Improvements in the Purification of Saccharine Juices by Electrolysis.
Year: 1894

page_text: Date of Application, 2nd Aug., 1894
Complete Specification Left, 1st May, 1895-Accepted, 2nd Aug., 1895
PROVISIONAL SPECIFICATION.
Improvements in the Purification of Saccharine Juices by
Electrolysis.
I JAMES YATE Johnson of 47 Lincoln's Inn Fields in the County of London
Gentleman do hereby declare the nature of this invention (which has been
communicated to me from abroad by Emile Javaux, Charles François Gallois and
François Dupont of 58 Chaussée d'Antin Paris in the Republic of France) to he
as follows:-
This invention relates to improvements in the purification of saccharine juices
extracted from beetroot cane sorghum or the like and also from syrups and
molasses.
The saccharine juices extracted by diffusion pressure or otherwise from beetroot
cane or the like as well as syrups or molasses are purified according to our invention
in such a manner that all the sugar contained may be extracted directly as white
sugar and even refined, dispensing with any treatment by carbonates and avoiding
the formation of bye products and molasses. The process consists essentially in
the following operations. Lime or baryta are added to the juices in order to
neutralise their natural acidity and prevent the partial inversion of the sugar and
also to precipitate from the commencement a large portion of the organic matters
which contaminate them.
The juices either in a filtered or unfiltered condition and either cold or heated
but preferably heated say to a temperature of about 75 degrees C. for juices
extracted from beetroot and 50° to 65° C. for juices from cane and sorghum are
submitted to the action of an electric current in electrolysing baths hereinafter
described.
The juices flow through one set of compartments separated by porous partitions
from another set of compartments in which latter water circulates. The anodes
dipping into the saccharine juices should be of soluble metals capable of forming
insoluble compounds with the acids and organic matters of the saccharine juices.
The anodes for the first set of compartments are formed of plates of oxide of
manganese combined with a conducting substance or aluminium or the two bodies
together or the two bodies united to lead and for the second set of compartments
of the electrolyser by plates of lead only and for the third set by plates of iron
aluminium or zinc. The cathodes of the negative compartments containing the
water may be of carbon iron or any other conducting material insoluble in alkali
but preference is given to sheet iron. The juices and the water flow from one
electrolysing vat into the following so as to leave the last in a purified condition.
The anodes and cathodes are connected to the two poles of a dynamo electric
machine which supplies the current for effecting the purification.
The juices to be treated may be considered as water holding in solution a large
amount of sugar and in smaller quantities organic and mineral foreign matters which
prevent the partial crystallisation of the sugar and give place to the formation of
molasses. The organic impurities consist on the one band of acids such as acetic,
lactic, butyric, formic malic and pectic acid and the like and on the other hand of
uitrated materials such as albumen asparagine ammonia betaine legumin tri-methyl-
amine and the like and of other matters free from nitrogen such as glucose arabinose
mannite pectin, and lastly of coloring matters, essential oils, guns and the like.
The mineral matters are represented by potassium sodium calcium magnesium

page_text: manganese iron and the like forming salts, either with the organic acids referred to
or with sulphuric phosphoric salicylic and nitric acid or with chlorine. The acids
are usually in excess of the bases so that the unrefined juices always have an acid
reaction weak in the case of beetroot but considerable in the case of cane and
sorghum. The organic acids always predominate; among the bases potassium
takes the first place. By the action of the current of electricity all these foreign
matters are more or less modified oxidised and decomposed, the salts are decomposed,
and the metallic radicals especially potassium and sodium pass through the porous
partition into the negative compartment where by the partial decomposition of the
water contained therein they are transformed into bases such as potash and soda
with the evolution of hydrogen. The lime and magnesium do not pass or only pass
in a small quantity into the water in the negative compartment. They form
insoluble salts which are precipitated in the bulk of the juices. A small amount
remains in solution in the juices and causes them to retain an alkaline reaction.
The acids and oxygen of the bases are carried to the positive pole on the soluble
anode with which they combine to form insoluble compounds such as phosphates
sulphates chlorides and various organic compounds of manganese alumina and lead.
The nitric acid is partially transformed into ammonia which is found in the
negative compartment. Many of the organic matters especially the albuminoids
are oxidised and rendered insoluble. Those which by their character or composition
nearly resemble alkaloids ammonia or amines usually pass into the negative liquid.
