GB/T 15076.5-1994 Chemical analysis methods for tantalum and niobium - Determination of molybdenum and tungsten content
Some standard content:
National Standard of the People's Republic of China
Chemical analysis method of molybdenum saw
Determination of molybdenum and tungsten content
Methods for chemical analysis of GB/T 15076.5--94
tantalum and niobium-Determination of molybdenum and tungsten contents Part I Method 1 Toluene-3;4-dithiol spectrophotometry 1 Subject content and scope of application
This standard specifies the method for determining the molybdenum content and tungsten content in molybdenum and saw. This standard is applicable to the determination of the molybdenum content and tungsten content in molybdenum and saw, and also to the determination of the molybdenum content and tungsten content in its hydroxide and oxide. Determination range: 0.0003% 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 of metallurgical products GB7729 General principles for spectrophotometric methods for chemical analysis of metallurgical products 3 Principles of the method
Molybdenum is dissolved in hydrofluoric acid and hydrochloric acid, and in sulfuric acid and ammonium sulfate. Leaching with hydrochloric acid-hydrofluoric acid solution, molybdenum is reduced with thiourea, and forms a green complex with dithiol, which is extracted with carbon tetrachloride, and the absorbance of molybdenum is measured at a wavelength of 690nm on a spectrophotometer. In the aqueous phase after the extraction clamp, tungsten is reduced with stannous cyanide, and forms a blue-green complex with dithiol, which is then extracted with carbon tetrachloride, and the absorbance of tungsten is measured at a wavelength of 650nm on a spectrophotometer.
4 Reagents
4.1 Ammonium sulfate.
4.2 Hydrofluoric acid (pl.14g/mL), high-grade pure. 4.3 Hydrochloric acid (p1.19 g/mL), high-grade purity. 4.4 Sulfuric acid (pl.84 g/mL), high-grade purity. 4.5 Carbon tetrachloride.
4.6 Hydrochloric acid-hydrofluoric acid mixed acid: Add 160 mL hydrochloric acid (4.3), 40 mL hydrofluoric acid (4.2) and 200 mL water into a 500 mL plastic bottle and mix.
4.7 Sulfuric acid (1+1).
4.8 Thiourea solution (100 g/L).
4.9 Toluene-3,4-dithiol (dithiol for short) solution: Weigh 1g dithiol (crystalline dithiol should be melted in a hot water bath not higher than 40C in advance) and place it in a 500mL beaker containing 200mL. 40℃ sodium hydroxide solution (10g/L), stir continuously to dissolve it, cool it, and slowly drop about 3mL of thioglycolic acid (80%, commercially available), and stir continuously to completely dissolve the generated white turbidity. Store it in a low temperature place, and the validity period is 1 week.
4.10 Stannous chloride solution (500g/L): Weigh 50g of stannous chloride (SnCl22H20) in a 300mL beaker, add 50mL of hydrochloric acid (4.3), heat at low temperature to dissolve, remove and cool. Add hydrochloric acid (4.3) to 100mL and mix. Prepare before use. 4.11 Molybdenum standard stock solution: Weigh 0.1840g of ammonium molybdate C (NH4). Mo,O2·4H0, extra pure in a 300mL beaker, dissolve with a small amount of water, transfer to a 1000mL volumetric flask, dilute to scale with water, and mix. 1mL of this solution contains 100μg of molybdenum. 4.12 Tungsten standard stock solution: weigh 0.1261g of tungsten trifluoride (99.9%) that has been pre-dried at 105℃ for 1h and cooled to room temperature in a desiccator, put it in a 300mL beaker, add 30mL of sodium hydroxide solution (200g/L), mix well, heat to dissolve, and cool. Transfer to a 1000mL volumetric flask, dilute to scale with water, and mix well. 1mL of this solution contains 100μg of tungsten. 4.13 Molybdenum-tungsten mixed standard solution: transfer 20.00mL of molybdenum standard stock solution (4.11) and 20.00mL of tungsten standard stock solution (4.12) to the same 200mL volumetric flask, dilute to scale with water, and mix well. 1mL of this solution contains 10μg of molybdenum and 10ug of tungsten. 5 Instruments
Spectrophotometer.
