GB573787A - Improvements in or relating to the manufacture of soap - Google Patents

Abstract

573,787. Soap. SHARPLES CORPORATION. Dec. 5, 1942, No. 17332. Convention date, Nov. 4, 1941. [Class 91] In the continuous method of making soap by the procedure described in Specifications 549,386 and 549,387 wherein the saponification is effected in a plurality of stages in each of which the fat and saponifying agent are intensively agitated together in a mixing apparatus, the soap being grained by addition of a salting out agent, followed by separation of the soap from the aqueous reagent phase in a centrifugal separation, and the soap being finally fitted by mixing with water to give the neat soap and nigre after centrifugation, the nigre is returned to one of the saponification stages of the method. The nigre emulsifies the saponifying agent with the fat; it may be returned just after the saponification stage with the single advantage of recovering its soap content. In the plant shown, comprising two saponification stages, and consisting of mixers 12, 15 and. 21 each followed by centrifugal separators 13, 16 and 18 with the feed and connecting lines as shown, the process is operated as stated above and as described in detail in the Specifications quoted as far as the centrifugal 18 from which the neat soap is obtained separated from the nigre. The latter is then returned at points 19, 20 or 22. In a modification of the process, a source of acid is added to the soap-containing mixture being fitted prior to entering the mixer 21 for the purpose of neutralizing free alkali and the centrifugal 18 is replaced by a centrifugal provided with outlets extending from the inner circumferential wall of its rotor for the discharge of separated dirt. In a further modification of the process, the nigre obtained from the centrifugal 18 or the modified centrifugal above is subjected to a separate centrifugal clarifying step with addition of a source of acid to neutralize free alkali as described in Specification 559,076 before being returned to the saponification cycle.