GB/T 5121.23-1996 Chemical analysis methods for copper and copper alloys - Determination of silicon content
Some standard content:
1 Scope
National Standard of the People's Republic of China
Chemical analysis methods for copper and copper alloys--Determination of silicon content Copper and copper alloys--Determination of silicon content Part I Method 1 Determination of silicon content by molybdenum blue extraction spectrophotometry This standard specifies the method for measuring silicon content in copper and copper alloys GB/T 5121.23
Replaces GB5122.16
GB6520.14
GR 8002.12
GB 8550.20
GB 8550.21
This standard applies to the determination of silicon content in copper and copper alloys. Determination range: 0.0010%~0.025%. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised. All parties using this standard should explore the possibility of using the latest versions of the following standards: GB1.4-88 Standardization work guidelines for the preparation of chemical analysis methods GB1467--78 General principles and general provisions for chemical analysis methods for metallurgical products GB7729-87 General principles for spectrophotometric methods for chemical analysis of metallurgical products 3 Method summary
The sample is dissolved with hydrochloric acid, nitric acid and hydrofluoric acid. In a slightly acidic solution, silicon and ammonium molybdate form silicomolybdic acid. It is extracted with MIBK in a nitric acid solution and stannous chloride is used to reduce silicic acid to molybdenum blue. The absorbance is measured at a wavelength of 740nm on a spectrophotometer. 4 Reagents
The water used in this method is secondary deionized water. The reagents are stored in butyl polyethylene bottles. 4.1 Urea.
4.2 Ethanol.
4.3 Mixed acid: add 30ml hydrochloric acid (pl.19g/mL, high purity) and 10ml nitric acid (pl.12g/ml., high purity) to 60ml water. 4.4 Hydrofluoric acid (ol.13g/mL) high purity. 4.5 Boric acid solution (50g/L).
4.6 Ammonium hydroxide (NH4OH) solution (100g/L), high purity. 4.7 Citric acid (C.H024·H,O) solution (500g/1.). 4.8 Nitric acid (1+3), high purity.
4.9 4-Methyl-pentanone-2.
4.10 Hydrochloric acid (1+9), high purity,
4.11 Tin chloride solution (10g/1): weigh 1g of stannous fluoride (SnCl2·2H20), add 20ml of hydrochloric acid (01.19g/ml, high purity). Heat to dissolve, cool. Dilute with water to 100ml. Prepare before use. Silicon standard stock solution: Weigh (.4279g) silicon oxide 4.12 (99.99%) pre-calcined at 1000C and cooled to room temperature in a desiccator. Place it in a platinum crucible pre-added with 3g of anhydrous sodium carbonate, cover with 1-2g of anhydrous sodium carbonate, heat at low temperature first, then melt at 950C until transparent and continue for 3min, soak it in a polyethylene beaker with water, transfer it to a 1000ml volumetric flask, wash the beaker with water, dilute to the scale, and mix. Transfer 10.00ml of the solution to a 100mL volumetric flask, dilute to the scale with water, and mix. This solution contains 1ml.20)μg silicon.
4.13 Silicon standard solution: Pipette 10.00mL of purchased silicon standard solution into a 100mL volumetric flask, dilute to scale with water and mix well. This solution contains 2μg silicon in 1mL.
5 Instruments
Spectrophotometer.