The glucose of certain other hydrates of carbon remain intact in the juice as well
as the crystallisable sugar or saccharose. When the process is finished almost the
whole of the potash and soda have been discharged into the negative solutions and
nearly the whole of the acids and organic matters other than the sugar and glucose
have been precipitated so that the purification may be said to be complete. The
juices are now clear and colourless. They form no precipitation under the influence
of sub-acetate of lead and their saline co-efficient or the proportion of sugar to
mineral matter which in the juice from beetroot and cane in its raw condition varies
between 20 and 40 now rises from 150 to 200 or more. The degree of purity or
the proportion of sugar to 100 parts of solid matter which in the same juices varies
between 75 and 85 per cent. now rises to 95 to 97 % for juices from cane and from
98 to 99 or even 995 for the juices from beetroot. The waters are found charged
with potash a small amount of ammonia amines and the like.
After the electrolysis all the saccharose which analysis had shewn to exist is
found entirely in the juice without modification or loss, not a trace of it having
passed into the water in the negative compartment. When the operation is
properly performed and the strength of the current is neither too strong nor too
weak there is no dialysis since the electro dynamic force compensates or
annihilates the osmotic force. Thus by one and the same electrolytic operation in
one series of vats the impurities which contaminate the juices are removed, that is
to say, the bases, acids mineral and organic matters.
There is no need for two separate operations, one with the positive current in the
vat for eliminating the bases the other changing the current for eliminating
the acids.
By the use of soluble anodes forming insoluble compounds with the impurities of
the saccharine juices and of the porous partitions with the circulating liquids this
double result is obtained by a single process of electrolysis.
As the juices are rendered alkaline or neutral from the commencement by the
use of lime or baryta and the acids as they are liberated combine with the metal of
the anodes the juices always remain alkaline and consequently there can be no
partial inversion of the sugar even at a high temperature whereas this inversion is
produced by the use of insoluble anodes which do not prevent the acidification of
the juices. This is also produced by the use of soluble anodes working at a high
temperature unless the natural acidity is neutralised at the commencement especially
when the temperature is raised as in case of juices from cane. The juices are
caused to pass successively through the three series of electrolysers containing.

page_text: anodes of different metals for the following reasons. In the first series of
electrolysers electrodes are used of aluminium or oxide of manganese so as to have
less lead in solution in the juices, since, the first acids liberated, which, when united
with the lead readily form soluble salts, will form insoluble salts when combined
with aluminium and manganese. Lead anodes are placed in the greater number of
electrolysers because the compounds formed afterwards are quite insoluble and the
lead is readily capable of being regenerated from the lead mud and finally the last
electrolyser is supplied with zinc or iron or aluminium anodes in order to remove by
electrolysis the last remnants of lead which may remain in solution.
The time for treating the juices by electrolysis varies according to the amount of
impurities they contain, their degree of dilution and the strength of the current.
The juices on leaving the electrolysing vats are decanted or filtered for
separation of the precipitate and they are then evaporated. If by chance any
traces of lead are held in solution they must be precipitated by a suitable reagent,
such as phosphoric acid or soluble phosphate of lime sulphuric acid or bisulphite
of lime. In this case they are again filtered or decanted before the evaporation
process. The syrups may be baked in a granulated state, or heated in a refined
condition without the necessity of filtering them as they contain no matter in
suspension. The heated or baked mass is found pure and practically colourless
and the sugar is extracted therefrom in the condition of white or refined sugar by
ordinary processes.
In the electrolysing vats hereinafter described the juices are caused to circulate
with variable speed so as to allow of their discharge just at the moment when they
are completely purified, that is, when they do not form precipitates by the addition
of subacetate of lead the circulation of the liquids is slower so as to permit of
concentration and prevent their discharge until they have reached a density of
from 4 to 6 degrees Baumé which corresponds to the proportion in potash of 40 to
50 grammes for the litre. The liquids are then evaporated for the caustic potash
or carbonate of potash which they may contain or the liquids may be employed for
watering or manuring purposes. The plumbie mud collected from the filtering
presses is treated for obtaining lead in the metallic state which may be then re-used
in the manufacture of the anodes. The mind which is an organic compound of lead
is mixed with carbon and treated in a reverberatory furnace or cupola. The oxide
of lead reduced to metallic lead is poured into moulds so as to give the exact
shape of the anodes; little or no carbon is required for this process as the
organic matters in the mud are sufficient to produce the reduction in the furnace.
