Method for Simultaneously Determining Total Barium and Sulfur in Barite by Inductively Coupled Plasma Optical Emission Spectrometry

Abstract

The invention discloses a method for simultaneously determining total barium and sulfur in barite by inductively coupled plasma emission spectrometry. In this method, the sample is decomposed by melting with sodium carbonate and sodium hydroxide. The molten slag is extracted with hot water, nitric acid and a chromium internal standard solution are added, the crucible and the beaker are washed with dilute hydrochloric acid, water is added and shaken well, heated to boiling gently on a hot plate and then taken off and shaken well. After cooling, it is determined on an inductively coupled plasma emission spectrometer. The method of the invention makes use of the characteristic that barium sulfate has a relatively large solubility in reverse aqua regia, enabling barium and sulfur to coexist stably, and then simultaneously determines total barium and sulfur by inductively coupled plasma emission spectrometry, which has the characteristics of high detection efficiency, high precision, simple operation and low cost, and solves the technical problems that when determining total barium and sulfur in barite by traditional methods, sulfur and barium are difficult to coexist in the solution, usually two different methods are required to complete the determination, and even barium and sulfur need to be separated in advance, resulting in a long process and low detection efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of mineral content detection, and particularly to a method for simultaneously determining total barium and sulfur in barite by inductively coupled plasma emission spectrometry. Background Art

[0002] The main component of barite is BaSO4. Pure barite is white and shiny, with stable chemical properties and a relatively large specific gravity. Due to these physical and chemical properties, it is widely used in industries such as weighting agents for oil drilling, pigments, paints, papermaking, and chemical engineering. In recent years, the mining and processing of barite ore have gradually received attention. Natural barite is usually associated with gangue minerals such as calcite, dolomite, and quartz in the process of ore formation, and its occurrence form is complex. The determination of barium and sulfur contents in barite ore has gradually attracted attention.

[0003] Among existing large-scale detection equipment, only the X-ray fluorescence spectrometry fusion method can simultaneously determine total barium and sulfur in barite. However, for multi-metal samples containing sulfides and iron, the platinum crucible is severely corroded during fusion, and the results are greatly affected by the ore type, resulting in great limitations in practical applications. In traditional methods, sulfur is usually determined by combustion method, gravimetric method, or high-frequency combustion-infrared sulfur-carbon analyzer. When using the combustion method, since the thermal decomposition temperature of barium sulfate is relatively high, fluxing agents (copper powder, iron powder, silicon dioxide) need to be added to lower the melting point, and the decomposition time is relatively long, so it is less used in the analysis of such samples. Usually, the gravimetric method is selected for accurate precipitation; when using a high-frequency combustion-infrared sulfur-carbon analyzer for determination, due to the low linear range, when determining high-content sulfur, the sampling amount is reduced, and the reproducibility is not as good as the gravimetric method. To precipitate total sulfur by the gravimetric method, the ore needs to be pre-fused to separate barium before precipitation. Although the accuracy is good, the process is cumbersome and the efficiency is low, making it difficult to meet the requirements of accurate and rapid precipitation. In short, when using traditional methods to determine total barium and sulfur in barite, sulfur and barium are difficult to coexist in solution, and usually two different methods are required to complete the determination, and even barium and sulfur need to be separated in advance, resulting in a long process and low detection efficiency.

[0004] For the determination of total barium in barite, traditional methods include gravimetric method, volumetric method, or inductively coupled plasma emission spectrometry. However, in all these methods, after the ore is fused, sulfur and barium need to be separated and then re-precipitated. For samples with high strontium content, strict precipitation conditions need to be controlled in the volumetric method and gravimetric method. Otherwise, the strontium result needs to be deducted to obtain accurate results, and the process is cumbersome. Since inductively coupled plasma emission spectrometry usually does not use an internal standard, and barium has high sensitivity, a large dilution ratio is required for determination. Therefore, it has a narrow linear range and poor precision, making it difficult to meet the determination requirements of relatively pure barite. Summary of the Invention

