反应详情

温度

40 °C

5 liters iron (II) sulfate solution is introduced into a reaction vessel (concentration: 90 g/l FeSO4.7H2O) and heated to a temperature of 40° C. Within 15 minutes 1700 ml potassium ferrocyanide solution (concentration: 85 g/l [Fe(CN)6 ]; temperature 40° C.) are introduced initially into this solution, followed within 45 minutes by 2700 ml sodium ferrocyanide solution (concentration: 85 g/l [Fe(CN)6 ]; temperature 40° C.). The pH values of the iron (II) sulfate solution and the [Fe(CN)6 ] solution are adjusted so that the precipitate has a pH of 3.0-3.5. The subsequent treatment of the white paste is as described in Example 1. Tests on the iron blue pigment thus obtained yielded the values shown in Tables I and II.