Method for measuring calcium, magnesium and aluminum in bentonite

Abstract

The invention discloses a method for measuring calcium, magnesium and aluminum in bentonite, which comprises the following steps: (1) weighing a bentonite sample in a polytetrafluoroethylene beaker, adding hydrochloric acid and hydrofluoric acid to dissolve at low temperature, and making a blank sample; (2) adding perchloric acid into the bentonite sample dissolved in the step (1) for fuming, and cooling to room temperature; (3) adding hydrochloric acid into the sample cooled in the step (2), dissolving salts at low temperature, and cooling to room temperature; (4) transferring the sample solution obtained in the step (3) into a volumetric flask, diluting with high-purity water to a constant volume, and shaking uniformly to obtain a sample solution and a blank sample solution for on-machine detection; and (5) introducing the sample solution and the blank sample solution into an inductively coupled plasma emission spectrometer, measuring the signal intensity of Ca, Mg and Al ions, and calculating the content of CaO, MgO and Al2O3 in the sample solution according to a standard solution calibration curve with known mass percent.

Description

Technical Field

[0001] The invention belongs to the technical field of steel metallurgy analysis, and specifically relates to a method for determining calcium, magnesium and aluminum in bentonite, and more particularly to an analysis method for directly determining calcium, magnesium and aluminum in a sample solution by using ICP-OES, wherein a bentonite sample is dissolved with hydrochloric acid and hydrofluoric acid, and after perchloric acid smokes and is nearly dry, hydrochloric acid is added to dissolve salts. Background Art

[0002] Bentonite is a clay rock, the main chemical components are silicon dioxide, aluminum oxide and water, and also contains iron, magnesium, calcium, sodium, potassium and other elements. The content of Al2O3 and CaO has a great influence on the physical and chemical properties and process performance of bentonite. Therefore, accurate determination of the content of calcium, magnesium and aluminum in bentonite is very important for the metallurgical industry.

[0003] So far, there are neither national standards nor enterprise standards for the detection of calcium, magnesium and aluminum in bentonite, nor any relevant reports. Summary of the invention

[0004] In view of the above problems, the present invention combines modern analytical technology, utilizes hydrochloric acid and hydrofluoric acid to dissolve, perchloric acid to generate smoke to remove silicon, adds hydrochloric acid to dissolve salts, and utilizes the characteristics of ICP-OES with a wide linear range and high accuracy, and adopts a vertical observation method to detect calcium, magnesium and aluminum in bentonite.

[0005] The method of the present invention comprises the following steps:

[0006] (1) Weigh a bentonite sample into a polytetrafluoroethylene beaker, add hydrochloric acid and hydrofluoric acid to dissolve at low temperature, and prepare a blank sample at the same time;

[0007] (2) adding perchloric acid to the bentonite sample dissolved in step (1) to generate fumes, and cooling to room temperature;

[0008] (3) adding hydrochloric acid to the cooled sample in step (2) to dissolve the salts at low temperature, and cooling to room temperature;

[0009] (4) Transfer the sample solution obtained in step (3) to a volumetric flask, dilute to volume with high-purity water, and shake well to obtain a test sample solution and a blank sample solution for machine detection;

[0010] (5) The sample solution and the blank sample solution are introduced into an inductively coupled plasma emission spectrometer to measure the signal intensity of Ca, Mg, and Al ions. The contents of CaO, MgO, and Al2O3 in the sample solution are calculated based on the calibration curve of the standard solution with known mass percentage.

[0011] In some embodiments, the content of CaO, MgO, and Al2O3 in the bentonite sample is calculated as follows:

[0012] W%=W i -W0

[0013] Where: W-mass percentage of the element in the bentonite sample;

[0014] W0-mass percentage of element in blank sample solution;

[0015] W i -The mass percentage of the element in the sample solution.

[0016] In some embodiments, the temperature of the low temperature in steps (1) and (3) is 270°C.

[0017] In some embodiments, the inductively coupled plasma optical emission spectrometer used in step (5) is Optima 7300DV (PE Company, USA).

[0018] In some embodiments, the spectral line positions of Ca, Mg, and Al ions measured in step (5) are respectively: Ca 4317.933nm, Mg 285.213nm, and Al 396.153nm.

[0019] In some embodiments, the detection range of the determination method: CaO, MgO, Al2O3 are all 0.10at~15.0at%.

