An Improved Process for Refining and Purifying Sugar.
Year: 1896

page_text: PROVISIONAL SP.
ATION.
An Improved Process for Refining and Purifying Sugar.
I, GEORGES RANSON of Phalempin (Nord) in the Republic of France, Engineer,
do hereby declare the nature of this invention to be as follows:-
The use of dioxide of barium which has been previously hydrated and washed
or transformed into chemically pure oxidised water for decolourising, purifying,
and refining juice, syrups, molasses, glucose and like substances of different nature
and origin containing sugar requires certain precautions to be taken to prevent
the subsequent deterioration of the sugar thus treated.
My invention consists in removing from the solutions of sugar the excess of
oxygen produced by the addition of dioxide of barium or its equivalent-the pure
oxidised water and for this purpose I add to the decolourising and purifying liquid
a substance having great affinity for oxygen such substance being an acid, oxide
or salt.
The salts with which I have obtained the most favourable results are hydro-
sulphites of zinc, baryta and alumina, of these I prefer the hydrosulphite of
alumina.
When a solution of sugar is to be treated with dioxide of barium I add the latter
in quantities varying from 1/10 per cent. to about 1 per cent. previously hydrated
and washed, I then allow it to act stirring the mass at the same time by means of
a current of air or mechanically for from half an hour to twelve hours until the
foreign organic substances are oxidised.
If too little dioxide of barium has been used it is necessary to precipitate the
baryta remaining in solution by a sulphate of soda, and if too much has been used
saturating with carbonic acid becomes necessary. The sucrate of baryta produced
becomes alkaline after the addition of the sulphate of soda which eliminates all
traces of baryta. Then one litre is titrated with aniline etc., in order to determine
the amount of hydrosulphite of alumina to be used. To the mass, hydrosulphite
is then added in small quantities which has been found useful for being neutral
or slightly acid, it is left to act and then to become alkaline with such a portion of
baryta or milk of lime, as to have the alcalinity of about 001 to 0.05 %.
The hydrosulphite used must be in sufficient quantity to destroy the active
oxygen and to precipitate the baryta forming grains in the gelatinous alumina,
whereby filtration becomes possible.
There is an advantage in adding to the liquid an inert substance such as car-
bonate of earths, clay kaolin and the like which affords points of attachment for
the sulphate of baryta and alumina in order to secure a quick and effective filtra-
tion.
When it is found that the quantity of hydrosulphite used is insufficient to pre-
cipitate all the baryta a soluble double sulphate is used giving an insoluble base
such for instance as sulphate of alumina.
If I do not add dioxide of barium directly to the solution of sugar I attack the
former first with phosphoric and sulphuric acids in order to obtain a chemically

page_text: pure oxidized water free from bases and acids, taking care to neutralize this water
with baryta or lime before using it. Saturation with carbonic acid is not necessary
but the bone black which I add to the solution of sugar in the form of an impalp-
able powder is previously treated with hydrochloric acid and undergoes a thorough
washing so as to get rid of the earthy carbonates and phosphates and of all soluble
salts.
In a common clear, the proportion of white sugar No. 3 to be used varies with
the number of Kilogrammes of syrupy water and of brown sugar to which different
substances are added as herein before described.
Dated this 8th day of September 1896.
BOULT & WADE,
Agents for the Applicant.
I, GEORGES RANSON of Phalempin (Nord) in the Republic of France, Engineer,
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 chief object of my invention consists in extracting from solutions of syrup of
sugar the excess of oxygen, produced by the addition of dioxide of barium or of its
equivalent chemically pure oxygenated water, commonly called peroxide of
.hydrogen.
While the dioxide of barium, in its various forms, has the property of thoroughly
oxidising coloured organic substances, I have found it useful to effect the reduction
by means of a substance readily combining with oxygen.
I use a large vat of any desired capacity in which constantly rotates a vertical
shaft provided with stirring mechanism in order to ensure during the operation
an intimate mixture of the syrup with the reagents used. A coiled pipe for heating
may be employed by means of which the temperature of the contents can be
regulated.
When it is desired to treat syrup of sugar by the alkaline process, I proceed as
follows: The desired quantity of syrup of sugar that is to be treated is introduced
into the vat, said syrup being in the form of remelted crystallized sugar or residues,
so that a syrupy liquid of a density of about 30° B is obtained at a temperature
of about 35° C. When the vat is full and after the liquid has been thoroughly
stirred, the temperature of the mixture is gradually raised to 50° C for each
100 Kilos of sugar a very small quantity of saturated baryta-water say half a litre
or carbonate of soda to a corresponding extent is added in order to obtain an
alcalinity of about one ten thousandth which is ensured before introducing hydrogen-
peroxide or chemically pure oxidised water in a proportion of from litre to 5 litres
per 100 kilos of sugar according to the colouring of the products to be decolourised
and purified. The introduction of dioxide of baryum in the form of oxygenated
water constitutes the chemical decolourising and purifying operation for syrup of
sugar which can be easily followed by taking samples from time to time. It will
be noticed that the decolourising is effected gradually and almost imperceptibly.
Nevertheless it is necessary to add at the beginning of this oxidising stage a few
grammes of animal black say 100 grammes per 100 Kilos of sugar in the form of
very fine powder, which has been previously treated with say hydrochloric acid
aud then washed, in order to remove earthy carbonates and phosphates generally
found in this substance. The animal black is used to quicken the liberation of

