighing the sample, adding a calcium-containing acetic acid solution, standing at normal temperature, and intermittently stirring to enable calcium oxide in the sample to be selectively dissolved by the calcium-containing acetic acid solution, wherein calcium fluoride is basically insoluble; c) Adding perchloric acid into the mixture in the step b), and heating until dense white smoke is emitted so as to remove fluorine ions in the solution; d) After acidification, salt dissolution and cooling, transferring the test solution into a volumetric flask for constant volume; e) Measuring the spectral intensity of the test solution under the characteristic spectral line of the calcium element by using an inductively coupled plasma emission spectrometer; f) According to a pre-drawn calcium element working curve, calculating the content of calcium in the test solution, and converting the content into the mass fraction of calcium fluoride.
2. 2. The method according to claim 1, wherein the calcium-containing acetic acid solution is used for selectively dissolving calcium oxide at normal temperature to fix the form of calcium element in the calcium fluoride, thereby locking the calcium to be tested from the calcium fluoride.
3. 3. The method of claim 1 wherein step c) is used to efficiently remove fluoride ions to eliminate fluorine transmission interference and spectral line interference on inductively coupled plasma emission spectrometry of calcium.
4. 4. The method of claim 1, wherein the linear correlation coefficient of the calcium element operating curve is greater than 0.999.
5. 5. The process of claim 1 wherein in step d) the acidification is by adding hydrochloric acid and heating to dissolve the soluble salts.
6. 6. The method according to claim 1, wherein the method is suitable for use in the determination of the calcium fluoride content of 0.15% to 30% in a desulphurisation agent.
7. 7. The method according to claim 1, wherein the calcium-containing acetic acid solution is prepared by weighing 5g of calcium carbonate, placing in a beaker, covering a surface dish, adding 100mL of acetic acid solution, heating and dissolving in a water bath, transferring into a 1000mL volumetric flask, diluting with acetic acid solution to marked line, and shaking.
8. 8. The method of claim 7, wherein the acetic acid solution is formulated with a volume ratio of acetic acid to water of 1:9.
9. 9. The method according to claim 1, wherein after measuring the spectral intensity of calcium by means of an inductively coupled plasma emission spectrometer, when the difference between the two independent test results does not exceed the allowable difference specified in the standard, the average value is taken as the final analysis result.

Description

Method for measuring content of calcium fluoride in desulfurizing agent Technical Field The invention belongs to the technical field of analytical chemistry and metallurgical detection, and particularly relates to a method for measuring the content of calcium fluoride in a desulfurizing agent. Background Desulfurizing agents are widely used in steel smelting processes for removing elemental sulfur from steel, wherein calcium fluoride (CaF 2) is an important component, and its content directly affects desulfurization efficiency and slag system characteristics. Therefore, accurate determination of the calcium fluoride content in the desulfurizing agent is important for quality control of iron and steel enterprises. Currently, common methods for determining calcium fluoride in desulfurizing agents include chemical titration methods (e.g., EDTA titration) and X-ray fluorescence spectroscopy (XRF). The chemical titration method involves a plurality of manual operation steps, such as sample dissolution, separation of interfering ions, repeated titration and the like, has long flow, long time consumption and complicated steps, and the result is easily influenced by experience and technical proficiency of operators, so that the precision and accuracy are difficult to ensure, the efficiency is low, and the method is not suitable for daily batch detection requirements of iron and steel enterprises. The X-ray fluorescence spectrometry has the advantages of high analysis speed, limited detection sensitivity to low-content components, increased measurement error especially when the content of calcium fluoride is low, sensitivity to matrix effects, poor applicability to the condition that the matrix components of industrial desulfurizing agent samples are changeable (such as calcium oxide, silicate, sulfate and the like with different proportions), need to establish a complex standard sample library for correction, huge equipment investment and high maintenance cost, and is unfavorable for popularization and application of detection centers of most iron and steel enterprises. In addition, the existing instrument analysis method often faces the problem of fluoride ion interference when being directly applied to the desulfurizing agent. Fluoride ions are easy to form calcium fluoride particles which are difficult to volatilize with calcium, so that the sample transmission efficiency is reduced, spectral line interference is generated in ICP-OES measurement, and the accurate measurement of calcium element is affected. Traditional pretreatment is difficult to thoroughly eliminate the interference, and the measurement result has larger deviation. The method for measuring the calcium fluoride content has the advantages of clear operation flow, high analysis speed, high precision, accuracy, reliability and moderate cost, and is suitable for batch detection, so as to meet the requirements of real-time production monitoring and quality stabilization. Disclosure of Invention In view of the above, an object of the present invention is to solve the above problems and to provide a method for measuring the calcium fluoride content in a desulfurizing agent. In order to achieve the above purpose, the present invention provides the following technical solutions: a method for measuring the content of calcium fluoride in a desulfurizing agent comprises the following steps: a) Grinding a desulfurizing agent sample to pass through a 240-mesh sieve, and drying at 105+/-1 ℃ to obtain a sample; b) Weighing the sample, adding a calcium-containing acetic acid solution, standing at normal temperature, and intermittently stirring to enable calcium oxide in the sample to be selectively dissolved by the calcium-containing acetic acid solution, wherein calcium fluoride is basically insoluble; c) Adding perchloric acid into the mixture in the step b), and heating until dense white smoke is emitted so as to remove fluorine ions in the solution; d) After acidification, salt dissolution and cooling, transferring the test solution into a volumetric flask for constant volume; e) Measuring the spectral intensity of the test solution under the characteristic spectral line of the calcium element by using an inductively coupled plasma emission spectrometer; f) According to a pre-drawn calcium element working curve, calculating the content of calcium in the test solution, and converting the content into the mass fraction of calcium fluoride. Furthermore, the calcium-containing acetic acid solution is used for selectively dissolving calcium oxide at normal temperature to fix the form of calcium element in the calcium fluoride, so that the to-be-detected calcium is locked from being derived from the calcium fluoride. Further, step c) is used for efficiently removing fluorine ions, and eliminating transmission interference and spectral line interference of fluorine on the inductively coupled plasma emission spectrometry for measuring calcium. Further, the linear co