GB/T 47571-2026Methods for the chemical analysis of synthetic diamond (English PDF)

5.2 Instruments and Equipment

5.2.1 High-temperature furnace, the maximum heating temperature should be able to reach 1200°C.

5.2.2 Analytical balance with a scale division of 0.0001g.

5.2.3 Quartz dish (or ceramic dish).

5.3 Test Procedure Weigh 3g to 5g of the sample, accurate to 0.0001g, and place it in a quartz dish (or ceramic dish) that has been preheated to constant weight in a high-temperature furnace at 1100°C. Record the total mass of the sample and the quartz (or ceramic) dish. Place the sample container in a high-temperature furnace at 1000°C±20°C for ignition. 2 hours. After removing and cooling slightly, transfer to a desiccator to cool to room temperature, then weigh. Repeat the ignition process (30 minutes each time) until the difference in mass between two consecutive weighings is reached. A weight less than 0.0003g is considered constant, and the final mass is recorded.

5.4 Experimental Data Processing The ash content is expressed as its mass fraction (w_ash), calculated according to formula (1).

5.5 Tolerance The allowable error is shown in Table 1.

6.Determination of Surface Impurity Elements by Inductively Coupled Plasma Atomic Emission Spectrometry

6.1 Measurement Range The measurement ranges for various surface impurity elements are shown in Table 2.

6.2 Method Principles The sample was treated with a mixture of nitric acid and hydrofluoric acid to dissolve surface impurities under heating conditions. The standard curve method was used, and inductively coupled plasma was employed. Intra-atomic emission spectrometry (ICP-OES) was used to determine the elemental impurities (aluminum, boron, calcium, cobalt, chromium, copper, iron, potassium, magnesium, manganese, molybdenum, sodium) on the surface of synthetic diamonds. Contents of niobium, nickel, phosphorus, lead, silicon, strontium, titanium, vanadium, tungsten, zinc, and zirconium.

6.3 Reagents and Materials Unless otherwise specified, only reagents confirmed to be of superior purity should be used in the analysis. For standard stock solutions, certified reference materials or standard reference materials should be used preferentially. Preliminary sample.

6.3.1 Nitric acid (rho=1.41g/mL).

6.3.2 Hydrochloric acid (rho=1.19g/mL).

6.3.3 Hydrofluoric acid (rho=1.15g/mL).

6.3.4 Nitric acid (1 1).

6.3.34 Mixed standard solution A. 40 µg/mL. Transfer

10.00 mL of each standard stock solution to a 250 mL volumetric flask, dilute to the mark with water, and mix well. 1 mL of this solution contains 40 µg of each element to be measured. Niobium, silicon, and tungsten standard stock solutions are alkaline matrices; phosphorus standard stock solution... It contains potassium, so standard solutions of niobium, silicon, tungsten, and phosphorus need to be prepared separately.

6.3.35 Mixed standard solution B. 20 µg/mL. Transfer

5.00 mL of each standard stock solution to a 250 mL volumetric flask, dilute to the mark with water, and mix well. 1 mL of this solution contains 20 µg of each element being analyzed. Niobium, silicon, and tungsten standard stock solutions are basic matrices; phosphorus standard stock solution... It contains potassium, so standard solutions of niobium, silicon, tungsten, and phosphorus need to be prepared separately.

6.4 Instruments and Equipment

6.4.1 Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-OES) It should meet the following performance indicators.

6.4.2 Electric heating acid removal device It has multiple pores and is compatible with PTFE digestion vessels. The heating temperature range is from room temperature to 250°C.

6.4.3 Analytical Balance The graduation value is no greater than 0.0001g.

6.5 Test Procedure

6.5.1 Preparation of analytical solutions Weigh 4-5g of the sample, accurate to 0.0001g, and place it in a 100mL polytetrafluoroethylene digestion vessel. Moisten with a small amount of water and add... Add 20 mL of nitric acid (1.1), sonicate to disperse the sample evenly, add

0.5 mL of hydrofluoric acid (1.1), cover with a plastic cap, and place at a temperature of [temperature missing]. Heating was performed in an electric acid-removing apparatus at 80°C for 2 hours. The digestion tube was then removed and allowed to cool to room temperature. The sample and solution were then completely disposed of. Transfer to a 100 mL plastic volumetric flask, dilute to volume with water, and mix well. Filter dry through a plastic funnel and slow-speed filter paper or membrane into a PTFE precipitate. Place in a cup or centrifuge tube. This analytical solution is used for the determination of surface impurity elements.

