Improvements in the Processes of Purifying and Clarifying Sugary Products in Sugar-Houses, Sugar and Molasses Refineries Refineries or Factories of Glucose, and the like.
Year: 1897

page_text: Date of Application, 23rd Oct., 1897
Complete Specification Left, 6th July, 1898-Accepted, 15th Oct., 1898
PROVISIONAL SPECIFICATION.
Improvements in the Processes of Purifying and Clarifying Sugary
Products in Sugar-Houses, Sugar and Molasses Refineries
Refineries or Factories of Glucose, and the like.
I, DESIRE LOISEAU, of 17, Rue St. Roch, Paris, in the French Republic, Civil
Engineer, do hereby declare the nature of this invention to be as follows:-
The sugar industry makes use of two calco-carbonic purifying processes which
give good results. One of these processes known as turbid carbonatation, double
carbonatation etc. is applied in beet-root sugar houses to the juice which is of but
low density or specific gravity, the other process which is preferable for purifying
sugary liquids of high specific gravity and is used in cane sugar refineries, is known
as the purifying process by means of sucrate of hydrocarbonate of lime.
The inventors of the former process attribute its good results to the properties of
carbonate of lime, which in the nascent state draw out the impurities of the beet-root
juice in the manner of lac; whilst the inventors of the second process attribute its
good effects to the properties which hydrocarbonate of lime possesses of forming
insoluble compounds with the organic matters of the juice.
Now, in studying the various calco-carbonic reactions in pure or impure sugary
liquids and which are more or less dense, I have found new phenomena which are
no better explained by the theory of hydrocarbonate of lime than other phenomena
are not explained by the theory of lime carbonate in the nascent state.
I first ascertained that there exist several well defined combinations of sugar, of
lime and carbonic acid, and not a single combination (the sucrate of hydrocarbonate
of lime) as I had believed with Monsieur Boivin; the one of these sucrates may be
considered as a bibasic sucrate of hydrocarbonate of lime for its composition can be
represented by the formula C₁₂ H₂ Ö„ 2 {(CaO, HO.) (CaO, CO,)}.
Another calco-carbonic sucrate may be regarded as a double sucrate; bibasic
sucrate of hydrocarbonate of lime and carbonate of lime, since its composition may
be represented by the formula C₁₂H₂O, 2 {(CaO, HO) (CaO, CO₂)}, 2 (CaO, CO₂).
This last sucrate is remarkable for the large proportion it contains of lime carbonate
and for its purifying properties which are the result of this large proportion of lime
carbonate.
Between the limits of the two foregoing sucrates a large number of mixtures can
be obtained and in particular a mixture of which the composition answers exactly to
that of the sucrate of lime hydrocarbonate of Messieurs Boivin and Loiseau.
Lastly there is a well-defined combination which may be regarded as a tribasic
sucrate of hydrocarbonate of lime because its composition can be represented by the
formula CgHgOg, 3 {(CaO HO) (CaO, CO,)}.
1
This last sucrate would be interesting to study if we wished to extract the sugar
of the sugary juices of low density. But as we are especially concerned with the
purification of various sugary products, it is of the sucrate which is richest in
carbonate of lime of which we are going to treat.

page_text: This sucrate (double sucrate of hydrocarbonate of lime and carbonate of lime)
C₁₂H,O,, 2 (CaO, HO) (CaO, CO₂)} 2 (CaO, CO₂) is easily obtained by causing
carbonic acid gas to act, at a temperature of about 25 degrees Centigrade, on the
limed sugary solutions in which latter the proportion of sugar to the amount of lime
dissolved, is relatively very great. Not only must there be no lime undissolved when
the carbonic acid gas is caused to act, but the sugary solution need not be saturated
with lime and the gas must be stopped so soon as the sugary calco-carbonic solution
gives up a gelatinous precipitate which thickens the mixture more or less according
as it is formed in a sugary solution more or less concentrated (richer to a greater or
less extent in sugar). In order that the double sucrate of hydrocarbonate of lime
and carbonate of lime C₁₂H,O,, 2 {(CaO, HO) (CaO, CO₂)} 2 (CaO CO₂) shall be
thoroughly precipitated in these conditions without being mixed with sucrate of
hydrocarbonate of lime it is necessary in the first place, that the sclution shall not
contain more than 12 grammes of real lime (CaO) to 100 grammes of sugar; and, in
the second place, that the temperature of the sugary calco-carbonic solution shall not
exceed 27 degrees Centigrade at the moment of the precipitation of the sucrate.
the temperature of 27 degrees be exceeded, the double sucrate could still be formed,
but then the sugary solution must be as much less limed than its temperature would
be greater. For example, if the temperature reached 40 Centigrade it would not be
necessary to dissolve more than 6 grammes of lime to each 100 grammes of sugar
before causing the carbonic acid gas to act.
If
Once formed, the double sucrate of lime hydrocarbonate and lime carbonate keeps
well in work-shops where the temperature is constant or above 27 degrees Centigrade;
but care must be taken in keeping it in cold workshops because dissociation takes
place the more quickly according to the lowness of temperature and then are obtained
(1) carbonate of crystallized hydrated lime, and, (2) sucrate which is dissolved.
If it is wished to obtain a bibasic sucrate of hydrocarbonate of lime, the sugary
solutions of fairly heavy density must be strongly limed, whilst to obtain a tribasic
sucrate of lime hydrocarbonate it would be necessary to heavily lime sugary solutions
of low density.
The bibasic and tribasic sucrates of hydrocarbonate of lime being submitted to
the action of carbonic acid gas that a continual agitation or mixture may renew the
surfaces played upon by the gas, can give a double sucrate of hydrocarbonate of lime
and carbonate of lime C₁₂H,O,, 2 {(CaO, HO) (CaO, CO₂)}, 2 (CaO, CO₂); but this
method is not to be recommended because it is surrounded with practical difficulties,
which are, however, avoided by the method previously given.
12
All sucrates and their mixtures finally result in lime carbonate when submitted
for a sufficient length of time to the action of carbonic acid; this carbonate is an
anhydrate or a hydrate.
It is completely anhydrate when the carbonatation is entirely affected at a tem-
perature exceeding 20 degrees Centigrade. Below 20 degrees Centigrade the
crystallized hydrated carbonate of lime is obtained more easily as long as the solution
contains dissolved lime, but if the carbonatation is carried as far as to the complete
neutralisation of the mixture not only is anhydrated carbonate of lime obtained
before the completion of carbonatation, but it will be found that the crystallized
hydrated carbonate of lime previously formed is dehydrated the more rapidly
according as the temperature alters more than 3 or 4 degrees Centigrade and as the
solution is nearer to the point of neutralisation.
M. Pelouse, in making known the conditions favorable to the formation of crystal-
lized hydrated lime, has given attention only to the influence of temperature. He
still sought for the effect of temperature in studying the stability of the carbonate.
Now after what I have just said it will be seen that there is another influence, and
one very important to know, namely the influence of the more or less alkaline con-
dition of the medium whence the crystallized hydrated carbonate of lime is obtained.
It will be seen how important it is to know this fact if due regard be given to the
industrial applications of crystallized bydrated carbonate of lime. By observing this
the crystallized hydrated carbonate of lime may be made much more economically

