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Previous Next The best candle and soap tips online! steam pass into the condenser E, which contains coke moist--ened with sulphuric acid. The liquids pass through the pipe K, while the gases pass through the tube F into the ash-pit G under the furnace. G has a door through which a powerful draft can be sent, carrying all the gases into the fire to be there consumed. In the rooms in which the raw materials are stored, there generally prevails such an unbearable smell, which the decomposing and putrefying substances diffuse, that it has been suggested to preserve the raw material in closed spaces, these to be connected by means of a pipe with a fireplace or with a high chimney into which all exhalations and the air that enters from the outside through ths door cracks may be carried. But this evil might !>e met in a moreefficacious way ; for instance, by working up the hides and bones, and treating them with phenyl acid, which is furnished to the industries by Dr. Calvert. These hides come from South 86 TECHNICAL TREATISE ON SOAP AND CANDLES. America and Australia- Before they are shipped they are placed in water which contains 2 to 3 per cent, of phenyl (carbolic) acid. Hides treated in this manner showed not a trace of bad smell. A similar contrivance, especially for the melting of tallow for candles and soap manufactories, iB used in the establishment of Price of Battersea, England. The raw fats are melted in large vessels which are covered with flat hermetically fitting covers of lead and meted to the wall. In the centre of the cover is a square opening of 80 centimetres' (81 inches) width, which is supplied with a water trap, and makes the attention to the vessel convenient. Upon the cover is placed the short end of an inverted 0 forming pipe of 15 centimetres' (5.89 inches) diameter, the other end of which being 4^ metres (14.76 feet) long runs under the flooring of the work-room and opens into a canal. In the lower part of the pipe enters another pipe which ia in connection with a force-pump which squirts water through a rose from above. The vsipors in the vessel condense as soon as they come in contact with that stream of water, and the descending liquid matter impregnated with all the miasms flows into the Thames. There are yet a number of other ways for rendering tallow, which, however, are mostly but modifications of the one or the other of the above-stated methods. Thus, the tallow in many establishments is rendered over an open fire or by steam, pressing the greaves and treating them again separately with diluted sulphuric acid and heat. By this means the cellular tissues are destroyed, the tallow flows out completely, and is washed out at first with a sub-lye and lastly with water. In more modern times in many of the larger soap manufactories, rendering modes have been introduced which are described in our article on lard. LARD. In the United States hog's lard has numerous applications in the arts, and occupies an important place in commerce on MATERIALS USED IN THE MANUFACTURE OF SOAPS. 87 account of the large quantities produced and the many useful purposes for which it is used, ffot the least important are Fig. 2. 88 TECHNICAL TREA1ISK ON SOAP ANP CANDLES, those of soap and candles. Lard consists of about 63 parts of oieine with 37 parts of stearine, the oieine or oil having many uses while the stearine is used in the fabrication of soap and candles. In making candles it is treated chemically, producing stearic acid and glycerine, being rich in this latter useful article; while the oieine or red oil is made into soap. This process will be detailed in our section on candles. Lard is much used in cooking and is generally pure, yet it is sometimes sophisticated with the stearine from cottonseed oil. It is rendered or melted in several ways, chiefly by the open fire, for it ia made ia nearly every farm-house. In eities and in large operations steam is found to present the moat economical mode. Many inventions are in use for rendering lurd, and among them few are more appropriate than the one here illustrated for rendering tallow and lard by steam and pressure, Fig. 2. Rendering by Steam. Wilson's Process. The apparatus consists of a series of steam-tight digesters, each of 1200 to 1500 gallons capacity. These digesters are composed of holler-iron plates tightly riveted together iu the form of an inclosed cylinder, in length about two and one-half times greater than the diameter, and are famished with diaphragms or false bottoms. The drawing, Fig, 2, is very explicit, and the mode of working these