Inductively coupled plasma emission spectrum detection method for total iron content in silica sand

Abstract

The invention discloses an inductively coupled plasma emission spectrum detection method for total iron content in silicon sand, which belongs to the technical field of chemical detection analysis, and comprises the following steps: preparing a sample, preparing the sample into powder, sieving, accurately weighing the silicon sand sample in a platinum crucible, adding a mixed flux, melting at high temperature, cooling to room temperature, and taking out the silicon sand sample; putting into a beaker containing pure water, adding nitric acid, heating and leaching at low temperature, cooling, filtering, fixing the volume in a volumetric flask by using pure water, and uniformly mixing for later use; the method comprises the following steps: preparing a group of silica sand solutions containing iron with different concentrations, respectively transferring 0mL, 1.0 mL, 5.0 mL, 10.0 mL, 20.0 mL, 30.0 mL, 40.0 mL and 50.0 mL of iron standard solutions into the group of silica sand solutions, and uniformly mixing with pure water at a constant volume; detecting silica sand solutions containing different concentrations of iron, and drawing a working curve of the Fe content; and detecting the detection sample solution, and calculating the content of Fe in the sample according to the working curve.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical detection and analysis, and particularly relates to an inductively coupled plasma emission spectrometry detection method for total iron content in silicon sand. Background Art

[0002] Silica sand, also known as silicon dioxide or quartz sand, is a refractory granular material with quartz as the main mineral component. It is divided into artificial silica sand and natural silica sand such as washed sand, scrubbed sand and selected sand according to different mining and processing methods. Silica sand is a silicate mineral that is hard, wear-resistant, high-temperature resistant and chemically stable. It is widely used in glass, smelting, casting, construction, ceramics and other industries.

[0003] Iron in silica sand usually exists in the form of Fe2O3 and FeO, of which Fe2O3 accounts for the vast majority, and a small amount or trace amount is FeO. Fe2O3 and FeO are generally considered harmful elements in silica sand, which have a direct impact on the refractoriness and acid consumption value of silica sand. At present, the national standard method for the determination of total iron in silica sand adopts spectrophotometry or atomic absorption spectrometry. The detection operation is cumbersome, many reagents are added, and the detection cycle is long, which is difficult to meet the requirements of production and scientific research for fast, accurate and high-precision testing.

[0004] Inductively coupled plasma optical emission spectrometry has the advantages of wide measurement range, high precision and good accuracy, and is widely used in the determination of total iron content in alloy and non-alloy minerals. Summary of the invention

[0005] The purpose of the present invention is to provide an inductively coupled plasma emission spectrometry detection method for total iron content in silicon sand, which uses inductively coupled plasma spectrometry to detect the total iron content in silicon sand, reduce the time for detecting the total iron content in silicon sand, and improve the smelting efficiency of the factory.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] An inductively coupled plasma emission spectrometry method for detecting the total iron content in silicon sand comprises the following steps:

[0008] Step S1, prepare the sample, make the sample into powder, sieve, accurately weigh the silica sand sample into a platinum crucible, add a mixed flux, melt at high temperature, cool to room temperature, put into a beaker filled with pure water, add nitric acid, heat at low temperature to extract, cool, filter, dilute to volume in a volumetric flask with pure water, mix well, and set aside;

[0009] Step S2, preparing a group of silica sand solutions containing different iron concentrations, weighing several portions of reference silica powder with the same mass as the sample into different platinum crucibles, adding the same mass of mixed flux in step S1 respectively, melting at high temperature, cooling to room temperature, putting into beakers filled with pure water, adding the same volume of nitric acid respectively, heating at low temperature for leaching, cooling, filtering, and transferring to a group of volumetric flasks respectively;

[0010] Pipette 0mL, 1.0mL, 5.0mL, 10.0mL, 20.0mL, 30.0mL, 40.0mL, and 50.0mL of the iron standard solution into the above-mentioned volumetric flasks, dilute to volume with pure water, mix well, and set aside;

[0011] Step S3, turning on the inductively coupled plasma emission spectrometer, setting the parameters of the inductively coupled plasma emission spectrometer, and stabilizing it for more than half an hour;

[0012] Step S4, testing the standard solutions of different concentrations in step S2, and drawing a working curve of Fe content;

[0013] Step S5: Detect the sample solution in step S1 and calculate the Fe content in the sample according to the working curve.

[0014] The further improvement of the technical solution of the present invention is that the parameter settings of the inductively coupled plasma emission spectrometer are: ignition power 1200W, cooling gas flow 12L / min, auxiliary gas 0.5L / min, peristaltic pump speed 100 rpm.

[0015] A further improvement of the technical solution of the present invention is that in step S1, the silica sand sample is sieved through a 0.125 mm hole sieve.