page_text: than by working according to the method of Pelouse. In fact, the carbonic acid
may commence to be put in action in the midst of the limed sucrate solutions at a
temperature above 20 degrees Centigrade and the action of the gas may be continued
until one or other of the calco-carbonic sucrates, or of the mixtures of the sucrates,
has been formed, the carbonatation then being effected whilst the temperature is
lowered in such a manner that it will be about 2 or degrees Centigrade when the
quantity of lime in the solution is not more than 2 grammes per litre.
Finally it is advantageons with a view to the preservation of the crystallized
hydrated carbonate of line which may remain in the midst of a solution containing
not less than 2 grammes of lime per litre, if it is rich in sugar; but this remainder
of lime may be only 1 gramme per litre if the sugary solution is only slightly concen-
trated. In every case, the alkaline condition of the mass is of great importance in
view both of the manufacture and of the stability of the crystallized hydrated
carbonate of lime.
The latter brought into contact with limed sugary solution gives rise to phenomena
similar to those which are obtained by the direct action of carbonic acid in the middle
of the same limed sugary solutions. For instance, if the temperature of a limed sugary
solution, in which crystallized hydrated carbonate of lime is uniformly distributed, be
raised slowly and progressively, the result will be that the latter will commence to
dissolve by causing the solutions to gradually lose the property of becoming turbid
by yielding a precipitate of compound sucrate of lime at the boiling temperature.
Then the carbonate of lime continuing to dissolve, the solutions regain the property
of growing turbid at boiling point, but giving then a precipitate containing not only
sugar and lime, but also carbonate of lime; and the proportion of carbonate of lime
in the precipitate grows greater in proportion as the temperature is raised. In this
way I may obtain the double sucrate of hydrocarbonate of lime and carbonate of
lime.
The crystallized hydrated carbonate of lime must never be used alone for purifying
the raw juices of beet-root, for the refining is almost nil in that case. Either
conjointly with lime, or conjointly with one or other of the calco-carbonic sucrates
and for completing a calco-carbonic refining.
To use the crystallized carbonate of lime conjointly with lime, it is only necessary
to lime the juice to be refined with a quantity of lime varying from 6 to 10 thousandth
parts (6 to 10 grammes of natural lime per litre of beetroot juice) and to add to this
limed juice, suitable doses of the crystallized hydrated carbonate of lime, to suitably
agitate it to obtain a uniform mixture, and to heat the mixture to boiling point.
Afterwards the mixture is to be filtered.
The minimum of crystallized hydrated carbonate of lime would appear to be
the equivalent of 1 gramme of natural lime for 100 of juice. The doses seem to
vary between 1 and 2 grammes of natural lime in the state of crystallized hydrated
carbonate for 100 of beetroot juice. As these doses depend on the quality of the
beetroot juice, it will be necessary to determine them by experience in each factory.
The crystallized hydrated carbonate of lime will in that case be made in the midst
of one of the portions of beetroot juice.
The crystallized hydrated carbonate of lime may be employed as an adjuvant for
the double carbonatation. In that case it will preferably be necessary to cause it to
act after the first carbonatation; either on the turbid juice or on the filtered juice.
In every case it is advantageous to cause it to act in the middle of a sufficiently
alkaline juice containing at least 1.5 gramme of caustic lime per litre, by taking
necessary precautions against the production of the dehydration of the carbonate
of lime in the middle of the limed juice the mixture with which should be
effected rapidly. The crystallized hydrated carbonate of lime may be again
employed;
(1). Either after having purified the juice of the beetroot by means of double
sucrate of hydrocarbonate of lime and carbonate of lime, or
(2). By causing it to act conjointly with the double sucrate of hydrocarbonate of

