GB/T 24890-2010Determination of chloride content for compound fertilizers (English PDF)

4.1

dibutyl phthalate;

4.2 nitric acid solution

11;

4.3

silver nitrate solution [c (AgNO3) = 0.05mol/L]. Weigh 8.7g of silver nitrate, dissolved in water and diluted to 1000mL, storage

In a brown bottle;

4.4 Chloride standard solution (1mg/mL)

Weigh accurately 1.6487g by 270 °C ~ 300 °C drying to constant reference mass chlorination

Sodium in a beaker, dissolved in water and transferred to 1000mL volumetric flask, dilute to volume, mix and store in a plastic bottle. This solution containing 1mL

1mg chloride (of Cl-);

4.5 ferric ammonium sulfate indicator solution (80g/L)

dissolve 8.0g of ammonium ferric sulfate in 75mL of water, filtered, add a few drops of sulfuric acid, so that the disappearance of brown, thin

Diluted to 100mL;

4.6

ammonium thiocyanate standard titration solution [c (NH4SCN) = 0.05mol/L]. weigh 3.8g ammonium thiocyanate is dissolved in water and diluted to

1000mL.

Calibration methods are as follows. Imbibe 25.0mL standard solution of chloride in 250mL conical flask, 5mL nitric acid solution and

25.0mL silver nitrate solution, shaken to precipitate stratification, dibutyl phthalate was added 5mL, shaking moment. Water was added, the solution overall

Area of about 100mL, was added 2mL ferric ammonium sulfate indicator solution, titration with ammonium thiocyanate standard solution of silver nitrate titration remaining, to appear light orange

Red or pale brick red so far. At the same time a blank test.

Ammonium thiocyanate standard titration solution concentration c (mol/L) according to equation (1).

c = m10.03545 × (V0-V1) (1)

Where.

Value V0 --- blank test (25.0mL silver nitrate solution) volume of ammonium thiocyanate standard titration solution consumed, in units of milli

L (mL of);

GB 18382-2021 | GB/T 22923-2008 | GB/T 22924-2008 | GB/T 47386-2026 | GB/T 19203-2026 | GB/T 24891-2010 | […]