GB/T 21994.4-2008Chemical analysis of magnesium fluoride - Part 4: Determination of magnesium - EDTA volumetric method (English PDF)

4.1

Hydrofluoric acid (40%).

4.2

sulfate (1 + 1).

4.3

hydrochloride (3mol/L).

4.4

methyl orange indicator (1g/L).

Ammonia 4.5 (1 + 1).

4.6 ammonium chloride washing solution

Weigh 1g of ammonium chloride dissolved in 500mL of water, add 2 drops of methyl orange indicator, with ammonia (1 + 1) and

Adjusted hydrochloric acid (3mol/L) just yellow, and 2 drops of excess.

4.7

nitric acid (1 + 1).

Triethanolamine 4.8 (1 + 2).

4.9 ammonia buffer solution (pH = 10)

Weigh 67.5g of ammonium chloride was dissolved in 200mL of water, 510mL of concentrated aqueous ammonia was added, diluted to

1000mL, mix, sealed.

4.10 calcium indicator

Weigh 1g and 10g anhydrous sodium sulfate and calcium indicator put an agate mortar and grind evenly, put the dryer saved.

4.11 Magnesium indicator

Weigh acid chrome blue K0.1144g, naphthol green B0.2856g, was dissolved in 100mL of water, stored in a brown bottle spare.

4.12 xylenol orange indicator (1g/L)

Weigh 0.1000g xylenol orange indicator directly dissolved in 100mL of water, stored in a

150mL brown dropper bottle aside.

4.13

HCl (1 + 1).

4.14

of potassium hydroxide.

4.15

potassium hydroxide solution (200g/L).

4.16

acetic acid - sodium acetate buffer solution pH = (5.5 ~ 6). Weigh 120.5g anhydrous sodium acetate is dissolved in water, was added 10mL of glacial acetic

Dilute acid, add water to 1000mL, mixing spare.

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