page_text: lime and carbonate of lime, but it cannot of itself effect complete purification
of the beetroot juice.
The action of the double sucrate of hydrocarbonate of lime and carbonate of
lime is quite different. In fact the use of this sucrate can produce a complete
purification if two successive operations are effected on the beetroot juice. Possibly
a single operation might suffice with beetroot juice of very good quality, but
generally it would be necessary to make two successive operations because the beet-
root juice does not contain a sufficient quantity of sugar to dissolve the lime
necessary for the production of the double sucrate of hydrocarbonate of lime and
carbonate of lime which must be used to obtain a complete purification.
In beet-root sugar refineries, good results may be obtained by practising calco-
carbonic purification on certain syrups (syrups of "triple effect"); and this calco-
carbonic purification will yield results as much better as the purification of the
beetroot juices may have been less complete. In the contrary case it is necessary
to reduce the doses of non-carbonated lime and to cease the heating as soon as the
calco-carbonic reaction is completed, which will readily be known by the physical
change of the mixture. Generally a temperature of 80 degrees Centigrade is
sufficient. The purification produced in the above mentioned syrups will still give
good results if it is practised with a suitable proportion of double sucrate of hydro-
carbonate of lime and carbonate of lime, especially if the action of the crystallized
hydrated carbonate of lime is caused to take place when it is desired to preserve
the glucose. Whether the juice of beetroot or of sugar-cane, syrup (of triple
effect) of cane sugar or beetroot factories, is concerned, it is necessary, after puri-
fication and filtration to thoroughly carbonatate. As for the rest of the operations,
they are performed under the usual conditions. To carry out the calco-carbonic
purification on sugary liquids of great density, such as syrups and clear juices used
in refineries, (and also for certain syrups in sugar factories) the best refining is
obtained ;-
(1). By using the double sucrate of hydrocarbonate of lime and carbonate of lime,
for producing complete refining.
(2). By using the saine conjointly with crystallized hydrated carbonate of
lime, or
(3). By first causing a reaction of the double sucrate of hydrocarbonate of lime
and carbonate of lime, and then completing the action of this sucrate by that of
the crystallized hydrated carbonate of lime.
After each refining operation the lime which remains in the syrups must be sub-
jected to thorough carbonatation. The syrups are then submitted to the operations
usually practised in refineries in order to obtain from them sugar in a crystallized
state.
By these operations a very satisfactory refining is effected with all kinds of syrups
and brown sugars where it is desirable not to destroy the glucose, since it is possible
to reduce the temperature and the proportion of double sucrate of hydro-carbonate
of lime and carbonate of lime to such an extent as will enable one or other of the
two results to be obtained; and if the operation is performed on brown sugars
deprived of glucose, but charged more or less with alkaline salts (salts of potassium)
there will be no risk of the development of an excess of alkaline quality in the syrups
or clear liquids, as sometimes occurs when the refining of brown beetroot sugar of
coarse quality is practised with the sucrate of hydro-carbonate of lime process of
M. M. Boivin and Loiseau.
If moreover the sulphate of potassium in brown beetroot sugar or in syrups which
do not contain it naturally, be transformed into sulphate of lime, as it is in refineries
where the process of M. M. Boivin and Loiseau is used, it will be very easy to effect
a complete elimination of the sulphate of lime by using the necessary doses of
crystallised hydrated carbonate of lime.
In order to carry out the various operations which comprise the manufacture and
use, 1. of the double sucrate of hydro-carbonate of lime and of carbonate of lime :
and 2. of the crystallised hydrocarbonate of lime; I make use of the several

page_text: apparatus already known in this connection, and I reserve the right of specifying
those which by preference I would adopt in practice.
Dated this Twenty-third day of October 1897.
Improvements in the Processes of Purifying and Clarifying Sugary
Products in Sugar-houses, Sugar and Molasses Refineries,
Refineries or Factories of Glucose, and the like.
I, DESIRE LOISEAU, of 17, Rue St. Roch, Paris, in the French Republic, Civil
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 :-
The sugar industry makes use of two calco-carbonic purifying processes which give
good results. One of these processes known as turbid carbonatation, double
carbonatation, etc., is applied in beet root sugar houses to the juice which is of but low
density or specific gravity; the other process which is applied in cane sugar
refineries, is known as the purifying process by means of the sucrate of hydrocarbonate
of lime.
The improvements which form the subject of this invention are based on new facts
which demonstrate the existence of several calco-carbonic sucrates (instead of a single
sucrate of hydrocarbonate of lime as Messieurs Boivin and Loiseau believed) and
which, further, make known properties of the hydrated crystallized carbonate of lime
which Pelouze has discovered.
Chemists have for a long time believed, and many still admit it to-day, that the
process of the double carbonatation owes its good results to the properties of the
carbonate of lime which, in the nascent state, draws the impurities from the beet
root juice in the manner of lacs.
But this theory became manifestly insufficient, when Messieurs Boivin and Loiseau
shewed 1°, that the deposits of the turbid carbonatation contained not only carbonated
lime but also lime not carbonated, and 2°, that there exists a suciate in which the
quantity of uncarbonated lime is almost equal to that of the carbonated lime.
Messieurs Boivin and Loiseau concluded from these facts that the organic substances
of the beet-root juice ought not to be drawn out by the nascent lime carbonate, but.
that they ought to form insoluble compounds with the lime hydrocarbonate (CO2 CaO),
(CaO, HO). Whence the theory which attributes to lime hydrocarbonate, the
property of forming insoluble compounds with the impurities of the juice and other
sugary products.
pure
Since then I have studied the various calco-carbonic reactions in the midst of
and impure sugary solutions, of greater or less density, and I have discovered new
phenomena, obtained from new results which interest both science and industry.
In the first place I have ascertained that there exist three distinct combinations
of sugar, time and lime carbonate without counting the numerous mixtures of these
sucrates, (instead of the single sucrate of hydrocarbonate of lime of Messieurs Boivin
and Loiseau).
One of these combinations is a tribasic sucrate of hydrocarbonate of lime, the
composition of which may be represented by the formula C12 H8 08, 3 {(CaO, HO)