6 Analysis steps
6.1 Quantity to be measured
Weigh two samples, measure them independently, and take the average value. 6.2 Samples
Weigh the samples according to Table 1. Accurate to 0.0001g. Table 1
Molybdenum content or tungsten content
0.0003~0.0008
>0. 0008～0. 0020
>0. 0020~0. 0080
>0. 0080~0. 020
>0.020~~0.050
6.3 Blank test
Carry out a blank test along with the sample.
6.4 Determination
6.4.1 Determination of molybdenum and tungsten in molybdenum
Carbon tetrachloride (4.5)
Absorption dish, cm
6.4.1.1 Place the sample (6.2) in 30mL of platinum, add 3mL of hydrofluoric acid (4.2) and 1ml of hydrochloric acid (4.3), cover the crucible, heat to dissolve (if the dissolution is incomplete, add hydrofluoric acid and hydrochloric acid according to the above proportion until the sample is completely dissolved), remove, rinse the crucible cover with a small amount of water, and add the washing liquid to the crucible. Evaporate the test solution on a low-temperature electric furnace until a precipitate just precipitates, remove, add 20mL of hydrochloric acid-hydrofluoric acid mixture (4.6), continue heating until the precipitate dissolves, and cool. Transfer to a 100mL separatory funnel, wash the crucible with 8mL of sulfuric acid (4.7), and add the washing liquid to the separatory funnel.
6.4.1.2 Add 2mL of thiophenol solution (4.8) and mix well. Add 3mL of dithiol solution (4.9), mix well and let stand for 15min. 6.4.1.3 Add carbon tetrachloride (4.5) according to Table 1, shake for 2min, let stand to separate layers, and filter the organic phase with filter paper into a dry colorimetric tube. 6.4.1.4 Transfer part of the organic phase (6.4.1.3) into the absorption blood according to Table 1, and measure the absorbance of molybdenum at a wavelength of 690nm using carbon tetrachloride (4.5) as a reference on a spectrophotometer.
GB/T 1 5076. 5--94
6.4.1.5 Add 3mL of carbon tetrachloride (4.5) to the aqueous phase after molybdenum extraction, shake for 1min, let stand to separate layers, discard the organic phase, and place the aqueous phase in a 100mL beaker.
6.4.1.6 Add 13mL hydrochloric acid (4.3) and 5mL stannous chloride solution (4.10) to a beaker, stir evenly, heat to near boiling, add 5mL dithiol solution (4.9) while hot, and stir continuously. Keep warm in a hot water bath at about 50°C for 15 minutes, take out and cool to room temperature. Transfer the test solution into a 100mL separatory funnel, and operate as in 6.4.1.3. 6.4.1.7 Transfer part of the organic phase solution into absorption III according to Table 1, and measure the absorbance of tungsten at a wavelength of 650nm on a spectrophotometer with carbon tetrachloride (4.5) as a reference.
6.4.1.8 Subtract the absorbance of the corresponding blank solution accompanying the sample. Find the corresponding clamp amount and tungsten amount from the corresponding working curve. 6.4.2 Determination of molybdenum and tungsten in iron
6.4.2.1 Place the sample (6.2) in a 50mL beaker, add 1g ammonium sulfate (4.1) and 4mL sulfuric acid (4.4), mix, cover with table blood, heat to dissolve, remove, and cool. Wash the table dish and the wall of the cup with 2mL sulfuric acid (4.7), and add the washing liquid to the beaker. 6.4.2.2 Add 15mL hydrochloric acid-hydrofluoric acid mixture (4.6), mix, and cool. Transfer to a 100mL separatory funnel, and then wash the beaker with 5mL hydrochloric acid-hydrofluoric acid mixture (4.6), and add the washing liquid to the separatory funnel. The following operations are carried out according to 6.4.1.2 to 6.4.1.8. 6.5 Drawing of working curve
6.5.1 Transfer 0, 0.30, 0.50, 1.00, 1.50, 2.00, 2.50mL of molybdenum-tungsten mixed standard solution (4.13) into a set of 100mL separating funnels, add water to 11mL, add 8mL of hydrochloric acid (4.3) and 8mL of sulfuric acid (4.7) to each, and mix well. The following operations are carried out according to 6.4.1.2 to 6.4.1.7.