6 Analysis steps
6.1 Test materials
Weigh the sample according to Table 1, accurate to 0.0001g. Table 1
Silicon content, %
0. 001 0 0. 005 0
≥0. 005 0~ 0. 025
Carry out two independent determinations and take the average value. 6.2 Blank test
Add 5.0mL of mixed acid to the test materials for a blank test. 6.3 Determination of
Amount of mixed acid.ml
6.3.1 Place the sample (6.1) in a 100mL polyethylene bottle, add the mixed acid according to Table 1, tighten the bottle cap, heat in a water bath to dissolve, remove, add 10 drops of hydrofluoric acid and about 1g of urea at no more than 60°C, mix, add 30mL of boric acid solution, transfer to a 50mL volumetric flask, dilute to the mark with water, and mix. Immediately transfer to the original polyethylene bottle. 6.3.2 Transfer 10.00mL of solution (6.3.1) to a 100mL polyethylene beaker, add 20mL of water and 3mL of ammonium molybdate solution, and place at 20C~~35C for 30min. Add 7mL of citric acid solution and place for 3min. 6.3.3 Transfer the solution (6.3.2) to a 125mL separatory funnel. Wash the beaker with 10mL of nitric acid in batches. Add the washing solution to the main solution. Add 10.00ml 4-methyl-pentanone-2, shake for 1min, stand to separate, and discard the aqueous phase. Add 10mL hydrochloric acid, shake for 15s, stand to separate, and discard the aqueous phase. Add 10mL stannous chloride solution, shake 10 times, stand to separate, and discard the aqueous phase. Add 1.00ml anhydrous ethanol to the organic phase and mix.
6.3.4 Transfer part of the solution into a dry 1cm absorption III, and measure the absorbance at a wavelength of 7401m on a spectrophotometer with 4-methyl-pentanone-2 as a reference.
6.3.5 Subtract the absorbance of the blank solution accompanying the sample and find the corresponding silicon content from the working curve. 6.4 Drawing of working curve
6.4.1 Weigh 2.000g pure copper (silicon content less than 0.0005%) and place it in a 100mL polyethylene bottle, add 26.0mL mixed acid, tighten the bottle cap, and heat in a water bath to dissolve. Add 20 drops of hydrofluoric acid and about 2g of urea, and shake to decompose nitrogen oxides. Add 60mL of boric acid solution, transfer to a 100mL volumetric flask, dilute to scale with water, and mix well. Immediately transfer to the original polyethylene bottle. 6.4.2 Transfer 6 portions of 10.00mL solution (6.4.1) to a group of polyethylene beakers, add 0, 1.00.2.00, 3.00.4.00.5.00mL silicon standard solution respectively, and add water to a volume of 30mL. Add 3ml of ammonium molybdate solution, add 7ml of citric acid solution at 20C~35C, and let stand for 3min. The following shall be carried out in accordance with 6.3.3 to 6.3.4. 6.4.3 Subtract the absorbance of the compensation solution and draw the working curve with the silicon content as the horizontal axis and the absorbance as the vertical axis. 298
Expression of analysis results
According to formula (1), calculate the percentage of silicon:
GB/T 5121.23—1996
mV×10
Si(%)
Where: mi. The silicon content found from the working curve, μg; V. -Total volume of test solution, mL
V,—Volume of test solution taken, mL:
m---Mass of the sample·g.
The obtained result shall be expressed to 3 decimal places. If the tin content is less than 0.010%, it shall be expressed to 4 decimal places. 8 Allowable difference
The difference between the analysis results of laboratories shall not be greater than the allowable difference listed in Table 2. Table 2
Silicon content
0. 001 0-~ 0. 003 0
0. 003 0~ 0. 008 0
0. 008 0~ 0. 015
>0.015~0.025
Part II Method 2
9 Scope
Full permission
Determination of silicon content by molybdenum blue spectrophotometry
This standard specifies the method for measuring the silicon content in copper and copper alloys. This standard is applicable to the determination of the silicon content of copper and copper alloys. Determination range: >0.025%~0.40%. 10 Reference Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. The versions shown are valid when this standard is published. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB1.4-88 Standardization work guideline for chemical analysis method standard preparation regulations GB1467-78 General principles and general provisions for chemical analysis method standards for metallurgical products GB7729-87 General principles for spectrophotometric method for chemical analysis of metallurgical products 11 Method summary
The sample is dissolved with nitric acid and hydrofluoric acid, urea is added to destroy nitrogen oxides, and boric acid complexes excess fluoride ions. In a slightly acidic solution, silicic acid and ammonium molybdate form silicomolybdic acid. After increasing the acidity, it is reduced to molybdenum blue with thiourea, and the absorbance is measured at a wavelength of 810nm on a spectrophotometer. 12 Reagents