Instead of obtaining the lead in its metallic state, the following may be obtained
directly, first, oxides of lead massicot and minium by roasting in the open air, or
litharge after fusion of the massicot; secondly, salts of lead, as nitrate, acetate or
chloride by causing nitric acetic or hydrochloric acid to react directly on the oxide
coming from the furnace. The following is a description of electrolysing baths
constructed according to our invention.
The electrolyser of the juices from beetroot being an electrolyser with fixed
anodes consists of a series of compartments containing alternately the juices to be
purified and the purifying liquid divided by partitions or porous membranes. The
number of compartments in the electrolyser may be varied in the apparatus for
example there may be 21 compartments, 11 of which are negative compartments
for the circulation of the water and 10 form positive compartments for the
circulation of the juices. The positive compartments are each formed of a frame
in the shape of a trapezium with the two upper angles right angles and constructed
of non-conducting material such as wood india-rubber or the like and they contain
the anodes. The negative compartments are formed in the same way but of half
the thickness and they take the cathodes dipping into the purifying water.
frames are held between two strong metal plates, on which are arranged, a feed
pipe for juice, a feed pipe for the water, a pipe for the discharge of the juice and a
pipe for the discharge of the water.
The
One of the metal plates is provided with two receivers variable as to level into

page_text: which the juices and solutions flow from one electrolyser to the other permitting
the condition of the circulating liquids to be at any moment ascertained. The
bi-rectangular trapeziumi shape given to the positive and negative frames gives the
apparatus an inclined bottom when put together. By this means the mud collects
in one of the angles whence it while circulating in channels or troughs can be
readily removed when required by the discharge cocks fixed to the frames of the
juice tanks; one of the metal plates also carries a discharge cock for removing
the liquids. The electrolyser is so arranged that the juices therein flow from one
end to the other in serpentine coils so as to pass in succession along two faces of
the anodes. In each of these compartments the juices circulate in a diagonal
direction, that is, they enter at the upper part of the uprights of the vats or baths
and leave by the lower part on the opposite side and vice versú, or in other words
the different compartments for the juices are connected in series so that the course
taken by the electrolyte in the apparatus is as extended as possible, the
compartments for the solutions may be connected in series or they may be
connected in parallel arc, the anodes and the cathodes are arranged in parallel
in each electrolyser. For the electrolysis of the juice of canes we preferably
slightly modify the apparatus thus described by rendering the anodes movable.
Apparatus so constructed is more especially designed for treating juices which
contain substances such as silica, gums, metallic salts and various impurities
capable of adhering more or less firmly to the faces of the anodes and so rendering
them inactive. To avoid this the anodes are made movable and in the movement
imparted to them they rub against series of brushes. The apparatus is provided
with like compartments and like feed and discharge pipes separated by like porous
partitions as that first described, the mud cocks are placed on the bottom side of
the apparatus, and the circulation of the liquids is precisely similar to that already
described. The removable anodes may be in the form of discs fixed on a metal
shaft to which is imparted a rotating motion.
This shaft transmits a rotary
motion to a second shaft on which are mounted cleaning brushes. The device for
moving the anodes may take any other form but whatever be the apparatus the
anodes are moved in front of fixed or movable brushes which detach from their
surface any adhering matters.
A modified arrangement consists in placing the two electrolysers in a position
parallel to each other and uniting the anodes of the one to the corresponding
anodes of the other by means of a rod moving on a horizontal axis by which the
current enters the apparatus, the two anodes mounted on the same rod would thus
be united in parallel and one set of cells contained in one casing for example,
would dip into the bath whilst the other set contained in the other casing will be
undergoing a cleansing process by the moving brushes. In some cases a screen
may be provided which returns to the electrolyser the liquids thrown off by the
brushes. The current enters the moving anodes by the shaft any suitable device
may be employed for conducting the current away such as by rings or brushes.
In any case the electrolyser should remove by mechanical means the bodies
adhering to the anodes. For reducing the electrical resistance and the polarization
of the baths we preferably work at a high temperature and cause the juices to be
purified and the negative liquid to circulate or else we agitate the electrodes
leaving the liquid stationary or combine the circulation of the liquids and the
movement of the electrodes.
