Improvements in and connected with the Manufacture of Sugar.
Year: 1890

page_text: Date of Application, 3rd July, 1890
Complete Specification Left, 3rd Apr., 1891-Accepted, 3rd July, 1891
PROVISIONAL SPECIFICATION.
Improvements in and connected with the Manufacture of Sugar.
. We, ADOLPHE LEFRANC, Sugar Manufacturer of Flavy-le-Martel, Louis
LEFRANC, Sugar Manufacturer, of Tracy-le-vol, and ARMAND VIVIEN, Consulting
Chemist, of 18, Rue de Bandreuil St. Quentin, all in France, do hereby declare the
nature of our invention to be as follows:-
In the early stages of the manufacture of sagar, the elimination of organic
admixtures or impurities was sought to be attained by the action of acids; subse-
quently the serious inconvenience attaching to the application of acids has led to
alkaline bases, and particularly lime, being employed instead.
The processes at present in use for the manufacture of sugar are so imperfect,
thut seldom more than an average of 75 % of the saccharine matter is obtained in
the crystallized condition; the remainder is left in the state of molasses without
much (commercial) value.
We have attempted to discover a process which would render a more complete
extraction possible by eliminating simultaneously almost the whole of both the organic
and mineral substances, and we have found, that this double result can be obtained
by treating the saccharine solutions with fluosilicates of the metals, (Si Fl¹ R)
or 2 (Si F13) 3 (R Fl).
We have thus been induced to formulate a process of purification based on
the employment of fluosilicates, preferably those of lead and iron in the condition
of acid salts.
The method of treatment employed for saccharine juices varies according to
whether the operation be applied to juices, syrups, washings or molasses.
FIRST INSTANCE.
PURIFICATION OF THE JUICE OF BEETROOT, SUGAR-CANE, SUGAR-MAPLE &C.
Basis on which the process depends.-The juices on leaving the extraction
apparatus (diffusion apparatus, presses, mills &c.) are run into a gauged vat.
When the juices contain oxidizable substances, such as those contained in beetroot,
they are kept in a vat as long as possible, in order to oxidize the organic
substances and colouring matters. To induce this oxidizing action, air may be
injected (into the liquid) or any other (suitable) oxidizing agent employed.
A solution of metallic fluosilicates is then added to the juices in such a proportion,
that the hydrofluosilicic acid of the fluosilicates saturates all the bases of the juice,
so as to form insoluble fluosilicates with them. The mixing is effected either by
a mixer or by blowing through air. A copious precipitate is produced which is
separated by filtration in bags or in filters. A liquid flows out which is slightly
acid and contains a slight excess of the reagent.
The liquid, which is collected in a vat, is neutralized by a base, and the sediment
is mixed and separated afresh by means of filtration.
The solution treated in this manner is purified. It is, however, advisable in order
that no traces of metal or silica may remain in it, to treat it with a current of
sulphuretted hydrogen, carbonic acid, sulphurous acid, or to add to it sulphuric
acid, phosphoric acid or others, or a sulphate, phosphate, or other reagent capable
of precipitating the silica and the metal in the condition of oxide or other compound,
or we may reduce the lead to the metallic state by boiling with shavings, file dust,'
zinc dust, or by electrolysis. We have found that to attain very rapid purification,
the juice may be desiccated by lime in the diffuser which causes the juice issuing
-P82]

page_text: METHOD OF APPLICATION TO BEETROOT JUICE TAKEN AS AN EXAMPLE.
2-5% of fluosilicate of lead (strength 35° Beaumé, about,) are poured into the
juice to be purified; the amount varies according to the composition of the liquid.
The whole is oxidized and mixed till the colour has been completely removed; the
precipitate formed contains the organic matters in the form of insoluble compounds,
and the greater part of the mineral substances; it is then filtered, rendered slightly
alkaline by means of milk of lime or baryta water, in order to get rid of the excess
of hydro-fluosilicic acid, and again filtered; then, after rendering slightly acid by a
current of sulphurous gas, or still better, by means of phosphoric acid or an acid
phosphate in order to precipitate all traces of lead and of silica, a slight excess of
lime or other base is added (potash, barytes, &c.) to impart a very slight alkalinity
to the juices, so as to insure their keeping during the subsequent operations of
filtering over bone black, evaporations, boiling down &c. By this process we have
succeeded in attaining a degree of purity of upwards of 95 and a degree of salinity
of over 100 results which have never before been obtained-the raw beetroot juice
taken on leaving the diffusers has not more than 86 of purity and 26 of salinity
approximately with the ordinary processes. The method of procedure is the same
when the fluosilicate of iron is employed.
The juices are so well purified, that they may be kept for a number of days, even
when they are in a neutral condition without undergoing any alteration.
The first filtration is not indispensable, and it may be omitted, if the two sediments
be mixed together and treated in one operation. If juices have to be purified
containing large quantities of organic matter in proportion to the amount of ashes
which they contain, the quantity of the agent which it is necessary to employ, is
determined by experiment, which is repeated once or several times successively;
or, what is still better and at the same time equally advantageous when the bydro-
fluosilicate of lead is employed, and in view of rendering a preparation of the reagent
economical as will be seen, a certain quantity of lime or lead in the condition of
metallic powder or of oxide or hydrate, or peroxide, or sucrate of lead, or double
sucrate of lead and lime is dissolved in the solution, before the amount of fluosilicate
of lead, that is required for the complete precipitation of the organic and mineral
substances present, is added.
The juices purified as has just been explained follow the chain of processes usual
in the manufacture for transforming them into concentrated syrup and finally into
raw sugar or directly into refined sugar. The sediments collected by means of
filtration contain the bases in the condition of fluosilicates and the acids, both
mineral and organic, in the state of metallic salts.
The purification is very perfect, mere infinitesimal quantities of the organic and
mineral substances which constitute impurities, remaining behind in the solutions.
The sediments are subsequently treated for obtaining the bases, the hydro-
fluosilicic acid, the metal and various other substances (which it may contain) such
as nitrogen, phosphorus, &c.
We have not mentioned, while describing the preceding series of reactions, what
are the temperatures at which they ought to be conducted. We generally prefer
to proceed at the lowest temperatures possible; however, there are certain
circumstances under which we have noticed that it is necessary to employ heat;
what the circumstances are may be readily ascertained by a few comparative
trials the composition of the sugar solutions to be treated being known.
Generally speaking, the process is conducted in the cold, by which means the
non-alteration of the sugar is secured, and the losses arising from heating are
avoided.