[0020] In some embodiments, the determination method comprises the following steps:

[0021] (1) Weigh 0.1000 g of bentonite sample into a polytetrafluoroethylene beaker, add 10 mL of hydrochloric acid and 5 mL of hydrofluoric acid and place on a 270 °C low-temperature electric hot plate, and prepare a blank sample at the same time;

[0022] (2) adding 2 mL of perchloric acid to the bentonite sample dissolved in step (1) to generate fumes until the solution reaches 1 mL, and cooling to room temperature;

[0023] (3) adding 5 mL of hydrochloric acid to the cooled sample in step (2), dissolving the salts on a 270° C. low-temperature electric hot plate, and cooling to room temperature;

[0024] (4) Transfer the sample solution obtained in step (3) to a 250 mL volumetric flask, dilute to volume with high-purity water, and shake well to obtain a test sample solution and a blank sample solution for machine testing;

[0025] (5) The sample solution and the blank sample solution are introduced into an inductively coupled plasma emission spectrometer to measure the signal intensity of Ca, Mg, and Al ions. The contents of CaO, MgO, and Al2O3 in the sample solution are calculated based on the calibration curve of the standard solution with known mass percentage.

[0026] The invention provides an ICP-OES method for determining calcium, magnesium and aluminum in bentonite with high sensitivity, fast determination speed, simple operation, less interference than other methods and good selectivity; a vertical observation method is adopted to improve determination stability and capable of providing accurate data for a smelting component control process.

[0027] The present invention has the following advantages:

[0028] 1. The present invention uses less chemical reagents: only 15 mL of hydrochloric acid, 5 mL of hydrofluoric acid, and 2 mL of perchloric acid are used, and less chemical reagents are used, which saves materials and reduces the waste discharge of chemical reagents.

[0029] 2. The present invention is simple to operate and can complete the determination of CaO, MgO and Al2O3 within 2 hours, with a short operation process and a short detection time.

[0030] 3. The present invention uses hydrofluoric acid to remove silicon, thereby avoiding the adsorption of calcium, magnesium and aluminum ions by silica gel and improving the accuracy of detection.

[0031] 4. Establish an ICP-OES method for determining calcium, magnesium and aluminum in bentonite, filling the gap in the method for detecting calcium, magnesium and aluminum in bentonite.

[0032] 5. The emission intensity of CaO, MgO and Al2O3 is reduced by vertical observation, and the accuracy of determination is improved. The detection range of the method: CaO, MgO and Al2O3 are all 0.10at~15.0at%. The present invention has good application effect through multiple inspections of bentonite samples. The present invention has the characteristics of wide linear range, high sensitivity, simple operation, fast analysis speed, accurate and reliable analysis results, and provides reliable data for the detection of calcium, magnesium and aluminum in bentonite. This method can be promoted in the metallurgical industry. DETAILED DESCRIPTION

[0033] The present invention is described in detail below through specific examples. The examples are intended to help understand the present invention but are not intended to limit the present invention.

[0034] 1. In the embodiments of the present invention, the reagents used are preferably:

[0035] Hydrochloric acid, perchloric acid, hydrofluoric acid: high purity;

[0036] Single element standard solutions of calcium, magnesium and aluminum: concentration is 1000μg / mL, sourced from the National Center for Standard Materials.

[0037] 250mL volumetric flask; Argon: Argon purity ≥99.9%; Compressed air.

[0038] The preferred inductively coupled plasma emission spectrometer model is Optima 7300DV produced by PE Company; the observation method is vertical observation.

[0039] 2. Sample Analysis

[0040] 2.1 Decomposition of samples

[0041] Weigh 0.1000g of sample into a polytetrafluoroethylene beaker, add 10mL hydrochloric acid and 5mL hydrofluoric acid to dissolve on a 270℃ low-temperature electric hot plate. Prepare a blank sample at the same time. After the sample is completely dissolved, add 2mL perchloric acid to make the solution 1mL, remove and cool to room temperature. Add 5mL hydrochloric acid, dissolve the salts on a 270℃ low-temperature electric hot plate, remove and cool to room temperature. Transfer the sample solution to a 250mL volumetric flask, dilute to the mark with high-purity water, and shake well.

[0042] 2.2 Preparation of standard calibration curve solution

[0043] Take 6 portions of (1+1) hydrochloric acid (10 mL) in a 250 mL volumetric flask, add calcium, magnesium, and aluminum single element standard solutions to prepare solutions containing CaO, MgO, and Al2O3 0, 0.50%, 1.00%, 5.00%, 10.00%, and 15.00%, respectively, dilute to the scale with high-purity water, and shake well. This solution is used to prepare the standard curve.

[0044] 2.3 Draw the calibration curve:

[0045] Select spectral lines: determine Ca 317.933nm, Mg 285.213nm, and Al 396.153nm as analysis lines.

[0046] The standard calibration curve solution was introduced into the inductively coupled plasma emission spectrometer to measure the signal intensity of Ca, Mg and Al ions, and a calibration curve was drawn with the mass percentage of the element as the abscissa and the emission intensity of the element as the ordinate.

[0047] Determination:

[0048] The sample solution and blank sample solution were introduced into the inductively coupled plasma emission spectrometer to measure the signal intensity of Ca, Mg and Al ions. The contents of CaO, MgO and Al2O3 in the sample solution were calculated based on the calibration curve of the standard solution with known mass percentage.

