Improvements in or relating to the preparation of ammonium sulphate crystals and apparatus therefor

摘要

In the manufacture of ammonium sulphate by passing an ammoniacal gas below the surface of a pool of sulphuric acid or sulphuric acid--containing ammonium sulphate solution, the absorption liquor is subjected to mechanical stirring in addition to the agitation imparted by the entrance of the ammoniacal gas whereby crystallized particles of less than the desired size are maintained in suspension while the larger crystals settle. The process may be carried out in a conical-bottomed saturator as shown in Fig. 1. The gas is passed into an annular conduit 13 around the periphery of the saturator from whence it passes via longitudinally inclined turbine-wise nozzles 15 into the saturator below the level of the liquid, thus imparting a rotary movement to the latter. A stirrer 21 attached to a perpendicular hollow shaft 24 passes through a tube 20 and is preferably rotated in such a direction as to assist the rotary motion imparted by the gases. A suction lift 19 for the removal of crystals is also introduced through the tube 20. According to a modification (Fig. 3) the outer ring of nozzles 15 is supplemented by an inner ring of nozzles 33, which are so inclined as to give the PICT:0361935/III/1 PICT:0361935/III/2 PICT:0361935/III/3 PICT:0361935/III/4 same direction of movement to the liquor as the outer ring 15. A paddle stirrer 21 is also provided to assist the rotary motion imparted by the gases. According to a further modification (Fig. 4), a saturator having two conical bottoms 12, 12 is employed, the tube 20 and suction lift 19 also being duplicated. The gas is introduced through a ring of inclined nozzles 15 of elliptical configuration. Each tube 20 has attached at its lower end a perpendicularly-adjustable funnel-like baffle 45. A conduit 50 has two branches 49 which communicate with the baffles 45 through openings 40. A paddle stirrer 51 (Fig. 5) is mounted within the conduit 50 and draws liquor through the conduit into the baffles. Such baffles can also be supplied in the modifications shown in Figs. 1 and 3. Specifications 152,766 and 315,700, [both in Class 1 (ii), Inorganic compounds, other than &c.], are referred to.