YS/T 254.2-2011Methods for chemical analysis of beryllium concentrate and beryl. Part 2: Determination of ferric oxide content. EDTA titrimetry and sulfosalicylic acid spectrophotometry (English PDF)

2.1 Method summary

Mixing the sample with an alkaline flux melted, remove the current flooding, acidified with hydrochloric acid. Acidic solution at a pH of 1.2 to 1.5 in order to sulfosalicylamide Acid as indicator, with disodium EDTA standard solution titration, determination of the amount of ferric oxide.

2.2 Reagents

2.2.1 ammonium persulfate.

2.2.2 hydrochloric acid (rho1.19g/mL).

2.2.3 Mixed flux. Anhydrous potassium carbonate, anhydrous sodium carbonate, sodium tetraborate proportionally 1.2.1 preparation, mix.

2.2.4 hydrochloric acid solution (15).

2.2.5 Ammonia (11), pure class distinctions.

2.2.6 sulfosalicylic acid solution (200g/L).

2.2.7 ferric oxide standard stock solution. Weigh 1.0000g advance at 105 °C ~ 110 °C bake 2h and placed in a desiccator to cool to Room ferric oxide [w (Fe2O3) >=99.9%], placed in 250mL beaker, add 30mL hydrochloric acid (2.2.2), cover the dish table, low Heated until completely dissolved, removed, cooled to room temperature and transferred to 1000mL volumetric flask, dilute with water to volume, and mix. This solution 1mL phase when to 1000µg ferric oxide.

2.2.8 ferric oxide standard solution. Pipette 100.00mL iron sesquioxide standard stock solution (2.2.7), placed in 500mL volumetric flask the diluted with water mark and shake. This solution was equivalent to 200µg 1mL ferric oxide.

2.2.9 Standard solution of disodium edetate

2.2.9.1 Preparation

Weigh 1.87g disodium edetate, placed in 250mL beaker, add 200 mL of water, dissolved by heating, cooled to room temperature, transferred to 1000mL volumetric flask, dilute with water to volume, and mix.

2.2.9.2 Calibration

Pipette three 10.00mL diiron trioxide standard solution (2.2.8), placed in three 250mL conical flask, 0.1g persulfate Ammonium (2.2.1), heated to a boil and keep 3min, remove the coolish, add 8 drops of sulfosalicylic acid solution (2.2.6), with ammonia (2.2.5) in and purple to disappear and appear reddish brown, immediately hydrochloric acid solution (2.2.4) and to purple just appeared and excess 2mL, temperature control solution is 60 °C ~ 80 °C, with disodium edetate standard solution (2.2.9) slow titration to the disappearance of the purple is the end.

According to formula (1) calculated standard solution of disodium ethylenediamine tetraacetate titer T.