page_text: (CaO, CO2)}. It is very soluble in sugared solutions. Therein it possesses a property
in common with the tribasic sucrate of lime (12H808, 3(CaO HO) of Peligot. For
example let me cause a large excess of lime to react on a sugary solution containing
about 100 grammes of sugar per litre, in such a manner as to saturate it with lime
at a temperature of 20° Centigrade; and let me afterwards cause carbonic acid to act
in the midst of the mixture, whilst holding in suspension the excess of undissolved
lime, and during the duration of the gassing, let me take off some samples in order
to proportion the whole of the dissolved lime as well as carbonic acid. I shall thus
ascertain easily :-
1º, that I can redissolve, under the action of carbonic acid, a fresh quantity of lime
almost equal to that which was normally dissolved in the sugary solution, and,
20, that the solution gives a precipitate (of calco-carbonic sucrate) in the gelatinous
state only when the quantity of carbonic acid in solution becomes sufficient to form
a neutral carbonate with the half of the dissolved lime. Under these conditions,
the tribasic sucrate of hydrocarbonate of lime has been substituted for the tribasic
sucrate of lime. And with the tribasic sucrate of hydrocarbonate of lime which
saturates a sugary solution, I can obtain a bibasic sucrate of hydrocarbonate of
lime, so that with the tribasic sucrate of lime which saturates a sugary solution I
can obtain the bibasic sucrate of lime discovered by Messieurs Boivin and Loiseau.
In reality, if after having saturated the sugary solution with line, by causing the
carbonic acid to act in the presence of a large excess of lime, I put the mixture
through a filter to obtain the pure solution, and if I continue the action of the
carbonic acid in the midst of this solution with the greatest precautions until the
moment when it commences to become turbid or thick, but then immediately
checking or stopping the gassing, it will be seen that the solution continues to
become turbid and to give, finally the bibasic sucrate of hydrocarbonate of lime
C12H90°, 2{(CaO, HO) (CaO CO2)} whilst an excess of gas would give a precipitate
richer in lime carbonate.
If, instead of separating the excess of lime in the solution, I continue to cause the
carbonic acid to act in the midst of the mixture containing the excess of lime, I
should still obtain the bibasic sucrate of hydrocarbonate of lime as long as the
solution was not too poor in sugar; but then the continuous action of the carbonic acid
gas in presence of the excess of lime would give a tribasic sucrate of hydrocarbonate
of lime which is but little soluble in water.
The foregoing will suffice to shew how out of the sucrates of relatively simple
composition, numerous mixtures can be obtained.
Now I do not seek a patent for the formation of these different compounds, but
out of them, I have obtained a combination remarkable for the greater proportion of
carbonated lime which it contains and for its purifying or clarifying properties which
are in proportion to this great amount of lime carbonate; it is a double combination;
a bibasic sucrate of lime hydrocarbonate and of lime carbonate, the composition of
which answers to the formula C2HO®, 2 {(CaO, HỌ) (CaO CO2)}, 2 (CaO, CO?). To
obtain this in a certain manner, three conditions must be fulfilled:-
1°. The sugary solution must not have too low or feeble a density; it should not
contain less than 100 grammes of sugar per litre, and preferably it should have
300 to 400 grammes.
2°. The temperature should not be too low or too high; temperatures of 20° to 40°
Centigrade must be considered as the extremes or limits, and it is preferable to main-
tain the temperature between 25° and 30° Centigrade.
3°. The sugary solutions must not be too strongly limed. Not only is it not
necessary to make use of the action of carbonic acid to make them dissolve or take up
in solution the lime, but they must not even be normally saturated with lime, in the
absence of carbonic acid. The maximum of liming must be considered as the pro-
portion of 12 grammes of real lime CaO, for 100 of
sugar.
If these conditions are properly carried out, it is easy to ascertain 1°, that the
action of carbonic acid in the midst of these solutions does not give rise to any pre-
cipitate so, long as the quantity of carbonated lime does not exceed that of the

page_text: un-carbonated lime, and 2°, that at the moment when the gelatinous precipitate is
formed, this precipitate may be considered as a double combination of bibasic sucrate
of hydrocarbonate of lime and of carbonate of lime, for its composition answers to the
fornula C12HO, 2 {(CaO, HỌ) (CaO, CO2)} 2 (COCO2); and there is no free cat -
bonate of lime in this case, for the gelatinous product is entirely soluble in the
calcareous solution (under the condition that this solution be used as a solvent before
making it absorb carbonic acid) whilst the free carbonate of lime is not soluble in
this solution. This is the combination which I prepare in view of carrying out the
calco-carbonic clarification or purification of syrups, raw sugars etc., as will be here-
after stated.
All the calco-carbonic sucrates and their mixtures are stable at the temperature of
30° Centigrade, but none of them can resist the action of carbonic acid when this
latter is sufficiently prolonged.
In this case the freed sugar is dissolved whilst the lime carbonate is formed either
in the anhydrous state, or in the crystallized hydrated state. The carbonate is
always anhydrous when the carbonatation takes place and finishes at a temperature
bordering on 25° Centigrade or at a higher temperature. Once formed, this carbonate
has no interest and is of no use for the applications which are herein considered; it
is an inert substance and from that time without value, from the point of view of the
purifying of the juice, the syrups or raw sugar to be effected. It is not the same for
the lime carbonate which is obtained in the crystallized hydrated state. This carbonate
to which Pelouze has given a composition answering to the formula CO₂CaO + 6 H₂O,
possesses in reality remarkable effects which I have for a long time studied and which
allow of its being utilised as a purifying agent in the sugar industry.
For example if I cause it to lose its water of crystallization in contact with sugary
solutions which contain sulphate of lime, (organates of lime,) calcium compounds of
unknown composition) these substances can be eliminated (in a state of insolubility) in
a greater or less proportion.
The improvements forming the subject of my present invention, and which I
am now going to particularly describe, are based on the new facts above set
forth.
To carry out the calco-carbonic purification of sugary juices, syrups, raw sugars,
it is necessary to perform a series of operations; to prepare the lime and
carbonic acid; to lime the juice, syrups
; to make the calco-
carbonic combinations which are to be used; to use these combinations; to filter
the juice, syrups
after the purification, then the carbonates throughly
.
or to the bottom etc.
If the beet root juice, syrups, raw sugar
contain only a single foreign
substance, or if the foreigu substances although numerous are always the same and
in the same proportions, in all the sugary products, the question of the calco-carbonic
purification is set out in very simple terms. But as this is not always the case, it
must be fully understood that as there exist in the various sugary products, foreign
substances very different in their composition and properties even from the point of
view of their elimination, it is necessary to allow for a variation of the means, if so
desired, in all cases, of obtaining the maximum of useful effect with the minimum
of cost.
Thus it is that in order to eliminate the organic matters or substances of the beet-
root juice, I may use a calco-carbonic sucrate less rich in lime carbonate with relation
to the non-carbonated lime, than for carrying out the purification of the syrups of
triple effect which contain sulphate of lime, organates of lime (the calcium compounds
before referred to)
which do not exist in beet root juice.
.
Thus, also, it is that in order to perform the calco-carbonic purification of sugary
products which contain glucose, it is necessary to act differently according as it is
wished to preserve or to destroy the glucose.
To explain the term " syrups of triple effect" I would point out that a triple effect
evaporating pan vessel or apparatus, as is well known, consists of a modified vacuum
pan, which works on the principle that the latent heat of vapour is given off in