page_text: The purified juice may be further treated in the evaporation apparatus and con-
centration apparatus at present in use.
condensers of large tubular surface, the
of the condensers and emerging from
about 60°.
For this purpose, we employ two heating
cold and pure juice entering at the bottom
them at the top at the temperature of

page_text: fluosilicate Fi Si³ F118 may be prepared by saturating hydro-fluosilicic acid by
means of ferric hydrate.
The fluosilicate of lead is prepared by dissolving lead in the form of thin sheets
(or foil) in powder or the thinnest possible grains, or better still, an oxide or
carbonate, or a silicate of lead in hydro-fluosilicic acid. In the first case, an
evolution of hydrogen takes place, which is collected for the purpose of being
utilized in the revivification furnaces. In the other instances, water which
remains in the reagent is formed as also carbonic acid which escapes, and silica,
which is precipitated.
66
"
In preparing the fluosilicate of lead of 35° Beaumé strength, by means of an
oxide of lead (red lead or litharge, for example) it is advisable, to conduct the
reaction with a 20° Beaumé solution of hydro-fluosilicic acid. If it is desired, to
prevent all decomposition of the reagent and to avoid even partial precipitation of
silica, hydro-fluosilicic acid which contains a very small quantity of free hydro-
fluoric acid is employed, and in this instance, the operation may be conducted with
acid of less than 20° Beaumé in strength. The addition of an excess of the metal
above the amount corresponding to the molecular formula Si Fl Pb, must be
avoided; in fact, rather less than this amount must be employed to avoid
decomposition.
In the case in which oxide of lead is first added to the juice, in the manner
which we have pointed out above, the reagent is prepared with a quantity of lead
corresponding at least to the lead added to the juice. This method of conducting
the operation acts very well, and the fluosilicate of lead is formed and decomposed
in the body of the liquid which has to be purified.
Fluorine
Lead
Lime
15 per cent.
14 "
30 ""
"
در
The amount of the reagent to be employed varies according to the purity of the
juice at the commencement; on the average (under average conditions) 5% of
the reagent is the maximum employed. We have obtained a very satisfactory
purification on employing 4% with a juice, the purity of which on leaving the
diffuser was 85. One may even go below this point. It must be understood, that
the nature of the precipitates varies according to the proportion of the reagent
employed.
The operations may be conducted by the method of separate precipitations which
gives the two deposits mentioned above, which are obtained directly, or by the
method of direct neutralization with lime, or baryta in the vat, in which the reagent
has been added, time having been allowed for it to react and to become intimately
mixed with the juice, a method which gives one single sediment composed of the
inixture described above; but in either case the process of "revivifying" these
residues is conducted by similar methods; these methods we have made the subject
of study, and we herewith proceed to point out the principles involved.
First method.-The residues are treated with sulphuric acid; fluoride of silica
escapes, which, on being collected in water, decomposes, and produces gelatinous