[0005] In view of the above technical problems, the present invention provides a method for simultaneously determining total barium and sulfur in barite by alkali fusion-inductively coupled plasma emission spectrometry. By taking advantage of the fact that barium sulfate has a relatively high solubility in reverse aqua regia, barium and sulfur can coexist stably. Then, inductively coupled plasma emission spectrometry is used to simultaneously determine total barium and sulfur. This method has the characteristics of high detection efficiency, high accuracy, simple operation, and low cost, providing an effective means for the detection of barite.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A method for simultaneously determining total barium and sulfur in barite by inductively coupled plasma emission spectrometry, comprising the following steps:

[0008] (1) Preparation of test solution: Pre-add 0.5 g of sodium carbonate into a 10 mL silver crucible. Weigh 50 mg (accurate to 0.01 mg) of the sample into the silver crucible, add 1 g of sodium hydroxide, place it in a muffle furnace, slowly heat to 750 °C at a low temperature, keep it warm for 15 min, take it out and cool. Transfer the crucible to a 100 mL polytetrafluoroethylene beaker, add 50 mL of boiling water for extraction until the slag in the crucible falls off the bottom and disperses. Transfer the solution and the precipitate to a 250 mL glass triangular beaker pre-added with 10.00 mL of chromium internal standard and 50 mL of 40% nitric acid. Wash the crucible and the beaker 3 - 4 times with water, and then wash the crucible and the beaker clean with 7 mL of concentrated hydrochloric acid and water. Collect the solutions together in the 250 mL glass triangular beaker, shake well, add water to 200 mL, shake well, heat to slightly boiling on a hot plate, take it off and shake well. After cooling, obtain the test solution and measure it on an inductively coupled plasma emission spectrometer;

[0009] (2) Preparation of working curve: Weigh a certain amount of analytical reagent grade barium sulfate in a series of silver crucibles, prepare the corresponding standard solutions according to step (1), shake well, measure on an inductively coupled plasma emission spectrometer, and draw the working curves of barium and sulfur according to the measurement results;

[0010] (3) Determination of sample: Treat the barite sample according to the treatment steps of step (1), measure the emission intensity count on an inductively coupled plasma emission spectrometer, and substitute the emission intensity count into the working curve to obtain the contents of the measured elements barium and sulfur in the solution.

[0011] As a further optimization of the present invention: The working conditions of the plasma emission spectrometer are as follows:

[0012] Name Technical Parameters Name Technical Parameters Plasma Power 1200W Injection Time 15S Cooling Gas (Ar) 12L / min Reading Time 6S Auxiliary Gas (Ar) 1.0L / min Injection Pump Speed 35rpm Nebulizer Flow Rate 0.7L / min Ba Measurement Wavelength 230.4nm Observation Mode Radial S Measurement Wavelength 182.0nm Observation Height 8mm Cr Internal Standard Wavelength 205.5nm

[0013] As a further optimization of the present invention: The particle size of the measured sample should be less than 0.097 mm. After drying at 105 °C for 2 h and cooling, it is ready for use.

[0014] As a further optimization of the present invention: the method further includes the verification and comparison of the working curve. The specific method is as follows: Select 2 to 4 national first-class standard substances of barite, prepare the corresponding solutions according to step (1), and simultaneously prepare a sample blank solution. Under the same working conditions, perform the verification and comparison with the standard values of each standard substance on an inductively coupled plasma emission spectrometer.

[0015] As a further optimization of the present invention: the internal standard method is also used for quantitative correction in this method. The internal standard method selects Cr as the internal standard element for determination. The internal standard element and nitric acid are pre-put into a glass triangular beaker and pumped into the atomization system through a single-tube peristaltic pump and then enter the plasma torch flame. The dosage of the nitric acid is 40% nitric acid of 50 mL; the dosage of the Cr internal standard is 10.00 mL, and the concentration is 1.5 mg / mL.

