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Previous Next The best candle and soap tips online! worked up for glycerine, by distilling it with surcharged steam. Should the soap not yet be sufficiently pure and solid, the "cutting of the pan" is to be repeated, with a stronger salted lye. , Now the process of boiling is proceeded with. The soap receives the addition of 1200 to 1400 litres (264 to 308 gals.) of good and strong lye, and is left boiling for several hours. The soap grains, which are insoluble in this strong lye, thicken still more and more, and they absorb alkali and separate water. The culinary salt and the surplus water remain in the sub-lye. It is permitted to settle, and thus but a very weak alkali is drawn off, in order to renew the addition of fresh and strong lye. This is proceeded with until the soap no longer absorbs any caustic soda, and the lye, by the longer boiling and evaporation, becomes specifically heavier, while the soap, by absorption of water and the solution of alkali specifically lighter. The soap, thus finished boiling, has a characteristic smell. It dissolves in hot water without separating any oily drops, and gives, when pressed between the thumb and index finger, a solid touch, and shows in this condition a dark blue-black color of sulphuret of iron. If fitted soap is to be produced from it, it must be made more fluid by adding more water. A workman climbs over a platform, which is placed over the boiler, and pushes the above-mentioned paddle down to the bottom. In the opening formed thereby, a second workman pours a few litres of weak lye or water. The first workman withdraws his paddle and pushes down in another place, and so on until 800 litres (176 gals.) water have been consumed, then a little less steam is admitted; the grains dissolve, and the muddy impurities fall to the bottom. To produce the peculiar marbling of the grain soaps, about 1J kilogramme (3.3 lbs.) of iron red or " kalkothar" are mixed with just as much strong lye as is necessary to dispose the formed precipitate into the peculiar division of flames and stripes. For this marbling a peculiar skill is required. If the soap is too watery or if it cools oft" too slowly, the precipitate settles too easily and the marbling is lost. 202 TECHNICAL TREATISE ON SOAP AND CANDLES. THE ESTABLISHMENT OF A SOAP FACTORY. 203 The finished soap is poured by means of copper scoops into the canals which lead to the frames, large basins which are about 75 centimetres (29.4 inches) high. The lye settles on the bottom, and the hardening occurs in 5 or 6 days. The soap mass is cut with long knives into large blocks which are divided by wire into smaller pieces. The soap, being still soft, is not yet suitable for shipment, and in order to make it hard without the loss of the latent water or to suffer too much shrinkage, it is dipped into a very strong lye, after which the hardening is accomplished by 12 or 14 days' drying. The soap is now finished and ready for shipment. The establishment in St. Quen possesses 8 soap boilers of 15,000 litres (3300 gallons) capacity, 24 basins for filtering the lye, and 30 receiving vessels. Every day 14,000 kilogrammes (30,800 lbs.) of soap are finished, which amounts to 4,000,000 kilogrammes (8,800,000 lbs.) annually. The workmen, 40 in number, cost daily for wages but 200 francs ($40), while the value of the soap daily produced amounts to at least li,000 francs ($2400). The market of Paris is nearly one-half supplied by this manufactory, while the northern provinces are almost entirely furnished by it. The proprietor of this establishment receives his orders six months in advance. Of course it is not in the power of many manufacturers to possess such extensive establishments, yet there is so much of interest and instruction in this description, that for this reason we give the details. We have often mentioned the importance of pure water in this manufacture, as well for soap as for the solution of the lyes as the usual impurities of water cause a waste in both; for a fuller treatise on this matter the reader is referred to another part of this work, in the section on materials. In the arrangement of the plant of a soap manufactory, much must depend upon the means at hand, yet so much depends upon the completeness of the different implements and machinery, for the rapid and economical production of the soaps, that we must endeavor to describe all the most useful and the latest inventions for conducting the different pro- cesses with the greatest facility. We will precede this with illustrations of two French soap factories which may prove useful as hints. Fi.ir. 13. Previous Next
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