US611381A - Georg kassner - Google Patents

Description

NiTnn STATES PATENT Trice,

PROCESS OF SEPARATING SUGAR S FROM MOLASSES.

SPECIFICATION formingpart of Letters Patent No. 611,381, dated September 2'7, 1898.

Application filed December 27, 1895.

T0 aZZ whom it may concern:

Be it known that I, GEORG KASSNER, professor, a subject of the German Emperor, and a resident of Munster, in the Province of estphalia and German Empire, have invented certain new and useful Improvements Relating to the Separation of Sugar from Sacchariferous Solutions, Juices of Plants, and the Like, of which the following is a specification. This invention relates to a process for the separation of cane-sugar and other varieties of sugar from sacchariferous solutions, juices of plants, and the like. 1

Experiments made with a view to testing the process of separation of cane-sugar or other sugar varieties in the form of lead sucrate by the employment of protoxid of lead, hydrated or not, or mixtures containing these bodies either originally or as a result of chemical treatment -such, for example, as combinations of salts of lead with caustic alkalies or alkaline earths or the like-have led to the discovery that it is not necessary to employ the sugar solutions to be treated in a state of concentration, as was suggested at first as lead throughoutthev mixture, may be dispensed with. I

It will be readily understood that the possibility of, first, doing away with mechanical means for agitating the liquid; second, avoiding artificial heating, and, third, employing Weak or only very slightly sacchariferous solutions constitutes a by no means unimportant improvement on the original process, for it enables not only a considerable proportion of power and labor to be saved, but also far less fuel and time to be expended than hitherto, since owing to this modification it is no longer necessary to boil down diluted or but slightly-sacehariferous solutions, vegetable extracts, and the like to a predetermined con- Serial No. 573,525. (No specimens.)

centration when such solutions are to be treated by means of oxid of lead for the purpose of separating the sugar contained there in, while by taking advantage of my recent observations, which shall be hereinafter reported, even the weakest sugar solutions may be without any difiiculty freed from the least vestiges of sugar without resorting to such boiling-down process.

The advantages named may be realized by employing the oxid (protoxid) of lead,whether hydrated or not, not in its original condition, but in a finely-divided, porous, and, asit were, spongy state. The abovementioned lead preparations are obtained in this form mainly by mixing them with indifferent foreign bodies, and as such may be particularly recommended light spongy voluminous substances-such as vegetable or animal fiber, wood-shavings, sawdust, wood-fi0ur,) cellu lose fiber, and the like, also asbestos, carbonate of magnesia, carbonate of lime, and other mineral bodiesprovided always that they are insoluble and capable of exercising no chemical action upon sugar and oxid of lead.

My experience points to the fact that a mixture of oxid (protoxid) of lead or mixtures containing these bodies either originally or as a result of chemical treatmentsuch, for

