Process for Purifying and Decolourising Saccharine Juices and Sugar Solutions.
Year: 1893

page_text: Date of Application, 19th Sept., 1893
Complete Specification Left, 16th Oct., 1894-Accepted, 11th Aug., 1894.
PROVISIONAL SPECIFICATION.
Process for Purifying and Decolourising Saccharine Juices and Sugar
Solutions. generally.
I, CARL STEFFEN of IV Hengasse 10 Vienna, Austria, Gentleman, do hereby
declare the nature of this invention to be as follows:-
This.invention consists mainly in subjecting the saccharine juices of beet root and
cane sugar factories after treatment in, the known manner with lime or baryta &c.
and saturation with carbonic acid, or after separation from the deposit and so called
saturation sludge, to a novel combined action firstly of sulphurous acid secondly
animal charcoal and thirdly of lime, baryta, strontia, alumina &c., under observance
of certain limits of, temperature, for obtaining an almost perfect and lasting
decoloration and purification thereof.
This process enables notably large quantities of sulphurous acid to be employed
for acting upon the saccharine solutions, without destruction of the sugar; and the
decoloration and purification of the saccharine juices by means of sulphurous acid
and small quantities of animal charcoal in the manner, to be presently described is
such, that the juices operated, upon according to this method yield, first, crystalline
filling material of so pure and slightly coloured a nature that not only these them-
selves, but also their by-products (syrups) can be worked directly into fine white
articles.of consumption. In the refining of raw sugar in sugar, refineries the process
for the decoloration and purification of the raw sugar solutions. is applied in the
same way, the thin cane or beetroot juice of the first described process being
replaced by, an aqueous solution of the raw, sugar in any desired degree of
concentration.
This new treatment of the above described, separated juice, which I will call
"thin juice," is. as follows. :-
1. The thin juice freed from the separation sludge or the separation and saturation
sludge is, in order to enable it to take up sulphurous acid in larger quantities without
danger to the sugar of the juice, cooled down to below those high temperatures
which are usually employed in the separation of the raw juice and its treatment
with lime or, lime and carbonic acid, or other means for effecting its separation
such cooling being effected, to at least below 60° C., preferably between 30 and 40°
or lower. The cooling is effected either by natural cooling of the juice in the
air, or preferably by known artificial means for more rapidly cooling, such as
graduating apparatus, reversed current refrigeration, surface evaporation refrige-
rators &c., with the use of cold water or other cooling liquids or cold air.
2. The thin juice cooled to below 60° C., preferably to between. 30 and 40° or
less, is (in the reverse manner to that in which sulphurous acid is employed at the
present day for beet juices) treated with such a quantity of sulphurous acid and
in such manner, that the liquor receives a strongly, acid reaction, and shews no
further decrease of colour, and all the colouring and non-saccharine constituents
of the juice have entered as far as possible into sulphite and acid sulphite
combinations, which exist. in solution in the strongly acid thin juice. The juices
so treated will, according to the higher or, lower quality thereof, contain in
100 litres of juice from 100 to 250 grammnes proportion of acid (expressed as
sulphurous acid). The sulphurous acid is supplied to the juices in the known
mainer either in the form of gas or, dissolved in water, in liquid form. In the
first case it is advisable to force the sulphurous acid gas, if produced by the
burning of sulphur, by means of a gas pump into the liquid, with effective
distribution, until the above described end is attained.

page_text: 3. This cooled strongly acid thin juice, treated as above described with
sulphurous acid, (contrary to the principle at present observed in practice, of only
filtering beet juices through animal charcoal in an alkaline condition and at, a
temperature of about 60° C.), is subjected at a low temperature (certainly below
60° C. and preferably between 30° and 40° or lower) to the action of animal char-
coal. The latter acts upon the compounds of the sulphurous acid with the colouring
matters and other non-saccharine matters in a very strongly absorbent manner in
the acid juice, so that for the thin juice treated with sulphurous acid in the
manner described only small quantities of animal charcoal are required, for taking
up nearly the whole of the colouring matter, as also large quantities of the other
non-saccharine matters, and consequently to almost completely purify and
decolorize the juice, in such manner as is not even attainable by the use of large
quantities of animal charcoal without the previous treatment of the juice, as
described, with sulphurous acid. Also in this process there is no destruction of
sugar.