12.1 Hydrofluoric acid (ol.13g/ml). Super pure. 12.2 Nitric acid (1+1).
12.3 Urea solution (100g/L), stored in a polyethylene bottle. 12.4 Boric acid solution (50g/L), stored in a polyethylene bottle. 29
GB/T 5121. 23--1996
12.5 Ammonium molybdate [(NH,)Mo,O24·4H,O] solution (50 g/L), stored in polyethylene bottle 12.6 Sulfuric acid (2+7).
12.7 Thiourea solution (100 g/1.).
12.8 Potassium permanganate solution (50 g/I.). 12.9 Sodium nitrite solution (100 g/L). 12.10 Silicon standard stock solution: weigh 0.4279 g of silicon oxide (99.99%) that has been previously calcined at 1000°C and cooled to room temperature in a desiccator, and place it in a platinum crucible pre-added with 3 g of anhydrous sodium carbonate, cover with 1~~2 g of anhydrous sodium carbonate, first heat at the bottom, then melt at 950°C until transparent, and continue for 3 minutes. Soak in a polyethylene beaker with water, transfer to a 1000mL volumetric flask, wash the beaker with water and dilute to the mark, mix well, and store in a polyethylene bottle. This solution contains 200μg silicon in 1ml. 12.11 Silicon standard solution: Transfer 10.00mL of silicon standard stock solution, place in a 200mL volumetric flask, dilute to the mark with water, mix well, and store in a polyethylene bottle. This solution contains 10μg silicon in 1mL. 13 Instruments
Spectrophotometer.
14 Analysis steps
14.1 Test materials
Weigh the sample according to Table 3, accurate to 0.0001g. Silicon
amount, %
≥>0. 025~0. 10
>0.10~0.20
0.20~0.40
Carry out two independent determinations and take the average value. 14.2 Blank test
Weigh the same amount of pure copper as the sample (silicon content is not more than 0.0005%) and make a blank test together with the sample. 14.3 Measurement
14.3.1 Place the sample (14.1) in a 200mL polyethylene beaker, add 5 drops of hydrofluoric acid and 12ml. nitric acid, and dissolve it in a warm water bath. (If analyzing a sample containing chromium, add potassium permanganate solution until the solution turns red, and add 20 drops in excess, place it in a boiling water bath and heat for 10~15min, and add sodium nitrite solution to dissolve the brown precipitate). Add 10 mL of urea solution, shake to decompose nitrogen oxides, add 30 mL of boric acid solution, transfer to a 100 mL volumetric flask, dilute to scale with water, and mix. Immediately transfer to the original polyethylene beaker. 14.3.2 Transfer 10.00 mL of solution (14.3.1) to a 200 mL polyethylene beaker, add 25 mL of water and 5 mL of ammonium molybdate solution, shake, and place at 20-35°C for 15 min. Add 20 mL of sulfuric acid, immediately add 20 mL of thiourea solution while shaking, transfer to a 100 mL volumetric flask, dilute to scale with water, and mix. Place for 5 min. 14.3.3 Transfer part of the solution to a 2 cm absorbent tube, use the blank solution accompanying the sample as a reference, measure the absorbance at a wavelength of 810 nm on a spectrophotometer, and find the corresponding silicon content from the working curve. 14.4 Drawing of working curve
14.4.1 Weigh 0.400g pure copper (silicon content not more than 0.0005%) and place it in a 200mL polyethylene beaker. Follow 14.3.1 (starting from "add 5 drops of hydrofluoric acid"). 14.4.2 Transfer 6 portions of 10.00mL solution (14.4.1) and place them in a set of 200mL polyethylene beakers. Add 0.1.00.2.0℃3.00, 4.00.5.00mL silicon standard solution respectively, and add water to 35mL. The following is in accordance with 14.3.1 (starting from adding 5 ml of ammonium molybdate solution) and 300
GB/T 5121.23-1996
14.4.3. Transfer part of the solution into 2 cm absorption III, use the compensation solution as reference, measure the absorbance at a wavelength of 810 nm on the spectrophotometer, and draw a working curve with the silicon content as the abscissa and the absorbance as the ordinate. 15 Expression of analysis results
Calculate the percentage of silicon according to formula (2):
ml .V。X 10-6
Si(%) =
Where: ml-silicon content obtained from the working curve, ug; V。 —Total volume of test solution, mL;
V, —Volume of test solution taken, mL;
Mass of test material, g.