[0016] A further improvement of the technical solution of the present invention is that the mixed flux used in the silica sand sample and the reference silicon dioxide powder in steps S1 and S2 includes anhydrous sodium carbonate, sodium tetraborate and sodium hydroxide.

[0017] A further improvement of the technical solution of the present invention is that the molar ratio of anhydrous sodium carbonate, sodium tetraborate and sodium hydroxide is 1:1:1.

[0018] The technical solution of the present invention is further improved in that: the concentration of the silica sand sample solution or the standard stock solution in steps S1 and S2 is 0.4 mg / mL, the mass ratio of the sample to the mixed flux is 1:25, and the mass volume ratio of the sample to nitric acid is 1:100.

[0019] A further improvement of the technical solution of the present invention is that in steps S1 and S2, the melting is performed at a high temperature of 1000° C. in a muffle furnace for 0.5 h.

[0020] A further improvement of the technical solution of the present invention is that the concentration of the Fe standard solution used in step S2 is 0.1 mg / mL.

[0021] Due to the adoption of the above technical solution, the technical progress achieved by the present invention is:

[0022] The inductively coupled plasma emission spectroscopy detection method for total iron content in silicon sand of the present invention has fast detection speed, high detection result precision, small relative standard deviation, simple operation of the entire detection method and low detection cost.

[0023] The present application adopts a method of high-temperature melting of a mixed flux to solve the problem of difficult sample dissolution. In an inductively coupled plasma emission spectrometer, a working curve of iron content is established to solve the problem of rapid detection of total iron content in silicon sand during the production and smelting process.

[0024] The method of the present application has fast detection speed, accurate data, simple operation, small amount of chemical reagents, low detection cost and is more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the standard curve diagram of Example 1. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with embodiments:

[0027] Example 1

[0028] 1. Turn on the computer

[0029] Detection instrument: iCAP6300 plasma emission spectrometer produced by Thermo Fisher Scientific was used, with a resolution of <0.006nm (at 200nm).

[0030] Reagents used: Use analytically pure or high-grade pure reagents and laboratory water that complies with the requirements of GB / T6682.

[0031] Ambient temperature 20-25 degrees Celsius; humidity 20%-80%; liquid argon purity ≥99.996%.

[0032] Parameter settings: ignition power 1200W, cooling gas flow 12L / min, auxiliary gas 0.5L / min, peristaltic pump speed 100 rpm.

[0033] The machine is stable for more than 0.5 hours.

[0034] 2. Sample dissolution:

[0035] Silica sand was made into powder sample and passed through a 0.125mm sieve. Accurately weigh 0.2000g (±0.0001g) sample into a platinum crucible, add 5g mixed solvent, melt at 1000℃ for 0.5h, remove, cool to room temperature, put it into a beaker containing 100mL pure water, add 20mL nitric acid, heat at low temperature on an electric furnace to extract, cool, filter, dilute to 500mL volumetric flask with pure water, mix well, and set aside.

[0036] 3. Curve drawing:

[0037] Accurately weigh a group of 0.2000g of standard silicon dioxide powder, respectively put it in a platinum crucible with 5g of mixed flux (anhydrous sodium carbonate, sodium hydroxide, sodium tetraborate mixed in a ratio of 1:1:1), mix well, place the platinum crucible in a muffle furnace, melt at 1000℃ for 0.5h, remove it, cool it to room temperature, put it in a beaker containing 100mL of pure water, add 20mL of nitric acid, heat it at low temperature to extract, cool it, filter it into a group of 500mL volumetric flasks, respectively transfer 0mL, 1.0mL, 5.0mL, 10.0mL, 20.0mL, 30.0mL, 40.0mL, 50.0mL of iron standard solution into this group of volumetric flasks, make up to volume with pure water, mix well, and set aside. Use this group of solutions to draw a working curve on the instrument.

[0038] The iron concentration of the iron standard solution used is 0.1 mg / mL. You can prepare it yourself or buy it.

[0039] Calculated with 0.2000g sample, the iron content in this set of standard solutions is shown in Table 1. The working curve is drawn using the iron concentration of this set of solutions and its response light intensity on the instrument. The curve uses linear fitting, and the linear coefficient must be greater than 0.999. The working standard curve is shown in Figure 1 .

[0040] Table 1

[0041] Serial number 1 2 3 4 5 6 7 8 Iron content / % 0 0.05 0.25 0.50 1.00 1.50 2.00 2.50

[0042] 4. Detection:

[0043] After the working curve is drawn, the sample solution to be tested is immediately tested and analyzed on the working curve to obtain the test result, which is the actual content of total iron in the silica sand sample.

