Improvements relating to the Separation of Sugar from Sacchari- ferous Solutions, Juices of Plants, and the like.
Year: 1895

page_text: Date of Application, 3rd Dec., 1895-Accepted, 15th Feb., 1896
COMPLETE SPECIFICATION.
Improvements relating to the Separation of Sugar from Sacchari-
ferous Solutions, Juices of Plants, and the like.
I, Dr. GEORG KASSNER, of 15 Nord Street Munster in Westphalia, in the
Empire of Germany, Professor, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
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.
Further experiments, made with a view to testing the process of separation of
cane sugar or other sugar varieties in the form of lead saccharate, by the employ-
ment of protoxide of lead,--hydrated or not,-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 in the Specification of former Patent No. 14925 August 7th 1895,
as one form in which the process therein described might be carried out.
Furthermore, it has been ascertained by recent experience that the mixtures
need not be heated by artificial mediums; and, again, provided certain conditions,
which shall be hereinafter stated are complied with,the energetic agitation and
stirring of the mixtures of protoxide of lead and sugar solution, which would other-
wise be necessary for the purpose of ensuring a uniformn division and suspension of
the oxide of lead throughout the mixture, may be dispensed with.
It will be readily understood that the possibility of (1) doing away with
mechanical means for agitating the liquid; (2) avoiding artificial heating; and
(3) 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 labour to be saved, but also far less
fuel and time to be expended than hitherto; since, owing to this modification, in
is no longer necessary to subject diluted, or but slightly sacchariferous solutions,
vegetable extracts and the like to a preliminary steaming process by means of
oxide of lead, for the purpose of separating the sugar contained therein; while
by taking advantage of the recent observations of the applicant, which shall be
hereinafter reported, even the weakest sugar solutions may be without any difficulty
freed from the least vestiges of sugar.
The advantages named may be realised by employing the oxide (protoxide) of
lead whether hydrated or not-not in its original condition, but in a finely
divided, porous and, as it were, spongy state. The above mentioned 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 fibre, wood-shavings saw-dust
("wood-flour"), cellulose fibre and the like; also asbestos, carbonate of magnesia,
carbonate of lime, and other mineral bodies, provided always that they are
insoluble and capable of exercising no chemical action upon sugar and oxide
of lead.
The applicant's experience points to the fact that a mixture of oxide (protoxide)
of lead with 1 of its weight of cellulose fibre will present the oxide of lead
divided or displayed in a porous spongy condition, and that it is uncommonly
effective in this form.
The applicant has ascertained, moreover, that it is not even necessary to add
foreign indifferent bodies to the oxide (protoxide) of lead-whether hydrated or
not-in order to ensure the best possible distribution of such oxide; but that

page_text: saccharate of lead itself affords the best medium for the fine division of the oxide
of lead, and the one most certainly conducive to success. As a matter of fact,
saccharate of lead is a spongy voluminous body as it is-per se-and, by means of
ifs numerous needle-shaped crystals, it has an action similar to that of cellulose
fibre inasmuch as it will keep oxide 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; saccharate of lead will become light and spongy, and
form what is known as 'polysaccharate" of lead if a somewhat considerable
proportion of oxide of lead be added thereto. Now the peculiarity of these
polysaccharates is that they exercise a very rapid action upon the sugar, producing
bisaccharate of lead as a result; such bisaccharate of lead being, in its turn,
adapted to fix or separate the oxide of lead in its vicinity, and to convert it into
polysaccharate of lead (trisaccharate and the like), and so on; and the saccharate
of lead, in a thorough mixture such as this will display a valuable transmitting
action, intermediate between the oxide of lead and the sugar.
These important discoveries may be applied to practical purposes in various
ways, some of which will be hereinafter described.
A mixture is prepared of oxide (protoxide) of lead-either hydrated or not-
and of one or more of the indifferent materials above named, such as cellulose fibre,
hairs, sawdust, wood shavings, magnesia, carbonate of lime and the like, or-better
still with saccharate of lead itself, no matter whether this saccharate comes from
a previous operation and has not yet been freed from the soluble salts, or whether
it has already been properly washed. Lead saccharate is most suitable as au
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.
When the mixture of hydrated or unhydrated oxide (protoxide) of lead with
one or more of the before-mentioned distributing agents, or with lead saccharate
itself (which mixture, while moist, is in the condition of pulp) has been prepared,
it is filled into suitable filtering apparatus, the cloths, frames or plates of the
filtering presses or the like being coated therewith; and then the sacchariferous
juice is simply allowed to filter through the pulp or semi-liquid mass containing
oxide 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 pulpy oxide of lead
mass; or, in accordance with the original Patent, it may, before filtering, be kept
in suspension by the agitating process therein described.
When the sugar solutions have been filtered, water is simply sent through the
apparatus and filtering sheets, whereby the saccharate, which has formed in them,
is soon washed out.
A better method of operation, than that of using pulpy oxide of lead mixture
will, in many instances (for 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 (i.e. semi-liquid or moist) lead saccharate is mixed with
oxide 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 shape 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 in the evacuation stage, the rarefied gases will escape
and inflate the lumps into spongy bodies.