6.5.2 Subtract the absorbance of the corresponding reagent blank solution respectively, and draw the working curve of the clamp or tungsten with the amount of molybdenum or tungsten as the horizontal axis and the absorbance as the vertical axis.
7 Calculation and expression of analysis results
Calculate the percentage of molybdenum or tungsten according to the following formula: m,×10
Mo or W(%)-
Wherein: ml—mass of molybdenum or tungsten found from the working curve, g; m. -mass of the sample + g.
8 Allowable difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 2. Table 2
Molybdenum content or tungsten content
0. 0003~0. 0005
>0. 0005~0, 0015
>0. 0015~ 0. 0070
>0. 0070~0. 0140
>0. 0140~0. 0250
>0.025-~0.050
Tolerance
9 Subject content and scope of application
GB/T 15076.5-94
Part II Method 2 Thiocyanate spectrophotometry This standard specifies the method for determining the molybdenum content in tungsten and molybdenum. This standard is applicable to the determination of the molybdenum content in tungsten and molybdenum, and also to the determination of the molybdenum content in its hydroxide, oxide and carbide. Determination range: 0.0003%~0.1%.
This standard is not used as an arbitration analysis method.
10 Reference standards
GB1.4 Standardization work guidelines Chemical analysis method standard writing rules GB1467 General principles and general provisions for chemical analysis methods of metallurgical products GB7729 General principles for spectrophotometric methods for chemical analysis of metallurgical products 11 Principle of the method
The sample is melted with potassium carbonate and separated by magnesium sulfate precipitation or niobium to eliminate the influence of the main body on the determination. In sulfuric acid solution [c(H,SO,)-0.5mol/L], copper sulfate-sulfur is used as a reducing agent to reduce molybdenum to form a thiocyanate complex, which is extracted with ethyl acetate and the absorbance is measured at a wavelength of 460nm on the spectrophotometer.
12 Reagents
12.1 Potassium carbonate.
Ethyl acetate.
Sulfuric acid (1+1).
Copper sulfate solution (10g/L).
12.5 Thiourea solution (100g/L).
12.6 Potassium thiocyanate solution (200g/L). 12.7 Magnesium sulfate solution (200g/L).
12.8 Molybdenum standard stock solution: Weigh 0.1840g ammonium molybdate [(NH4) Mo,Oz·4H,0, extra pure] in a 300mL beaker, dissolve with a small amount of water, transfer to a 1000mL volumetric flask, dilute to scale with water, and mix well. This solution contains 100μg silver in 1mL. 12.9 Molybdenum standard solution: Transfer 10.00mL of molybdenum standard stock solution (12.8) to a 200mL volumetric flask, dilute to scale with water, and mix well. This solution contains 5μg molybdenum in 1mL.
13 Instruments
Spectrophotometer.
14 Analysis steps
14.1 Determination quantity
Weigh two samples, measure independently and take the average value. 14.2 Samples
Weigh the sample according to Table 3. Accurate to 0.0001g. 499
Pthium content
0. 0003~0. 0010
>0. 0010~0. 0050
>0. 0050~~0. 0100
>0. 0100~0.040
0. 040~0. 100
14.3 Blank test
Carry out a blank test along with the sample.