6.5.2 Preparation of blank test solution Prepare a blank solution according to

6.5.1 without adding a sample.

6.5.3 Plotting Working Curves According to the elemental content, transfer mixed standard solution A (6.3.34) or mixed standard solution B (6.3.35) to a 100 mL volumetric flask. After adding water to a final volume and mixing thoroughly, the concentrations corresponding to the standard curve in Table 4 are obtained. Adjust the instrument to its optimal operating conditions according to the instrument's instruction manual, and then... The emission intensity of each analyte was determined at the recommended analytical spectral lines using a coupled plasma atomic emission spectrometer, with the mass concentration of each element as the metric. The horizontal axis and the corresponding emission intensity are used to plot the working curves.

6.5.4 Measurement Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used to determine the analytical solution (6.5.1) and the blank solution (6.5.2). The instrument was operated according to the working curve. The system automatically processes data, calculates and outputs the content of each element. When the mass fraction of the element to be tested in the sample is greater than 0.100%, it is analyzed according to Table 5. Take the test solution into a 100mL volumetric flask, dilute with water to the mark, and mix well. Perform two parallel tests and take the average value.

6.7 Permissible Error The allowable error is shown in Table 6.

7.Determination of Ash Impurity Elements by Inductively Coupled Plasma Atomic Emission Spectrometry

7.1 Measurement Range The determination ranges of various ash impurity elements are shown in Table 7.

7.2 Method Principles The sample was calcined in a high-temperature furnace at 1000°C±50°C to remove the synthetic diamond. The residue was then melted at high temperature with lithium metaborate or sodium carbonate. The molten material was dissolved in hydrochloric acid, and the impurity elements (aluminum, boron, calcium, cobalt, chromium, copper) in the artificial diamond lime were determined by ICP-OES using the standard curve method. Contents of iron, potassium, magnesium, manganese, molybdenum, sodium, niobium, nickel, phosphorus, lead, silicon, strontium, titanium, vanadium, tungsten, zinc, and zirconium.

7.3 Reagents and Materials

7.3.1 Lithium metaborate. Superior grade.

7.3.2 Sodium carbonate. Superior grade.

7.3.3 Gelatin. analytical grade.

7.3.4 Silver nitrate solution.

0.1 mol/L.

7.3.5 Hydrochloric acid (1 1).

7.3.6 Hydrochloric acid (5 95).

7.3.7 Hydrochloric acid (15 85).

7.3.8 Standard stock solution. Same as 6.3.11~6.3.35.

7.4 Instruments and Equipment

7.4.1 High temperature furnace. Same as 5.2.1.

7.4.2 ICP-OES. Same as 6.4.1.

7.5 Test Procedure

7.5.1 Preparation of analytical solutions for the determination of ash impurity elements (excluding boron) Weigh 4-5g of the sample, accurate to 0.0001g, place it in a platinum crucible, and ignite it in a high-temperature furnace at 1000°C±50°C until constant temperature. Remove the sample, cool it, add 1g of lithium metaborate, melt it in a high-temperature furnace at 1000°C±50°C for 30min, remove it, cool it, and add 30mL of [unclear text - possibly a typo, should be "30mL"]. Hydrochloric acid solution (1.1), heated until the melt is completely dissolved, then transferred to a 100 mL polytetrafluoroethylene volumetric flask and diluted to the mark. Mix well. This solution is used for the determination of ash impurity elements (except boron).

7.5.2 Preparation of analytical solutions for boron element determination Weigh 4-5g of the sample, accurate to 0.0001g, place it in a platinum crucible, and ignite it in a high-temperature furnace at 1000°C±50°C until constant temperature. Recover, remove, cool, add 1g of sodium carbonate (7.3.2), and partially open the crucible lid to allow the decomposed gases to escape. Perform at a high temperature of 900°C±50°C. Melt in the furnace for 15 minutes, then remove and cool. Add hot hydrochloric acid (15-85°C) to a 250 mL beaker, and shake the beaker continuously to accelerate the melting of the molten material. Solution. After the molten metal has completely leached out, wash the crucible and lid with water, transfer the solution to a 250 mL volumetric flask, cool, dilute to the mark with water, mix well, and set aside. Use. This solution is used to determine the elemental boron.