example, as combinations of salts of lead with caustic alkalies or alkaline earths or the like with one-tenth of its weight of cellulose fiber will present the oxid of lead divided or displayed in a porous spongy condition, and that it is uncommonly efiective in this form. I have ascertained, moreover, that it is not even necessary to add foreign indifferent bodies to the oxid (protoxid) of lead, whether hydrated or not, or mixtures containing these bodies either originally or as a result of chemical treatmentsuch, for example, as combinations of salts of lead with caustic alkalies or alkaline earths or the likein order to insure the best possible distribution of such oxid, but that sucrate of lead itself affords the best medium for the fine division of the oxid of lead and the one most certainly conducible to success. As a matter of fact sucrate of lead is a spongy voluminous body as it is per se, and by means of its numerous needle shaped crystals it has an action similar to that of cellulose fiber, inasmuch as it will keep oxid of lead in suspension when it is added thereto in a pulpy condition, and will consequently prevent it from precipitating. Moreover, an extremely important chemical catalytic effect has to be taken into account in this connection. Sucrate of lead will become light and spongy and form what is known as basic sucrate of lead if a somewhat considerable proportion of oxid of lead be added thereto. Now the peculiarity of these basic sucrates is that they exercise a very rapid action upon the sugar, producing bisucrate, G, I I O,,(PbO) as a result, such bisucrate of lead being in its turn adapted to fix or separate the oxid of lead in its vicinity and to convert it into basic sucrate of lead, trisucrate, (O, I*I,,,Pb O,,,) and the like, and so on, and the sucrate of lead in a thoroughmixture such as this will display a valuable transmitting action intermediate between the oxid of lead and the sugar. The divers kinds of sugar have a tendency to combine in different proportions with oxid of lead; but only certain combinations are sufficiently constant to form the basis of a technical process. The others do not resist certain influences, such as water, diluted alkalies, heat, and the like. Thus, taking, for instance, cane-sugar, the constant sucrate is the di lead sucrate or the combination correspondingtotheformula O H O flbOh,forming a compound which excels by its insolubility and its capacity to crystallize. I have heretofore published the formula of the above composition with water as Pb,O,. I-I, O 5H O and C, I*I, O,,2PbO5H,O in Dt'nglers Poly technische Journal, 1895, volume 298, pamphlet 5. Nevertheless it must be assumed that when cane-sugar is mixed with a larger percentage of lead oxids than would correspond to the above formula the sugar inclines to form other sucrates containing a greater percentage of lead. Now I have discovered that in the act of becoming decomposed from these poly lead sucrates, or, as the phrase is, in stain nascendi, these lead oxids are specially active and greedily combine with sugar if an opportunity offers. Thus the advantage is explained which is gained by using a mixture of already-form ed sucrates and lead oxid. In this mixture, which is prepared before operating upon the sugar solutions that are to be worked, an excess of lead compounds is present, and therefore poly lead sucrates are formed. Upon adding this mixture to sugar solutions these polysucrates are decomposed, forming a mixture of the above-mentioned disucrate, C, I*I O,,(PbO) and oxids of lead in stain nascendi, and the latter then combine with the sugar contained in the solution much more greedily than if pure lead oxids were employed, forming in their turn the same di lead sucrate as above. This I have discovered by observing the surprisingly-quick formation of the constant sucrates when this method is employed. The formation takes place without the aid of heat when the sugar solution is simply filtered through a stratum of lead oxid and lead sucrate. Above the stratum sugar solution is found, but below pure water is filtered off. Thus perfectly is the sugar retained, an effect which cannot be obtained by using pure lead oxids as a filter. These important discoveries may be applied to practical purposes in various ways, some of which will be hereinafter described.

A mixture is prepared of oxid (protoxid) of lead, either hydrated or not, and of one or more of the indifferent materials above named, such as cellulose fiber, hairs, sawdust, wood-shavings, magnesia, carbonate of lime, and the like, or, better still,with sucrate of lead itself, no matter whether this sucrate comes from a previous operation and has not yet been freed from the soluble salts or whether it has already been properly washed. Lead sucrate is most suitable as an admixture and a distributing medium for this further reason, that no superfluous weight is added with it to the substances under treatment. The mixture thus obtained may be used either in a moist and pulpy or in a dry powdered condition or, indeed, in the form of porous lumps, sufficiently rigid, however, not to get readily out of shape.

WVhen the mixture of hydrated or unhydrated oxid (protoxid) of lead or mixtures containing these bodies with one or more of the before-mentioned distributing agents or with lead sucrate itself (which mixture while moist is in the condition of pulp) has been prepared, it is filled in'to suitable filtering apparatus, the cloths, frames, or plates of the filtering-presses or the like being coated therewith,and then the sacohariferous juice is simply allowed to filter through the pulp or semiliquid' mass containing oxid of lead, preferably under pressure.

It will of course be understood that the sugar solution before being filtered may be stirred up once or several times together with the pulpyoxid-of-lead mass, or, in accordance with the original application for patent, bearing date August 21, 1895, and serially numbered 559,987, it may before filtering be kept in suspension by the agitating process therein described. \Vhen the sugar solutions have been filtered,water is simply sent through the apparatus and filteringsheets, whereby the sucrate which has formed in them is soon washed out.