14.4 Determination
GB/T 15076.5-94
Potassium carbonate (12.1)
Magnesium sulfate solution
(12.7),mL
Working curve number
14.4.1 Place the sample (14.2) in 30mL of platinum according to Table 3, burn it into oxides in a high-temperature furnace at 600~650℃, remove it, and cool it. Add potassium carbonate (12.1) according to Table 3, mix well, melt it on a blowtorch until it is red and transparent, remove it, and cool it. 14.4.2 Place the crucible in a 200mL beaker, add 40mL of boiling water and heat it to dissolve the sintered block, wash the crucible with water, heat it to a slight boil, remove it, add magnesium sulfate solution (12.7) while stirring while hot according to Table 3, and cool it. Transfer to a 100mL volumetric flask, dilute to the mark with water, mix, and dry filter with double-layer filter paper into a dry small beaker. Transfer 25.00mL of the filtrate into a 50mL colorimetric tube. 14.4.3 Add 8mL of sulfuric acid (12.3), 2mL of copper sulfate solution (12.4), and 2mL of thiourea solution (12.5) to the colorimetric tube and mix them in sequence. Let stand for 10 minutes, add 2mL of potassium thiocyanate solution (12.6), mix, and let stand for 30 minutes. Add 8mL of ethyl acetate (12.2) and shake for 1 minute. Let stand to separate.
14.4.4 Use a dry pipette to transfer part of the organic phase into the corresponding absorption dish (14.2) according to Table 3, use ethyl acetate as a reference, and measure the absorbance at a wavelength of 460nm on a spectrophotometer.
14.4.5 Subtract the absorbance of the blank solution accompanying the sample. Find the amount of molybdenum from the corresponding working curve according to Table 1. 14.5 Drawing of working curve
14.5.1 Working curve IWww.bzxZ.net
14.5.1.1 Transfer 0, 0.10, 0.20, 0.60, 1.00, 1.40 mL of molybdenum standard solution (12.9) into a 50 mL colorimetric tube, add water to 25 mL, and proceed as in 14.4.3 and 14.4.4. 14.5.1.2 Subtract the absorbance of the reagent blank, and draw the working curve with the amount of molybdenum as the horizontal axis and the absorbance as the vertical axis. 14.5.2 Working curve
Pipette 0, 0.40, 1.00, 2.00, 3.00, 4.00, 5.00mL of molybdenum standard solution (12.9) into a set of 50mL colorimetric tubes, add water to 25mL, and then follow the steps in 14.4.3, 14.4.4 and 14.5.1.2. 15 Calculation and expression of analysis results
Calculate the percentage of molybdenum according to the following formula:
Mo(%)=mVc×10-6
Where: ml—the amount of molybdenum found from the working curve, μg; V. Total volume of test solution, mL;
V,—volume of test solution taken, mL;
16 Allowable difference
—mass of the sample·8.
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 4. 500
Additional Notes:
Molybdenum Content
0. 0003~-0. 0005
>0. 0005~ 0. 0015
>0.0015~0.0070
>0. 0070~0. 0140
>0.0140~0.0250
>0. 025~0. 045
>0.045~0.100
GB/T15076.5—94
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 drafter of this standard is Wu Xinyou.
Allowance
From the date of implementation of this standard, the former Ministry of Metallurgical Industry of the People's Republic of China issued the Ministry of Standard YB942 (4) - 78 Determination of molybdenum and tungsten in sawdust (dithiol absorption photometry)" shall be invalid.4 Guidelines for Standardization Work Rules for the Preparation of Chemical Analysis Methods GB1467 General Rules and General Provisions for Chemical Analysis Methods for Metallurgical Products GB7729 General Rules for Spectrophotometric Methods for Chemical Analysis of Metallurgical Products 11 Principle of the Method
The sample is melted with potassium carbonate and separated by magnesium sulfate precipitation or niobium to eliminate the influence of the main body on the determination. In sulfuric acid solution [c(H,SO,)-0.5mol/L], copper sulfate-sulfur is used as a reducing agent to reduce molybdenum to form a thiocyanate complex, which is extracted with ethyl acetate and the absorbance is measured at a wavelength of 460nm on a spectrophotometer.
12 Reagents
12.1 Potassium carbonate.
Ethyl acetate.
Sulfuric acid (1+1).
Copper sulfate solution (10g/L).