The result is expressed to 2 decimal places. If the silicon content is less than 0.10%, express it to 3 decimal places. 16 Allowable difference
The difference between the analysis results of laboratories should not be greater than the allowable difference listed in Table 4. Table 4
Silicon content
>0.025~0.050
>0. 050~0. 10
>0.10~～0.20bzxz.net
>0.20~0. 40
Part 3 Method 3 Gravimetric determination of silicon content
17 Scope
This standard specifies the method for measuring the silicon content in copper and copper alloys. Allowable difference
This standard is applicable to the determination of silicon content in copper and copper alloys. Determination range: >0.40%～5.00%. 18 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision. Parties using this standard should explore the possibility of using the latest versions of the following standards. GB1.4-88 Standardization work guidelines for chemical analysis methods GB1467-78 General principles and general provisions for chemical analysis methods for metallurgical products 19 Method summary
The sample is dissolved with mixed acid, and the acid-insoluble matter is melted with anhydrous sodium carbonate and repeatedly evaporated with hydrochloric acid to dehydrate the silicic acid, filter it, and burn it into silicon dioxide. Treat it with sulfuric acid and hydrofluoric acid to generate silicon tetrafluoride, which is volatilized and removed. The percentage of silicon is calculated from the mass difference before and after silicon removal 20 Reagents
20.1 Anhydrous sodium carbonate.
20.2 Hydrochloric acid (pl.19 g/mL).
20.3 Hydrofluoric acid (pl.13 g/mL).
20.4 Hydrochloric acid (5+95).
20.5 Sulfuric acid (1+1).
GB/T 5121.23—1996
20.6 Mixed acid: 1 unit volume of nitric acid (p1.42g/mL) and 2 unit volumes of hydrochloric acid (20.2) are mixed evenly. 21 Analysis steps
21.1 Sample
Weigh the sample according to Table 5, accurate to 0.0001g. Table 5
Silicon content, %
>0. 40~2. 00
>2. 00~5. 00
Sample amount
Carry out two independent determinations and take the average value. 21.2 Blank test
Carry out a blank test with the sample
21.3 Determination
Amount of water added mL
Amount of mixed acid added.ml
21.3.1 Place the sample (21.1) in a 200mL beaker, add water and mixed acid according to Table 5, and dissolve the sample completely at room temperature. If the effect is slow, slightly heat it.
21.3.2 Filter with medium-speed quantitative filter paper and a small amount of quantitative filter paper pulp. Collect the filtrate in a 300mL beaker. Wash the beaker with hot hydrochloric acid (20.4) and wash until the precipitate is free of copper ion color. Wash it 5 times. Keep the filter paper. If there is black insoluble matter, it should be treated according to Appendix A. 21.3.3 Hang a glass hook on the edge of the beaker containing the filtrate, cover it with a watch glass, evaporate it to dryness at low temperature, and cool it. Add 10ml hydrochloric acid (20.2), evaporate to dryness, then add 10ml hydrochloric acid (20.2) and evaporate to dryness. Add 10mL hydrochloric acid (20.2), let stand for 3~5min. Wash Table III and the wall of the cup with water, add 70~80mL hot water, stir to dissolve the salts. 21.3.4 Immediately filter with the filter paper and pulp reserved in 21.3.2, carefully wipe off the precipitate adhering to the wall of the cup with a wiper, and remove with hot hydrochloric acid (20.4) Wash the beaker and wash until the precipitate has no copper ion color, then wash it 5 times, and then wash it 3 times with hot water. Keep the precipitate. 21.3.5 Transfer the filtrate and washing liquid to the original beaker, and proceed as in 21.3.3~21.3.4. When filtering, use medium-speed quantitative filter paper and a small amount of quantitative filter paper pulp.