Our electrolysers formed with soluble anodes yielding insoluble compounds avoid
the inversion of the sugar and the formation of glucose, they are based on the
simultaneous use of positive compartments containing the syrups to be purified and
of soluble anodes such as lead or the like interposed between negative compartments
containing insoluble electrodes of such a kind as to effect the transference of the
sults from the solution to be purified to the purifying solution. The circulation of
the positive juices and negative liquids in a heated condition in combination with
the movement of the electrodes yield juices of a purity varying between 95 and
99 per cent, which after evaporation and heating yield directly white and even

page_text: refined sugars while avoiding entirely treatment with carbonates and the formation
of molasses so that the final yield of sugar usually contained in the molasses is
increased.
נה.נית
1
100
JOHNSONS & WILLCOX,
Agents.
Improvements in the Purification of Saccharine Juices by
Electrolysis.
I, JAMES YATE JOHNSON, of 47 Lincoln's Inn Fields in the County of
Loudon Gentleman, do hereby declare the nature of this invention (which has
been communicated to me from abroad by Emile Javaux, Charles François
Gallois and François Dupont, of 58 Chaussée d'Antin Paris in the Republic of
France) 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 improvements in the purification of saccharine juices
extracted from beetroot, cane, sorghum or the like and also from syrups and
inolasses.
The saccharine juices extracted by diffusion pressure or otherwise from beetroot
caue or the like as well as syrups or molasses are purified according to our invention
in such a manner that all the sugar contained may be extracted directly as white
sugar and even refined, dispensing with any treatment by carbonates and avoiding
the formation of bye products and molasses. The process consists essentially in
the following operations. Lime or baryta are added to the juices in order to
neutralise their natural acidity and prevent the partial inversion of the sugar and
also to precipitate from the commencement a large portion of the organic matters
which contaminate them.
The juices either in a filtered or unfiltered condition and either cold or heated
but preferably heated say at a temperature of about 75 degrees Centigrade for
juices extracted from beetroot and 50° to 65° Centigrade for juices from cane and
sorgho are submitted to the action of an electric current in electrolysing baths
bereinafter described.
The juices flow through one set of compartments separated by porous partitions
from another set of compartments in which latter water circulates. The anodes
dipping into the saccharine juices should be of soluble metals capable of forming
insoluble compounds with the acids and organic matters of the saccharine juices.
The anodes for the first set of compartments are formed of plates of oxide of
manganese combined with a conducting substance or aluminium or the two bodies
together or the two bodies united to lead and for the second set of compartiments
of the electrolyser by plates of lead only and for the third set by plates of iron
aluminium or zinc. The cathodes of the negative compartments containing the
water may be of carbon iron or any other conducting material insoluble in alkali
but preference is given to sheet iron. The juices and the water flow from one
electrolysing vat into the following so as to leave the last in a purified condition.
The anodes and cathodes are connected to the two poles of a dynamo electric
machine which supplies the current for effecting the purification.
The juices to be treated may be considered as water holding in solution a large
amount of sugar and in smaller quantities organic and mineral foreign matters
which prevent the partial crystallization of the sugar and give place to the
formation of molasses. The organic impurities consist on the one hand of acids
such as acetic, lactic, butyric, formic, malic and pectic acid and the like and on the
ther hand of nitrated materials such as albumen asparagine ammonia betaine

page_text: legumin tri-methylamine and the like and of other matters free from nitrogen such
as glucose, arabinose mannite pectin, and lastly of colouring matters essential oils
guns and the like. The mineral matters represented by potassium, sodium,
calcium magnesium manganese iron and the like forming salts either with the
organic acids referred to or with sulphuric phosphoric salicylic and nitric acid or
with chlorine. The acids are usually in excess of the bases so that the unrefined
juices always have an acid reaction weak in the case of beetroot but considerable
in the case of cane and sorgho. The organic acids always predominate among the
bases potassium takes the first place. By the action of the current of electricity
all these foreign matters are more or less modified oxidised and decomposed, the
salts are decomposed, and the metallic radicals especially potassium and sodium
pass through the porous partition into the negative compartment where, by the
partial decomposition of the water contained therein they are transformed into
bases such as potash and soda with the evolution of hydrogen. The lime and
magnesium do not pass or only pass in a small quantity into the water in the
negative compartment. They form insoluble salts which are precipitated in the
bulk of the juices. A small amount remains in solution in the juices and causes
them to retain an alkaline reaction. The acids and oxygen of the bases are carried
to the positive pole on the soluble anode with which they combine to form insoluble
compounds such as phosphates sulphates chlorides and various organic compounds
of manganese alumina and lead.