[0016] Compared with the prior art, the advantages and beneficial effects of the present invention include:

[0017] 1. This method utilizes the characteristic that barium sulfate has a relatively large solubility in nitric acid, enabling barium and sulfur to coexist stably. Then, the inductively coupled plasma emission spectrometry is used to simultaneously determine total barium and sulfur. It has the characteristics of high detection efficiency, high accuracy, simple operation, and low cost, and solves the technical problem that when using traditional methods to determine total barium and sulfur in barite, it is difficult for sulfur and barium to coexist in the solution, usually two different methods need to be used to complete the determination, and even barium and sulfur need to be separated in advance, resulting in a long process and low detection efficiency. This method provides an effective means for the detection of barite.

[0018] 2. This method adds a chromium internal standard, which improves the stability and precision of the determination, broadens the determination range, is simple, rapid, accurate, and the efficiency is more than 3 times higher than that of traditional methods.

[0019] 3. This method does not require accurate volume fixing, the method is stable, the operation is simple, easy to master, and has good reproducibility. Description of the Drawings

[0020] Figure 1 is the standard curve diagram of barium;

[0021] Figure 2 is the standard curve diagram of sulfur. Detailed Embodiments

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] Embodiment 1

[0024] A method for simultaneously determining total barium and sulfur in barite by inductively coupled plasma emission spectrometry, comprising the following steps:

[0025] (1) Preparation of test solution: Pre-add 0.5 g of sodium carbonate into a 10 mL silver crucible, weigh 50 mg (accurate to 0.01 mg) of the sample into the silver crucible, add 1 g of sodium hydroxide, place it in a muffle furnace, slowly heat to 750 °C at low temperature, keep warm for 15 min, take it out and cool. Transfer the crucible into a 100 mL polytetrafluoroethylene beaker, add 50 mL of boiling water for extraction until the slag in the crucible falls off the bottom and disperses; transfer the solution and the precipitate into a 250 mL glass triangular beaker pre-added with 10.00 mL of chromium internal standard and 50 mL of 40% nitric acid, wash the crucible and the beaker 3 - 4 times with water, then wash the crucible and the beaker with 7 mL of hydrochloric acid and water, collect all the solutions in the 250 mL glass triangular beaker, shake well, add water to 200 mL, shake well, heat on a hot plate until slightly boiling, take it off and shake well, and obtain the test solution after cooling for determination on an inductively coupled plasma emission spectrometer.

[0026] The working conditions of the inductively coupled plasma emission spectrometer are as follows:

[0027]

[0028]

[0029] (2) Preparation of working curves: Weigh a certain amount of high-purity barium sulfate in a series of silver crucibles, prepare the corresponding standard solutions according to step (1), shake well, and determine on an inductively coupled plasma emission spectrometer. Draw the working curves of barium and sulfur according to the determination results, as shown in Table 1, Table 2 and Figure 1 、 Figure 2 respectively.

[0030] Table 1: Determination results of the working curve of barium element

[0031]

[0032] Table 2: Test results of the working curve of sulfur element

[0033]

[0034] (3) Determination of samples: Treat the barite sample according to the treatment steps in step (1), measure the emission intensity count on an inductively coupled plasma emission spectrometer, and substitute the emission intensity count into the working curve to obtain the contents of the measured elements of barium and sulfur in the solution.

[0035] Treatment of the sample: The particle size should be less than 0.097 mm. After drying at 105 °C for 2 h, it is cooled and put into a small ground-glass bottle for standby.

[0036] To improve the stability and precision of the determination, the internal standard method is adopted as the quantitative calibration method in this method. Cr is selected as the internal standard element for determination. First, 50 mL of 40% nitric acid and 10.00 mL (concentration 1.5 mg / mL) of chromium internal standard are placed in a glass triangular beaker, and then pumped into the atomization system through a single-tube peristaltic pump and enter the plasma torch flame.