For 100 litres of thin juice treated with sulphurous acid as described there are
only required from one to two kilogrammes of animal charcoal, according to the
original quality of the juice, which is applied in the usual manner in charcoal
filters, or charcoal filter presses, and which is afterwards reburnt and again
employed for the same purpose.
4. The decolorised acid juice coming from the animal charcoal filters, is, within
the above mentioned limits of temperature, treated according to its percentage of
acid (reckoned as sulphurous acid) with lime (milk of lime or baryta strontium,
alumina &c.), a slight excess being employed for juices from beetroot, in order to
I produce an alkaline reaction, while for cane juice only sufficient is added for
obtaining a neutral reaction of the juice, whereby the acid present is converted
into an insoluble lime salt (or baryta salt &c.), which is precipitated from the
liquid under heating and is separated from the juice by known means, such as filter
presses, filter bags &c. in order that, in the following treatment thereof at a
higher temperature in the evaporating apparatus or vacuum pan, any destruction
of sugar by acid is prevented.
The juice separated from the precipitate shows with beetroot juices slightly
alkaline, and with cane juice neutral reaction (for 100 litres clear juice from
beetroot about one to two thousandth part alkalinity, expressed as lime alkalinity,
is sufficient); it is nearly colorless, and is further worked in the known manner
for filling material.
This is so colorless and clear that it may be directly used for the production of
the finest refined sugars of all kinds for consumption; in the same way these
filling materials yield such clear and colorless syrups in all products that from the
filling materials of the after products fine sugar and sugar crystals for consumption
can be obtained.
Lastly, there results a molasses which is remarkable for its slight light yellow
coloration.
The above described process can be applied not only to thiu juices, but also, for
producing the same result, to medium and thick juices of all degrees of concentra-
tion, as also to the syrups resulting from the working of the filling materials.
Lastly, the same process can be repeatedly applied to sugar solutions that have
already been treated in the above described manner for partial decoloration and
purification, for the pupose of completing the decoloration and purification.
In the refining of the sugar in sugar refineries the sugar is dissolved in water,
preferably at its natural temperature (about 20° to 30° C., but in any case at a
temperature below 60° C.) in such quantities until the ordinary degree of concentra-
tion of the solution (called clarified liquor) is obtained; this solution is then
subjected in the described manner to the action of the sulphurous acid until the
liquid has a strong acid reaction and the properties described with reference to
thin juice are indicated (in 100 litre of refined clarified liquor, a per-centage of acid
of from 100 to 300 grammes, expressed as sulphurous acid is advisable, according

page_text: to the per-centage of the non-saccharine and coloring matters contained in the
clarified liquors).
This clarified liquor thus acidified, is now passed, at the above named temperature.
of water (but in any case below 60° C.) over animal charcoal for filtration (to 100
litres of clarified liquor from 5 to 6 kilos. animal charcoal are sufficient for ordinary
raw sugar). The clarified liquor, almost without colour and purified and strongly
acid, coming from the filters is then mixed in the above described manner with
lime (or baryta, strontia, alumina &c.) for the purpose of precipitating the free acid
as insoluble salt; it is heated somewhat (to about 50 to 55° C.), separated by
suitable means (filter presses, filter bags &c.) from the precipitate, and is boiled
for the production of refined filling material.
This alkaline clarified liquor (or neutral for cane sugar) coming from the filter
presses can be again filtered on from 1 to 2 per cent. of animal charcoal before being
boiled for filling material.
Dated this 19th day of September 1893.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Process for Purifying and Decolourising Saccharine Juices and Sugar
Solutions generally.
1, CARL STEFFEN of IV Heugasse 10 Vienna, Austria, Gentleman, 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 consists mainly in subjecting the saccharine juices of beet root
and cane sugar factories, after defecation, in the known and usual manner, with lime
or baryta &c. and after saturation with carbonic acid, and in some cases separation
from the scum from the defecation, and in some cases also from the so-called
saturation sediment, to a novel and newly-combined action, firstly, of sulphurous
acid, secondly animal charcoal and thirdly of lime or baryta, strontia, alumina &c.,
under observance of certain limits of temperature, for obtaining an almost perfect
and lasting decoloration and purification thereof..
