Alumina in Thermal insulation Material
- Burette – 50 ml
- Measuring Cylinder – 50ml
- Pipette – 10 ml
- EDTA solution 0.025 M – Dissolve 9.31 g of EDTA (disodium salt) in 1 litre of water.
- Methyl Orange indicator- 0.05 percent (m/v) in ethanol.
- Dilute ammonia solution – 1:2 (v/v).
- Buffer solution (pH 5.3]
- Xylenol orange indicator solution 0.7 % (m/v) – Dissolve 0.1 g of xylenol orange indicator in 100 ml of water containing 2-3 drops of dilute hydrochloric acid (1: 1).
- Standard zinc acetate solution (0.025 M) – Dissolve 5.50 g of zinc acetate in 1 000 ml of water containing 25 ml of buffer solution (pH 5.3). Standardize against standard aluminum solution.
- Standard aluminum solution (0.025 M) -Take an aluminum foil and wash it with absolute alcohol and dry in a desiccator. Weigh O.674 5 g of aluminum foil into a beaker containing 25 ml of water and 25 ml of concentrated hydrochloric acid. Heat the solution to dissolve the metal. Cool and dilute the solution to 1000 ml in a volumetric flask (1 ml – 0.001275 g of Al2O3).
- Sodium fluoride – Solid.
- Dilute hydrochloric acid – 1: 3 (v/v)
- Transfer 25 ml of main solution (Determination of silica – IS: 12107 (Part 2)-I 987) to a 250 conical flask.
- Add 35 ml of EDTA solution and 2-3 drops of methyl orange indicator solution.
- Add dilute ammonia solution dropwise to just yellow color. Add 15 ml of buffer solution and boil for 5 minutes. Cool to room temperature.
- Add 5-6 drops of xylenol orange indicator and titrate the solution with standard zinc acetate solution to just pink color.
- Add 1 g of sodium fluoride to the solution followed by 2-3 drops of dilute hydrochloric acid. Boil the solution again for 5 minutes. Cool to room temperature.
- Add 5 ml of buffer solution and titrate the released EDTA with standard zinc acetate solution using 5-6 drops of xylenol orange indicator to pink end Point. The second titrate (V ml) corresponds to the amount of titanium and aluminum.
Aluminum (as Al2O3), % = V × E × 500 × 100 / 25 × M – (0.6738 × T)
= ml of zinc acetate consumed,
= equivalent Al2O3 in g/ml of zinc acetate solution,
= mass in g of sample taken, and
= percent of TiO2 by mass. [The value obtained by the method given
in IS: 12107 (Part 5)-1987: Part 5 Determination of titanium’]