GB/T 15076.8-1994 Chemical analysis method of tantalum and niobium - Determination of sulfur content in niobium
Some standard content:
National Standard of the People's Republic of China
Chemical analysis methods of molybdenum and niobium
Determination of sulphur content in niobium
Methods for chemical analysis of tantalum and niobium--Determination of sulphur content in niobium1 Subject content and scope of application
This standard specifies the method for the determination of sulphur content in saws. GB/T 15076.8-94bZxz.net
This standard is applicable to the determination of sulphur content in saws, and also to the determination of sulphur content in its hydroxide and oxide, with a determination range of 0.005%~~0.05%.
2 Reference standards
GB1.4 Guidelines for standardization work Provisions for the preparation of chemical analysis methods GB1467 General principles and general provisions for chemical analysis methods for metallurgical products GB7729 General principles for spectrophotometric methods for chemical analysis of metallurgical products 3 Principle of the method
The sample is dissolved in phosphoric acid-stannous phosphate to reduce sulfur to hydrogen sulfide, heated and distilled in a nitrogen stream, absorbed by an alkaline solution, and hydrogen sulfide reacts with N, N-dimethyl-p-phenylenediamine to form methylene blue, and its absorbance is measured at a wavelength of 660nm on a spectrophotometer. 4 Reagents
4.1 Nitrogen (compressed cylinder).
4.2 Potassium permanganate-mercuric chloride solution: Weigh 2g potassium permanganate and 2g mercuric chloride and place them in a 200mL beaker, dissolve them in a small amount of water, and add water to 100mL. Mix
4.3 Potassium hydroxide solution (200g/L).
4.4 Phosphoric acid-stannous phosphate solution:
4.4.1 Weigh 27g of stannous chloride (SnCl2·2H,O) and place it in a 300mL beaker, add 200mL of phosphoric acid (p1.70g/mL), and heat to dissolve.
4.4.2 Heat the solution to boiling, wait for small bubbles to disappear, continue heating until phosphoric acid smoke just emerges, remove and cool. Transfer 15mL to a dry distillation flask (Figure 1), and follow the procedures in 6.4.2 to 6.4.4. 4.4.3 Transfer part of the solution to a 1cm absorption dish, use water as a reference, and measure its absorbance at a wavelength of 660nm on a spectrophotometer. The measured absorbance should not be greater than 0.010, otherwise, repeat the process in 4.4.2. 4.5 Sodium hydroxide solution (20g/L).
4.6 Ferric chloride solution: weigh 1g ferric chloride into a 200mL beaker, add 50mL hydrochloric acid (1+20) to dissolve, add hydrochloric acid (1+20 approved by the State Administration of Technical Supervision on May 9, 1994 and implemented on December 1, 1994) to 100mL, and mix well.
4.7 Hydrochloric acid (1+1).
GB/T 15076.8-94
4.8N, N-dimethyl-p-phenylenediamine (PADA) solution: weigh 0.75g PADA into a 250mL beaker, add 208mL hydrochloric acid (o=1.19g/mL) to dissolve, transfer to a 250mL brown volumetric flask, dilute to the mark with water, and mix well. 4.9 Mixed color developer: ferric chloride solution (4.6) + hydrochloric acid (4.7) + PADA solution (1 + 2 + 4). 4.10 Sulfur standard stock solution: weigh 1.1075g of anhydrous sodium sulfate (superior purity) that has been pre-dried at 105℃ for 1h and cooled to room temperature in a desiccator, put it in a 200mL beaker, dissolve it with 30mL hydrochloric acid (1 + 19), transfer it to a 250mL volumetric flask, dilute it to the mark with hydrochloric acid (1 + 19), and mix it. This solution contains 1mg sulfur in 1mL. 4.11 Sulfur standard solution
4.11.1 Transfer 0, 2.00.5.00, 10.00, 15.00, 20.00mL of sulfur standard stock solution (4.10) respectively, place it in a group of 100mL volumetric flasks, dilute it to the mark with hydrochloric acid (1 + 19), and mix it. 1 mL of each sulfur standard solution contains 0.20.50, 100150, 200 μg sulfur. 4.11.2 Take 0, 5.00, 10.00, 15.00, 20.00, 25.00 mL of sulfur standard stock solution (4.10) and place them in a set of 100 mL volumetric flasks, dilute to the mark with hydrochloric acid (1+19), and mix well. 1 mL of each sulfur standard solution contains 0, 50, 100.150.200, 250 μg sulfur.