21.3.6 Place the precipitate obtained twice together with the filter paper and pulp in platinum, ash, place in a high-temperature furnace at 500~~600℃, continue to heat to 1000~1050℃, and burn for 30 minutes. Take it out and cool it slightly, place it in a desiccator, weigh it after cooling it to room temperature, and repeat the burning until the constant weight. 21.3.7 Add a few drops of water, 3 drops of sulfuric acid, and 2~4mL of hydrofluoric acid along the inner wall of the platinum crucible, and heat carefully until the sulfuric acid smoke disappears. Place the platinum glass in a high temperature furnace at 1000-1050°C and burn it for 25 minutes. Take it out and cool it slightly. Place it in a desiccator. After cooling it to room temperature, weigh it and repeat the burning until constant temperature.
22 Expression of analysis results
Calculate the percentage of silicon according to formula (3):
Si(%) = [(m me) - (ms - m,)I × 0. 467 4m.
Mass of platinum crucible and precipitate before hydrofluoric acid treatment, g: Where: mi-----
me—Mass of platinum crucible and residue after hydrofluoric acid treatment,, m3—Mass of platinum crucible and blank sample precipitate before hydrofluoric acid treatment, g; 302
GB/T5121.23-1996
m.—Mass of platinum crucible and blank sample residue after hydrofluoric acid treatment + g: me———Mass of sample + g;
0.4674—Conversion factor for silicon dioxide to silicon. The result is expressed to two decimal places.
Allowable difference
The difference between the analysis results of laboratories shall not be greater than the allowable difference listed in Table 6. Table 6
Silicon content
>0.40~2. 00
>2. 00~5. 00
GB/T 5121.23—1996
Appendix A
(Appendix of the standard)
Treatment method of acid-insoluble matter
A1Put the black acid-insoluble matter obtained in the analysis step 21.3.2 together with the filter paper and pulp in a crucible, ash it, burn it in a high-temperature furnace at 800~900℃ until the carbon is completely removed, take it out and cool it. A2Move the acid-insoluble matter into a dry platinum crucible that has been pre-added with 0.5g of anhydrous sodium carbonate, and then add 1.5g of anhydrous sodium carbonate. Place the platinum crucible in a high-temperature furnace at 700~800℃, continue to heat to 950~1000℃ and melt for 10min, then take it out and cool it. Use 20mL of hot water to pour the melt into a 200mL beaker, take out the platinum crucible, slowly add 10mL of hydrochloric acid (20.2) to the beaker while shaking, drip a small amount of hydrochloric acid (20.2) along the inner wall of the platinum crucible, heat to completely dissolve the residue, merge it into the main solution, boil it to completely dissolve the salts, combine this solution with the filtrate obtained in the analysis step 21.3.2, and proceed as follows in the analysis step 21.3.3. A4 Filter with medium-speed quantitative filter paper and a small amount of quantitative filter paper pulp, carefully wipe off the precipitate adhering to the wall of the cup with a wiper, clean the beaker with hot hydrochloric acid (20.4), and wash the precipitate until there is no copper ion color, then wash it 5 times, and then wash it 3 times with hot water. Keep the precipitate. A5 Transfer the filtrate and washing liquid into the original beaker, and proceed as per 21.3.3~21.3.4. When filtering, use medium-speed quantitative filter paper and add a small amount of quantitative filter paper pulp, and then proceed as per 21.3.6~21.3.7.
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.