Methods for chemical analysis of iron, steel and alloy - The sodium (potassium) periodate photometric method for the determination of manganese content
Methods for Chemical Analysis of Iron, Steel and Alloy
The Sodium (Potassium) Periodate Photometric Method for the Determination of Manganese Content
钢铁及合金化学分析方法
高碘酸钠(钾)光度法测定锰量
This standard is applicable to the determination of the manganese content in pig iron, iron powder, carbon steel, alloy steel, high temperature alloy and the precision alloy. The determination scope: 0.010%~2.00%.
This standard complies with GB 1467-78 "General Rules and Regulations of the Chemical Analysis Methods for Products of Metallurgical Industries".
This standard complies with GB 7729-87 "Chemical Analysis of Metallurgical Products-General Rule for Spectrophotometric Methods".
1 Method Summary
After the dissolution of the sample by acid, in the medium of the sulfuric acid and phosphoric acid, the manganese is oxidized into septivalency with sodium periodate (kalium) and then measure its absorbance.
2 Reagent
2.1 Hydrofluoric acid (ρ 1.15g/ml).
2.2 Hydrochloric acid (ρ 1.19g/ml).
2.3 Nitric acid (ρ 1.42g/ml).
2.4 Nitric acid(1+4).
2.5 Nitric acid(2+98).
2.6 Sulfuric acid (1+1).
2.7 Phosphoric acid-perchloric acid mixed acid: is mixed with three portions of phosphoric acid and a portion of perchloric acid.
2.8 Sodium periodate(kalium)solution (5%):weigh 5g of sodium periodate (kalium), place it in the 250 beaker, add 60ml of water and 20ml of nitric acid (2.3), tepefy them into solution and cool them. Dilute with water into 100ml and mix them uniformly.
2.9 Sodium nitrite solution (1%).
2.10 Manganese standard solution
2.10.1 Weigh 1.4383g of standard potassium permanganate, place it in the 600ml beaker, add 300ml water for solution, then add 10ml of sulfuric acid (2.6), drop hydogen peroxide (ρ 1.10g/ml ) until red disappears just right, then heal to boil for 5~10min, cool it. Move it in the 1 000mL volumetric flasks and dilute it with water to the scale and mix uniformly. Every 1ml solution contains 500μg manganese.
Alternatively, Weigh 0.5000g of electrolytic manganese (over 99.9%)[the electrolytic manganese need be cleaned in the sulfuric acid (5+95) in advance, take it out after no manganese oxide on the surface, then immediately clean it repeatedly with distilled water, wash for 4~5 times in absolute alcohol, take it out and place in the drying apparatus, use it until it is dried.], place it in 250 ml beaker, add 20ml of nitric acid (1+3), heat and boil to drive all nitrogen oxides, cool until room temperature, move into 1 000mL volumetric flask and dilute it with water to the scale and mix uniformly. Every 1ml solution contains 500μg manganese.
2.10.2 Shift 20.00ml of manganese standard solution (2.10.1), place it in the 100mL volumetric flask and dilute it with water to the scale and mix uniformly. Every 1ml solution contains 500μg manganese.
2.11 Water free of reducing substances: Heat and boil the deionized water (or distilled water). Acidize it with 10 mL of sulfuric acid (1+3) each litre, add some sodium periodate (kalium), boil it for some minutes, use it after cooling.
3 Analysis Procedures
3.1 Sample quantity
Weigh sample according to Table1.
Table 1
Content range, % 0.01~0.1 0.1~0.5 0.5~1.0 1.0~2.0
Specimen quantity, g 0.500 0 0.200 0 0.200 0 0.100 0
Manganese standard solution concentration, μg/ml 100 100 500 500
Shift manganese standard solution volume, ml 0.50
2.00
3.00
4.00
5.00 2.00
4.00
6.00
8.00
10.00 2.00
2.50
3.00
3.50
4.00 2.00
2.50
3.00
3.50
4.00
Absorption vessel, cm 3 2 1 1
3.2 Determination
3.2.1 Place sample (3.1) in 150ml conical flask, add 15ml nitric acid (2.4) [add 3~4 drip of hydrofluoric acid (2.1) on high silicon sample; dissolve pig iron sample with nitric acid (1+4), add 3~4 drip of hydrofluoric acid (2.1), cool it after dissolution, filter it with fast filter paper on another 150ml conical flask, clean the formal conical flask and filter paper with heating nitric acid (2.5) for four times; dissolve High Nickel-Chrome with proper proportion of hydrochloric acid (2.2) and nitric acid (2.3); as for the solution containing high wolfram (over 5%) or indissolvable sample, add 15ml of phosphoric acid-perchloric acid mixed acid (2.7)], dissolve it by low temperature heating.
3.2.2 Add 10 ml of phosphoric acid-perchloric acid mixed acid (2.7)[if sample containing high wolfram is dissolved by 15ml phosphoric acid-perchloric acid mixed acid (2.7), no need add again], heat it and evaporate it until perchloric acid emits (samples containing high chromium need oxidize chromium), cool a while, add 10ml of sulfuric acid (2.6), dilute with water to about 40ml.
3.2.3 Add 10ml of sodium periodate (kalium) solution (2.8), heat it until boiling and keep for 2~3min (prevent spilling of the test solution), cool until room temperature, move into 100mL volumetric flask, dilute it to the scale with water free of reducing substances, mix uniformly.
