GB662648A - Improvements in the manufacture of soap - Google Patents

Abstract

<PICT:0662648/III/1> <PICT:0662648/III/2> Kettle soap remaining after the spent lye and glycerine have been removed from the mass resulting from the saponification of fats is finished by conditioning it with sufficient water to convert it to a homogeneous condition having a fatty acid content of 40-66 per cent, agitating, withdrawing a continuous stream, mixing a stream of electrolyte therewith sufficient to cause a neat soap phase to be formed having a fatty acid content of 38-62 per cent, maintaining at a temperature of not less than 180 DEG C. and centrifuging the mixed stream to separate neat soap therefrom. The conditioning step is preferably carried out near the boiling temperature, and if necessary sufficient sodium chloride or caustic soda or both are added to close the grain to such an extent that the mass is substantially homogeneous and may be so maintained by the mild agitation provided by pumping through a pipe system. Preferably the fatty acid content of the conditioned mass is between 50 and 59 per cent, and that of the mixed soap and electrolyte stream from 45 to 55 per cent. Referring to Fig. 1, a batch of kettle soap is introduced into a tank 10 and boiled with water and, if necessary, small amounts of electrolyte by live steam entering from the pipe 11. The conditioned soap is circulated by a pump 16 through a strainer 14 and back to the tank, while a portion is continually bled off through a pipe 20 and pump 21 to be mixed with electrolyte pumped in by a pump 24 from a constant level tank 30. The mixture passes to a circuit 37 containing a pump 36, a heat exchanger 39, a drain 40, and a throttle valve 46 leading to one or more centrifuges 44 from which neat soap is discharged on the light side 47 and nigre or lye on the heavy side 49. If desired the electrolyte may be added in the dry state by depositing it on a vibrating screen 71 from which it is guided by a sloping plate 72 to a funnel 56, as shown in Fig. 3.