Method for determining calcium, magnesium and aluminum in bentonite

Abstract

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

Description

Technical Field

[0001] This invention belongs to the field of iron and steel metallurgical analysis technology, specifically relating to a method for determining calcium, magnesium and aluminum in bentonite, and more particularly to an analytical method that involves dissolving a bentonite sample with hydrochloric acid and hydrofluoric acid, fuming it with perchloric acid until it is nearly dry, adding hydrochloric acid to dissolve the salts, and then directly determining the calcium, magnesium and aluminum in the sample solution using ICP-OES. Background Technology

[0002] Bentonite is a clay rock whose main chemical components are silicon dioxide, aluminum oxide, and water. It also contains elements such as iron, magnesium, calcium, sodium, and potassium. The content of Al2O3 and CaO has a significant impact on the physicochemical properties and processing performance of bentonite. Therefore, accurately determining the calcium, magnesium, and aluminum content in bentonite is very important for the metallurgical industry.

[0003] To date, there are no national or enterprise standards for detecting calcium, magnesium, and aluminum in bentonite, nor have there been any related reports. Summary of the Invention

[0004] To address the aforementioned problems, this invention combines modern analytical techniques, utilizing hydrochloric acid and hydrofluoric acid for dissolution, perchloric acid for fuming and silicon removal, the addition of hydrochloric acid to dissolve salts, and leveraging the wide linear range and high accuracy of ICP-OES, employing a vertical observation method to detect calcium, magnesium, and aluminum in bentonite.

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

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

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

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

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

[0010] (5) Introduce the sample solution and blank sample solution into the inductively coupled plasma atomic emission spectrometer to measure the signal intensity of Ca, Mg and Al ions. Based on the calibration curve of the standard solution with known mass percentage, calculate the content of CaO, MgO and Al2O3 in the sample solution.

[0011] In some implementations, the contents of CaO, MgO, and Al2O3 elements in the bentonite sample are calculated using the following formula:

[0012] W%=W i -W0

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

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

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

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

[0017] In some implementations, the inductively coupled plasma atomic emission spectrometer used in step (5) is an Optima 7300DV (PE Corporation, USA).

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

[0019] In some embodiments, the detection range of the determination method is 0.10% to 15.0% for CaO, MgO, and Al2O3.

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

[0021] (1) Weigh 0.1000g of bentonite sample into a polytetrafluoroethylene beaker, add 10mL of hydrochloric acid and 5mL of hydrofluoric acid to a 270℃ low temperature electric hot plate, and make a blank sample at the same time.

[0022] (2) Add 2 mL of perchloric acid to the bentonite sample dissolved in step (1) until the solution is fuming to 1 mL, and cool to room temperature;

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

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

[0025] (5) Introduce the sample solution and blank sample solution into the inductively coupled plasma atomic emission spectrometer to measure the signal intensity of Ca, Mg and Al ions. Based on the calibration curve of the standard solution with known mass percentage, calculate the content of CaO, MgO and Al2O3 in the sample solution.

[0026] This invention provides an ICP-OES method for determining calcium, magnesium, and aluminum in bentonite, which is highly sensitive, fast, easy to operate, has less interference than other methods, and has good selectivity. It adopts a vertical observation method to improve the stability of the determination and can provide accurate data for the control of smelting composition.

[0027] The present invention has the following advantages:

[0028] 1. This invention uses fewer chemical reagents: only 15mL hydrochloric acid, 5mL hydrofluoric acid, and 2mL perchloric acid are used. The use of fewer chemical reagents saves more materials and reduces the waste of chemical reagents.

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

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

[0031] 4. A method for determining calcium, magnesium, and aluminum in bentonite using ICP-OES was established, filling the gap in methods for detecting calcium, magnesium, and aluminum in bentonite.

[0032] 5. By utilizing vertical observation, the emission intensity of CaO, MgO, and Al2O3 is reduced, improving the accuracy of the determination. The detection range of the method is 0.10%–15.0% for CaO, MgO, and Al2O3. This invention has demonstrated good application results through multiple tests on bentonite samples. This invention features a wide linear range, high sensitivity, simple operation, fast analysis speed, and accurate and reliable analytical results, providing reliable data for the detection of calcium, magnesium, and aluminum in bentonite. This method can be promoted within the metallurgical industry. Detailed Implementation

[0033] The present invention will be described in detail below through specific embodiments. These embodiments are intended to help understand the present invention and are not intended to limit the scope of the present invention.

