GB/T 14949.10-1994 Chemical analysis methods for manganese ores - Determination of cobalt content
Some standard content:
National Standard of the People's Republic of China
Chemical analysis method of manganese ore
Determination of cobalt content
Manganese ores- Determination of cobalt contentGB/T14949.10--94
Replace GB151779
This standard is equivalent to the international standard IS03161982 "Manganese ore-Determination of cobalt content---nitroso R salt photometric method" 1 Subject content and scope of application
This standard specifies the determination of cobalt content by nitroso R salt photometric method. This standard is applicable to the determination of cobalt content in manganese ore and manganese concentrate. Determination range: 0.0050%~～0.100% 2 Method summary
In acetate solution, trivalent cobalt reacts with nitroso R salt to form a red complex, and the solution turns red. Add nitric acid to boil the solution to eliminate the interference of interfering elements (iron, copper, nickel), and perform photometric determination on a spectrophotometer at a wavelength of 520nm. 3 Reagents
3.1 Anhydrous sodium carbonate.
3.2 Hydrochloric acid (pl.19g/mL).
3.3 Hydrochloric acid (1+1).
3.4 Nitric acid (pl.42g/mL),
3.5 Sulfuric acid (1+1).
3.6 Hydrofluoric acid 40% (m/m)
3.7 Nitrogen water (1+1).
3.8 Manganese solution (20mg/1mL): Weigh 55.0g anhydrous manganese sulfate, add 10ml sulfuric acid (3.5) and 200~300ml. water to dissolve, cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with water, and mix well. 3.9 Iron solution (20mg/1mL): Weigh 2.86g of ferric oxide (high purity). Dissolve it with 30ml of hydrochloric acid (3.3), cool it and transfer it to a 100ml volumetric flask, dilute it to the mark with water, and mix it. 3.10 Sodium acetate solution (500g/L) (NaC,H.0:·3H:0): If there is a precipitate, it can be filtered out. 3.11 Nitroso R salt solution (10g/L): Weigh 10g of nitroso R salt (CuH,NOgS,Na), dissolve it with water, transfer it to a 1000ml volumetric flask, dilute it to the mark with water, and mix it. 3.12 Cobalt standard stock solution: Weigh 1.0000g of cobalt metal (99.9%) that has been pre-washed with nitric acid (1+3) (to remove surface oxides), then washed with anhydrous ethanol, and dried in a 250ml beaker. Dissolve it with 50ml hydrochloric acid (1+4) and a small amount of nitric acid (3.4). Boil the solution until the nitrogen oxides disappear, and then cool it. Transfer it to a 1000ml volumetric flask, dilute it with water to the mark and mix it well. This solution contains 0.0010 g of cobalt in 1mL.
3.13 Cobalt standard solution: Transfer 100.00mL of cobalt standard stock solution (3.12) to a 1000ml volumetric flask, add 10mL of hydrochloric acid (3.3), dilute it with water to the mark, and mix it well. This solution contains 100μg of cobalt in 1mL. Approved by the State Administration of Technical Supervision on January 18, 1994, implementation of 1994-1001
4 Instruments and equipment
Common laboratory instruments and
4.1 Platinum glass.
GB/T14949.10-94
4.2 Alcohol burner or muffle furnace, which can control the temperature within the range of 900~~1000℃4.3 Spectrophotometer: absorbance can reach 1.500.5 Sample
The sample should pass through a 0.100 mesh and be ventilated under laboratory conditions. 6 Analysis steps
6.1 Sample quantity
Weigh 0.95~1.05g of sample, accurate to 0.0001g. At the same time as the measurement, weigh the sample to determine the mass percentage of wet water (A). When calculating the amount of cobalt, the result (mass percentage) should be multiplied by the conversion factor K, which is the mass percentage of the cobalt measured in the completely dry sample. Conversion factor = 100~A
6.2 Blank test
Perform a blank test with the sample.