12.5 Thiourea solution (100g/L).
12.6 Potassium thiocyanate solution (200g/L). 12.7 Magnesium sulfate solution (200g/L).
12.8 Molybdenum standard stock solution: Weigh 0.1840g ammonium molybdate [(NH4) Mo,Oz·4H,0, extra pure] in a 300mL beaker, dissolve with a small amount of water, transfer to a 1000mL volumetric flask, dilute to scale with water, and mix well. This solution contains 100μg silver in 1mL. 12.9 Molybdenum standard solution: Transfer 10.00mL molybdenum standard stock solution (12.8) to a 200ml volumetric flask, dilute to scale with water, and mix well. This solution contains 5μg molybdenum in 1mL.
13 Instruments
Spectrophotometer.
14 Analysis steps
14.1 Determination quantity
Weigh two samples, measure them independently, and take the average value. 14.2 Test material
Weigh the test material according to Table 3. Accurate to 0.0001 g. 499
Ca content
0. 0003~0. 0010
>0. 0010~0. 0050
>0. 0050~~0. 0100
>0. 0100~0.040
0. 040~0. 100
14.3 Blank test
Carry out a blank test along with the test material.
14.4 Determination
GB/T 15076.5-94
Potassium carbonate (12.1)
Magnesium sulfate solution
(12.7),mL
Working curve number
14.4.1 Place the sample (14.2) in 30mL of platinum according to Table 3, burn it into oxides in a high-temperature furnace at 600~650℃, remove it, and cool it. Add potassium carbonate (12.1) according to Table 3, mix well, melt it on a blowtorch until it is red and transparent, remove it, and cool it. 14.4.2 Place the crucible in a 200mL beaker, add 40mL of boiling water and heat it to dissolve the sintered block, wash the crucible with water, heat it to a slight boil, remove it, add magnesium sulfate solution (12.7) while stirring while hot according to Table 3, and cool it. Transfer to a 100mL volumetric flask, dilute to the mark with water, mix, and dry filter with double-layer filter paper into a dry small beaker. Transfer 25.00mL of the filtrate into a 50mL colorimetric tube. 14.4.3 Add 8mL of sulfuric acid (12.3), 2mL of copper sulfate solution (12.4), and 2mL of thiourea solution (12.5) to the colorimetric tube and mix them in sequence. Let stand for 10 minutes, add 2mL of potassium thiocyanate solution (12.6), mix, and let stand for 30 minutes. Add 8mL of ethyl acetate (12.2) and shake for 1 minute. Let stand to separate.
14.4.4 Use a dry pipette to transfer part of the organic phase into the corresponding absorption dish (14.2) according to Table 3, use ethyl acetate as a reference, and measure the absorbance at a wavelength of 460nm on a spectrophotometer.
14.4.5 Subtract the absorbance of the blank solution accompanying the sample. Find the amount of molybdenum from the corresponding working curve according to Table 1. 14.5 Drawing of working curve
14.5.1 Working curve I
14.5.1.1 Transfer 0, 0.10, 0.20, 0.60, 1.00, 1.40 mL of molybdenum standard solution (12.9) into a 50 mL colorimetric tube, add water to 25 mL, and proceed as in 14.4.3 and 14.4.4. 14.5.1.2 Subtract the absorbance of the reagent blank, and draw the working curve with the amount of molybdenum as the horizontal axis and the absorbance as the vertical axis. 14.5.2 Working curve
Pipette 0, 0.40, 1.00, 2.00, 3.00, 4.00, 5.00mL of molybdenum standard solution (12.9) into a set of 50mL colorimetric tubes, add water to 25mL, and then follow the steps in 14.4.3, 14.4.4 and 14.5.1.2. 15 Calculation and expression of analysis results
Calculate the percentage of molybdenum according to the following formula:
Mo(%)=mVc×10-6
Where: ml—the amount of molybdenum found from the working curve, μg; V. Total volume of test solution, mL;
V,—volume of test solution taken, mL;
16 Allowable difference
—mass of the sample·8.
