AN IMPROVED METHOD OF OBTAINING CRYSTALLISABLE SUGAR FROM RAW SUGAR SACCHARINE JUICES, SYRUP, AND MOLASSES
Year: 1882

page_text: LETTERS PATENT to John Henry Johnson of 47 Lincolns Inn Fields in the
County of Middlesex Gentleman for an invention of "AN IMPROVED METHOD
OF OBTAINING CRYSTALLISABLE SUGAR FROM RAW SUGAR SACCHARINE JUICES,
SYRUP, AND MOLASSES."-A communication from abroad by August Wernicke
of Halle on the Saale Prussia Engineer and Wilhelm Pfitzinger of Prague
Austria Chemist.
COMPLETE SPECIFICATION filed by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 17th April 1882.
JOHN HENRY JOHNSON of 47 Lincolns Inn fields in the county of Middlesex,
Gentleman, AN IMPROVED METHOD OF OBTAINING CRYSTALLIZABLE SUGAR FROM
RAW SUGAR, SACCHARINE JUICES, SYRUP AND MOLASSES, a communication from
abroad by August Wernicke of Halle on the Sanle, Prussia, Engineer, and Wilhelm
Pfitzinger of Prague, Austria, Chemist.
The method of obtaining crystallizable sugar which forms the subject matter of
the present invention, is based on the property of acetic acid of being a solvent of
all foreign matter contained in raw sugar, in saccharine juices, in syrup and in
molasses, while crystallizable sugar is absolutely insoluble therein.
In order to obtain crystallizable sugar from raw sugar, it is advantageous first
of all, to free the latter from the greater part of the water which it contains, by a
drying-process carried out with application of heat. After having been cooled to
below 70 degr. centigr., the sugar is intimately mixed with from 50 to 70 per cent.
or thereabout, of its weight of concentrated acetic acid, the mixing being carried
out in a closed receptacle having, by preference, the form of a horizontal cylinder,
and provided with a stirring-apparatus. The mixture is thereupon drawn off, and
allowed to remain at rest and to cool in other vessels fitted with covers, and which
may have a capacity of eight cubic feet. After a certain time, say from 36 to
48 hours, nearly all sugar has separated or crystallized out in pure state, while the
mother-lye consists in the acetic acid containing in solution all the foreign
substances with but traces of sugar. The bulk of this liquid having been drained
off from the sugar, the rest is extracted on a centrifugal drying-machine or in any
other known manner. If it should be required, the sugar is comminuted before it
is brought into the said machine. In order to complete its purification of adhering
lye, the sugar is washed on the machine with some pure acetic acid, whereupon it
is dried in a closed iron cylinder provided with a stirring-apparatus and heated by
steam to a temperature of about 106 to 110 degr. centigr. For the purpose of
recovering the acetic acid which is evaporated from the sugar, the vapours are

page_text: conducted into a condensing-worm. Instead of washing out the sugar on tho
centrifugal machine by means of acetic acid, it may also be freed from the residuo
of mother-lye by means of a solution of sugar.
When the sugar contained in saccharine juices, molasses or syrup is to be
extracted, the liquid is concentrated as much as possible, i.c. to from 45 to 50 degr.
Benumé, by evaporation in vacunın. After having been cooled to below 70 degr.
centigr., the concentrated acetic acid is added, of which in this case from 75 to
90 per cent of the weight of the saccharine liquor are required, according as it is
more or less concentrated. The mixing with the acid, which requires but a few
minutes of time, is again carried out in a closed vessel with stirring-apparatus.
Also tho further treatment of the liquor and of the sugar separating or crystallizing
out therefrom, is substantially the same as hereinbefore described.
In case the raw sugar, the molasses, &c., are not mechanically mixed with
impurities, the sugar obtained by this process is generally sufficiently white; in the
contrary case it must be subjected to a further purification by dissolving, filtering
and reconcentrating it.
The acetic acid to be employed must be of a high degree of concentration,
Cepecially when saccharine liquors, syrup or molasses are to be trented. In this
case it is preferable to use an acid containing from 98 to 100 per cent of pure acid.
For molasses and other saccharine liquors which are evaporated to a density of
from 50 to 52 degr. Beaumé, an acid of a strength of 90 per cent would, however,
bo suflicient, and for raw sugar an acid still somewhat less concentrated might be
used.
In order to recover the acetic acid from the mother-lye, the latter is distilled,
preferably in a still made of cast iron and provided with a cover and n condensing-
worm of earthen-ware. The acid thus obtained is subsequently to be freed from
the water which it has taken up from the sugar, the molasses, &c. This may be
done by means of bisulphate of soda or of chloride of calcium, either of which have
to be employed in anhydrous state. If the latter sult is used, it is necessary to
cause the inuriatic acid evolved during the process of distillation, to be absorbed
by the medium of dry acetate of soda, which is put into a vessel inserted between
the head of the still and the condenser. If the degree of concentration attained by
the aforesaid salts should not be sufficient, the acid has to be converted by addition
of lime into acetate of lime, which, after having been completely dessicated, is
decomposed again by sulphuric acid for the purpose of liberating the acetic acid,
which is then completely concentrated.
The residue froin the distillation of the acetic acid may be utilized as manuro
or for producing ammonia, methyl, potash, &c.
Having thus described the nature and object of this invention and the manner
in which it is to be carried out in practice, as communicated to me by my
correspondents, I hereby claim as new and important feature of the same:
The method of obtaining puro crystallizable or crystallized sugar from raw sugar,
saccharine juices, syrup and molasses, by adding concentrated acetic acid to the
raw sugar or the saccharine liquor, allowing the sugar to separate or crystallize
out, liberating the sugar from the mother-lye by mechanical means; and finally
evaporating the residue of acetic acid or water, or of acid and water, substantially
as herein before described.
In Witness whereof 1, the said John Henry Johnson, have hereunto set my
hand and seal this fifteenth day of April in the year of our Lord One