6.3 Determination
6.3.1 Place the sample (6.1) in a 100mL beaker, add a few drops of water to moisten it, add 15mL of hydrochloric acid (3.2), cover with table IIIL, and heat at low temperature to decompose for 15~20min. Add 3~5mL of nitric acid (3.4), continue heating, and evaporate to nearly zero. Add 5mL of hydrochloric acid and heat for 1~2min to remove nitric acid. Blow water to wash table III and the wall of the beaker, and dilute to 15~~20mL, heat to boiling, and dissolve the soluble salts. 6.3.2 Filter with filter paper, wipe the precipitated particles on the wall of the beaker with a glass rod with a piece of filter paper, transfer all of them to the filter paper, and wash the beaker, filter paper and residue with hot water 7 to 8 times. Collect the filtrate in a 250mL beaker and keep the filtrate. 6.3.3 Transfer the filter paper with residue (6.3.2) to a platinum crucible for drying, ash, and burn at 700~750C until the filter paper is completely ash. Cool the volute, add a few drops of water to moisten the residue, and add 5~7 drops of sulfuric acid (3.5) and 5~7mL hydrofluoric acid (3.6), and slowly heat until white smoke just appears. Cool slightly, add 2~3ml. Hydrofluoric acid (3.6), continue heating until all white smoke is emitted, and cool. 6.3.4 The residue is slightly burned at 500-600°C, cooled, and 2-3 g of sodium carbonate (3.1) is added, mixed, and melted at 900-1000°C for 15-20 min. The melt is leached with 40 mL of hydrochloric acid (3.3). The solution is evaporated until the salts are precipitated to remove all carbon dioxide, and then combined with the filtrate (6.3.2). The volume of the evaporated and combined solution is about 50 mL. Cool, transfer to a 100 mL volumetric flask, dilute to the mark with water, and mix. 6.3.5 When there is an insoluble precipitate (sulfate of lead or barium), the solution should be filtered with slow filter paper before the solution is separated. 6.3.6 Take 25.00 ml of the solution (6.3.4) in a 100 mL beaker, adjust the solution with ammonia water (3.7) until hydroxide precipitation occurs, and then immediately add hydrochloric acid (3.3) dropwise until the precipitate is just dissolved. 6.3.7 Add 5 ml of sodium acetate solution (3.10) and 3.0 ml of nitroso salt solution (3.11) to the solution (6.3.6) and shake the spoon. Heat to boiling, shake the solution from time to time, and keep it at a slight boiling state for 8 to 10 minutes. At this time, the volume of the solution should not be less than 25 ml. While shaking continuously, add 6 to 7 ml of nitric acid (3.4) to the heat, boil for 1 to 2 minutes, cool the solution, transfer it to a 50 ml volumetric flask, dilute it to the mark with water, and mix it well. 6.3.8 Transfer the colored solution (6.3.7) to a 1 cm or 3 cm absorption dish. When the cobalt content is greater than 0.03%, use a 1 cm absorption dish. When the cobalt content is less than 0.03%, use a 3 cm absorption dish. Using water as a reference, measure the absorbance of the solution at a wavelength of 520 nm on a spectrophotometer, subtract the absorbance of the test blank solution, and find the corresponding cobalt content from the working curve. 6.4 Drawing of working curveWww.bzxZ.net
Pipette 0, 1.00, 2.00, 4.00, 6.00, 8.00, 10.00 mL of cobalt standard solution (3.13) into 7 100 mL beakers, add 16 mL of manganese solution (3.8), 4 mL of iron solution (3.9) and 15 mL of hydrochloric acid (3.2) to each beaker, and proceed as in 6.3.1 to 6.3.8. 85.1
GB/T 14949.10-94
Subtract the absorbance of the reagent blank solution from the measured absorbance. Draw a curve with the amount of cobalt as the horizontal axis and the absorbance as the vertical axis. 6.4.1 Select 1cm absorption III for measurement according to 6.4 and draw a working curve. 6.4.2 Take 10ml of solution according to 6.3.6 (addition of manganese, iron solution or no addition of manganese, iron solution will not affect the curve) and dilute it to 25ml with water. Perform the operation according to 6.3.6~6.3.8, select 3cm absorption blood for measurement, and draw a T curve. 7 Calculation of analysis results
Calculate the percentage of cobalt according to the following formula:
Co(%) - m, y
X 100 XK
formula,
the amount of drilling obtained from the working curve, g;
the total volume of the test solution, mL;
the volume of the test solution taken, mL;
m——the mass of the sample, g;
——the conversion factor of the drilling amount in the completely dry sample. 8 Precision
The precision listed in this standard is sufficient. In 1990, 8 laboratories conducted tests on 4 uniformly distributed samples within the measurement range of this method according to the analysis steps of this standard. After summarizing the data and following the national standard (GI36379, the repeatability and reproducibility R are shown in Table 1. The original data are shown in Appendix A (Supplement). Table 1
Level, % (m/m)
0. 007 7-~0. 102
Repeatability,
-2.382+0.333 4 igm
Reproducibility
igR=--1.845+0.5455lgm
Repeatability is the maximum difference between two independent test results at the 95% probability level, when the method is used under normal and correct operation conditions, by the same operator, in the same laboratory, using the same instrument, and in a short period of time, on the same sample. Reproducibility is the maximum difference between two independent test results at the 95% probability level, when the method is used under normal and correct operation conditions, by two operators, in different laboratories, on the same sample, on each single test result. The maximum difference between two independent test results at the 95% probability level. If the difference between two independent test results exceeds the corresponding repeatability and reproducibility values, the two results are considered to be suspicious. S.
Additional Notes:
GB/T14949.10--94
Appendix A
Original Data of Precision Test
(Supplement)
Original Data
This standard is proposed by the Ministry of Metallurgical Industry of the People's Republic of China Co·3
t0. 101 4
9. 101 0)
In this standard, the Mineral Geology Research Institute of China Nonferrous Metals Industry Corporation and the Changsha Mineral Geology Research Institute of Metallurgical Industry are responsible for drafting. This standard is drafted by the Mineral Geology Research Institute of China Nonferrous Metals Industry Corporation. The main drafters of this standard are Zhang Jinian, Wu Shuangfeng, Shu Baichong and Wang Yijun. 8
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