 |
Home > TECHNICAL TREATISE ON SOAP...
Previous Next The best candle and soap tips online! TECHNICAL TREATISE ON SOAP AND CANDLES. MATERIALS USED IN THE MANUFACTURE OP SOAPS. 29 vegetables which furnish it, or from the countries it comes from. However, vegetables are not the only source from which potash ia extracted. A great part of the minerals which compose the crystalline rocks contain it in variable quantities, in combination with different acids, principally silicic acki. Pure potash is not met with in nature. However, the principal source of potash is the combustion of vegetables. The presence of potash in vegetables was an enigma for a long time, for vegetables, properly so called, do not create potash; but they have the valuable faculty of borrowing from the soil and manures the soluble salts they contain, among which are potash and soda, combined with various acids, and especially organic acids. During the combustion the organic acids are decomposed, and the carbonic acid resulting from this decomposition combines with potash and soda to form subearbonates of these bases. Of late years potash has been procured in great abundance from the salt-rocks in Stassfurt, in Prussia, and Kalucz, in Hungary, principally from carnalite, a chloride of potassium and magnesium. The magnesia is precipitated from the solution with hydrochloric acid, leaving the potassium salt; the chloride of potash is then submitted to the process described for the production of caustic soda from chloride of soda (Leblanc's process), and. caustic potash is thus produced in quantities that have almost superseded, on the continent, all potashes from other sources. Independently of the carbonates of potash and soda, the ashes of vegetables contain also several other salts, particularly the chlorides of potassium and sodium, sulphates of potash and soda, carbonates and phosphates of lime and magnesia, silicate of alumina, and a certain quantity of organic matters not decomposed, which color the .saline residuum obtained by the lixiviation of the ashes. By calcining this residuum to redness in a reverberatory furnace, white potash is obtained. We must here make an important observation. Vegetables which grow on the sea-shore, or in the neighborhood of salt mines, gire by their incineration very small quantities of potasli; they principally contain soda. Those, on the contrary, which grow inland and in soils free from chloride of sodium, yield, by their combustion, ashes which contain, principally carbonate of potash, mixed with very small proportions of soda. These vegetables are the only ones employed in the preparation of the carbonate of potash. Independently of the culture, it -is easily demonstrated that the quantity of ashes furnished by different vegetables is not identical. It varies considerably according to the different species, the influence of climate, and particularly the nature of the soil in which thevhave'grown. Experience also proves that the young parts of the plants, in which circulates a rich and abundant Bap, are those which contain the greater percentage of salts of potash. It is thus that the leaves of a tree yield niore potash than the branches, and these more than the body of the tree. D'Arcet, who has experimented much on the manufacture cf alkalies, has published an interesting paper on' the extraction of potasli from the ashes of the horsechestnuti He ascertained that one hundred parts of dried chestnuts yielded nearly half their weight of ashes at 65 alkslimetric degrees. The following table gives the quantity of potash contained in certain vegetables:— 30 TECHNICAL TREATISE OX SOAP AND CANDLES. MATERIALS USED IK THE MAHUFARTURB OP SO/PS. 31 of (he 100 parts of— Willow Elm .... Oak .... Poplar Yoke-elm . Beech .... Pitch-pine tree . Vine .... Stalks of corn Wormwood Fumitory . Fumitory . Vines of hops Vines of Windsor beans Common lie Lib . Common thistle . Ferns . Reed . Beed . Turnsole Genista Heath . Stalks of com . Erigeron Cans.deuse . ; Horseclicstmittree hark, Centaury . Burdock leaves Camomile . Orange leaves Comparative Table of the Quantities of Ashes and Potash contained in different Vegetable*. Quntltrof Qa»Btlty of Cb«nl't who mftda the uh>i. alkali. 2.80000 0.28400 Kirwan. 2.36727 0.39000 . " 1.851 «r> O.tf.343 Pert tits. 1.2:1176 0.07481 1.12$:i0 0.1!io40 li 0.5H4Jta O.H.ri72 0.31740 0.73180 de Fontenelle. 3.375)00 0..V.0OO Kirwaa. 8.S60OO 1.7.1000 !>. 74400 7.30000 LI 21.9W00 7.90000 t( 2'3.101100 8.01500 de Fontenelle. lo.ooimo 8.01500 Tliillaye. 10.00000 4.12900 11 10.fi7lt*U 3.50330 Porluis. 4! 04205 0.53734 "? r,.oo;si O-fiSoiK) it 3.tCiHU5 0.72334 11 3.;i;f.VJ3 0.50811 it 2U.7OO0O 4.00000 " 3.00-.00 1.30870 dB Fontenelle. 2.010W 0.84000 (1. Hi 100 2.00100 10 HOI UK) 2.B.V300 BotiilloQ Lagrange. 18.4WO0 4.84000 de Ponteuelle. 8.44000 2.00800 Ktnvnn. 4.^4000 0.W84O0 di? Fontenelle. 5.63!M)0 1.80000 it 14.240U0 2.40400 it The above numbers give in approximative idea of the quantities of ashes left by the different species of vegetables, but these numbers are not absolute. The different parts of the same plaits do not yield the same quantity of ashes, as is shown by the following tab.e:— Oik. Beech. Toke-olm. Ptnc. Bark 8.00 6.02 13.4 Leaves 5.50 ... ... 2.00 Trunk 3.30 0.01 0.6 1.19 Aahes, whatever h the part of the vegetable which has furnished them, present a complex composition, variable with each species, and even with every individual. The compounds they contain are, some solubla, some insoluble. The first, among which is the carbonate of potasli, are the only onea employed in industry, after separating them, by washing, from the insoluble compounds. The relative proportions of the soluble and insoluble salts present great differences, as is shown in the following table, in which Berthier has given the quantities per cent, of soluble and insoluble matters. Previous Next
|
|
