Manganese metal ferromanganese-silicon ferromanganese and nitrogen-bearing ferromanganese—Determination of iron content—The ortho-phenanthrdine spectrophotometric method and the titanium trichloride-potassium dichromate titrimetric method
Manganese metal, ferromanganese-silicon, ferromanganese and nitrogen-bearing ferromanganese—Determination of iron content—The ortho-phenanthrdine spectrophotometric method and the titanium trichloride- potassium dichromate titrimetric method
WARNING——Persons using this document shall be familiar with normal laboratory practice. This part does not address all potential safety problems. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions.
1 Scope
This part of GB/T 8654 specifies the determination of iron content in manganese metal, ferromanganese-silicon, ferromanganese and nitrogen-bearing ferromanganese using the ortho-phenanthrdine spectrophotometric method and the titanium trichloride-potassium dichromate titrimetric method.
This part is applicable to the determination of iron content in manganese metal, ferromanganese-silicon, ferromanganese and nitrogen-bearing ferromanganese. The ortho- phenanthrdine spectrophotometric method is suitable for the determination of iron content in manganese metal, with a measurement range (mass fraction) of 0.001% to 1.00%; the titanium trichloride-potassium dichromate titrimetric method is suitable for the determination of iron content in manganese metal, ferromanganese-silicon, ferromanganese and nitrogen-bearing ferromanganese, with a measurement range (mass fraction) of 1.00% to 35.00%.
2 Normative references
The following standards contain provisions which, through reference in this part of GB/T 8654, constitute provisions of this part. For dated references, subsequent amendments (excluding corrections) to, or revisions of, any of these publications do not apply. However, all parties coming to an agreement according to this part are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document applies.
GB/T 4010 Ferroallys sampling and preparation of samples for chemical analysis
3 Method I: Ortho-phenanthrdine spectrophotometric method
3.1 Principle
Decompose the sample by hydrochloric acid, then adjust the pH value by adding hydroxylamine hydrochloride, and add the phenanthroline solution to color the iron, then measure the absorbance at 517 nm wavelength of spectrophotometer.
3.2 Reagents and materials
Unless otherwise stated, only the recognized analytical reagents and distilled water or deionized water or water with equivalent purity shall be used during the analysis.
3.2.1 Hydrochloric acid, 1+1.
3.2.2 Hydrochloric acid, 1+50.
3.2.3 Ammonium acetate solution, 500 g/L.
3.2.4 Hydroxylamine hydrochloride solution, 100 g/L.
3.2.5 Ortho-phenanthrdine solution: weigh 0.36g of ortho-phenanthroline hydrochloride (C12H8N2HCl·H2O), and dissolve it in 100 mL of water.
3.2.6 Iron standard solution
3.2.6.1 Weigh 0.5000g of super pure iron powder, with the purity not less than 99.9%, place it into a 300 mL beaker, and add 30 mL of hydrochloric acid (3.2.1); heat it to dissolve, then cool and transfer it to a 500 mL volumetric flask, dilute it to the scale with water and mix well. The iron content of the solution is 1.0 mg/mL.
3.2.6.2 Pipette 25.00 mL of the iron standard stock solution (3.2.6.1) into a 1,000 mL volumetric flask, add 20 mL of hydrochloric acid (3.2.1), dilute it to the scale with water and mix well. The iron content of the solution is 25 μg/mL.
3.3 Apparatus
General laboratory apparatus shall be used in the analysis.
3.4 Collection and preparation of samples
Carry out sampling and preparation of samples in accordance with GB/T 4010. The specimen shall pass through a sieve with an aperture of 0.149 mm.
3.5 Analytical procedure
3.5.1 Mass of samples
Weigh the specimen according to Table 1, accurate to 0.0001g.