page_text: The lumps of lead oxide 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 distribution or expansion of the hydrated or non-hydrated oxide of lead in a
light spongy form, and to the spongy structure of the lumps in the vessels, the
sugar in accordance with the laws of endosmose (or dialysis)-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 oxide (protoxide) of lead, accessible
on all sides, or from the above-mentioned polysaccharates of lead, and finally
obtained in the form bi-saccharate of lead.
When 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 oxide 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
oxide of lead are still contained in the porous lamps 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
oxide 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 oxide 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 oxide of lead
mixture, after having been stirred up, with or without oxide of lead mixture,-50
that the sugar therein is brought to a state of suspension.
A further advantage of the process herein described is, that the washing of the
saccharate, and more particularly that saccharate which is obtained in the form of
the spongy porous oxide of lead mixture, as originally employed, may readily be
performed in the identical vessels on the walls of which the saccharate 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 eudosmose, upon the pieces of
saccharate 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 may be proceeded
with in the same vessels; the pieces or lumps of saccharate, 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 saccharate 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 saccharate
being then saturated in this crushed condition. Part of the pulp may be
subsequently utilized in the preparation of fresh mixtures.
The protoxide of lead (or mixtures containing these bodies either originally or
as a result of chemical treatment, such for example as combination of salts of lead
with caustic alkalies or alkaline earthis or the like) brought in the described
manner to a finely divided, porous and spongy state, is for carrying out the
improved process employed in such a quantity that a well defined relation should

page_text: be maintained between the oxide of lead and sugar. The proper proportion for
example, may be to every one molecule of cane sugar, a little over two molecules
of oxide of lead and to every one molecule of " dextrose or "inverted "sugar,
say, from about 1 to 2 molecules of oxide of lead.
"
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
(1.) The separation of cane sugar or other varieties of sugar, from their
solutions, by their treatment with a mixture of hydrated or non hydrated oxide of
lead with indifferent solid bodies of an organic or inorganic nature, such as fibrous
cellulose, carbonate of magnesium, carbonate of calcium or saccharate of lead the
preparation of which may have been completed beforehand and which may also be
mixed with solid substances; the mixtures being employed either in a moist pulpy
condition or in the form of solid resistant material, in lumps or blocks.
(2.) The separation of cane sugar and other varieties of sugar from their
solutions by their treatment with a mixture of hydrated or non-hydrated oxide of
lead with indifferent solid bodies of an organic or inorganic nature such as fibrous
cellulose, carbonate of magnesium, carbonate of calcium or lead saccharate which
may have been formed beforehand and be mixed with indifferent solid substances,
such mixtures being suspended in the solutions; or the solutions along with the
mixtures being allowed to stand at rest; or the solutions being filtered through the
mixtures; or the several methods of treatment herein mentioned being carried out
at the same time.
(3.) In the performance of the process referred to in the 1st and 2nd claims,
the employment of particularly active mixtures obtainable by mixing oxide of lead
with saccharate of lead or inorganic or organic substances capable of exercising no
chemical action upon oxide of lead, saccharate of lead or sugar solutions; the
mixture, unless it be moist already, being made into a pulp by the addition of
water or a small amount of sugar solution, molasses or the like; and pieces, lumps
or blocks of any suitable shape or size being formed from the pulp and allowed to
solidify or harden by exposure to the atmosphere, by the action of heat or by
means of a vacuum, so that, when placed in water, they may not dissolve or become
reduced again to the pulpy condition.
(4.) In the performance of the process referred to in the 1st and 3rd claims, the
decomposition of the separated lead saccharate by its treatment with carbonic acid
-or a gas containing carbonic acid.
Dated this 3rd day of December 1895
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.