Methods for chemical analysis of iron,steel and alloy; The pulse heating inert gas fusion-coulometric titration method for the determination of oxygen content
Methods for chemical analysis of iron, steel and alloy - The pulse heating inert gas fusion - Coulometric titration method for the determination of oxygen content
This standard is applicable to the determination of oxygen content in iron and steel. Determination range: 0.002~0.10%.
This standard complies with GB 1467-78 Method for chemical analysis of metallurgy product - General rules and regulations.
It is not applicable to the determination of oxygen content in powder, powder metallurgy products and iron and steel with manganese or aluminum content exceeding 1%.
1 Method summary
The specimen is placed and melted in a graphite crucible which is directly heated by a low-voltage alternating current in an argon flow at about 2,500℃. Oxygen in the specimen is precipitated as carbon monoxide, and converted into carbon dioxide by copper oxide. The carbon dioxide is absorbed by the barium perchlorate solution with a pH value of about 9.5 to reduce the pH value. The required equivalent amount of alkali is produced by electrolysis to restore the pH value of the solution to the original given value. The oxygen content is calculated using pulse counts of electricity consumed by electrolysis.
2 Reagents and materials
2.1 Argon: with a purity greater than 99.99%.
2.2 Copper oxide in wire form.
2.3 Active copper, prepared by reducing copper oxide (2.2) with hydrogen at 580℃.
2.4 Caustic asbestos.
2.5 Magnesium perchlorate [MgClO4] or phosphorus pentoxide.
2.6 Carbon tetrachloride.
2.7 Acetone.
2.8 Glass wool.
2.9 Cathode cell (main cup) solution: Dissolve 100g of barium perchlorate [Ba(ClO4)2·3H2O] in 2,000ml of water, add 60ml of isopropanol, mix well, and store the solution in a ground bottle for later use.
2.10 Anode cell (supplementary cup) solution: Dissolve 100g of barium perchlorate [Ba(ClO4)2·3H2O] in 500ml of water, and store the solution in a ground bottle for later use.
2.11 Reference electrode cell (small cup) solution: Dissolve 5g of barium perchlorate [Ba(ClO4)2·3H2O] and 3g of sodium chloride in 100ml of water completely, then add a few drops of 5% silver nitrate solution, heat the mixed solution to 60 ~ 70℃, cool, mix well, and store it in a ground bottle for later use.
1 Method summary
2 Reagents and materials
3 Apparatus
4 Specimen
5 Analytical procedures
6 Calculation of analytical result
7 Tolerance
Additional explanation
