Improvements in the Process of and Means for Refining Sugar.
Year: 1898

page_text: Date of Application, 12th Apr., 1898-Accepted, 20th May, 1898
COMPLETE SPECIFICATION.
Improvements in the Process of and Means for Refining Sugar.
I, ROBERT AUGUSTUS CHESEBROUGH, of No. 24, State Street, in the Borough of
Manhattan, in the City of New York and State of New York, United States of
America, Manufacturer, 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 :—-
My invention relates to the refining of sugar by means of a filtering agent
consisting of natural clay prepared as herein described, such agent taking the place
of bone-black, as now commonly used by sugar refiners. The natural clay which I
prefer, and have most successfully used for the purpose of my invention, is one
found in certain parts of the States of Florida and Georgia, United States of
America, and is now mined in quantities at Quincy in the County of Gadsden in
the State of Florida.
It has at present no specific name, though it is sometimes called "Florida fuller's
earth" and "infusorial earth." For the purpose of identification, it may be described
as of a greyish-white color, of a shale-like or laminated structure, and clinging to
the lips when a piece of it is inserted between them. The composition of one
somnla dried in a steam bath is as follows

page_text: state for this purpose. As mineral, animal, and vegetable oils and products do not
so act upon this clay, there is no difficulty to be overcome in their case, but for
refining sugar, unless means could be provided for preventing the disintegration of
the clay by the water in the saccharine solution without injury to its decolorizing
power, it could not be used.
My invention is based upon the discovery that, by carbonizing the pores of the
clay as hereinafter explained, I not only render it insoluble or not liable to
disintegration in water, but also increase its decolorizing power on sugar.
To effect this carbonization, I take the clay as it comes from the mine, dry it in
the sun until dry enough to grind, then grind it in mills to a suitable degree of
fineness which ordinarily is from 20 to 50 mesh, but varies amongst the different
sugar refiners.
I then heat it slowly in ordinary retorts of any shape or pattern
to about 320° F., which expels all the moisture, and while hot, I mix it thoroughly
with about 25 per cent. (more or less) of residuum of a specific gravity of about
28° by Baumé at 60° F., obtained by the evaporation of crude petroleum. The
mixture of clay and oil is then slowly and carefully heated to about 800° F., either in
closed clay retorts, or, preferably, in revolving iron retorts, until the oil is burnt off,
leaving behind a residual carbon or coke which will be found to have coated the
pores of the clay, giving it the appearance of bone-black. In this condition, it is
suitable for use in filtering saccharine liquids, exactly in the manner that bone-
black is now used.
Care must be taken that the heat of the retort is not high enough to fuse the
clay in any degree, because, through such fusion, the pores are closed and welded,
thus decreasing their number and the decolorizing power of the clay. It is better
to use a retort which rotates, or the contents of which can be stirred from time to
time, without admitting air to any appreciable extent.
Practice and experience will soon teach the operator how to obtain the best
results in the operation of the retort, the amount of heat to be used, and the
amount of stirring required. After the clay is withdrawn from the retort, and
sufficiently cooled for use in the filter, it will be found that it has assumed physical
property similar to that of bone-black in regard to its behaviour with water, in that,
instead of slaking or disintegrating, as did the new clay, it now merely absorbs
water without its structure being disintegrated. After the clay, thus carbonized,
has been employed for some time for filtration, the saccharine matter remaining in
it can be washed out with water, and the clay again revivified for use by reheating
in the retorts, and this process may be repeated many times.
If its power of
decolorizing the sugar weakens after using several times, it may be restored by
again adding, say, five to ten per cent. of the petroleum residuum, and then retort-
ing as before. Other hydrocarbon oils, or other oils and carbonaceous substances,
may be used to carbonize the pores of the clay to more or less extent, but the
petroleum residuum herein described has been proved by my experiments to be the
best and cheapest material which I know of, and has given the best results.
By the use of this invention, a reduction in the cost of manufacturing sugar is
obtained, as the cost of the clay is less than that of bone black, and when prepared
as herein shown, its relative power to decolorize is equal, if not superior.
Another advantage over bone black, is that it contains no decomposing animal
matter, or ammoniacal products, which often contaminate bone-black.
This clay, which has been used in its natural state as hereinbefore described by
refiners for filtering mineral oils and their products, is, after that use, available,
with the absorbed oil contained therein, for carbonization as herein described, and
may then be used for sugar refining.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is :-
1. The improvement in the process of refining sugar, consisting in filtering the 5
saccharine solution through clay the nores of which ha

page_text: coated with carbon or coke, to prevent the disintegrating action of the water of
said solution on said clay, substantially as herein described.
2. Carbonized porous clay as a new medium for refining saccharine solution by
filtration.
NEWTON & SON,
Agents for the Applicant.