GB/T 8151.9-2012Methods for chemical analysis of zinc concentrates - Part 9: Determination of fluorine content - The ion selective electrode method (English PDF)

3.1

Potassium hydroxide, pure class distinctions.

3.2

nitric acid (11).

3.3 ammonium citrate solution

Weigh 243g of ammonium citrate, dissolved in about 700mL of water with nitric acid (3.2) adjusted to pH6.0 ~ 6.5, with

Diluted with water to 1000mL, and mix.

3.4 fluoro standard stock solution

Weigh 2.2110g pre-dried at 120 °C 2h sodium fluoride (excellent pure), was dissolved in water and go

1000mL volumetric flask, constant volume of water, mix, transferred to drying plastic bottles saved. 1mL solution containing 1mg fluorine.

3.5

fluoro standard solution A. Pipette 50.00mL fluoro standard stock solution (3.4) in 500mL volumetric flask, dilute to the mark, mix

Uniform, moved into dry plastic bottles. This solution 1mL containing 100µg fluorine.

3.6 fluoro standard solution B

Pipette 50.00mL fluoro standard solution (3.5) in 500mL volumetric flask, dilute to the mark, mix, shift

Into dry plastic bottle solution 1mL containing 10µg fluorine.

3.7 bromocresol green indicator

Weigh 0.1g bromocresol green dissolved in 20mL of anhydrous ethanol, dilute with water to 100mL, and mix.

4.1 FISE

Requires fluorine content in 10-1mol/L ~ 10-5mol/L, the negative electrode potential and the logarithm of the concentration showed a good line

Sexual relations. Electrode before use, should be soaked in a solution of sodium fluoride 10-3mol/L activated in 1h, then washed with water to a fluorine-containing little

In 10-5mol/L only after the measurement.

4.2

saturated calomel electrode.

4.3 potential measurement instrument

accuracy 0.1mV.

4.4

magnetic stirrer.