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1、International Standard ,NTEANAT,ONAL ORGANlZATlON FOR STANDARDIZATIONaMEYHAPOAHAR DPrAHMBALHh n0 CTAHAAPTbl3AWlM.OoRGANlSATlON INTERNATIONALE DE NORMALISATION Steel and cast iron - Determination of manganese content - Spectrophotometric method Aciers et fontes - Dosage du mangan b) for Mn contents b
2、etween 0,05 and 2 % (m/m) : m ap- proximately 1 g; c) for Mn contents greater than 2 % (m/m) : m approx- imately 0.5 g. 7.2 Determination 7.2.1 Preparation of test solution Place the test portion (7.1) in a 250 ml conical flask, add 50 ml of the sulphuric/phosphoric acid mixture (4.7) and heat gentl
3、y until effervescence ceases. When the attack is complete, oxidize with a few drops of the nitric acid (4.4) and add 20 ml of the perchloric acid (4.5). Evaporate until white perchloric acid fumes are given off and keep at this temperature for 10 min. After cooling, take up with water, dilute to 70
4、to 80 ml and boil. If necessary, filter and wash with the hot perchloric acid (4.6). Collect the filtrate in a 100 ml one-mark volumetric flask. Dilute to the mark with water and mix. This gives solution S,. NOTE - For samples that do not dissolve readily in the sulphuric/phosphoric acid mixture (4.
5、71, add also 10 ml of the hydrochloric acid (4.3) and 10 ml of the nitric acid (4.4) to facilitate the dissolution. 7.2.2 Formation of coloured compound for test portion Introduce into a 250 ml conical flask the following quantities of solution St, and reagents specified in table 1, depending on the
6、 presumed manganese content. Bring to the boil, add 10 ml of the sodium periodate solution (4.81, boil for 2 min and maintain at 90 “C for 10 min. Cool to 7.2.3 Preparation of the compensation solution Take the same volumes of solution St, water and sulphuric/phosphoric acid mixture (4.7) as for the
7、 formation of the coloured compound for the test portion (7.2.2). Add 2 or 3 drops of the hydrochloric acid (4.3) and boil for several minutes. After cooling, transfer into a 100 ml one-mark volumetric flask, dilute to the mark with water and mix. 7.2.4 Spectrophotometric measurement Carry out the s
8、pectrophotometric measurements on the test solution (7.2.2), using the spectrophotometer 15.1) at a wavelength about 545 nm, after having adjusted the in- strument to zero absorbance against the compensation solution (7.2.3). 7.2.5 Establishment of calibration curve 7.2.5.1 Preparation of reference
9、solutions 7.2.5.1.1 For manganese contents less than 0,05 % (m/m) Weigh, to the nearest 0,001 g, 2,000 g of the pure iron (4.2). Transfer into a series of six 250 ml conical flasks, add 50 ml of the sulphuric/phosphoric acid mixture (4.7) and heat gently un- til effervescence ceases. When the attack
10、 is complete, oxidize with a few drops of the nitric acid (4.4) and add 20 ml of the perchloric acid (4.5). Evaporate until white perchloric acid fumes are given off and keep at this temperature for 10 min. After cooling, take up with water, dilute to 70 to 80 ml and boil. If necessary, filter and w
11、ash with the hot perchloric acid (4.6). Collect the filtrate in a 100 ml one-mark volumetric flask. After cooling, dilute to the mark with water and mix. This gives solu- tion S2. Introduce into a series of six 250 ml conical flasks the quantities of manganese standard solution B (4.9.3) specified i
12、n table 2. Dilute the above volumes to 25 ml with water, add 40,O ml of solution S2 and 5 ml of the sulphuric/phosphoric acid mixture (4.7). Continue in accordance with sub-clause 7.2.2, beginning at “Bring to the boil.“. 7.2.5.1.2 For manganese contents between 0,05 and 4 % (m/m) Weigh, to the near
13、est 0,001 g, approximately 1 g of the pure iron (4.2). Transfer into a 250 ml conical flask, add 50 ml of the sulphuric/phosphoric acid mixture (4.7) and heat gently until effervescence ceases. When the attack is complete, oxidize with a few drops of the nitric acid (4.4) and add 20 ml of the perchl
14、oric acid (4.5). Evaporate until white perchloric acid fumes are given off and keep at this temperature for 10 min. 2 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 23:13:30 MDT
