抄録
(1) It is found that pH of the Solution is suitable to be 4.0 to separate iron and aluminium as phosphate from much calcium. (2) 1 mol ammonium acetate buffur Solutin(pH 4.0) was used instead of the old method using a proper quantity of acetate. (3) Phosphate solution was added previbusly to preciptitate iron and aluminium as phosphate. (4) Hot 5% ammonium nitrate solution is used as the washing solution of the precipitate. (5) The effect of silicate and fluorine was examined and it was found to be necessary to remove them.
