| 摘要 |
To prepare alkali metal polyphosphates, in particular alkali metal triphosphates, alkali metal phosphate solutions or suspensions are sprayed by means of one or more jets in a spraying tower through a flame zone produced by a burner ring. In addition, fine particulate alkali metal polyphosphates, in particular alkali metal triphosphates, are introduced into the spraying tower from above and are uniformly distributed over the spraying area of the jet(s) with formation of agglomerated products. A plant for carrying out the process comprises a cylindrical spraying tower (1) closed by a lid (2), which spraying tower has a lower part (3) tapering to a point. The lid (2) is penetrated in the centre by a solution feed tube (5) connected to a spraying device (6) and by a plurality of burners (11) concentrically arranged about the feed tube. Furthermore, the lower part (3) is penetrated by an exhaust gas tube (4) inclined in an upwards direction. A solids shaft (8) penetrating the lid (2) is arranged concentrically to and at a distance from the solution feed tube (5), which shaft has a conical shape inside the spraying tower (1) and into which shaft a solids feed tube (10) opens outside the spraying tower (1). <IMAGE> |