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 4. 500
Additional Notes:
Molybdenum Content
0. 0003~-0. 0005
>0. 0005~ 0. 0015
>0.0015~0.0070
>0. 0070~0. 0140
>0.0140~0.0250
>0. 025~0. 045
>0.045~0.100
GB/T15076.5—94
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 drafter of this standard is Wu Xinyou.
Allowance
From the date of implementation of this standard, the former Ministry of Metallurgical Industry of the People's Republic of China issued the Ministry of Standard YB942 (4) - 78 Determination of molybdenum and tungsten in sawdust (dithiol absorption photometry)" shall be invalid.4 Guidelines for Standardization Work Rules for the Preparation of Chemical Analysis Methods GB1467 General Rules and General Provisions for Chemical Analysis Methods for Metallurgical Products GB7729 General Rules for Spectrophotometric Methods for Chemical Analysis of Metallurgical Products 11 Principle of the Method
The sample is melted with potassium carbonate and separated by magnesium sulfate precipitation or niobium to eliminate the influence of the main body on the determination. In sulfuric acid solution [c(H,SO,)-0.5mol/L], copper sulfate-sulfur is used as a reducing agent to reduce molybdenum to form a thiocyanate complex, which is extracted with ethyl acetate and the absorbance is measured at a wavelength of 460nm on a spectrophotometer.
12 Reagents
12.1 Potassium carbonate.
Ethyl acetate.
Sulfuric acid (1+1).
Copper sulfate solution (10g/L).
12.5 Thiourea solution (100g/L).
12.6 Potassium thiocyanate solution (200g/L). 12.7 Magnesium sulfate solution (200g/L).
12.8 Molybdenum standard stock solution: Weigh 0.1840g ammonium molybdate [(NH4) Mo,Oz·4H,0, extra pure] in a 300mL beaker, dissolve with a small amount of water, transfer to a 1000mL volumetric flask, dilute to scale with water, and mix well. This solution contains 100μg silver in 1mL. 12.9 Molybdenum standard solution: Transfer 10.00mL molybdenum standard stock solution (12.8) to a 200ml volumetric flask, dilute to scale with water, and mix well. This solution contains 5μg molybdenum in 1mL.
13 Instruments
Spectrophotometer.
14 Analysis steps
14.1 Determination quantity
Weigh two samples, measure them independently, and take the average value. 14.2 Test material
Weigh the test material according to Table 3. Accurate to 0.0001 g. 499
Ca content
0. 0003~0. 0010
>0. 0010~0. 0050
>0. 0050~~0. 0100
>0. 0100~0.040
0. 040~0. 100
14.3 Blank test
Carry out a blank test along with the test material.
14.4 Determination
GB/T 15076.5-94
Potassium carbonate (12.1)
Magnesium sulfate solution
(12.7),mL
Working curve number
14.4.1 Place the sample (14.2) in 30mL of platinum according to Table 3, burn it into oxides in a high-temperature furnace at 600~650℃, remove it, and cool it. Add potassium carbonate (12.1) according to Table 3, mix well, melt it on a blowtorch until it is red and transparent, remove it, and cool it. 14.4.2 Place the crucible in a 200mL beaker, add 40mL of boiling water and heat it to dissolve the sintered block, wash the crucible with water, heat it to a slight boil, remove it, add magnesium sulfate solution (12.7) while stirring while hot according to Table 3, and cool it. Transfer to a 100mL volumetric flask, dilute to the mark with water, mix, and dry filter with double-layer filter paper into a dry small beaker. Transfer 25.00mL of the filtrate into a 50mL colorimetric tube. 14.4.3 Add 8mL of sulfuric acid (12.3), 2mL of copper sulfate solution (12.4), and 2mL of thiourea solution (12.5) to the colorimetric tube and mix them in sequence. Let stand for 10 minutes, add 2mL of potassium thiocyanate solution (12.6), mix, and let stand for 30 minutes. Add 8mL of ethyl acetate (12.2) and shake for 1 minute. Let stand to separate.
