Leys, caustic

When tallow is boiled for a considerable time in a solution of caustic soda (or ley, as the solution is called) the fiaity matters , stearine and palmitine, assume a granular or curd-like appearance, entirely losing their greasy and oily charaoter and if a small portion be pressed between the folds of a piece of paper it will not produce a greasy... 

It is well known that caustic ley acts differently upon the various fatty bodies with which it comes in contact. For example, a weak ley will act upon tallow until its alkali becomes exhausted, or nearly so whereas a ley of equal strength will scarcely, if at all, saponify cocoa-nut oil When, however, cocoa-nut oil is blended with other fatty substances, it will readily become acted upon by weak leys. Again, resin, although it is readily converted... 

The addition of salt, or a solution thereof, to a concentrated alkaline solution of soap in water, precipitates the soim in gelatinous flocculss, and the mixture behaves precisely like solid soap boiled with a ddute solution of salt. Owbonated and caustic potassa act exactly like salt, by separating soap from tbe alkaline fluid (ley) in which it is absolutely insoluble. ... 

The Jjey Tanks, containing caustic alkali of various ascertained strengths, are sometimes placed at one end of the series of soap-pans, and at a suitable height above them, so that the leys may be conveniently run olF by iron shoots into each pan, by turning the tap connected to either tank. Those tanks are commonly made of wrought iron plates riveted together,... 

One of the most important and at the same time most disagreeabloj operations connected with a soap-works is that of making the caustic leys. This is generally conducted in a building at a convenient distance from the boiling room and in such a situation that the lime-waste resulting from... 

In order to ascertain whether th e soda has been properly and fully causticised, a few drops of hydrochloric acid (muriatic acid) are added to a small quantity of the ley, and if effervescence takes place it is a sure indication that uncaustioised carbonate of soda is present In this case the ley must be returned to the lime again and again, if necesBary, until it is perfectly caustic. Boiling the lime and soda ash is a method frequently, if not generally, adopted, and indeed there is no doubt that it is a surer memod of rendering alkalies caustio than by a cold process. 

Since resin will not make a soap of itself, when treated with caustic leys, it is usually introduced into the soap-pans when the other goods, or fatty matters, have undergone the process of saponification. Indeed, if the resin were put into the pan with the first charge of materials, the caustic ley would seize it at once and dissolve it, and thus prevent the ley from performing its proper function—that of... 

Oocoa-nut oil does not t eadily saponify with caustic soda leys, when by itself, but when added to tallow, or palm-oil, it does so without difficulty. When saponified by itself it forms a soap of almost unusable hardness, and for this reason, besides its objectionable odour, it is always associated with other fatty materials when employed in the manufacture of soap. 

The proportions of tallow or palm-oil which may be successftilly employed with cocoa-nut oil for a genuine— that is, not a reduced, or Kquored" soap—should be 60 parts cocoa-nut oil and 40 parts tallow or equal parts palm and cocoa-nut oils. For the latter combination, an equal volume of caustic soda ley at 27° B. and a third of a volume of caustic potash ley at 10° B. are used with the boiling until perfect combination takes place. A small... 

It had long been the desire of soap-makers to possess some process of saponification less tedious and costly than the ordinary systems of soap-boiling. It was well own that caustic alkalies would convert into saponaceous matter fats and oils, without the application of heat, and it was also well known that during the process of saponification by the ordinary system of boiling over caustic leys, a considerable amount of glycerine was set free, and which, being a substance soluble in water, passed away with the spent or waste leys, causing a direct and positive loss in the manufacture. 

The adoption of the cold process in this country has not, we believe, extended much beyond the limits oi very small operations, such as toilet-soap making, for example. Indeed, the difficulty of obtaining leys sufficiently concentrated, without evaporation, would, to some extent, stand in the way of its extended application. At the present time, however, when soap-makers are supplied with caustic soda in a solid state, which renders ic... 

For maMng small quantities of Soap by the cold process, the ley should have a density of about 36 B. This may be obtained either by evaporating strong new caustic ley prepared in the ordinary way, or by dissolving commercial caustic soda in water until the required strength is reached. 

After the leys of the last operation have been removed, a second service of strong caustic ley is given. This ley should be of 27 or 28 B. From 60 to 76 gallons of this ley are now run into the pan. steam tmmed on, and gentle boiling appHed for four or five hours, during which the... 

Into an ordinary soa H)opper is tien put 30 cwt. of tie same mixture of fatty, oily, or resinous matters, and 40 cwt of caustic soda (sp. gr. 1 180) mixed with 20 cwt. of water, tie wide being boiled togetier until saponification is complete. Tie former mixture of tly matters, silicato of soda, and soda leys is tien added to m above, and tie whole again boiled togetier, wien 3 cwt of common salt are to be added. Tie boiling is to be continued until tie... 

Oum s Process.—The ol ect of this process is to combine silicates of soda or potash with soap, under pressure, whereby a more perfect union is stated to be effected, and the same method is said to be applicable to ordinary soaps. For yellow soap Mr. Dunn takes tbe materials in tne usnal proportions,—say, tallow 7, palm-oil 3, lesin 3 parts, and caustic soda leys at 21 B. from 140 to 150 g ons. These are placed in a steam boiler (Fig. 20), which is furnished with a man-hole, safety-valve, and all other appendages of such an apparatus, with a thermometer pping into a chamber of meronty. At A is a feed-pipe, and at b a... 

---