GB/T 23513.4-2009Chemical analysis methods for germanium concentrate - Part 4: Determination of fluoride content - ISE (English PDF)

3.1

Sodium peroxide (Na2O2).

3.2

Sodium hydroxide (NaOH).

Nitrate 3.3 (rho1.42g/mL).

3.4

absolute ethanol (CH3CH2OH).

3.5

nitric acid (1 + 1).

3.6

sodium citrate buffer solution [Ba (Na3C6H5O7 · 2H2O) = 1mol/L]. 294g sodium citrate were dissolved in 900mL of water, plus

10mL of nitric acid (3.3), add water to 1000mL, pH of about 6.5.

3.7 fluoro standard stock solution

Weigh 2.2100g advance at 105 °C excellent pure sodium sulfate 2h time, placed in a plastic cup, add water

Dissolved and transferred to 1000mL volumetric flask, immediately constant volume of water, and mix. Move quickly into dry plastic bottle preservation, this solution of fluorine

1mg/mL.

3.8

fluoro standard solution A. Pipette 20.00mL fluoro standard stock solution in 200mL volumetric flask with water to volume, and mix. Into dry

Plastic bottle, a fluorine-containing solution was 100µg/mL.

3.9 fluoro standard solution B

Pipette 10.00mL fluoro standard solution in 100mL flask with water to volume, and mix. Into dry plastic

Bottle, the solution of fluorine 10.00µg/mL.

4.1

Nickel Crucible, with cover, 30mL.

4.2

ion meter or pH, mV readings to 1/10mV.

4.3

FISE.

4.4

saturated calomel electrode.

4.5

polyethylene beaker.200mL, 50mL.

4.6

plastic flask.200mL, 100mL, 50mL.

4.7 magnetic stirrer

a stirring rod coated with polyethylene.

4.8

plastic funnel.