14.4.4 Use a dry pipette to transfer part of the organic phase into the corresponding absorption dish (14.2) according to Table 3, use ethyl acetate as a reference, and measure the absorbance at a wavelength of 460nm on a spectrophotometer.
14.4.5 Subtract the absorbance of the blank solution accompanying the sample. Find the amount of molybdenum from the corresponding working curve according to Table 1. 14.5 Drawing of working curve
14.5.1 Working curve I
14.5.1.1 Transfer 0, 0.10, 0.20, 0.60, 1.00, 1.40 mL of molybdenum standard solution (12.9) into a 50 mL colorimetric tube, add water to 25 mL, and proceed as in 14.4.3 and 14.4.4. 14.5.1.2 Subtract the absorbance of the reagent blank, and draw the working curve with the amount of molybdenum as the horizontal axis and the absorbance as the vertical axis. 14.5.2 Working curve
Pipette 0, 0.40, 1.00, 2.00, 3.00, 4.00, 5.00mL of molybdenum standard solution (12.9) into a set of 50mL colorimetric tubes, add water to 25mL, and then follow the steps in 14.4.3, 14.4.4 and 14.5.1.2. 15 Calculation and expression of analysis results
Calculate the percentage of molybdenum according to the following formula:
Mo(%)=mVc×10-6
Where: ml—the amount of molybdenum found from the working curve, μg; V. Total volume of test solution, mL;
V,—volume of test solution taken, mL;
16 Allowable difference
—mass of the sample·8.
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 4. 500
Additional Notes:
Molybdenum Content
0. 0003~-0. 0005
>0. 0005~ 0. 0015
>0.0015~0.0070
>0. 0070~0. 0140
>0.0140~0.0250
>0. 025~0. 045
>0.045~0.100
GB/T15076.5—94
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 drafter of this standard is Wu Xinyou.
Allowance
From the date of implementation of this standard, the former Ministry of Metallurgical Industry of the People's Republic of China issued the Ministry of Standard YB942 (4) - 78 Determination of molybdenum and tungsten in sawdust (dithiol absorption photometry)" shall be invalid.2 Place the crucible in a 200mL beaker, add 40mL boiling water and heat to dissolve the frit, wash out the crucible with water, heat to a slight boil, remove and add magnesium sulfate solution (12.7) according to Table 3 while hot and stirring, and cool. Transfer to a 100mL volumetric flask, dilute to scale with water, mix, and dry filter with double-layer filter paper into a dry small beaker. Transfer 25.00mL of filtrate to a 50mL colorimetric tube. 14.4.3 Add 8mL sulfuric acid (12.3), 2mL copper sulfate solution (12.4), and 2mL thiourea solution (12.5) to the colorimetric tube and mix them in turn. Let stand for 10min, add 2mL potassium thiocyanate solution (12.6), mix, and let stand for 30min. Add 8mL ethyl acetate (12.2) and shake for 1min. Let stand to separate.
14.4.4 Use a dry pipette to transfer part of the organic phase to the corresponding absorption dish (14.2) according to Table 3, and measure the absorbance at a wavelength of 460nm on a spectrophotometer with ethyl acetate as a reference.
14.4.5 Subtract the absorbance of the blank solution accompanying the sample. Find the amount of molybdenum from the corresponding working curve according to Table 1. 14.5 Drawing of working curve
14.5.1 Working curve I
14.5.1.1 Transfer 0, 0.10, 0.20, 0.60, 1.00, 1.40mL of molybdenum standard solution (12.9) to a 50mL colorimetric tube, add water to 25mL, and proceed as in 14.4.3 and 14.4.4. 14.5.1.2 Subtract the absorbance of the reagent blank, and draw the working curve with the amount of molybdenum as the horizontal axis and the absorbance as the vertical axis. 14.5.2 Working curve
Pipette 0, 0.40, 1.00, 2.00, 3.00, 4.00, 5.00mL of molybdenum standard solution (12.9) into a set of 50mL colorimetric tubes, add water to 25mL, and then follow the steps in 14.4.3, 14.4.4 and 14.5.1.2. 15 Calculation and expression of analysis results
Calculate the percentage of molybdenum according to the following formula:
Mo(%)=mVc×10-6
Where: ml—the amount of molybdenum found from the working curve, μg; V. Total volume of test solution, mL;
V,—volume of test solution taken, mL;
16 Allowable difference
—mass of the sample·8.