page_text: condensing to a liquid whilst the sensible heat is retained, that is, the steam
generated from the ebullition in one vessel is used to boil another, the steam from
which in like manner boils a third.
The first pan or effect may be heated by live steam from the boiler or the waste or
exhaust steain from various engines in the factory or works, this being the only one
heated by extraneous means, the latent heat of the vapour from the boiling liquor in
this first pan being utilised to heat the liquor in the next or second and the
latent heat of the steam from the liquor in the latter to heat that of the third or
last.
The juice or liquor passes through such triple effect apparatus from one pan to
another on account of the difference of vacuum and may be withdrawn from the last
pan or effect by a suitable pump.
Doubtlessly, with the theory of the lime carbonate in the nascent state, one was
scarcely able to think of making serious modifications in the process of turbid
carbonatation, of double carbonatation
There is no great difference between this and previous processes, in the practical
application of the process of purifying by sucrate of hydro-carbonate of lime, with
the idea of the existence of a single sucrate or with the idea that there existed no
chemical combinations but only mixtures. But it is otherwise with the knowledge of
the different calco-carbonic combinations previously named.
PURIFICATION OF BEET ROOT Juice.
Since beet root juices especially contain organic matters deprived of lime, they
do not need a combination as rich in lime carbonate as sugary products charged with
calcic salts. I have obtained the best results (the best useful effect) by making the
calco-carbonic sucrate in the midst of a part of the beet root juice strongly limed,
then mixing this limed and sucrated juice with once to twice its volume of the same
juice but un-limed, then causing this mixture to boil before submitting it to
filtration.
Before forming the sucrate it is necessary to lime the part of the juice where it
ought to be obtained. The liming is made by known means with anhydrous lime or
with hydrated line, although I prefer the anhydrous lime. The point to be here
observed concerns the dose of lime to be used; it should be about 2.5 grammes of
real lime for each 100 of juice, (2.5 kilos) of real lime for each hectolitre of juice)
for juices containing about 100 grammes of sugar per litre. This dose of lime could
be increased or lessened proportionately to the increase or to the reduction in richness
in sugar from 100 grammes of sugar per litre; but for regularity of work, it is
preferable to fix the dose of lime for the case in which one has juices of medium
richness in sugar.
Under these conditions the lime cannot be wholly and naturally dissolved by the
juice, but it ought to be entirely dissolved therein under the action of the car-
bonic acid, so as to exist wholly in the calco-carbonic combination at the moment
when this is precipitated in the gelatinous condition. If it were otherwise, if the
caleo-carbonic sucrate were precipitated in the gelatinous state before the lime were
totally dissolved, this would be more harmful than useful, by reason of the difficulties
which it would cause in the working, during boiling, filtration etc.
If a current of carbonic acid gas (as is well known this gas might be obtained in
large volumes from limestone heated in a lime-kiln) be passed into the midst of the
beet root juice (raw juice or juice of first sucratation) limed as just stated with 2.5
of real lime per 100 of juice, at a temperature of 25° to 30° Centigrade, an abun-
dant froth or foam will be seen to appear which is maintained within certain limits
by means of suitable skimmers or skimming devices, mechanical or otherwise;
then, at a certain moment, the froth begins to lessen or decrease and there is formed
a gelatinous precipitate which is the sucrate it is wished to obtain.
This preci-
pitate confines the froth in a nearly uniform manner. The result is the same
whether the sucrate be made with limed raw juice or whether it be made with juice
which has been submitted to the calco-carbonic purification, as said just now;

