| 摘要 |
<p>Granular transition element hexacyanoferrates suitable for column use are produced from a soluble hexacyanoferrate compound and a salt of said transition element by way of slowly adding the aqueous solution of said soluble hexacyanoferrate compound to the aqueous solution of said transition element salt with simultaneous stirring in order to produce a precipitate of said transition element hexacyanoferrate. The precipitate is washed, then separated from the slurried solution by centrifuging, and finally dried at an elevated temperature. According to the invention, the concentration of said transition element salt solution is at least 0.35 mol/l, whereby the hexacyanoferrate compound of the transition element thus obtained has the fraction of the exchangeable transition element smaller than 30 %, preferably smaller than 28 %. The fraction of the exchangeable transition metal can be further lowered by washing the product with a solution of alkali metal-EDTA complex. By virtue of the invention, a product is obtained having a distribution coefficient greater than 10,000 ml/g.</p> |