15、No reproduction or networking permitted without license from IHS -,-,- IS0 629-1982 (El After cooling, take up with water, dilute to 70 to 60 ml and boil. If necessary, filter and wash with the hot perchloric acid (4.6). Collect the filtrate in a 100 ml conical flask. After cooling, dilute to the ma
16、rk with water and mix. This gives solution Ss. reference solutions (7.2.5.1 .I and 7.2.5.1.21, using the spec- trophotometer (5.1) at a wavelength about 545 nm, after having adjusted the instrument to zero absorbance against the reference solution “0”. Introduce into a series of six 250 ml conical f
17、lasks the quantities of manganese standard solution A (4.9.2) specified in table 3. 7.2.5.3 Plotting of calibration curve or calculating of angular coefficient of the straight line Dilute the above volumes to 25 ml with water, add IO ml of solution Ss and 20 ml of the sulphuric/phosphoric acid mixtu
18、re (4.7). Continue in accordance with sub-clause 7.2.2, beginning at “Bring to the boil.“. Plot the absorbance against the known mass of manganese, in milligrams, in 100 ml of reference solution. 7.2.5.2 Spectrophotometric measurements Calculate the angular coefficient (a), the mass, in milligrams,
19、of manganese in 100 ml by absorbance per optical pathlength of 1 cm, from the slope of the calibration curve if it is a straight Carry out the spectrophotometric measurements on the line. Table 1 - Dilution guide for test solution Volume of Presumed Mn Mass of original Volume of Mass of the Volume o
20、f sulphuric/ content test portion solution S, equivalent water added phosphoric test portion acid mixture (4.7) added % h/m) 9 ml 9 ml ml Less than 0,05 2 a,0 0,80 10 5 0.05 to 0,s 1 40,o 0,40 10 5 0.10 to 1,oo 1 20.0 0.20 20 15 0,20 to 2,00 1 10,o 0,lO 25 20 0.40 to 4,00 0,5 IO,0 0,05 25 20 Table 2
21、 - Preparation guide for reference solution of manganese less than 0,05 % (m/m) Introduce 1 2 3 4 0 2.0 5.0 10,o 5 6 15,0 20,o Flask ml of standard solution B (4.9.3) containing corresponding to for a test portion of a test volume of 0 0,050 0,125 0,250 0,375 0,500 mg of manganese 29 40 ml I 0 0,008
22、 0,016 0,031 0,047 0,063 % (m/ml of manganese I Table 3 - Preparation guide for reference solution of manganese between 0,050 and 4 % (m/m) Introduce 1 2 3 4 6 6 0 2,o 5.0 10.0 15,0 20.0 Flask ml of standard solution A (4.9.2) containing 0 0.20 0,50 l,oo 1.50 2.00 mg of manganese corresponding to fo
23、r a test a test portion of volume of 40 ml 0 0,050 0,125 0,250 0,375 0,500 ISI 20 ml 0,100 0,250 0,500 0,750 1,000 % (m/m) of 10 ml i 0,200 0,500 1,000 1,500 2,ocil manganese I Or5 9 10 ml 0 0,400 1,000 2,000 3,000 4.000 3 Copyright International Organization for Standardization Provided by IHS unde
24、r license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 23:13:30 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 629-1982 (El 8 Expression of results The manganese (Mn) content, as a percentage by mass, is ob- tained in accordance wi
25、th the calibration curve or calculated from the formula Mn%(m/m)=nx$x 2!LxlxLx I()() V m 103 = a x D x 10 dx Vxm where a is the angular coefficient, in mg Mn/100 ml absorbance/cm D is the absorbance of the test solution corrected with the absorbance of its compensating solution (7.2.5.3); d is the o
26、ptical pathlength, in centimetres, used for the measurement (7.2.4 or 7.2.5.2); V is the volume, in millilitre, of the test solution used for the determination (7.2.2); m is the mass, in grams, of the test portion (7.1). 9 Test report The test report shall include the following particulars : a) the
27、method used by reference to this International Standard; b) the results, and the form in which they are expressed; c) any unusual features noted during the determination; d) any operation not specified in this International Stan- dard, or any optional operations which may have influenced the result. 4 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 23:13:30 MDTNo reproduction or networking permitted without license from IHS -,-,-
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