저널

The present work addresses how to measure the amount of dissolved aluminum in phosphoric acid, based on volumetric and gravimetric measurements of the precipitates formed by reaction between the $H_3PO_4$ solution containing dissolved aluminum ions and 10 % KF solution. The volume of the precipitates increased with dilution of the dissolved aluminum-containing $H_3PO_4$ solution up to 1/4 dilution above which it decreased with further dilution. The lowered amounts of the precipitates at low dilution less than 1/4 and high dilution more than 1/4 are attributed to high acidity of the solution and decreased amount of dissolved aluminum in the solution, respectively. Volumetric measurement of the amount of precipitates was found not to be very reliable with the experiments, while weight measurement of the precipitates after drying for 80 min at $60^{circ}C$ appeared to be very reproducible. In the present work, it is suggested that the amount of Al dissolved in 85 % $H_3PO_4$ solution can be calculated by multiplying 50 to the weight of precipitate obtained by reacting 8 ml of 1/4 diluted $H_3PO_4$ solution containing dissolved aluminum ions with 6 ml of 10 % KF solution.

Dissolved aluminium;Phosphoric acid;Precipitation;Electropolishing;