[0044] 5. Accuracy and precision test:

[0045] The standard solution (iron content 1.00%) was used as the sample for the test. The sample solution was tested under the working curve for 10 consecutive times to determine the accuracy and precision of the test method. The test results are shown in Table 2:

[0046] Table 2

[0047]

[0048] From the data in Table 2, it can be found that the test results are slightly different from the standard values. Compared with the error required in the relevant chemical standard method GB / T7143-2010, the accuracy is better; the data fluctuation is small, which meets the requirements for the internal coefficient of variation of the laboratory in the "Guidelines for Verification and Validation of Chemical Analysis Methods" GB / T27417-2017 for conformity assessment, and the precision is good.

[0049] 6. Conclusion

[0050] The above experimental work proves that this analytical method is feasible and the test results are accurate and reliable. It solves the problem of silica sand being difficult to dissolve and achieves the purpose of using inductively coupled plasma emission spectrometer to detect the total iron content in silica sand.

[0051] Comparative Example 1

[0052] The method and reagents used in this comparative example are the same as those in Example 1, the only difference being that the mixed solvent used in this comparative example is anhydrous sodium carbonate and sodium tetraborate, and the ratio thereof is 1: 1. During the experiment, it was found that when anhydrous sodium carbonate and sodium tetraborate were used as mixed solvents to prepare the sample solution, they could also be dissolved to obtain a clear solution.

[0053] The standard solution (Fe content is 1.00%) was used to test under the working curve of this comparative example, and the test was performed 10 times continuously. The results after the test are as follows:

[0054] Table 3

[0055]

Claims

1. An inductively coupled plasma emission spectrometry method for detecting total iron content in silica sand, characterized in that The following steps are involved: Step S1, prepare the sample, make the sample into powder, sieve, accurately weigh the silica sand sample into a platinum crucible, add a mixed flux, melt at high temperature, cool to room temperature, put into a beaker filled with pure water, add nitric acid, heat at low temperature to extract, cool, filter, dilute to volume in a volumetric flask with pure water, mix well, and set aside; Step S2, preparing a group of silica sand solutions containing different iron concentrations, weighing several portions of reference silica powder with the same mass as the sample into different platinum crucibles, adding the same mass of mixed flux in step S1 respectively, melting at high temperature, cooling to room temperature, putting into beakers filled with pure water, adding the same volume of nitric acid respectively, heating at low temperature for leaching, cooling, filtering, and transferring to a group of volumetric flasks respectively; Pipette 0mL, 1.0mL, 5.0mL, 10.0mL, 20.0mL, 30.0mL, 40.0mL, and 50.0mL of the iron standard solution into the above-mentioned volumetric flasks, dilute to volume with pure water, mix well, and set aside; Step S3, turning on the inductively coupled plasma emission spectrometer, setting the parameters of the inductively coupled plasma emission spectrometer, and stabilizing it for more than half an hour; Step S4, testing the standard solutions of different concentrations in step S2, and drawing a working curve of Fe content; Step S5: Detect the sample solution in step S1 and calculate the Fe content in the sample according to the working curve.

2. The inductively coupled plasma emission spectrometry method for detecting total iron content in silicon sand according to claim 1, characterized in that: The parameter settings of the inductively coupled plasma optical emission spectrometer were as follows: ignition power 1200 W, cooling gas flow 12 L / min, auxiliary gas 0.5 L / min, and peristaltic pump speed 100 rpm.

3. The inductively coupled plasma emission spectrometry method for detecting total iron content in silicon sand according to claim 1, characterized in that: In step S1, the silica sand sample is sieved through a 0.125 mm pore sieve.

4. The inductively coupled plasma emission spectrometry method for detecting total iron content in silicon sand according to claim 1, characterized in that: The mixed flux used in the silica sand sample and the reference silicon dioxide powder in steps S1 and S2 includes anhydrous sodium carbonate, sodium tetraborate and sodium hydroxide.

5. The inductively coupled plasma emission spectrometry method for detecting total iron content in silicon sand according to claim 4, characterized in that: The molar ratio of anhydrous sodium carbonate, sodium tetraborate and sodium hydroxide is 1:1:

1.

6. The inductively coupled plasma emission spectrometry method for detecting total iron content in silicon sand according to claim 1, characterized in that: The concentration of the silica sand sample solution or the standard stock solution in steps S1 and S2 is 0.4 mg / mL, the mass ratio of the sample to the mixed flux is 1:25, and the mass volume ratio of the sample to nitric acid is 1:

100.

7. The inductively coupled plasma emission spectrometry method for detecting total iron content in silicon sand according to claim 1, characterized in that: In steps S1 and S2, the melting is carried out at a high temperature of 1000° C. in a muffle furnace for 0.5 h.

8. The inductively coupled plasma emission spectrometry method for detecting total iron content in silicon sand according to claim 1, characterized in that: The concentration of the Fe standard solution used in step S2 is 0.1 mg / mL.

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