machines, and the use and application of their various appointments will he mentioned in reciting the process as practically carried through in the laboratory of the inventor. It ia as follows: The false bottom being arranged in its place, and the discharging hole closed up, the ateam-tight iron tank or cylinder is tilled through the man-hole with the rough htrd material, to within about two and a half feet of the top. This dune, the man-plute E is securely fitted into the man-hole H, and steam let on from an ordinary steam boiler, through the foot valve, into the perforated pipe G within the tank. Set the weight on the valve at tlie requisite pressure, and during the steaming, frequently ami carefully assay as to the state of the contents of the tank by opening the try.cock R. If the quantity MATEBLALS USED IN THK MANUFACTURE OF SOAPS. 89 of condensed steam in the tank is too great, it will be indicated by the ejection of the fatty contents in a spurt. In such a case it is then requisite immediately to open the regulating cock X and draw off the condensed steam, through it, into the receiving tub T, until the fatty matter ceases to run from the try-cock aforesaid. After ten or fifteen hours' continued ebullition, the steam is stopped off, and that excess already in and uneondensed, allowed to escape through the try-cock antl safety-valve. After sufficient repose, the fatty matter separates entirely from water and foreign admixture, and forms the upper stratum. It is drawn off through the cocks pp in the side of the tank, into coolers of ordinary construction* The tank being emptied of its lard contents, the cover F is raised by means of the rod G-, from the discharging hole E, and the residual matters at the bottom let out into the tub T. If, on inspection, the contents of this tub have retained any fat, it must be again returned to the tanks, when they are being filled for a fresh, operation. Experience has determined that, to produce the best result, tlie steam pressure should be not less than fir'ty poumls to the square inch, though that often used is seventy-five pounds, and may be augmented to one hundred pounds when it ia desired to expedite the operation. We 3hould, however, sidvise against so high a pressure in the preparation of tallow ; it may do well enough for lard ; but if these closed tanks are made to operate as digesters, the effect produced by the decomposition of bones and other matters, which, in the wholesale way of preparing fiits at the West, are generally thrown in indiscriminately with the rough euet, would be to deteriorate its quality- The better way is to take a little more time,and thus insure a better result. The process is sufficiently economical as it is, for, whilst by a pressure of between fifty and seventy pounds, the bones, etc., are made to yield all their oleaginous or fatty matter, there is no action occasioned which will conveit them into an offensive constituent. In making lard from the whole carcass of the hog, excepting the hams and shoulders, a yield is always obtained, by the use of this apparatus, full twelve per cent. 90 TECHNICAL TREATISE ON SOAP AND CANDLES. greater than by any other methods; whilst in rendering tallow, the gain exceeds the produetfurnished by the ordinary plans at least six per cent. To say nothing of the economy both of time and labor (fifty per ceut. of each), the material obtained 13 so much superior, that it always commands, if not the preference, at least a slight advance of price, in the market. The marc or residuum, thrown out into the tub T, being rich in nitrogenous and phosphated matter, when dried and mixed with bog or street earth, and gypsum, makes manure equalling the best guano. Proper management of the apparatus will generally prevent any escape of the offensive vapors incident to the operation ; but occasionally leaks will occur at the valve. The condensed steam carries down all the impurities of the fat, and leaves it clean and white. Moreover, it is firm if rapidly cooled in vessels of smalt capacity, for the temperatures of large volumes fall so slowly, that partial granulation ensues and softens its consistency. With all these advantages, however, this process is not wholly faultless j for the difficulty of separating all the water slightly endangers the purity of the fat, as the former introduces, in solution, a portion of animal matter, which, in time, becomes putrescent, and imparts an offensive smell to the latter. Repeated washing of the fat with fresh water, and careful remelting and settling, would remedy this defect in a great measure. BUTTER finds but little application in the manufacture of soap, on account of its cost, though if it were less costly it would prove a very advantageous material particularly for toilet soaps, as soap made with it is of beautiful consistency and appearance, and It is subject to less loss in saponifieation than most other fatty bodies. Butter is the fatty substance with which the globules of miik are formed. These globules do not freely float in this liquid ; they are surrounded by a very thin membrane, which MATERIALS USED IN THE MANUFAOTFBE 01* SOAPS. 