GB/T 3253.4-2009Methods for chemical analysis of antimony and antimony trioxide - Determination of sulfur content in antimony - Burning and sodium hydroxide titration method (English PDF)

3.1

potassium hydroxide.

3.2

anhydrous calcium chloride.

3.3

Absorption of hydrogen peroxide solution (98 + 2).

3.4 methyl red - methylene blue mixed indicator

20 unit volume of methyl red ethanol solution (0.3g/L) and 3 per unit volume of methylene blue solution (1g/L) and mixed.

3.5

sodium hydroxide standard titration solution.

3.5.1 preparation

Weigh 0.2g sodium hydroxide, placed 250mL beaker, cooled boiled water to dissolve, dilute to 1000mL, and mix. store

Plastic bottle.

3.5.2 Calibration

Weigh 5.0000g advance by 100 °C ~ 105 °C drying potassium hydrogen phthalate (reference reagent) 2h, and placed in 500mL beaker

Water, heated to boiling to dissolve the cooled clear, transferred to 1000mL volumetric flask, dilute with boiled water after cooling to the mark and mix.

1mL solution containing 0.0050g of potassium hydrogen phthalate.

Accurate Pipette 5.00mL potassium hydrogen phthalate standard solution was placed in 300mL conical flask, add 50mL boiling water after cooling,

2 drops of phenolphthalein ethanol solution (10g/L), with a drop of sodium hydroxide standard titration solution to light red is the end.

Along with the calibration blank test.

According to equation (1) to calculate the actual concentration of sodium hydroxide standard titration solution.

Ba = Vp × 0.0050 (Vp Vp 1- 0) × 0.2042 ×

100 (1)

Where.

Ba --- the actual concentration of sodium hydroxide standard titration solution, expressed in moles per liter (mol/L);

Vp --- pipetting volume of potassium hydrogen phthalate standard solution, in milliliters (mL);

Volume consumed Vp 1 --- Calibration sodium hydroxide standard titration solution, in milliliters (mL);

V0 --- when nominal volume of sodium hydroxide solution consumed in the blank standard titration solution, in milliliters (mL);

0.0050 --- concentration of potassium hydrogen phthalate standard solution, in grams per milliliter (g/mL);