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 4. 500
Additional Notes:
Molybdenum Content
0. 0003~-0. 0005
>0. 0005~ 0. 0015
>0.0015~0.0070
>0. 0070~0. 0140
>0.0140~0.0250
>0. 025~0. 045
>0.045~0.100
GB/T15076.5—94
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 drafter of this standard is Wu Xinyou.
Allowance
From the date of implementation of this standard, the former Ministry of Metallurgical Industry of the People's Republic of China issued the Ministry of Standard YB942 (4) - 78 Determination of molybdenum and tungsten in sawdust (dithiol absorption photometry)" shall be invalid.2 Place the crucible in a 200mL beaker, add 40mL boiling water and heat to dissolve the frit, wash out the crucible with water, heat to a slight boil, remove and add magnesium sulfate solution (12.7) according to Table 3 while hot and stirring, and cool. Transfer to a 100mL volumetric flask, dilute to scale with water, mix, and dry filter with double-layer filter paper into a dry small beaker. Transfer 25.00mL of filtrate to a 50mL colorimetric tube. 14.4.3 Add 8mL sulfuric acid (12.3), 2mL copper sulfate solution (12.4), and 2mL thiourea solution (12.5) to the colorimetric tube and mix them in turn. Let stand for 10min, add 2mL potassium thiocyanate solution (12.6), mix, and let stand for 30min. Add 8mL ethyl acetate (12.2) and shake for 1min. Let stand to separate.
14.4.4 Use a dry pipette to transfer part of the organic phase to the corresponding absorption dish (14.2) according to Table 3, and measure the absorbance at a wavelength of 460nm on a spectrophotometer with ethyl acetate as a reference.
14.4.5 Subtract the absorbance of the blank solution accompanying the sample. Find the amount of molybdenum from the corresponding working curve according to Table 1. 14.5 Drawing of working curve
14.5.1 Working curve I
14.5.1.1 Transfer 0, 0.10, 0.20, 0.60, 1.00, 1.40mL of molybdenum standard solution (12.9) to a 50mL colorimetric tube, add water to 25mL, and proceed as in 14.4.3 and 14.4.4. 14.5.1.2 Subtract the absorbance of the reagent blank, and draw the working curve with the amount of molybdenum as the horizontal axis and the absorbance as the vertical axis. 14.5.2 Working curve
Pipette 0, 0.40, 1.00, 2.00, 3.00, 4.00, 5.00mL of molybdenum standard solution (12.9) into a set of 50mL colorimetric tubes, add water to 25mL, and then follow the steps in 14.4.3, 14.4.4 and 14.5.1.2. 15 Calculation and expression of analysis results
Calculate the percentage of molybdenum according to the following formula:
Mo(%)=mVc×10-6
Where: ml—the amount of molybdenum found from the working curve, μg; V. Total volume of test solution, mL;
V,—volume of test solution taken, mL;
16 Allowable difference
—mass of the sample·8.
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 4. 500
Additional Notes:
Molybdenum Content
0. 0003~-0. 0005
>0. 0005~ 0. 0015
>0.0015~0.0070
>0. 0070~0. 0140
>0.0140~0.0250
>0. 025~0. 045
>0.045~0.100
GB/T15076.5—94
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 drafter of this standard is Wu Xinyou.
Allowance
From the date of implementation of this standard, the former Ministry of Metallurgical Industry of the People's Republic of China issued the Ministry of Standard YB942 (4) - 78 Determination of molybdenum and tungsten in sawdust (dithiol absorption photometry)" shall be invalid.
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