91 prevents them from joining together. When, by any process, they can be united, butter is formed. A butter well prepared must be of a fine yellow oolor, of a middling consistency, with a peculiar and slightly aromatic odor, ftnd an agreeable taste. It must be easy to cut into slices. The composition of butter seems to be very complex. M. Chevreul has demonstrated that this body contains five neutral substances, which are, olein, viargarin, butyrin,eaprin, and eaproin. These fatty bodies, treated by alkalies, are saponified and transformed into oleie, margaric, butyric, cap-rie, and caproic acids; the last three are volatile, and can be separated from the two others by distillation. According to Heintz, butter contains ordinarily olein, much palmitin, a little stearin, and small quantities of neutral bodies giving by saponification myristio and butyric acids. Butter dissolves in 28 parts of boiling alcohol at 3oQ C. (95° F.); it melts at 36° C. (96.8° F.). It becomes rancid very easily; this alteration can be prevented by salting or melting it. Butterwashed with warm water, cooled and pressed yields, by successive crystallizations in a mixture of alcohol and ether, a substance melting at 48° C. (118.4° F.),which presents the characteristics of margarin. The liquid fatty body extracted from butter by pressure is almost entirely formed of a substance different from olein, and is transformed by saponification into glyc-eryl oxide and a new acid, uko-butyrk acid. The relative proportions of the immediate principles of butter vary under different circumstances; however, the following composition has been assigned to it:— . SO . 3 Mil rga rin Butyrolein Bntyrin \ Caprin V Caproiu * TECHNICAL TREATISE ON SOAP AND CANDLES. BONE FAT. The grease contained in the bones of the sheep and the ox is a very useful material for soap, saponifying in the same manner as talbvv, though making a softer soap, its melting point being much lower. It usually contains many impurities ; that extracted from fresh bones finds application as a very fine lubricator for machinery. To produce this fat, the bonesare broken, as much as possible in a lengthwise direction. Where large quantities are worked up—as in bone-kilns—they are crushed by passing them through iron rollers. The crushed bones are then put into a kettle, partly filled with water, and heated to the boiling point, which c;iuses the fat to float on the surface, where it is skimmed oft" with a flat iron-spoon and passed through a sieve, which retains tiie solid particles. When it is noticed that no more fat separates, the bones are taken out, by means of a large perforated shovel, and replaced by fresh ones, so that the water may be used several times. The fat thus obtained is generally of a brownish color and of an unpleasant odor, and when cooled off, congeals to a grainy, smeary consistency, and retains some water, which may be separated by remelting and settling. The soda soap made with bone fat is not very solid, but with a suitable quantity of linseed or hempseed oil and potash lye a soft soap is made, which after some little time shows a very tine so-called natural grain derived from the crystallized Btearic and palmitic acid potash soap. In several places still another kind of bone fat is yielded, in the process of making glue. This fat is at the ordinary temperature liquid like oil, and has a dark brown color, which, however, does not pass over into the soaps boiled therein, but by salting passes down into the sub-lyes, so that a nearly white soap is yielded, which is not very hard. Hence it is customary to mix it with other fats, palm oil, tallow, etc. This fat often contains from two to three per cent, of lime, most likely lactic acid lime, which is soluble in fat oils. MATERIALS USED IN THE MANUFACTURE OF S0AF5. 