This process enables notably large quantities of sulphurous acid to be employed
for acting upon the saccharine solutions, without destruction of the sugar; and the
decoloration and purification of the saccharine juices by means of sulphurous acid
and small quantities of animal charcoal in the manner to be presently described
is such that the juices operated upon according to this method yield, first,
crystalline filling mass of so pure and slightly coloured a nature that not only these
themselves, but also their by-products (syrups) can be worked directly into fine
white articles of consumption. In the refining of raw sugar in sugar refineries the
process for the decoloration and purification of the raw. sugar solutions is applied
in the same way, the thin cane or beetroot juice of the first described process being
replaced by an aqueous solution of the raw sugar in any desired degree of
concentration.
This new treatment of the above described juice, which I will call "thin juice,"
is as follows:-
1. The thin juice, freed from the defecation scum or, in some cases, from the
defecation and saturation sediment is, in order to enable it to take up sulphurous
acid in larger quantities without danger to the sugar of the juice, cooled down to
below those high temperatures which are usually employed in the defecation of the
raw juice and its treatment with lime, or lime and carbonic acid, or other means
for effecting its defecation, such cooling being effected to at least below 60° C.,

page_text: preferably between 30° and 40° or lower. The cooling is effected either by natural
cooling of the juice in the air, or preferably by known artificial means for more
rapidly cooling, such as graduating apparatus, "reversed current refrigeration,
surface evaporation refrigerators &c. with the use of cold water or other cooling
liquids or cold air.
2. The thin juice cooled to below 60° C., preferably to between 30° and 40° or
less, is (in the reverse manner to that in which sulphurous acid is employed at the
present day for beet juices) treated with such a quantity of sulphurous acid and in
such manner, that the liquor 'receives a strongly acid reaction, and shews no further
decrease of colour, and all the colouring and non saccharine constituents of the
juice have entered as far as possible into sulphite and acid sulphite combinations,
which exist in solution in the strongly acid thin juices. The juices so treated will,
according to the higher or lower quality thereof, contain in 100 litres of juice from
100 to 250 grammes of proportion of acid (expressed as sulphurous acid). The
sulphurous acid is supplied to the juices in the known manner either in the form of
gas or, dissolved in water, in liquid form. In the first case it is advisable to force
the sulphurous acid gas, if produced by the burning of sulphur, by means of a gas
pump into the liquid, with effective distribution, until the above described end is
attained.
3. This cooled strongly acid thin juice, treated as above described with sulphurous
acid-contrary to the principle at present observed in practice, of only filtering beet
juices through animal charcoal in an 'alkaline condition and at a temperature higher
than 60°, is subjected, at a low temperature (certainly below 60° C. and preferably
between 30° and 40° or lower) to the action of animal charcoal. The latter acts
upon the compounds of the sulphurous acid with the colouring matters and other
non-saccharine matters in the acid juice in a very strongly absorbent manner, so
that for the thin juice treated' with sulphurous acid in the "manner described, only
small quantities of animal charcoal are required, for taking up nearly the whole of
the colouring matter, as also large quantities of the other non-saccharine matters,
and consequently to almost completely purify and decolorize the juice, in such
manner as is not even attainable by the use of large quantities of animal charcoal
without the previous treatment of the juice, as described, with sulphurous acid.
Also in this process there is no destruction of sugar.
For 100 litres of thin juice treated with sulphurous acid as described there are
only required from one to two kilogrammes of animal charcoal, according to the
original quality of the juice, which is applied in the usual manner in charcoal
filters, or charcoal filter presses &c. and which are afterwards revivified and again
employed for the same purpose.
4. The decolorised acid juice coming from the animal charcoal filters, is, within
the above mentioned limits of temperature, treated according to its per-centage of
acid (reckoned as sulphurous acid) with lime (milk of lime or baryta. strontium,
alumina, &c.), a slight excess being employed for juices from beetroot, in order to
produce an alkaline reaction, while for cane-juice only sufficient is added for
obtaining a neutral reaction of the juice, whereby the acid present is converted
into au insoluble lime salt (or baryta salt &c.), which is precipitated from the
liquid under heating and is separated from the juice by known means, such as filter
presses, bag-filters, &c., in order that, in the following treatment thereof at a
higher temperature in the evaporating apparatus or vacuum pan, any destruction of
sugar by acid is prevented.
