GB/T 20975.7-2008 Methods for chemical analysis of aluminium and aluminium alloys - Part 7：Determination of manganese content Potassium periodate spectrophotometric method
Methods for chemical analysis of aluminium and aluminium alloys - Part 7：Determination of manganese content Potassium periodate spectrophotometric method
This part specifies the determination of manganese content of aluminium and aluminium alloys.
This part is applicable to the determination of manganese content of aluminium and aluminium alloys. Determination scope: 0.004%~1.80%.
2 Method Summary
Dissolve specimen with sodium hydroxide, acidify with sulfuric acid and nitric acid, and oxidize and develop color with potassium periodate. Measure the absorbance at wave length 525nm of spectrophotometer.
3 Reagents
3.1 Sulfuric acid (ρ1.84 g/mL).
3.2 Nitric acid (ρ1.42 g/mL).
3.3 Phosphoric acid (ρ1.69 g/mL).
3.4 Hydrofluoric acid (ρ1.14 g/mL).
3.5 Sulfuric acid (1+1).
3.6 Caustic soda solution (200g/L).
3.7 Fluoroboric acid: put 800mL saturated boric acid solution under 20℃ and 200mL hydrofluoric acid (3.4) into plastic bottle, and mix uniformly.
3.8 Potassium periodate solution (50 g/L): weight 5g potassium periodate to dissolve in water, add 20mL nitric acid (3.2), dilute to 100mL with water, and mix uniformly.
3.9 Sodium nitrite solution (20 g/L).
3.10 Sodium sulfite solution (10g/L): dissolve 1g sodium sulfite in 100mL sulfuric acid (1 +20), and mix uniformly.
3.11 Water without reducer: add 10mL sulfuric acid (3.5) in one liter water to acidify and boil, add little potassium periodate, continue to boil about 10min for standby after cooling.
3.12 Standard manganese storage solution: weight 1.000g manganese into beaker, add 20mL sulfuric acid (3.5) and about 80mL water, boil 3min after dissolution, and then cool. Move into to 1000mL volumetric flask, dilute with water to scale, and mix uniformly. 1mL this solution contains 1mg manganese.
3.13 Standard manganese solution: move 50.00mL standard manganese storage solution (3.12) into 1000mL volumetric flask, dilute with water to scale, and mix uniformly. 1mL this solution contains 0.05mg manganese.
