GB/T 22660.6-2008Chemical analysis methods of lithium fluoride - Part 6: Determination of silica content - Molybdenum blue photometric method (English PDF)

4.1

anhydrous sodium carbonate.

4.2

boric acid.

Nitrate 4.3 (8mol/L).

4.4 Sodium molybdate solution (195g/L)

Weigh 19.5g of sodium molybdate dihydrate (NaMo4 · 2H2O), placed in a plastic cup with water and dissolved,

Diluted to 100mL, and mix. Stored in polyethylene bottles.

4.5

tartaric acid solution (100g/L).

4.6

sulfuric acid solution (8mol/L).

4.7

Ascorbic acid (20g/L).

4.8 silica standard stock solution

Weigh 0.5000g (accurate to 0.0001g) in advance and placed in 1h 1000 °C burning dry

Desiccator cooling to room temperature silica [(SiO2) > 99.9%] and 5g of anhydrous sodium carbonate (4.1), placed in a platinum crucible and mix. Place

950 °C high temperature furnace to melt molten transparent. Cooled, heated with hot water until completely dissolved frit. Moved into 1L volumetric flask, dilute to the mark

Degree, and mix. Immediately transferred to plastic bottles. This silica-containing solution 1mL 0.50mg.

4.9 silica standard solution

Pipette 10.00mL silica standard stock solution (4.8), placed in 1L volumetric flask, dilute with water to

Volume, and mix. Immediately transferred to plastic bottles. The concentration of the solution is a silica. 5µg/mL. Before using now formulated.

5.1 platinum and platinum dish lid

diameter 70mm, height 35mm.

5.2 Furnace temperature

the temperature can be controlled at 550 °C ± 25 °C.