[0049] The content of CaO, MgO and Al2O3 in the sample is calculated as follows:

[0050] W%=W i -W0

[0051] Where: W-mass percentage of the element in the sample;

[0052] W0-mass percentage of element in blank sample solution;

[0053] W i -The mass percentage of the element in the sample solution;

[0054] The detection range of this method is: CaO, MgO, Al2O3 0.10at~15.0at%.

[0055] Example 1

[0056] The working curves were prepared according to the above method. The correlation coefficients r of the curves of Ca, Mg and Al were all greater than 0.9991. Eleven blank solutions were prepared according to the experimental method and measured three times. According to the detection limit formula C defined by the International Union of Pure and Applied Chemistry (IUPAC), L =3S b / k(S b is the standard deviation of the blank, k is the corresponding slope of the calibration curve), the detection limits of CaO, MgO and Al2O3 were calculated to be 0.076μg / mL, 0.024μg / mL and 0.039μg / mL, respectively.

[0057] Example 2

[0058] In order to evaluate the accuracy of the method, bentonite sample 1 # , 2 # A recovery test was conducted and the results of the recovery test for the upper limit were shown in Table 1 below.

[0059] Table 1: Spike recovery test

[0060]

[0061] Example 3

[0062] Under the selected experimental method, weigh the bentonite sample 3 # , 4 # 8 sample solutions were prepared in parallel for precision investigation. The standard deviation (SD) and relative standard deviation (RSD) of the determination results of each component were calculated, and the results are shown in Table 2 below.

[0063] Table 2: Precision test results

[0064]

[0065] Therefore, through the verification of the above-mentioned implementation examples, it can be seen that the detection range of CaO, MgO and Al2O3 in bentonite by ICP-OES can be 0.10at~15.0at%. The present invention has a good application effect through multiple inspections of bentonite samples. The present invention has the characteristics of wide linear range, high sensitivity, simple operation, fast analysis speed, accurate and reliable analysis results, and provides reliable data for the detection of calcium, magnesium and aluminum in bentonite.

[0066] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for determining calcium, magnesium and aluminum in bentonite, comprising the following steps: (1) Weigh a bentonite sample into a polytetrafluoroethylene beaker, add hydrochloric acid and hydrofluoric acid to dissolve at low temperature, and prepare a blank sample at the same time; (2) adding perchloric acid to the bentonite sample dissolved in step (1) to generate fumes, and cooling to room temperature; (3) adding hydrochloric acid to the cooled sample in step (2) to dissolve the salts at low temperature, and cooling to room temperature; (4) Transfer the sample solution obtained in step (3) to a volumetric flask, dilute to volume with high-purity water, and shake well to obtain a test sample solution and a blank sample solution for machine detection; (5) The sample solution and the blank sample solution are introduced into an inductively coupled plasma emission spectrometer to measure the signal intensity of Ca, Mg, and Al ions. The contents of CaO, MgO, and Al2O3 in the sample solution are calculated based on the calibration curve of the standard solution with known mass percentage.

2. The determination method according to claim 1, wherein the contents of CaO, MgO and Al2O3 in the bentonite sample are calculated as follows: W%=W i -W0 Where: W-mass percentage of the element in the bentonite sample; W0-mass percentage of element in blank sample solution; W i -The mass percentage of the element in the sample solution.

3. The determination method according to claim 1 or 2, wherein the temperature of the low temperature in steps (1) and (3) is 270°C.

4. The determination method according to claim 1 or 2, wherein the inductively coupled plasma emission spectrometer used in step (5) is Optima 7300DV (PE Company, USA).

5. The determination method according to claim 1 or 2, wherein the spectral line positions of Ca, Mg and Al ions measured in step (5) are respectively: Ca 4317.933nm, Mg 285.213nm, Al 396.153nm.

6. The determination method according to claim 1 or 2, wherein the detection range of CaO, MgO and Al2O3 is 0.10 at ~ 15.0 at %.

7. The assay method according to claim 1 or 2, comprising the following steps: (1) Weigh 0.1000 g of bentonite sample into a polytetrafluoroethylene beaker, add 10 mL of hydrochloric acid and 5 mL of hydrofluoric acid and place on a 270 °C low-temperature electric hot plate, and prepare a blank sample at the same time; (2) adding 2 mL of perchloric acid to the bentonite sample dissolved in step (1) to generate fumes until the solution reaches 1 mL, and cooling to room temperature; (3) adding 5 mL of hydrochloric acid to the cooled sample in step (2), dissolving the salts on a 270° C. low-temperature electric hot plate, and cooling to room temperature; (4) Transfer the sample solution obtained in step (3) to a 250 mL volumetric flask, dilute to volume with high-purity water, and shake well to obtain a test sample solution and a blank sample solution for machine testing; (5) The sample solution and the blank sample solution are introduced into an inductively coupled plasma emission spectrometer to measure the signal intensity of Ca, Mg, and Al ions. The contents of CaO, MgO, and Al2O3 in the sample solution are calculated based on the calibration curve of the standard solution with known mass percentage.

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