GB/T 23273.4-2009Methods for chemical analysis of cobalt oxalate - Part 4: Determination of silicon content - Molybdenum blue spectrophotometry (English PDF)

3.1

sulfate (rho1.84g/mL).

3.2

perchloric acid (rho1.67g/mL).

3.3

sulfate (1 + 3).

3.4

sulfuric acid (7 + 93).

3.5

hydrofluoric acid (1 + 1).

3.6

HCl (1 + 1).

3.7

saturated solution of boric acid.

3.8 ammonium molybdate solution (100g/L)

Weigh 10g of high purity ammonium paramolybdate [(NH4) Mo7O24 · 4H2O] was dissolved in 80mL water, cooled,

Diluted with water to 100mL, mix, use filtered.

3.9

citric acid solution (500g/L).

3.10

Hydrazine sulfate solution (2.5g/L), formulated with sulfuric acid (1.5 + 98.5).

3.11 stannous chloride (100g/L)

Weigh 10g excellent pure stannous chloride dissolved in 100mL of hydrochloric acid (3.6), and mix using now.

3.12

ammonia, saturated Refining.

3.13

n-butanol, AR.

3.14 Silicon Storage standard solution

Weigh 0.2142g silica (silica mass fraction >=99.9%) in a platinum crucible added

5g excellent pure anhydrous sodium carbonate, mix, cover, placed in a muffle furnace 400 °C, the temperature was raised to 900 °C, melting 1h, removed, washed with water crucible

Outer crucible, placed in hot water containing 100mL of polytetrafluoroethylene cup, cold dissolution, removed, cooled to room temperature. Moved 1000mL volumetric flask

Diluted with water to the mark, mix and immediately transferred to dry plastic bottles. This solution 1mL containing 100µg silicon.

3.15 Silicon standard solution

Pipette 50.00mL silicon standard stock solution (3.14) in 1000mL volumetric flask, dilute to the mark, mix

Uniform, immediately moved into dry plastic bottles. This solution 1mL containing 5µg silicon.