Methods for chemical analysis of iron,steel and alloy; The sodium arsenite-sodium nitrite titrimetric method for the determination of manganese content
This standard is applicable to the determination of manganese content in pig iron, carbon steel, alloy steel and iron powder. Determination scope: 0.10%~2.50%.
This standard complies with GB 1467-78 "General Rules and Regulations of the Chemical Analysis Methods for Products of Metallurgical Industries".
1 Method Summary
Dissolve the sample with sulfuric acid or phosphoric acid, use silver nitrate as the catalyst, use ammonium persulfate to oxidize manganese into septivalency and use sodium arsenite-standard sodium nitrite solution to titrate. If the cobalt content in the test solution is more than 5mg, observation for the end point will be impacted, add nickel to counteract tinctorial impact of cobalt ions.
2 Reagents
2.1 Nitric acid (ρ1.42g/ml);
2.2 Nitric acid (2+98);
2.3 Hydrochloric acid (ρ1.19g/ml);
2.4 Perchloric acid (ρ1.67g/ml);
2.5 Sulfuric acid (ρ1.84g/ml);
2.6 Sulfuric acid (2+3);
2.7 Hydrofluoric acid(ρ1.15g/ml);
2.8 Ammonium hydroxide (ρ0.90g/ml);
2.9 Mixed acid of sulfuric acid and phosphoric acid: slowly add 150 ml sulfuric acid (2.5) and 150 ml phosphoric acid (ρ1.70g/ml) into to 700 ml water, keep agitating, and then cool it down.
2.10 Mixed acid of sulfuric acid and phosphoric acid: mix with isometric sulfuric acid (2.5), phosphoric acid (ρ1.70g/ ml) and water, and then cool it down.
2.11 Aqua regia: mix with 3 shares of hydrochloric acid (2.3) and 1 share of nitric acid (2.1).
Contents
1 Method Summary
2 Reagents
3 Analysis Procedures
4 Calculation (Expression) of Analytic Results
5 Precision
Appendix A Source Data Common Precision Test