[0037] To verify the accuracy of this method, the working curve is also verified and compared in this method. Multiple national first-class standard substances of barite are selected. According to step (1), the corresponding solutions are prepared, and a sample blank solution is also prepared. Under the same working conditions, it is carried out on a plasma emission spectrometer and verified and compared with the standard values of each standard substance. The comparison results are shown in Table 3:

[0038] Table 3: Verification and comparison results of this method with the standard values of each standard substance

[0039]

[0040] The detection limit of this method: The detection limits of each element are detected by the method of three times the signal-to-noise ratio in the blank solution. The detection results are shown in Table 4:

[0041] Table 4: Detection limit determination results of barium and sulfur elements determined by this method

[0042]

[0043]

[0044] It can be seen from the test results that the detection limit of barium determined by the method of the present invention is 0.005%, and the detection limit of sulfur is 0.1%.

[0045] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several alternatives or modifications can be made to these described embodiments, and these alternative or modified forms should be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for simultaneously determining total barium and sulfur in barite by inductively coupled plasma optical emission spectrometry, characterized in that: It includes the following steps: (1) Preparation of test solution: Pre-add 0.5 g of sodium carbonate into a 10 mL silver crucible, weigh 50 mg of the sample into the crucible, accurate the sample to 0.01 mg, add 1 g of sodium hydroxide, place it in a muffle furnace, slowly heat to 750 °C at low temperature, keep warm for 15 min, take it out and cool. Transfer the crucible into a 100 mL polytetrafluoroethylene beaker, add 50 mL of boiling water for extraction until the slag in the crucible falls off the bottom and disperses. Transfer the solution and precipitate into a 250 mL glass Erlenmeyer flask pre-added with 10.00 mL of chromium internal standard and 50 mL of 40% nitric acid, wash the crucible and beaker 3 - 4 times with water, then wash the crucible and beaker with 7 mL of concentrated hydrochloric acid and water, collect the solution together in the 250 mL glass Erlenmeyer flask, shake well, add water to 200 mL, shake well, heat on a hot plate until slightly boiling, take it off and shake well, and after cooling, obtain the test solution for determination on an inductively coupled plasma emission spectrometer; (2) Preparation of working curve: Weigh a certain amount of primary standard barium sulfate in a series of silver crucibles, prepare the corresponding standard solutions according to step (1), shake well, and determine on an inductively coupled plasma emission spectrometer. Draw the working curves of barium and sulfur according to the determination results; (3) Determination of sample: Treat the barite sample according to the treatment steps of step (1), measure the emission intensity counts of barium and sulfur on an inductively coupled plasma emission spectrometer, and substitute the emission intensity counts into the working curve to obtain the contents of the measured elements barium and sulfur in the solution.

2. The method for simultaneously determining total barium and sulfur in barite by inductively coupled plasma optical emission spectrometry according to claim 1, wherein: The working conditions of the plasma emission spectrometer are as follows: 。 3. The method for simultaneously determining total barium and sulfur in barite by inductively coupled plasma optical emission spectrometry according to claim 1, characterized in that: The particle size of the measured sample should be less than 0.097 mm. After drying at 105 °C for 2 h, cool it and reserve for use.

4. The method for simultaneously determining total barium and sulfur in barite by inductively coupled plasma emission spectrometry according to claim 2, characterized in that: The method also includes the verification and comparison of the working curve. The specific method is: Select 2 - 4 national primary standard substances of barite, prepare the corresponding solutions according to step (1), and simultaneously prepare a sample blank solution. Conduct on an inductively coupled plasma emission spectrometer under the same working conditions, and verify and compare with the standard values of each standard substance.

5. The method for simultaneously determining total barium and sulfur in barite by inductively coupled plasma emission spectrometry according to claim 2, characterized in that: This method also uses the internal standard method for quantitative correction.

6. The method for simultaneously determining total barium and sulfur in barite by inductively coupled plasma optical emission spectrometry according to claim 5, wherein: The internal standard method selects Cr as the internal standard element for determination. The internal standard element and nitric acid are pre-put into a glass Erlenmeyer flask and pumped into the atomization system through a single-tube peristaltic pump and then enter the plasma torch flame.

7. The method for simultaneously determining total barium and sulfur in barite by inductively coupled plasma optical emission spectrometry according to claim 6, characterized in that: The dosage of nitric acid is 50 mL of 40% nitric acid; the dosage of Cr internal standard is 10.00 mL, and the concentration is 1.5 mg / mL.

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