3.2.4 According to those specified in Table 1, move partial colour rendering solution into absorption vessel, drop sodium nitrite solution (2.9) shakingly to the left colour rendering solution until claret fades exactly [if reddish color of cobalt in sample containing cobalt doesn't fade with sodium nitrite solution for fading, the following method may be used: shake continuously the volumetric flask, drop slowly sodium nitrite solution (2.9), if reddish color has no change, put the test solution into the absorption vessel, measure its absorbance, add again sodium nitrite solution (2.9) into the left solution, remeasure absorbance until no change in both absorbances, this solution may be used as reference solution], move this solution into another absorption vessel for reference and measure its absorbance at 530nm wave length of spectrophotometer.
3.2.5 According to measured absorbance, look up corresponding manganese content in the working curve.
3.3 Drawing of working curve
According to those specified in Table 1, shift manganese standard solution to place them respectively into 150 ml conical flask. Follow those specified in 3.2.2~3.2.4 to have the following procedure and measure their absorbance. Draw the calibration curve taking the manganese content as the lateral coordinate and the absorbance as the longitudinal coordinate.
4 Calculation (Expression) of Analytic Result
Percentage content of manganese is calculated according to the following formula:
Where:
m1——Manganese content got from working curve, g;
m0——Sample quantity, g.
5 Precision
The precision specified in this standard refers to the repeatability r and reproducibility R got by from statistic analysis of data collected from the tests for seven identical uniform samples distributed in this determination scope of this method by ten labs and with this methods in 1987, according to GB 6379-86 "Precision of Test Methods; Determination of Repeatability and Reproducibility for a Standard Test Method by Interlaboratory Tests" (See Table 2).
Table 2
Probability,%(m/m) Repeatability r Reproducibility R
0.010~2.00 lg r=-1.756 1+0.611 4 lg m lg R=-1.571 9+0.540 4 lg m
Repeatability is the maximum difference value between the two independent tests results with 95% Probability which is acquired by making two tests for the identical sample with the identical instrument by the identical operator in the identical lab in the short term under normal and correct operation of this method.
Reproducibility is the maximum difference value between the two independent tests results with 95% Probability which is acquired by making two tests for the identical sample by two operators in the different labs under normal and correct operation of this method.
If the difference between the two independent tests exceeds the corresponding repeatability and reproducibility value, the two results are regarded as doubtful.
Appendix A
Source Data Common Precision Test
(Additional)
Horizontal
Laboratory 1 2 3 4 5 6 7
1 0.011
0.011
0.011 0.105
0.107
0.110 0.255
0.260
0.260 0.688
0.684
0.695 0.999
0.989
0.988 1.556
1.549
1.539 2.051
2.051
2.019
2 0.011
0.011
0.011 0.099
0.102
0.100 0.255
0.253
0.255 0.680
0.688
0.685 0.990
1.000
0.980 1.530
1.536
1.520 2.030
2.016
2.000
3 0.011
0.011
0.011 0.104
0.100
0.101 0.257
0.253
0.258 0.676
0.678
0.682 0.981
0.982
0.989 1.503
1.508
1.516 2.011
2.019
2.015
4 0.013
0.013
0.013 0.102
0.101
0.102 0.262
0.265
0.262 0.702
0.700
0.706 1.000
1.010
0.995 1.524
1.534
1.534 2.024
2.024
2.007
5 0.011
0.011
0.012 0.102
0.104
0.104 0.260
0.255
0.260 0.713
0.688
0.713 1.019
1.013
0.988 1.535
1.500
1.550 2.030
2.025
2.025
6 0.010
0.010
0.010 0.100
0.100
0.100 0.260
0.260
0.265 0.675
0.687
0.685 1.000
1.000
1.000 1.515
1.535
1.517 2.030
2.028
2.033
7 0.012
0.011
0.011 0.103
0.105
0.103 0.260
0.259
0.260 0.699
0.692
0.692 0.990
0.980
0.990 1.534
1.534
1.534 2.018
2.018
2.005
8 0.012
0.013
0.012 0.100
0.099
0.100 0.254
0.255
0.256 0.688
0.686
0.685 0.998
0.990
0.992 1.548
1.531
1.537 2.028
2.028
2.025
9 0.012
0.012
0.012 0.104
0.106
0.105 0.272
0.262
0.260 0.690
0.690
0.690 1.000
0.990
0.995 1.518
1.513
1.515 2.020
2.006
2.011
10 0.012
0.011
0.011 0.099
0.102
0.100 0.253
0.255
0.255 0.564
0.680
0.678 1.000
1.000
0.980 1.530
1.525
1.520 2.050
2.030
2.040
Additional Explanation:
This standard is under the jurisdiction of Technology Department of Central Iron and Steel Research Institute, Ministry of Metallurgical Industry.
This standard was drafted by Central Iron and Steel Research Institute, Ministry of Metallurgical Industry.
This standard was drafted by Central Iron and Steel Research Institute, Ministry of Metallurgical Industry and Jiang Xi Steel Mill.
Chief drafting staff of this standard is Ke Ruihua.
The grade mark of this standard is GB 223.63-88Y .