The nitric acid is partially transformed into ammonia which is found in the
negative compartment. Many of the organic matters especially the albuminoids
are oxidised and rendered insoluble. Those which by their character or com-
position nearly resemble alkaloids ammonia or amines usually pass into the
negative liquids. The glucose of certain other hydrates of carbon remain intact
in the juice as well as the crystallisable sugar or saccharose. When the process is
finished almost the whole of the potash and sɔda have been discharged into the
negative solutions and nearly the whole of the acids and organic matters other
than the sugar and glucose bave been precipitated so that the purification may be
said to be complete. The juices are now clear and colourless. They form no
precipitation under the influence of sub-acetate of lead and their saline co-efficient
or the proportion of sugar to mineral matter which in the juice from beetroot and
came in its raw condition varies between 20 and 40 now rises from 150 to 20:) or
more. The degree of purity or the proportion of sugar to 100 parts of solid
matter which in the same juices varies between 75 and 85 per cent. now rises to
95 to 97% for juices from cane and from 98 to 99 or even 99.5 for the juices from
beetroot. The water is found to be charged with potash a small amount of
ammonia amine and the like.
After the electrolysis all the saccharose which analysis bad shewn to exist is
found entirely in the juice without modification or loss, not a trace of it having
passed into the water in the negative compartment. When the operation is
properly performed and the strength of the current is neither too strong nor too
weak there is no dialysis since the electro dynamic force compensates or annihilates
the osmotic force. Thus by one and the same electrolytic operation in one series
of vats the impurities which contaminate the juices are removed, that is to say, the
bases, the acids and the mineral and organic matters.
There is no need for two separate operations one with the positive current in
the vat for eliminating the bases the other changing the current for eliminating
the acids.
By the use of soluble anodes forming insoluble compounds with the impurities
of the saccharine juices and of the porous partitions with the circulating liquids
this double result is obtained by a single process of electrolysis.
As the juices are rendered alkaline or neutral from the commencement by the
use of lime or baryta and the acids as they are liberated combine with the metal
of the anodes the juices always remain alkaline and consequently there can be no
partial inversion of the sugar even at a high temperature whereas this inversion is

page_text: The
produced by the use of insoluble anodes which do not prevent the acidification of
the juices. This is also produced by the use of soluble anodes working at a high
temperature unless the natural acidity is neutralised at the commencement
especially when the temperature is raised as in case of juices from cane.
juices are caused to pass successively through the three series of electrolysers
containing anodes of different metals for the following reasons. In the first serie-
of electrolysers electrodes are used of aluminium or oxide of manganese so as to
have less lead in solution in the juices, since the first acids liberated which when
united with the lead readily form soluble salts will form insoluble salts when
combined with aluminium and manganesc. Lead anodes are placed in the greater
number of electrolysers because the compounds formed afterwards are quite
insoluble and the lead is readily capable of being regenerated from the lead muds
and finally the last electrolyser is supplied with zinc or iron or aluminium anodes
in order to remove by electrolysis the last remnants of lead which may remain in
solution.
The time for treating the juices by electrolysis varies according to the amount
of impurities they contain, their degree of dilution and the strength of the
current.
The juices on leaving the electrolysing vats are decanted or filtered for
separation of the precipitate and they are then evaporated. If by chance any
traces of lead are held in solution they must be precipitated by a suitable reagent,
such as phosphoric acid or soluble phosphate of lime sulphuric acid or bisulphite
of lime. In this case they are again filtered or decanted before the evaporation
process. The syrups may be baked in a granulated state or heated in a refined
condition without the necessity of filtering them as they contain no matter in
suspension. The heated or baked mass is found pure and practically colourless
and the sugar is extracted therefrom in the condition of white or refined sugar by
ordinary processes.