93 This lime causes the fats boiled in the soda lyes to become spongy, and can only be separated by adding culinary salt, and then with difficulty. To avoid these troubles, the lime should be separated, which can very easily IK done if the fat is worked with a sufficient quantity of water containing sulphuric or muriatic acid. Whether or not such a fat contains lime, can be ascertained, if a sample thereof is mixed with a solution of oxalic acid and well stirred. If lime be present there appears after a little while a liquid, which becomes muddy by the formation of oxalate of lime; in the other ease the water which ia under the oil appears, after separating from the oil, entirely clear. HORSE PAT. This fatty body, though repulsive on account of the careless manner in which it is prepared from the carcass, is yet, when extracted from the recently slaughtered animal, a very suitable and good material for the manufacture of common soap, the product with soda lye being white and of good consistency. The appearance of this fat varies according to the organs from which it is taken, and the care given to its production. It is either solid, forming: a real tallow, or it is more or less of the consistency of lard, and is generally of a dirty-white color. The horse fat which appears in commerce, and which comes from slaughtered horses, and appears to be produced with more care, of course deserves in many respects the preference. It is almost odorless, of a yellowish tinge, of the consistency of butter, and yields just as white and solid soap as pure (allow or bleached palm oil, and does not impart to the clothes washed therewith that disagreeable smell which they acquire from the eon+noii horse fat eoap. GLUE FAT. In making glue from hides, tendons, etc., much fat is collected which if well prepared can be usefully employed in 04 TECHNICAL TRE4TI8E ON SOAP AND CANDLES. making soap. As found in commerce glue fat contains a large amount of lime and other impurities, which can, however, be extracted with dilute sulphuric acid. When the fat is boiled in a five per cent, solution of sulphuric acid for about an hour, the lime and other imparities are carried down with the water, the clear grease floating on the surface whence it can be ladled off. This sebacic acid will then make with soda lye with or withont rosin a good and firm soap, useful for all domestic purposes. It should be boiled, for in the Swiss or cold soaps it would not answer so well. NEAT'S FOOT OIL. If this product were abundant it could be usefully applied in making soap3 of good quality, but it is generally used for dressing leather, for which it is admirably adapted. It is prepared by boiling in water the feet of cattle deprived of flesh and sinews, and removing the grease which floats upon the surface. It is of a greenish-yellow color, and if fresh has no odor, is limpid at ordinary temperatures, becoming solid in the cold. It forms with soda lye a very fine white soap partaking of the nature, of the fat, being somewhat soft, olein beiug the largest constituent of the oil. KITCHEW FAT. The refuse fat of families, hotels, restaurants, etc., finds a very useful purpose in soap manufacture, and when it is systematically collected and properly purified becomes of much value. It is, however, often of inferior quality, being soft, green, and limpid, and in this state is termed weak stock. In this condition it may be much improved by boiling with salt and alum, but a much better mode would be the purification with dilute sulphuric acid, a process often mentioned in this treatise. We deem the utilization of this and other refuse greases and fats of so much importance that we shall give a special section more fully explaining it. MATERIALS USED IN THE MANUFACTURE OF SOAPS. 95 FISH OILS. In this category are classed the oik from a very numerous variety of animals many of which are not, strictly speaking, fishes. The oils of commerce are extracted from whales, seals, porpoises, and many kinds of iishes, and arc almost always designated by the name of the source, as whale, seal, cod-liver oil, etc. Many called train oils are extracted from the seal, herring, etc. Train oil has a specific gravity of 0.925 to 0.930, and ia principally composed of common olein with palmitin. Its peculiar smell originates from valerianic acid, glyceryl oxide, and a substance which is considered to be a combination of a special acid, viz., dolphic or phocenic acid, with glyceryl oxide. Various means are applied in purifying the bad smelling and dark colored train oils. Shaking with milk of lime, with diluted potash or soda lye, culinary salt, and copperas ia common, as well as filtering with wcod ashes. According to Davidson, train oil should be shaken with a decoction made of oak bark, then have mixed with it 4 parts of chloride of lime (bleaching powder) stirred into 12 parts of water, permitting it to clear