page_text: but the froth is relatively less with juice already purified than with raw juice. The
fact that the calco-carbonic sucrate when being precipitated into the gelatinous
state, confines or encloses the froth, constitutes a very precise empirical sign or
characteristic for indicating the moment at which it is necessary to cease the
action of the carbonic acid gas. It justifies, at the same time, the proportion of
lime adopted to lime the juice.
To utilise the sucrate thus obtained, the suerated juice is mixed with a sufficient
proportion of raw unlimed juice or raw juice only very slightly limed; the propor-
tion generally varies from one volume to a volume and a half of raw juice to one
volume of sucrated juice, and filtration is then proceeded with. If the juice filters
rapidly leaving a well-drained deposit in the filters, the proportion of calco-carbonic
sucrate has not been too great; it would he even too weak if the alkalimetrical stan-
dard or degree of the filtered juice were lower than the equivalent of 1 gramme of
lime per litre.
If the juice filter slowly, leaving a deposit which is with difficulty drained off in the
filters, the proportion of calco-carbonic sucrate was too great. In this case the filtered
juice possesses a too great calcic alkalinity; this latter ought not to exceed the
equivalent of 1.50 gramme of lime per litre. Besides warning is given that the doses
of lime leave or do not leave something to be desired :-
By the aspect afforded by the mixtures when heated to boiling; if the boiling or
ebullition is frothy and if the bubbles of air do not freely escape, it is because,
generally, the proportion of sucrate is too great; and the boiling or ebullition is less
and less frothy with mixtures according as the proportion of sucrate is less.
If as complete as possible a purification in a single operation be desired, it would
be necessary to make use of a strong dose of sucrate. But the operation would be
liable to be very slow and to the loss of sugar in the state of insoluble sucrate in the
froth or scum. It would be preferable to carry out two operations, (two successive
sucrates); the one on the raw juice and the other on the juice purified for the first
time. But from an economical point of view as to the results of the purification, it
is preferable to not push too far the purification of the juice, and to complete it by
carrying out the calco-carbonic purification of the syrups of triple effect.
PURIFICATION OF SYRUPS OF TRIPLE EFFECT.
To carry out calco-carbonic purification on syrups of triple effect, it is well to
employ the calco-carbonic sucrate, which is the richest in lime carbonate, that is to say
the bibasic sucrate of hydrocarbonate of lime and of carbonate of lime C¹²º0° 2
(CaO, HO) (CaO CO²), 2 (CaO, CO2) which is obtained in the midst of the syrups
which are relatively little limed.
To lime these syrups, I cannot proceed as when it is a question of juice of low
density as in the case of beet root juice; for when the lime is put into contact with
the syrups a sticky or sticking sucrate of burnt-sugar-almond appearance is produced,
which it is necessary to avoid. For that purpose it is necessary to give the preference
to hydrated lime and, in order to dissolve it, to make use of syrups at higher and
higher temperatures as the density of the syrup increases. For example, if the
density of the syrup does not exceed 25° Beaumé at a temperature of 15° to
20° Centigrade, the lime can be dissolved without forming the sticky sucrate, if the
mixing (the liming) takes place at a temperature bordering on 60° Centigrade; and
if the density of the syrup reaches 29° to 30° Beaumé it is better to employ it at a
temperature of 90° Centigrade than at a lower temperature. However, the liming
of dense syrups can be effected at a higher or an increased temperature, without
formation of the sticking sucrate, by proceeding in the following manner.
In the first place it is necessary that the lime should be completely hydrated and
in the state of milk of lime; but it is not necessary that the hydratation should
have taken place or been made in the midst of pure water, it can also be hydrated in
the middle of a sugary liquid of low density, ordinary precaution being taken to avoid
alteration of the sugar. In the second place it is necessary to cause the syrup to
slowly reach or attain the milk of lime, by shaking or stirring without ceasing, in such

page_text: a manner as to slowly raise the density of the sugary liquid in which the non-dissolved
lime is soaked or held. Under these conditions, the lime remains in excess so long as
the density of the solution is too feeble or low to form the sticking sucrate, and when
the density becomes too great to favor or be conducive to the formation of this sucrate,
it is no longer able to do it because the whole of the lime has been dissolved. There
should be, really, in the limed syrups, a large excess of sugar with relation to the lime
which is therein dissolved since there ought not to be more than 12 grammes of real
lime CaO for 100 grammes of sugar.
The liming of the syrups of triple effect can be performed by two different
methods:-
1º. With a view to forming the purifying sucrate with the whole of the syrup to
be purified. In this case, it is necessary to cause the dose of lime to be varied in
such manner as to effect the purification which it is wished to obtain, taking note
that the dose of 15 grammes of real lime per litre of syrup, should be regarded as a
maximum.
And 2°. With a view to forming the purifying sucrate with only a portion of the
syrup. In this case the syrups should be carefully limed with the same proportions
of lime; and what must be then varied, are the proportions of sucrated syrup and of
natural syrup, so as to use the dose of bibasic sucrate of hydrocarbonate of lime
and of carbonate of lime, to obtain or bring about the most satisfactory calco-
carbonic purification.
To obtain this sucrate with limed syrups, as above stated, the latter are submitted
to the action of carbonic acid at a temperature of 25° to 30° Centigrade. The
temperature may even reach 40° Centigrade if the limed syrups do not contain
more than 15 to 20 grammes of real line per litre of syrup containing 350 to 400
grammes of sugar which corresponds to a proportion of lime of 4 to 6 grammes per
100 of sugar; under the action of the carbonic acid, there is at first produced a
fairly abundant froth or foam which more or less increases and with which it is
useless to trouble if the boilers are sufficiently raised, but the volume of which can
be easily reduced by means of mechanical skimmers or corresponding devices. On
continuing the admission of gas, at a certain moment the sucrate C2HºOº
2 {(CaO, HO) (CaO, CO2)}, 2 (CaO, CO2) is precipitated into the gelatinous state,
completely enclosing the froth and imparting to the whole of the mixture a uniform
gelatinous appearance; this fact constitutes an empirical character very precise for
or noteworthy as indicating the moment at which the action of the carbonic acid
inust cease. It is important at this point not to prolong this action, for the bibasic
sucrate of hydrocarbonate of lime, is the sucrate which can most rapidly be decom-
posed by carbonic acid, whilst it is sufficiently stable at the temperature of its
formation (about 30° Centigrade) to be kept in the factories until required for use.
To obtain the purification of syrups, it is sufficient to heat, until boiling, those
syrups containing the sucrate evenly distributed as when formed in the midst of
the whole of the syrups to be purified. It is to be understood that the mixture
should contain a sufficient and not an excessive dose of bibasic sucrate of hydro-
carbonate of lime and lime carbonate. In this case it is found that, under the
action of heat, the gelatinous condition of the mixture decreases more and more so as
to completely disappear and sometimes quite suddenly, before reaching the boiling
stage; at the same time the confined froth reappears at the surface without remaining
there very long, and what is formed at the moment of boiling abates or sinks down
rather quickly when heat is no longer applied. The boiling mixture being filtered
or passed on to the filter presses, gives or results in a syrup which flows easily
leaving a deposit which drains well and which can be completely deprived of sugar
in suitable filter presses. In general, syrups thus purified undergo a great decolora-
tion and no longer contain calcic salts, (sulphate of lime or organates of lime).
If the mixture contained an excessive dose of the bibasic sucrate of hydrocarbonate
of lime and of carbonate of lime, the gelatinous state would remain much longer and
would even be able not to disappear completely; under the action of heat there would
be produced a fine froth so abundant that it would become an obstacle to the heating