The juice separated from the precipitate shows with beetroot juices slightly
alkaline, and with cane juice, neutral reaction (for 100 litres clear juice from
beetroot about one to two thousandth part alkalinity expressed as lime alkalinity is
sufficient); it is nearly colorless, and is further worked in the known manner for
filling masses.
These filling masses are so colorless and clear that they may be directly used
for the production of the finest refined sugars of all kinds for consumption; in the
same way these filling masses yield such clear and colorless syrups in all products

page_text: that from the filling masses of these syrups fine sugar and sugar crystals for
consumption can be obtained.
Lastly, there results a molasses which is remarkable for its slight light yellow
coloration.
The above described process can be applied not only to thin juices, but also, for
producing the same result, to medium and thick juices of all degrees of concentra-
tion, as also to the syrups resulting from the working of the filling masses. Lastly,
the same process can be repeatedly applied to sugar solutions that have already
been treated in the above described manner for partial decoloration and purification,
for the purpose of completing the decoloration and purification.
In the refining of the sugar in sugar refineries the sugar is dissolved in water,
preferably at its natural temperature (about 20° to 30° C. but in any case at a
temperature below 60° C.), in such quantities until the ordinary degree of con-
centration of the solution (called clear or fine-liquor) is obtained; this solution is.
then subjected in the described manner to the action of the sulphurous acid until
the liquid has a strong acid reaction and the properties described with reference to
thin juice are indicated (in 100 litres of fine-liquor a per-centage of acid of from 100.
to 300 grammes, expressed as sulphurous acid, is advisable, according to the per-
centage of the non-saccharine and coloring matters contained in the liquor).
This fine-liquor, thus acidified, is now passed, at the above named temperature of
water (but in any case below 60° C.) over animal charcoal for filtration (to 100 litres
of liquor from 5 to 6 kilos animal charcoal are sufficient for ordinary raw sugar).
The liquor, almost without color and purified and strongly acid, coming from the
filters is then treated in the above described manner with lime, (or baryta, strontia,.
alumina, &c.) for the purpose of precipitating the free acid as insoluble salt; it is
heated somewhat (to about 50° to 55° C.) separated by suitable means (filter
presses, bag-filters, &c.) from the precipitate, and is boiled for the production of
refined filling masses.
This alkaline liquor (or neutral for cane sugar) coming from the filter presses
can be again filtered on from 1 to 2 per cent. of animal charcoal before being
boiled for filling mass.
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. A process for obtaining colourless sugar solution as pure as possible, and
crystalline sugar producible therefrom, by treatment of the juices of beetroot and
cane sugar manufacture, defecated and in some cases saturated and freed from the
defecation and saturation-scum according to known methods and cooled down to
below the defecating temperature (below 60° C. and preferably between 30° and 40°
and below), with sulphurous acid in such quantities that the coloring and non-
saccharine substances are as much as possible made to form sulphite compounds,
which remain in solution in the said acid-reacting juices, the so-prepared juices
being then subjected at the above named limitation of temperature to the action of
proportionately small quantities of animal charcoal, for the purpose of removing
the sulphite compounds of the coloring and non-saccharine matters from the acid
juices, after which the acid still contained in the filtered juices is precipitated by
means of corresponding quantities of lime (or baryta, strontia, alumina, &c.,) in
the form of insoluble salts, the resulting juices freed from the precipitates being
obtained in a slightly alkaline or neutral condition free froni colour and
impurities.
2. The application of the process referred to in the first claim to medium and
thick juices of any degree of concentration, as also to all syrups of sugar
manufacture, for attaining the same object set forth.
3. The repeated employment of the process referred to in the first claim for
sugar solutions that have been already partly decolorised and purified by the same

page_text: process, in any state of their manufacture, for the purpose of further decolorising
and purifying the same.
4. The employment of the process referred to in the first claim for the treatment
of the cleare or fine liquors of beetroot-sugar and cane-sugar refineries and the
syrups thereof.
ABEL & IMRAY,
Agents for the Applicant.