off, when a thick whitish mass will be separated, and add diluted sulphuric acid to settle the lime which becomes free. We are convinced, by experiments which we have made on a large scale, that this means is by far the best of all those used for disinfecting, since train oil loses by this treatment the greater part of ita disgusting smell, so that such train oil un3aponified appears almost odorless. But nevertheless the smell reappears when the train oil is changed into soap. Hence train oil can only be ueed in manufacturing very common soaps, or by mixing small quantities of it with otljer fats. COD-LIVER OIL is obtained from three species of fish, viz., from the torsk (Gndus callarias), the 6a,y.(Gadus cartonarius), and the shark 96 TECHNICAL TREATISE ON SOAP AND CANDLES. {(fadus poUachius); in France, according to Gobeley, from the livers of Baja bath and Rnjacavata. It lias been proposed to term the first sorts Morrhua oil, and the latter Raja oil. The shark livers furnish the oil but slowly ; they must therefore be cut up into pieces ami boiled down. The say livers, as well as the torsk livers, when thrown into water have a great portion of their oil to flow out spontaneously; that of the latter is a thinner liquid but somewhat darker, while that of the former is lighter but of a thicker consistency. All livers are finnlly boiled down,and furnish ordinarily the common cod-liver oil, which, liowever, never possesses the disagreeable smell of common train oil. The main built of cod-liver oil is likewise composed of palmitic acid (11 to 16 per cent.),oleicacid (70 to 74 percent,), and glycerine (9 per cent.)*, furthermore of a peculiar substance, called gaduin, a body of the nature of a weak acid, email portions of lactic acetic acid, valerianic acid, gall substances, iodine, pbosphorus, sulphur, traces of bromine and inorganic salts. By shaking up with water the dark cod-liver oil becomes somewhat lighter, since a part of the pigment substances are dissolved. Diluted sulphuric acid causes the separatioa of brownish Hakes; concentrated sulphuric acid causes the train oil to become of a brown color. Train oil has the property of dissolving large quantities of colophony, without thereby changing its consistency, i.e., not becoming a thicker liquid. Rosin being usually much cheaper than train oil, this peculiarity has been utilized for the purpose of adulterating it. Such an adulteration is, however, easily detected by placing the suspected train oil in a flask with an equal volume of alcohol, and shaking it, when the rosin will be completely dissolved. When left to settle, both liquids separate into two layers, of which the lower is the train oil. By keeping a record of its original volume we may conclude how large a quantity of rosin bad been added, making an allowance for a small portion which had been dissolved in the alcohol. Sometimes the fat of salim-phymallus^ known under the name of ash/at, is brought into commerce in place of train MATERIALS USED IN THE MAXUFACTUEE OF SO/PS. 97 oil. It is a mild yellow oil, which has a we*tk fishy smell, and is for making soap no less applicable than train oil. OILS AWD FATS OF VEGETABLE ORIGIN. The vegetable oils applied to the manufacture of soaps are very numemus and valuable, and are found in the fruits, seeds, etc., of plants. They ure usually lermed fixed oils, and are generally limpid at ordinary temperatures; f=ome, however, have more or less consistency, containing; palmitin, stearin, etc., combined with the olein. All have a specific gravity less than water, or about 0.920. "We append tables of the usual vegetable fatty bodies employed in making soap, with their sources of production and their yield from the seedri, etc.:— Fixedolls, Vefjetnli's* whlh produce them. Olive oil Olea Europsea. Groundnut oil Araehis liypogteft. Hempseed oil Cannabissativa. Almond oil Amygdalus communis. Coleseed oil Bnissica oleracen. Rapeseed oil Brsssica napus. Cocoanutoii . . . . . . Cocos nucifera. Cottonseed nil flnssypium lierbaceum. Beechnut oil Fagus sylvalica. Cocoa butler Theobroma cacao. Hazel-nut oil Oorylus avelbina. Poppy fiil . Paj.aVLT somniferum. Ben oil Gnilandina moringa. Iiaurel oil Laurus nobilis. Linseed oil Linum usitaiissimum. Castor oil Hicinus commnnis. CiimcHna oil Myagrum satinim. Nut oil .Tuglans regia. Sunflower-seed nil Heiianthus aniiuna. Sesamum oil Stsamtmi orientate, Pilcu-tree oil Pinus allies. Piueoil Piniisaylvestrs. Etc. etc. The following table gives the quantities of oils wliieh may he extracted from the vegetables:— 7 Previous Next
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