A better method of operation than that of using pulpy oxid-of-lead mixture will in many instancesfor example, in treating concentrated juice-be found to consist in forming and making use of rigid porous lumps made of the said mixtures. To obtain these, pulpy 2'. e., semiliquid or moist-lead sucrate is mixed with oxid-of-lead powder,a small quantity of sugar solution, molasses, or the like being first added, if desired, and lumps or blocks of spherical, brick, or other shapes are formed with the mixture. After allowing the blocks to rest exposed to the atmosphere for a short time they will be found to have hardened sufficiently not to become pulpy again in water. To accelerate the hardening process, heat, either by itself or in combination with a vacuum, may be employed, if necessary. This method is particularly to be recommended when it is desirable to produce very light lumps, traversed by hollow spaces or interstices, for as the vacuum is being produced the rarefied gases will escape and the bulk of the lumps will thereby be increased, and they will be converted into spongy bodies. The lumps of lead oxid mixture are now charged into suitable vessels in such a manner that while the vessels are filled somewhat closely there yet remain numerous interstices between the lumps to allow the liquid to be subsequently introduced and then discharged to pass without encountering any resistance. The sacchariferous liquors thus prepared are now admitted into the vessels. Owing to the formation of the hydrated or non-hydrated oxid of lead in a light spongy form and to the spongy structure of the lumps in the vessels the sugar may penetrate the porous lumps to the core and be thus readily and in a comparatively short time separated from the hydrated or non-hydrated oxid (protoxid) of lead or mixtures containing these bodies, accessible on all sides, or from the above-mentioned basic sucrates of lead, and finally obtained in the form bisaccharate of lead. Vhen the sacchariferous fluid after having been left in the vessels for a more or less protracted space of time has yielded up either the whole or the greater part of its sugar to the oxid-of-lead mixture, the fluid remaining behind is drawn off and fresh sugar solution is admitted and caused to act in the same way as the preceding supply, this being continued as long as any appreciable amounts of free oxid of lead are still contained in the porous lumps or blocks.

The fluids which in the course of the operation have become poor in sugar, and consequently more diluted and weak, are freed from the last remnants of their sugar by the first-mentioned process of filtration through the medium of pulpy oxid-of-lead mixtures, so as to scarcely retain any traces thereof.

It will thus be seen that a rational desaccharification is the object to be attained. It is advisable to combine the two methods of operation herein described, which are merely two different forms in which the identical process may be carried out, the concentrated solutions, together with porous lumps or blocks of oxid-of-lead mixture, being first allowed to remain at rest for a short time, after which the solutions poor in sugar (which may be simply the residual liquors from the solutions first treated) are filtered through layers or sheets of pulpy oxid-of-lead mixture after having been stirred up, with or without oxid of lead mixture, so that the sugar therein is brought to a state of suspen- S1011.

A further advantage of the process herein described is that the washing of the sucrate, and more particularly that sucrate which is obtained in the form of the spongy porous oxid-of-lead mixture as originally employed, may readily be performed in the identical vessels 011 the walls of which the sucrate has formed. After the discharge of the desaccharified solution the vessels need only be filled with water or with the diluted liquors or lyes remaining behind after the washing operations in accordance with the principle of counter-currents, such liquors being then allowed to act for a certain space of time by endosmose upon the pieces of sucrate still containing salt, after which the washing liquid (or salt solution) is removed and, if necessary, replaced by a fresh supply. Upon the completion of the washing operation saturation of the sucrate may be proceeded with in a the same vessels, the pieces or lumps of sucrate lightly superposed in layers having the advantage not only of offering no resistance to the saturation-gases containing carbonic acid, but, indeed,-of presenting a widely-extended surface to such gases, and thereby materially facilitating saturation, owing to their porous nature.

It will be understood that the pieces of sucrate may also be triturated or crushed into a pulpy mass, if desired, such an operation being attended with no difficulty whatever and requiring but a moderate display of power, the sucrate being then saturated in this crushed condition. Part of the pulp may be subsequently utilized in the preparation of fresh mixtures.

The lead sucrates obtained by this process are separated from the solution byffiltering and are then decomposed by treatment with carbonic acid, whereby sugar and lead carbonate are obtained. The latter substance is freed from organic admixtures by heating and is then decomposed byroasting, so as to obtain lead oxid and carbonic acid, which can again be used for the treatment of sacchariferous solutions.

\Vhile the following claims refer in terms to the employment of oxid of lead, I would state that in its place hydrate of lead, either originally or as a result of chemical treatment, might be used without departing from the spirit of my invention or avoiding the scope of said claims.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, 1

with oxid of lead and treating the mixture with such solution.

3. In the separation, extraction or manufacture of sugar from aqueous solutions, the process herein described of producing sucrates, which consists in mixing lead sucrate with powdered oxid of lead, forming blocks out of the mixture so produced, and treating this mixture with aforesaid solution.

4. In the separation, extraction or manufacture of sugar from aqueous solutions, the

process herein described of producing sucrates, which consists in mixing lead sucrate with powdered oxid of lead, producing therefrom bodies of a porous nature, and treating the mixture with such aqueous solution.

Signed at Cologne, in the Empire of Germany, this 10th day of December, 1895;

GEORG KASSNER.

\Vitnesses:

MARIA NAGEL, WILLIAM H. MADDEN.