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Previous Next The best candle and soap tips online! TECHNICAL TREATISE ON SOAP AND CANDLES. MATERIALS USED IN THE MANUFACTURE OF SOAPS. mercial potashes may be transformed into caustic potash by the following process:— In a large iron kettle, heat 250 gallons of water, which raise quickly to the boiling poin£; add, in successive doses, , 400 pounds of carbonate of potash, and stir the mixture to facilitate the solution. When the suit is entirely melted, pour into the kettle, in portions, 200 pounds of quicklime, previously mixed with double its weight of water, and boil the mixture for two or threehours. The lime combines with the carbonic acid which is united to the potash, and forms an insoluble carbonate of lime, while the Cfiustic potash remains in solution in. the liquor. After a settling of 18 or 20 hours, decant the clear liquor carefully, without disturbing the lime which is at the bottom of the kettle, and this liquor is rapidly evaporated to dry ness in cast-iron kettles. The crude potash obtained is heated to redness in a thick cast-iron kettle, so as to melt it. To give this substance the red color, characteristic of the caustic American potash, add to the melted mass one per cent, of protoxide of copper, the oxidation of which is determined by email proportions of saltpetre. "When the ahade is obtained, run the melted mass into small cast-iron kettles, in which it becomes very hard by cooling. This is tlio usual process of manufacturing caustic potash; but in this country it is conducted more economically. The ashes are directly treated by lime, and the mixture is lixiviated by water. Lyes in a caustic state are obtained, and arc concentrated to drvnesa, and the mass is melted as we have seen. American potash is very caustic, and quickly attracts the moisture of the air. It is much used in the industries, principally in the fabrication of soft soap. In Paris is manufactured a fictitious article, which must not be confounded with the American potash. The latter has really potash for a bast, while the first is a mixture of Caustic soda, salt, and sulphate of potash. The materials are melted together, and are colored red with oxide of copper. Fictitious potash is distinguished by a very strong saline taste, which. American potash does not possess. Ashes made from Tartar.—These ashes are prepared only in countries where whie is made, a ad can be produced ad ran* tageously in California, Ohio, New Jersey; and other States where the culture of the vine is advanced. This alkali, the purest found in commerce, is obtained by the calcination of the dregs of wine. To produce the combustion of these dregs, it is essential to have them perfectly dry. To obtain them in this state, they are introduced into cotton bags, then submitted to a graduated but energetic pressure, so as to extract the wine they contain. This wine is generally very acid, and is used to make vinegar. After the pressure, break the cakes into pieces, and expose them for some time to the air to dry; then burn them in large furnaces having a circular form. Like all vegetable suits with potash for a base, the Ices of wine give carbonate of potash by calcination. This salt results from the decomposition of the tartrate of potash contained in the dregs. When carefully manufactured, the ashes of dregs give one of the best commercial potashes. In this state they contain only a very small proportion of chloride of potassium and sulphate of potash. This alkali is generally in a porous and light mass, having a greenish color with/ blue veins. This color is due to the oxides of iron and manganese. Pure ashes dissolve almost entirely in water, and leave only a. residuum of 7 to 8 per cent, of insoluble matters. 200 pounds of good dregs, perfectly dfy, produce from 10 to 12 pounds of ashes, the titer of which varies between 25 and 33 alkali-metric degrees. When the dregs contain much tartrate of O CD potash, they give, by their combustion, an alkali of a much higher titer. The white potash is obtained by treating the ashes by water, which dissolves the soluble salts, and amongst them the carbonate of potash. The lye is evaporated to dryness, and the mass is bleached in a reverberatory furnace. By this refining, ashes give about half of their weight of white potash; But it is generally in the form of ashea that this alkali is found in commerce. 38 TECHNICAL TREATISE OS SOAP AND CANDLES. MATERIALS USED IN THE MANUPACTUEE OP SOAPS. 39 Potash made from Hett-root Molasses.—Chemical analysis has long since demonstrated that the gaits of potash exist in a lar^e proportion in beet-root molasses. This fact has found a UBeful application in industry. It is to M. Dubrunf'ault that is due the discovery of the processes for extracting potash from the saline residues left after the distillation of the molasses, which is extensively used in the production of alcohol. It is from the saline residues that potash is obtained. Potash, being undecomposable in the conditions in which the operation takes place, is found, after the decomposition of the sugar by fermentation and the extraction of the alcohol by distillation, in the liquid residuum. It is extracted from this residuum by evaporating the water, and by the incineration of the concentrated residuum. The product of the incineration constitutes a light, porous, and friable ma®. It is crude potash ; its titer is from 40 to 50 alkalimetric degreea. The white potash is obtained by lixiviating the crude potash in sheet-iron filters having a cylindrical form. The exhaustion takes place with warm or cold water; the use of warm water is more advantageous, but it dissolves some of the sulphuret. Cold water gives a purer product, but the operation takes longer, and the residuum is not so well exhausted of its alkali. The lyes marking from 25° to 30° Baumd are evaporated In cast-iron kettles until they mark from 45° to 46°. They are poured while boiling into sheet-irou vats; and after eight or ten ilays, a very abundant crystallization of different salts is obtained. Among the crystals we meet chloride of potassium, and the larger part of the carbonate of soda, which was dissolved in the lyes. The mother liquors are very rich in carbonate of potash. To extract this salt, they are concentrated in cast-iron kettles with flat bottoms, until they are reduced to a syrupy consistency. By continuing the operation, the niaas swells considerably, and becomes dry and friable. The drying is accelerated by stirring with an iron stirrer. Thus obtained, the potash is not pure, but is mixed with extractive matters, which color it; it contains besides from twelve to eighteen Previous Next
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