In the electrolysing vats hereinafter described the juices are caused to circulate
with variable speed so as to allow of their discharge just at the moment when they
are completely purified, that is, when they do not form precipitates by the addition
of subacetate of lead the circulation of the liquids is slower so as to permit of
concentration and prevent their discharge until they have reached a density of
from 4 to 6 degrees Baumé which corresponds to the proportion in potash of 40 to
50 grammes for the litre. The liquids are then evaporated for the caustic potash
or carbonate of potash which they may contain or the liquids may be employed for
watering or manuring purposes. The plumbie mud collected from the filtering
presses is treated for obtaining lead in the metallic state which may be then
re-used in the manufacture of the anodes. The mud which is an organic compound
of lead is mixed with carbon and treated in a reverberatory furnace or cupola.
The oxide of lead reduced to metallic lead is poured into moulds so as to give the
exact shape of the anodes, little or no carbon is required for this process as
the organic matters in the mud are sufficient to produce the reduction in the
furnace.
Instead of obtaining the lead in its metallic state the following may be obtained
directly, first, oxides of lead massicot and minium by roasting in the open air, or
litharge after fusion of the massicot; secondly, salts of lead as nitrate acetate or
chloride by causing nitric acetic or hydrochloric acid to react directly on the oxide
coming from the furnace.
And in order that our process may be readily put into practical use we will
describe with reference to the accompanying drawings electrolysing apparatus
suited for carrying our invention into effect.
Figure 1 shews an electrolysing vat in which the electrodes are fixed.
Figure 2 is a horizontal section illustrating the circulation of the liquids in
the vats.
Figures 3 and 4 shew a modification in the arrangements of the anodes permitting
ready cleaning of the electrodes.

page_text: Figure 5 shews a part of the apparatus drawn to a larger scale illustrating the
receiver K through which the liquid can flow from one vat to another.
Figure 6 is a plan of the said receiver, and
Figure 7 shews, a coupling plate or flange, in elevation, used for connecting the
receiver to the end plate of the vat.
In Figures 1 and 3 the cathodes are shewn by a dash and dot line (-
and the anodes by a broken line (———).
-)
---
The electrolyser with fixed anodes (Figure 1) is more especially intended for
the treatment of juices from beetroot and consists of a series of compartments
containing alternately the juices to be purified and the purifying liquid divided by
partitions or porous membranes.
The number of compartments in the electrolyser may be varied the apparatus in
Figure has twenty-one compartments eleven of which are negative compart-
ments E for the circulation of the water and ten of which are positive
compartments J for the circulation of the juices.
The positive compartments are each formed of a frame in the shape of a
trapezium with the two upper angles right angles and constructed of non-conducting
material such as wood india-rubber or the like and they contain the anodes
arranged in succeeding sets of different kinds as hereinhefore described. The
negative compartments are formed in the same way but of half the thickness an.!
they receive the cathodes dipping into the purifying water. The frames are held
between two strong metal plates P P on which are arranged a feed pipe A for
juice, a feed pipe is for the water, a pipe C for the discharge of the juice and a
pipe D for the discharge of the water.
One of these plates P is provided with two receivers R variable as to level into
which the juices and solutions flow from one electrolyser to the other permitting
the condition of the circulating liquids to be at any moment ascertained.
The said receiver R is formed with an inner tube t sliding vertically in
frictional contact with the part t' so that by adjusting the height of the said tube
the level of the liquid in the vats may be regulated. u is a tube of india rubber
or the like insulating material connecting the exit from one vat to the entrance of
an adjacent one. e is a coupling plate or flange formed in two parts to permit of
the insertion of a washer ¹ of rubber or the like for insulating the receiver from
the plate of the vat.
The juices leave the vat by the exit o and flowing up and over the tube which
has been previously adjusted in height pass through the inclined tube u into the
adjacent vat in the direction shewn by the arrow (Fig. 5). As they pass out over
the tube t the juices can be removed and the state of purity to which they have
reached can be ascertained.
In a similar manner the state of purity of the water can also be tested.
The bi-rectangular trapezium shape given to the positive and negative frames
gives the whole apparatus an inclined bottom so that the mud collects at the lowest
part and can be readily removed when required by the discharge cocks Q fixed to
the frames of the anode compartments J. One of the plates (P) also carries a
discharge cock V for removing the liquids. The electrolyser is so arranged that
the juices therein flow from one end to the other in alternately opposite directions
so as to pass in succession along two faces of the anodes. In each of these com-
partments the juices circulate in a diagonal direction, that is, they enter at the
upper part of the uprights of the vats or baths and leave by the lower part on the
opposite side and vice versa or in other words the different compartments for
the juices are connected in series so that the course taken by the electrolyte in the
apparatus is as extended as possible.