5 Instruments and equipment
5.1 Spectrophotometer.
5.2 Distillation apparatus (Figure 1).
Figure 1 Schematic diagram of distillation apparatus
Quartz distillation flask (g×h, cm: 4×12) 2--Thermometer (300C); 3. Electric furnace (1.5kW): 4-Graphite insulation ring; 5--Connect to the power supply of the temperature controller; 6.9 Buffer bottle (250mL), 7, 8--Nitrogen purification bottle (250ml): respectively contain 100ml potassium permanganate-mercuric fluoride solution (4.2), 100ml. Potassium hydroxide solution (4.3); 10-Condenser; 11-Condensate receiver; 12 Absorption tube (50mL colorimetric tube); 13--Polyethylene air guide tube 512
6 Analysis steps
6.1 Determination quantity
GB/T 15076.8-94
Weigh two samples, measure them independently, and take the average value. 6.2 Test material
Weigh the sample according to Table 1, accurate to 0.0001g. Table 1
Sulfur content, %
0. 005~0. 012
>0. 012-0. 025
>0. 025~0. 05
6.3 Blank test
Carry out a blank test along with the test material.
6.4 Determination
Test material,
Absorption dish, cm
Working curve number
6.4.1 Place the test material (6.2) in a dry distillation flask (Fig. 1, and add 15mL of phosphoric acid-stannous phosphate solution (4.4) along the wall. 6.4.2 Connect the distillation apparatus with a sulfur-free rubber hose as shown in Fig. 1, and insert a thermometer. 6.4.3 Add 30mL of sodium hydroxide solution (4.5) to a 50mL colorimetric tube, insert the air guide tube into the bottom of the colorimetric tube, pass nitrogen at a rate of 2 to 3 bubbles per second, turn on the cooling water, turn on the power supply, adjust the voltage to 220V, and boil the solution in the distillation flask within 4 minutes. When the temperature indicated by the thermometer reaches When it reaches 180℃, reduce the voltage, maintain the temperature between 180℃ and 200℃, and continue distillation for 15 minutes. 6.4.4 Remove the colorimetric tube, wash the gas tube with a small amount of water, merge the washing liquid into the colorimetric tube, add 7mL of mixed color developer solution (4.9), immediately cover the stopper, shake vigorously for 15 seconds, leave for 30 minutes, dilute to the scale with water, and mix well. 6.4.5 Transfer part of the solution (6.4.4) to the corresponding absorption dish according to Table 1, use water as a reference, and measure its absorbance at a wavelength of 660nm on a spectrophotometer.
6.4.6 Subtract the absorbance of the blank solution accompanying the sample, and find the sulfur content from the corresponding working curve according to Table 1. 6.5 Drawing of working curve||tt ||6.5.1 Working curve 1:
6.5.1.1 Take 0.20mL of sulfur standard solution (4.11.1) and place them in a set of dry distillation flasks (Figure 1-1). 6.5.1.2 Add 15mL of phosphoric acid-stannous phosphate solution (4.4) along the wall of the distillation flask (Figure 1-1), and operate according to 6.4.2 to 6.4.4. 6.5.1.3 Pipette part of the solution (6.5.1.2) into the corresponding absorption dish according to Table 1, use the reagent blank as the reference, and measure its absorbance at a wavelength of 660mm on the spectrophotometer.
6.5.1.4 Draw a working curve with sulfur content as the horizontal axis and absorbance as the vertical axis. 6.5.2 Working Curve 1
Pipette 0.20mL of sulfur standard solution (4.11.2) and place them in a set of dry distillation bottles (Figure 1-1). The following operations are carried out according to 6.5.1.2~6.5.1.4.
? Calculation and expression of analysis results
Calculate the percentage of sulfur according to the following formula:
S(%)=m,×106
Where: m——the amount of sulfur found from the working curve, ug. moThe mass of the sample, g.
8Allowance difference
GB/T15076.8—94
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 2. Table 2
0. 005 0~0. 008 0
0. 008 0~0.020 0
0. 020 0~0. 030 0
>0. 030-~0.050
Additional Notes:
This standard was proposed by China Nonferrous Metals Industry Corporation. This standard was drafted by Ningxia Nonferrous Metals Smelter. This standard was drafted by Beijing Nonferrous Metals Research Institute. The main drafters of this standard are Xu Shaoling and Wu Huiqi. 514
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.