page_text: of the mixture up to free or complete boiling. The filtration of the syrup, the drain-
ing of the deposits, etc., would take place under adverse conditions.
If the mixture contained an insufficient dose of purifying sucrate, the whole of
the operations, boiling, filtration, draining and washing of the deposits, would on
the contrary, take place well and rapidly; but the purification would be incomplete ;
there would remain in reality, calcic salts in the syrups and the decoloration would
leave something to be desired.
In carrying out the calco-carbonic purification, at first on the juice and then on the
syrups of triple effect, as I have just pointed out, the greatest useful effect with a
minimum of cost, is obtained.
Good results can also be obtained by carrying out the calco-carbonic purification
of the syrups of triple effect after having performed the double carbonatation of the
juice in the most economical manner.
It is a known fact that in carrying out the double carbonatation of the juice, the
cost is relatively greater for eliminating the last remaining foreign matters or sub-
stances than for eliminating the preceding; that to produce the same useful effect,
it is necessary to make use of quantities of lime and carbonic acid as much stronger
as the operation is advanced; that, sometimes the result is negative, in the sense
that or inasmuch as the substances previously precipitated are re-dissolved if sufficient
alkalinity be not left in the juice. Now instead of endeavouring to obtain the
maximum purification of the juice, it is better, from the point of view of the useful
effect to be produced, to limit to strictly what is necessary the disbursements of
lime and carbonic acid into this juice to the condition that caleo-carbonic purification
will be carried out on the syrups of triple effect and will form an integral part of the
work of purification.
I have just shewn how caleo-carbonic purification should be performed in the case
of syrups which do not contain glucose. But if I had to perform such purification on
products containing glucose it would be necessary to distinguish between two cases;
the case in which the glucose would be destroyed and the case in which it would be
preserved.
If it he wished to destroy the glucose, I carry out or effect complete calco-carbonie
purification with the bibasic sucrate of hydrocarbonate of lime and carbonate of
lime which contains sufficient lime to destroy the glucose and which contains,
besides, a strong proportion of active lime-carbonate (ready to act.) to render
insoluble the coloured calcic-salts derived from the glucose.
PURIFICATION OF SUGARY PRODUCTS (SYRUPS, RAW SUGAR
OF GLUCOSE.
.) IN PRESENCE
But if it be not wished to destroy the glucose, it is not necessary that the hibasic
sucrate of hydrocarbonate of lime and carbonate of lime should be used alone; it is
necessary to add to it a proportion of hydrated crystallized carbonate of
lime (CO2CaO) +6 HO as much stronger as it is necessary to eliminate a larger
quantity of calcic salts (sulphates of lime, organates of lime . . .). However in
this case I can dispense with the use of the bibasic sucrate of hydrocarbonate of lime and
carbonate of lime on condition of using hydrated crystallized carbonate of
lime (CO²CaO) + 6 HO conjointly with a dose of lime sufficient to contribute to the
decoloration of the syrups but insufficient to destroy the glucose.
The crystallized hydrated carbonate of lime is very easily obtained by proceeding
as Pelouze has shewn; but this method convenient for laboratory purposes or studies,
would leave much to be desired in its commercial application. I substitute for it a
method of manufacture based on the fact that the crystallized hydrated carbonate of
lime is formed and preserved at a temperature considerably lower when the medium
remains alkaline than in neutral media. It can, thus, easily be obtained and
preserved at a temperature of 15° Centigrade in a sufficiently alkaline medium, when
it is not formned and is not even preserved in a neutral medium at a lower
temperature.
The syrup intended for the manufacture of the crystallized hydrated carbonate of

page_text: lime can be much more strongly limed than the limed syrup with a view to forming
the bibasic sucrate of hydrocarbonate of line and carbonate of lime, but in the two
cases it is necessary to carry out the liming at the lowest temperature possible to
avoid the destruction of the glucose, and the best plan-when working with products
unequally charged with glucose-is to select as much as possible for liming them,
syrups which contain the minimum of glucose and to lime them to a low density.
The syrup for forming the crystallized hydrated carbonate of lime which can be
limed with 30 grammes of real lime and more, per 100 grammes of sugar, does not
need cooling below 25° Centigrade when the operator begins to cause the carbonic
acid to act, considering that the carbonate of lime which is formed from the moment
the operation of passing gas commences, until the moment when the gelatinous
precipitate of calco-carbonic sucrate is obtained, is not free. But when the calco-
carbonic sucrate is precipitated, it is necessary to rapidly lower the temperature of
the mixture below 20° Centigrade to about 15° Centigrade, if it be wished to continue
causing the carbonic acid to act and to form crystallized hydrated carbonate of lime;
the carbonate of lime is in reality well formed in the crystallized hydrated state at a
temperature of 15° Centigrade as long as there remains a sufficient quantity of sucrate
in the gelatinous state to maintain the calcic alkalinity of the solution; but starting
or commencing from the time when the calcic alkalinity dimishes, it is necessary to
continue cooling the mixture in such a manner that its temperature will be about 1°
to 2° Centigrade when there remains no more than 1 to 2 grammes of dissolved lime
per litre of solution; for if the solution became neutral without its temperature being
sufficiently lowered below 15° Centigrade not only would anhydrous carbonate of lime
be formed with the last portions of carbonated lime, but there would occur dehydration
and dislocation or breaking up of the crystals of hydrated carbonate of lime previously
formed in the alkaline medium. On the other hand, at a temperature bordering on
zero, only crystallized hydrated carbonate of lime is formed when the solution reaches
neutrality and what has been formed at a higher temperature is completely preserved
in an alkaline medium.
When the carbonatation is stopped if there remains no more dissolved lime, the
operator should dissolve from 1 to 2 grammes of it per litre to form a medium
suitable for the preservation of the crystallized hydrated carbonate of lime, at a higher
temperature of 2° Centigrade, whilst awaiting use.
By reason of or according to the foregoing description, it is easy to carry out the
calco-carbonic purification of products more or less charged with glucose. To fix this
idea, I am supposing that the process of purification will be performed on raw cane
sugar containing 5 to 8% of glucose.
1º. With bibasic sucrate of hydrocarbonate of lime and carbonate of lime in the
gelatinous state in a mixture containing per 100 parts,
Lime in the state of sucrate
=
2.61
27.60
-
66.00
Raw sugar
Water
Carbonic acid and impurities
= 3.80
Water
60.00
Carbonic acid and impurities
= 8-80
And to properly judge or estimate the useful effect of each product, I will employ 5
them by comparison, either separately or together in the same syrups or in the same
raw sugars.
For this purpose I form four distinct mixtures with each sugary
product viz.,
1°. I first form a natural syrup containing all impurities by dissolving 50 parts of
raw sugar in 50 of water.
R

