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Home > (996.6 lbs.) of tallow, about...
Previous Next The best candle and soap tips online! (996.6 lbs.) of tallow, about 50 hectolitres (140 bushels) of wood ashes are to be put in. The boiling with soda lye presents this advantage, that the soap may be finished in one water. The first lye is applied at a strengthof frtfm 10° to 20° B. The entire fat is placed in the kettle with one-quarter of the requisite lye for saponifi-cation, with proper attention to the fire. After boiling up, it should be examined as to whether the combination has taken place. This being the case, further portions of lye are added. Commonly this is taken of a strength of from 16° to 18° B. The adding of lye is continued, until a sample of the soap upon the glass plate appears perfectly clear. Thereupon the " cutting up of the pan" follows. This operation has here only the purpose of freeing the soap of glycerine and surplus water, hence much less salt is required than in the boiling with potash lye. For 100 lbs. of fat 10 to 12 lbs. of salt are required. The salt may be applied dry or in solution. After this the operations are the same as previously described. Soda soaps made by the process above described have some advantages, principally because it is impossible to remove all the potash, and they are generally very neutral and plastic. 314 TECHNICAL TREATISE ON SOAP AND CANDLES. THE FABRICATION OF SOAPS. 315 SECTION XIII. THE FABRICATION OP SOAPS (CONTINUED). SOFT SOAPS. SOFT soaps are essentially a combination of the sebacic acid soap in a solution of potash with glycerine. On account of the great affinity of potash soaps for water, these soaps do not dry in the open air, but always retain their soft consistency ; and the glycerine dissolved therein to a certain degree adds to this peculiarity. In its fabrication linseed oil, hemp-seed oil, sesame oil, cotton-seed oil, 'oleic acid of the stearic acid manufactories, with or without the addition of tallow or palm oil, are used. For winter soaps, the more liquid fats are chiefly used, such as linseed oil, hemp-seed oil, etc., since these do not congeal so easily; while in summer principally south sea train oil and rapeseed oil are applied in varied proportions. A good soft soap (except the so-called Elaidin soap) must appear as a clear mass, in which at times, especially if it has been standing for a long period, white grains are formed— crystalline separations of stearic acid potash or soda. It must possess the requisite consistency, not draw into threads like rosin, but when taken between the finger and thumb break off short like butter or lard. According to temperature it should be somewhat more consistent than these latter articles. It may have a somewhat sourish touch when tasted with the tongue, but not too strong, i. e., have a little overplus of potash. A large surplus is denoted by the dulness of the soap. When the soap is in want of alkali, it does not appear clear, has, however, in that case no sourish touch; so that it may be easily discerned, whence the surplus or the want of alkali originates. Until lately, all soft soaps were manufactured only by saponification of the neutral fats with caustic potash, and contained therefore only the small portions of soda that are naturally in the potash. But later, caustic soda was used simultaneously in a fixed proportion to the potash, partly to obtain a somewhat more consistent soft soap, and partly too, in order to enhance the yield, in a certain given quantity of ingredients. Gentele has given a certain proportion for this, where, without a muddiness of the soap occurring, the maximum yield is reached. For this purpose 5 parts neutral fat are boiled with 3 parts of potash and 2 parts of soda. There are 3 equivalents of potash and 2 equivalents soda, or 7 weight parts potash, about 3 weight parts soda; and the soft soap thus produced consists, therefore, of 3 equivalents sebacic acid potash and 2 equivalents sebacic acid soda, besides the glycerine and water. A very advantageous result was obtained by Gentele by the application of the following weight proportions:— 1420 kilogrammes (3124 lbs.) 73 per cent, potash. 970 kilogrammes (2134 lbs.) puve crystallized soda. 3753 kilogrammes (8256 lbs.) hempseed oil. 40 kilogrammes (88.0 lbs.) tallow. 102 kilogrammes (224 lbs.) oleic acid. These materials yield 9720 kilog. (21384 lbs.) of good soft soap, hence almost 250 kilog. (550 lbs.) soap from 100 kilog. (220 lbs.) fat. It must, however, be remarked, that this soap contains a great surplus of alkali; for the 3895 kilog. (8569 lbs.) fat'taken, to be worked up, require when they are saponified with f potash and f soda, of the former 658 kilog. (1448 lbs.), of the latter 201 kilog. (442 lbs.), whereby it is supposed that to saponify 100 kilog. (220 lbs.) fat for soft soaps 19.6 kilog. (43.12 lbs.) potash or 12.75 kilog. (28 lbs.) soda are necessary. But since 1420 kilog. (3124 lbs.) of a 73 per cent, potash correspond with 706.5 kilog. (1554 lbs.) caustic potash, and 970 kilog. (2134 lbs.) crystallized carbonate of soda correspond to 210.3 kilog. (463 lbs.) soda, it follows that Gentele has applied 2486 kilog. (5469 lbs.) potash and 9.3 kilog. (20.5 lbs.) soda too much. With such an overplus 316 Previous Next
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