7.5.3 Preparation of blank test solution Without adding a sample, prepare blank test solutions according to

7.5.1 And

7.5.2 respectively.

7.5.4 Plotting the Working Curve According to the elemental content, transfer mixed standard solution A (6.3.34) or mixed standard solution B (6.3.35) to a 100 mL volumetric flask. After adding water to a final volume and mixing thoroughly, the concentrations corresponding to the standard curve in Table 8 are obtained. Adjust the instrument to its optimal operating conditions according to the instrument's instruction manual, and then... The emission intensity of each analyte is determined at the recommended analytical spectral lines using a coupled plasma atomic emission spectrometer, with the mass concentration of each element as the metric. Plot the working curves with the corresponding emission intensity on the x-axis and y-axis respectively. The correlation coefficient of the working curves for each element should not be less than 0.999.

7.5.5 Measurement Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used to determine the analytical solutions (7.5.1, 7.5.2) and blank solutions (7.5.3). The instrument was designed according to the specifications of the instrument. The system automatically processes data, calculates and outputs the content of each element, and plots curves. When the mass fraction of the element to be measured in the sample is greater than 0.050%, it follows the... Table

9.Take the test solution into a 100mL volumetric flask, dilute with water to the mark, and mix well. Perform two parallel tests and take the average value.

7.5.6 Determination of high silicon content (silicon content greater than 1%) Weigh 4-5g of the sample, accurate to 0.0001g, place it in a platinum crucible, and ignite it in a high-temperature furnace at 1000°C±50°C until constant temperature. Retrieve, remove, and cool. Add 1g of lithium metaborate, melt in a high-temperature furnace at 1000°C±50°C for 30 minutes, remove, and cool. Place in a platinum crucible. Add 30 mL of hydrochloric acid (1.1) to the crucible, heat until the molten material is completely dissolved, and then transfer the solution completely to a 100 mL polytetrafluoroethylene beaker. Place the beaker in a water bath at 95°C~100°C. When the solution evaporates to a wet salt state, add 0.5g of gelatin and 10mL of concentrated hydrochloric acid, and stir for 2 minutes. After 3 minutes, keep warm in a water bath at 60°C~70°C for 20 minutes, remove it, add 15mL of hot hydrochloric acid (5 95), and stir to dissolve the salt. Filter with medium-speed quantitative filter paper, wash the beaker and filter paper 7-8 times with hot hydrochloric acid (5-95°C), then wash the filter paper and precipitate 7 times with hot water. Eight rinses until chloride ions are eliminated (take the last rinse filtrate, add a small amount of silver nitrate solution; if no white precipitate appears in the filtrate, it is considered chloride-free). (Ions), the filtrate was collected in a 250 mL polytetrafluoroethylene volumetric flask, cooled, diluted to the mark, and mixed well. This solution is the filtrate analysis reagent. Simultaneously prepare a blank solution. Determine the silicon content in the filtrate according to 7.5.5. The silica precipitate, along with the filter paper, was placed in a platinum crucible, dried, and ashed, then calcined in a high-temperature furnace at 1000°C±50°C. After 1 hour, remove, cool slightly, place in a desiccator, cool to room temperature, weigh, and repeatedly ignite until constant weight. Add 1-2 drops of water to moisten the precipitate, then add... 10 mL hydrofluoric acid, 2-3 drops sulfuric acid (1.1), evaporate to dryness, ignite in a high-temperature furnace at 1000°C for about 15 minutes, remove and cool in a desiccator However, it was weighed and repeatedly heated until constant weight was achieved. The mass loss before and after hydrofluoric acid treatment is the silica in the precipitate, which can be converted to obtain the silica content in the precipitate. Silicon content. The mass fraction of silicon in the filtrate and precipitate is calculated by combining the results according to formula (4).

7.6 Experimental Data Processing

7.6.1 The content of each element to be tested is expressed as a mass fraction (wx) and calculated according to formula (3).

7.7 Tolerance The allowable error is shown in Table 10.

8.3.10 Mixed standard solution. 100 µg/mL. Transfer

50.00 mL from each of the seven anion standard stock solutions (8.3.3-8.3.9) into a 500 mL volumetric flask, and add

10.00 mL of each solution. Elute the stock solution, dilute to the mark with water, and mix well. 1 mL of this solution contains 100 µg each of fluorine, chloride, bromine, nitrite, nitrate, and phosphate. Root, sulfate.