The compartments for the water may be connected in series or in parallel. In
Figure 2 they are shewn connected in parallel. For the electrolysis of the juice
of sugar cane we preferably slightly modify the apparatus thus described by
rendering the anodes movable. Apparatus so constructed (Figure 3) is more
especially designed for treating juices which contain substauces such as silica,

page_text: gums, metallic salts and various impurities capable of adhering to the faces of the
anodes and so interfering with their action. To avoid this the anodes M are maile
movable and in the movement imparted to them they rub against series of brushes B.
The apparatus is provided with compartments separated by porous partitions and
feed and discharge pipes A. B. C. D. R. V as in that first described the mud cocks Q
being however placed on the bottom side of the apparatus and the circulation of
the liquids is like that already described. The removable anodes M Figure 3 may
be in the form of discs fixed on a shaft N to which is imparted a rotating motion.
This shaft transmits a rotary motion to a second shaft S on which are mounted the
cleaning brushes B. The device for moving the anodes shewn in Figure 3 may
take any other form but whatever be the apparatus the fixed or movable brushes
are arranged so that they detach from the surface of the anodes any adhering
matters.
A modified arrangement consists in placing the two electrolysers in a position
parallel to each other and uniting the anodes of the one to the corresponding
anodes of the other by means of a rod moving on a horizontal axis by which the
current enters the apparatus, the two anodes mounted on the same rod will thus be
united in parallel and one set of cells contained in the casing F' (Figure 4) for
example will dip into the bath whilst the other set contained in the casing F will be
undergoing cleaning by the brushes B.
In Figure 3 a screen T is shewn for the purpose of returning to the electrolyser
the liquids thrown off by the brushes B. The current enters the moving anodes by
the shaft N. Any suitable device may be employed for conducting the current
away such as by rings or brushes. In any case the bodies adhering to the anodes
should be removed by mechanical means. For reducing the electrical resistance
and the polarization of the baths it is preferable to work at a high temperature
and cause the juices and the negative liquid to circulate or else to agitate the
electrodes leaving the liquid stationary or the circulation of the liquids and the
movement of the electrodes may be combined. Electrolysers formed with soluble
anodes yielding insoluble compounds prevent the inversion of the sugar and the
formation of glucose, they are based on the simultaneous use of positive compart-
ments containing the juices to be purified and of soluble anodes such as lead or the
like interposed between negative compartments containing insoluble electrodes of
such a kind as to effect the transference of the salts from the solution to be purified
to the purifying solution. The circulation of the juices and the water in a heated
condition in combination with the movement of the electrodes yield by electrolysis
juices of great purity which after evaporation and heating yield directly white and
even refined sugars while avoiding entirely treatment with carbonates and the
formation of molasses so that the final yield of sugar includes what would otherwise
be contained in the molasses.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
:-
1. In the purification of saccharine juices by electrolysis first the addition to
the juices of lime and baryta for neutralizing acidity, preventing the partial
inversion of the sugar and eliminating impurities and then subjecting juices to
electrolysis in electrolysing apparatus provided with anodes of the different
characters set forth substantially as herein before described.
2. In the purification of saccharine juices by electrolysis the use in the electro-
lysing apparatus of anodes of aluminium or oxyde of manganese or both in
combination with anodes of lead for yielding insoluble compounds the juices being
brought into contact with the said anodes successively substantially as hereinbefore
described.
3. The elimination by electrolysis of the lead in solution in saccharine juices by
passing the juice after previous purification in contact with anodes of iron
aluminium or zinc substantially as hereiubefore described.

page_text: 4. The purification of saccharine juices by electrolysis by the means herein-
before described, consisting in first heating the juices then causing them to circulate
or pass through electrolysing baths first in contact with anodes of aluminium or
oxide of mangauese or both and then with anodes of lead (provided with cleaners)
substantially as herein before described.
5. The purification of saccharine juices by adding thereto lime or baryta and
electrolysing the juices whilst heated by subjecting them to the action of anodes
first of alumina or oxide of manganese or both then of lead and then of iron,
aluminium or zine all substantially as hereinbefore described.
Dated this 1st day of May 1895.
JOHNSONS & WILLCOX,
Agents.

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