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

[0035] Hydrochloric acid, perchloric acid, hydrofluoric acid: analytical grade;

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

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

[0038] The preferred inductively coupled plasma atomic emission spectrometer is the PE Optima 7300DV; 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 of hydrochloric acid and 5mL of hydrofluoric acid, and dissolve on a 270℃ low-temperature hot plate. Prepare a blank sample simultaneously. After the sample is completely dissolved, add 2mL of perchloric acid to fume until the solution reaches 1mL, remove the heat and cool to room temperature. Add 5mL of hydrochloric acid and dissolve the salts on a 270℃ low-temperature hot plate, remove the heat and cool to room temperature. Transfer the sample solution to a 250mL volumetric flask, dilute to the mark with high-purity water, and mix well.

[0042] 2.2 Preparation of Standard Calibration Curve Solution

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

[0044] 2.3 Plot the calibration curve:

[0045] Spectral lines were selected: Ca 317.933 nm, Mg 285.213 nm, and Al 396.153 nm were determined as analytical lines.

[0046] The standard calibration curve solution was introduced into an inductively coupled plasma atomic emission spectrometer to measure the signal intensity of Ca, Mg, and Al ions. The calibration curve was plotted with the mass percentage of the element on the x-axis and the emission intensity of the element on the y-axis.

[0047] Measurement:

[0048] The sample solution and blank sample solution are introduced into an inductively coupled plasma atomic emission spectrometer to measure the signal intensity of Ca, Mg, and Al ions. Based on the calibration curve of the standard solution with known mass percentages, the contents of CaO, MgO, and Al2O3 in the sample solution are determined.

[0049] The contents of CaO, MgO, and Al2O3 in the sample are calculated using the following formula:

[0050] W%=W i -W0

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

[0052] The mass percentage of W0- element in the 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 0.10%~15.0%. Example

[0055] Working curves were prepared using the method described above. The correlation coefficients (r) for Ca, Mg, and Al were all greater than 0.9991. Eleven blank solutions were prepared according to the experimental method and measured in three separate determinations. The detection limits were determined according to the formula defined by the International Union of Pure and Applied Chemistry (IUPAC). C L =3 S b / k ( S b The standard deviation of the blank. k The detection limits for CaO, MgO, and Al2O3, calculated using the slope of the corresponding calibration curve, were 0.076 μg / mL, 0.024 μg / mL, and 0.039 μg / mL, respectively. Example

[0056] To evaluate the accuracy of the method, bentonite sample 1 was tested. # 2 # Recovery tests were conducted, and the results of the upper limit recovery tests are shown in Table 1 below.

[0057] Table 1: Spiked Recovery Test

[0058] Example

[0059] Under the selected experimental method, weigh 3 bentonite samples. # 4 # Eight sample solutions were prepared in parallel for each assay to assess precision. The standard deviation (SD) and relative standard deviation (RSD) of the determination results for each component were calculated, and the results are shown in Table 2 below.

[0060] Table 2: Precision Test Results

[0061]

[0062] Therefore, through the verification of the above implementation examples, it can be seen that the detection range of calcium, magnesium, and aluminum, as well as CaO, MgO, and Al2O3 in bentonite using ICP-OES as described in this invention is 0.10% to 15.0%. The invention has demonstrated good application results through multiple tests on bentonite samples. This invention features a wide linear range, high sensitivity, simple operation, fast analysis speed, and accurate and reliable analytical results, providing reliable data for the detection of calcium, magnesium, and aluminum in bentonite.

[0063] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within 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 0.1000g of bentonite sample into a polytetrafluoroethylene beaker, add 10mL of hydrochloric acid and 5mL of hydrofluoric acid to a low temperature electric hot plate at 270℃, and make a blank sample at the same time. (2) Add 2 mL of perchloric acid to the bentonite sample dissolved in step (1) until the solution is fuming to 1 mL, and cool to room temperature; (3) Add 5 mL of hydrochloric acid to the sample cooled in step (2), dissolve the salts on a 270°C low-temperature hot plate, and cool to room temperature; (4) Transfer the sample solution obtained in step (3) to a 250 mL volumetric flask, dilute with high-purity water to make up to volume, shake well, and obtain the sample solution and blank sample solution for instrument testing. (5) Introduce the sample solution and blank sample solution into the inductively coupled plasma atomic emission spectrometer to measure the signal intensity of Ca, Mg and Al ions. Based on the calibration curve of the standard solution with known mass percentage, calculate the content of CaO, MgO and Al2O3 in the sample solution.

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

3. The determination method according to claim 1 or 2, wherein 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 atomic emission spectrometer used in step (5) is an Optima 7300DV.

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

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

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