page_text: oxygen from the peroxide of hydrogen in order to cause it to oxidise more particu-
larly the organic substances capable of being decolourised.
This period of oxidation is the longest che and takes say from an hour to an
hour and a half, there still remains an excess of oxygen which is removed in the
manner hereinafter described in order to avoid any recolouring or alteration of the
syrups treated.
The reactions hereinafter described are shorter for their purpose is only to stop
this oxidation, then to start reduction and finally to convert the sulphites thus
obtained into sulphates.
The removal of the above mentioned excess of oxygen is effected by adding to the
syrup hydro-sulphites of alumina, barium etc., or an aqueous solution of hydro-
sulphurous acid or by producing hydrosulphurous acid in a nascent state in the
syrup to be decolourised and purified, in order to produce a new result which con-
sists in providing for the oxygen liberated from the peroxide of hydrogen a body
readily absorbing oxygen in order to destroy any excess of oxygenated water which
might remain.
The method of operation will vary according to the plant used in the sugar-
refinery. In order to prepare hydrosulphite of alumina, barium etc., a hermetically
closed tank is used the bottom of which is filled with zinc in the form of powder
or granulated, and the bisulphate is added which is generally preferred by chemists
for instance, bisulphate of barium which has numerous reducing properties and
the whole is left in contact for about 30 minutes the receptacle is cooled, the liquid
decanted and added to the syrup for the purpose described. Hydrosulphurous
acid can also be produced in the interior of the vat by using liquid sulphurous
acid gas (S 0) containing say from 100 to 200 grammes of sulphurous acid per
litre and about 20 grammes of zinc powder is added to each litre. This solution
of hydrosulphurous acid gas is then poured into the syrup to be treated.
In order to prepare hydrosulphurous acid in a nascent state in the syrup itself,
a current of sulphurous acid (S O₂) (from a sulphur furnace or from an apparatus
filled with liquefied sulphurous acid) is caused to enter the syrup till the acidity
becomes from 01 to 02 grammes of sulphurous acid for every litre of syrup,
then about 10 grammes of zinc powder are added for each 100 litres of syrup,
the whole is stirred and thus hydrosulphurous acid is produced in a nascent state
in the syrup and acts for the purpose specified.
These hydrosulphites and hydrosulphurous acid having been added or prepared
in the syrup, the temperature is raised to 60° C so as to accelerate the desired
reaction. Afterwards baryta water is added in such quantity as to leave the syrup
an alcalinity of from 001 to 002 per litre.
These two periods of oxidation and reduction described leave an excess of sul-
phites which are then converted into sulphates in the manner hereinafter described
so as to avoid any taste of sulphur in the refined product.
A. sample must be taken in order to judge of the quantity of hydrogen-peroxide
required to be added in order to ensure the conversion of the sulphites into sul-
phates. The temperature of syrupy mixture is then raised to about 78° C in
order to allow a more efficient filtering, although if an inert substance has been
added during the last period, it would be found on the filter-bag together with the
zinc-powder and baryta.
The result is that the heated mass is freed from all these solid substances and
the excess of sulphurous acid evaporates and escapes through conduits or pipea
as soon as the syrupy liquid begins to boil, so that it becomes alcaline and changing
of the sugar cannot take place.
To decolourise and purify syrups by an acid treatment the proceeding to the
point when hydrosulphurous acid is formed, consists in saturating the syrupy
liquid at a temperature below 50° C. with sulphurous acid which is employed to
saturate the alkalies, lime, potash soda, etc., and to decompose organic matters
etc., in order to form sulphites and to convert them into sulphates by the introduc-
tion of hydrogen peroxide.

page_text: After filtration a fresh saturation with sulphurous acid gives an acid syrup
of from 5 to 5 grammes of S O, per litre. Then a few grammes of zinc powder
are added say 10 to 50 grammes per litre of syrup and the whole mixed for 15
to 20 minutes hydrosulphurous acid in a nascent state being formed in the syrup
the reaction being as follows:-
2 (H,SO,)+ZnH₂SO₂+ZnSO,+H₂O
Sulphurous acid. Zinc hydro. Zinc-sulphite. Sulphurous acid.
This hydrosulphurous acid decolourises syrup in a very energetic manner
liquefies viscous substances and eliminates certain organic matter.
Before filtering the initial temperature of 50° C is raised to 75° C in order
to take advantage of the instability of hydrosulphurous acid at this temperature
at which it is transformed into S O, taking oxygen from the organic matt. n
the syrup. The peroxide of hydrogen must be added in the same manner as for
the alcaline process.
These residues are treated by baryta, sucrate of baryta or any other alcali,
lime etc., then boiled. In this way good products without baryta, zinc etc., are
obtained all these substances being retained by the filters.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what I
claim is :-
1. In refining or purifying sugar by an alkaline treatment for the purpose of
neutralising the excess of oxygen liberated on the addition of baryta water or
carbonate of soda and of peroxide of hydrogen together with animal black, the
chemical combination for producing hydrosulphurous acid in the presence of
zinc-powder and finally the conversion of sulphites into sulphates substantially
as described.
2. In refining or purifying sugar by an acid treatment the chemical combina-
tion which upon the addition of zinc-powder produces hydrosulphurous acid at
the moment when sulphurous acid is liberated, whereby said hydrosulphurous
acid effects the decolourising and refining of the syrup of sugar substantially as
described.
Dated this 1
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