page_text: 2º. I obtain a second syrup also containing 50 per cent. of raw sugar but in which
only the crystallized hydrated carbonate of lime CO2CaO + GHO has been made to
react.
3°. I also obtain a third syrup likewise containing 50 per cent. of raw sugar but
in which only the calco-carbonic sucrate C12H90°, 2 {(CaOHO) (CaOCO²)}, 2 (CaO CO²)
has been caused to react.
4°. Finally I obtain a fourth syrup similarly containing 50 per cent. of law sugar
but in which the above named sucrate and carbonate have been simultaneously caused
to react.
Under these conditions syrups are obtained which have undergone or been sub-
mitted to a greater or less decoloration and an elimination of the calcic salts, which
the results shewn in the following table will permit of being readily understood.

page_text: I wish to remark that if the two purifying products (the calco-carbonic sucrate and
the crystallized hydrated carbonate of lime) be used, it is necessary to cause them to
act simultaneously or to commence by causing the sucrate to react and not to com-
mence the reaction by the crystallized hydrated carbonate of lime.
If instead of raw sugar, a syrup is to be purified, a portion or, if necessary, the whole
of this syrup is utilised to form the bibasic sucrate of hydrocarbonate of lime and of
carbonate of lime, as well as to forin hydrated crystallized carbonate of lime; then
mixtures with suitable proportions of the natural syrup and of the two purifying
products are made, the temperature of which mixtures is afterwards raised to boiling
point.
From a perusal of the results set out in the above chart or table, it is easy to see
that there are serious differences in the methods of action of the crystallized hydrated
carbonate of lime, and of the suerate which is the richer in lime carbonate. In reality
with the crystallized hydrated carbonate of lime, the action is more felt on the
calcic salts than with the sucrate, since (syrups No. 2) the hydrotimetrical degree
has been lowered from 160° to 105° for the first raw sugar and from 310° to 140°
for the second raw sugar with the crystallized hydrated carbonate of lime, whilst
with the sucrate (syrups No. 3) the hydrotimetrical degree has been raised
from 160° to 210° for the first raw sugar and from 310° to 380° for the second
raw sugar.
On the other hand the decoloration is less great with the crystallized
hydrated carbonate of lime (although it be accompanied by lime added to the
syrup, of from 1 to 2 grammes per litre) than with the sucrate. In reality the
decoloration has been lowered only from 1.00 to 9 for the first raw sugar and from 1.0
to 0.5 for the second raw sugar with the crystallized hydrated carbonate of lime,
whilst with the sucrate the decoloration has been lowered from 10 to 0-56 for the
first raw sugar and from 10 to 18 for the second.

page_text: If it be wished to obtain the maximum of purification (decoloration and elimination
of the salts) in every case, it is necessary to simultaneously employ the two purifying
compositions in the best proportions.
By the use of my invention I obtain in purification, in sugar houses and
sugar-refineries, the maximum of useful effect or result with a minimum of
cost.
In sugar factories, the calco-carbonic purification can be economically performed
on syrups of triple effect if account be taken that this purification forms an integral
part of the work of purification and allows the cost of purifying the juice to be
considerably reduced, whilst finally obtaining better purified products.
In sugar refineries, all commercial advantages inay be profited by, for calco-
carbonic purification can be carried out and all the qualities of raw sugars can be
cultivated or improved whether they contain glucose or not and whether it is wished
to preserve or destroy this glucose. In every case there are eliminated the calcic
salts, which are the inost harmful to the charcoal or bone black, the use of which
cannot be avoided in refineries which seek to obtain the choicest refinings or
results.
The purified products can, in addition, under the best conditions, be subjected to
the Ranson, sulphurous acid
processes.
•
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 :-
1º. The new double combination of bibasic sucrate of hydrocarbonate of lime
and carbonate of lime, the composition of which answers to the formula C¹²H°()º
2 {(CaO HO) (CaO CO²)} 2 (CaO CO). It is option l on my part to obtain this
product by any means.
2°. The method of manufacturing the hydrated crystallized carbonate of lime, as
above specified.
30. The application of the bibasic sucrate of hydro-carbonate of lime and of
carbonate of lime to be employed alone, or to be employed in conjunction with
crystallized hydrated carbonate of lime, for the purification of the various sugary
products (juice, syrups, raw sugars etc.)
4°. The applications of the crystallized hydrated carbonate of lime to be used alone
or with the sucrate C12H, 2 {(CaO CO2) (CaO HO)}, 2 (CaO CO²) for the purification
of the various sugary products, and as adjuvant to the other calco-carbonic purifying
processes, especially when sugary products rich in glucose are being treated for
purification, without destroying this glucose.
50. The method of purifying juice, as specified in the foregoing description and
which consists in making calco-carbonic sucrate with a portion of the juice strongly
limed and in using it in mixture with another portion of the juice unlimed or very
feebly or weakly lined.