page_text: silica which may be employed for the manufacture of dynamite &c., hydroflucsilicic
acid is also formed.
There remains a mixture of sulphates, which are lixiviated to obtain the soluble
sulphates of potash, soda &c. separate from the insoluble sulphates, such as that
of lead.
If it be desired to recover the sulphuric acid, the sulphates are calcined with
silica, the sulphuric acid is distilled off; there remain soluble alkaline silicates and
silicate of lead, which, when dissolved in bydrofluosilicic acid, leaves the silica
behind in the form of gelatinous silica.
By this process, the fluosilicate is "reconstituted" and the alkaline bases, potash,
soda, &c. are obtained in the form of sulphates or carbonates.
Second method.-The dried residues are heated in a retort, blast-furnace, or
cupola, after having been mixed with coal, coke, or any other suitable fuel. The
lead flows out in the metallic state and is collected, as are also the liquid fluorides-
the silicon fluoride, phosphoros, and the gases, originating in the decomposition of
organic substances distills over. These gaseous products pass through a tube or
chamber heated to redness and converted into nitrogen, carbonic acid &c. and
escape from the water which serves to collect the silicon-fluoride and phosphoros,
or, if oxidation has taken place, the phosphoric acid.
A current of air may also be introduced into the top of the retort, or blast
furnace, in order to effect the combustion of the greater part of the organic
matter, and the process may be conducted in such a manner, as to produce an
oxidizing atmosphere at the top, and a neutral or reducing atmosphere at the
bottom, if it be desired to recover the lead in the metallic state, or the
atmosphere may be kept oxidizing throughout, if it be desired to produce litharge.
We have observed, that our residues may be easily fused by heat after the
organic matter has been burned away.
In this calcination process, the lead; whether oxidized or not, flows along the
bottom of the hearth, as also do the fluorides, silicates &c. and the fluoride of
silicon escapes as in the preceding case and is collected as has been described.
Three tapholes are arranged, one above the other; the lead flows out through the
lowest, the fluorides from the one in the middle, and the silicious "
the highest hole.
gangue" from
The fused products are decomposed by sulphuric acid in closed vessels and in the
presence of silica, silicon fluoride is set free, causing the regeneration of the hydro-
fluosilicic acid; sulphates of lime, lead, potash &c. remaining behind, and these
are treated with silica, as we have described, when it is desired to recover the
sulphuric acid. Or better, still the insoluble sulphate of lead is separated and
reduced by coal, in order to obtain metallic lead and the sulphurous acid which is
employed in the process of purifying the juices.
If a current of steam be introduced into the blast-furnace or retort, or even if
small drops of water be injected into it, the fluorine escapes in the form of hydro-
fluosilicic acid. It is advisable, in this case, to add silica, in order that the
hydrofluosilicic acid may be completely formed (i.e. that all the fluorine may be got
into this condition). It is condensed by cooling in order to obtain it in the
concentrated form.
Third method.-The first precipitate coming from (or originating in) the
treatment of the juice, contains large quantities of alkaline fluosilicates decom-
posable by beat in fluoride of potassium, sodium &c. and into fluoride of
silicon; if it be desired to recover the alkalies which it contains in the caustic
state, the alkaline fluorides are heated with an excess of lime; silicate of lime
is formed, together with fluoride of calcium, potash, caustic soda &c. which
continue in solution in the liquid.
The fluoride of calcium and the silicate remaining in combination with the
other fluorides, are treated, as we have just described, in order to obtain the
hydro-fluosilicic acid.
Fourth method. The residues are calcined, in order to get rid of the organic

page_text: matter, and to recover the fluoride of silicon arising from the decomposition of the
alkaline fluosilicates. The atmosphere is rendered oxidizing at the top of the
furnace by an addition of air, and reducing at the lower part by injecting carbon
monoxide or by any other suitable means. The lead runs out, as well as the
fluorides of potassium, sodium, calcium, &c.
The lead is separated, and the fluorides, &c. recovered by means of liquation.
The alkaline Aluorides crushed and dissolved in water, are treated by heat,
the fluoride of calcium is precipitated, and the soda, and caustic potash obtained.
By this means, the alkaline fluorides are converted into insoluble fluoride of
calcium, which is treated as follows:
The crushed calcium fluoride is mixed with a powdered felspar which is rich
in potash and calcined; silicon fluoride is produced which, received in the water,
is decomposed into silica and hydro-fluosilicic acid; if the employment of aqueous
vapour be resorted to, the hydro-fluosilicic acid distills over directly. A mixture
of lime and potash remains behind; in this way in the first instance potash and,
in addition, gelatinous silica, is extracted from the domite-two products which are
of value and cover the expenses of revivification.
By this method all expenses for sulphuric acid for the purpose of decomposing
the fluorides are avoided and the potash is recovered from the beetroot juice, as
well as from the domite.
If it be desired, to obtain silicates of soda, instead of potash, rocks rich in
the felspars having soda for a base, such as the albite of Finbo, which, according
to the analysis of M. Mène, contains 10 to 50% of soda, and 48 to 70% of silica,
are selected.
Dated this 3rd day of Inly 1890
FAIRFAX & WETTER,
433, Strand, London, Agents.
COMPLETE SPECIFICATION.
Improvements in and connected with the Manufacture of Sugar.
We, ADOLPHE LEFRANC, Sugar Manufacturer, of Flavy-le-Martel, LOUIS
LEFRANC, Sugar Manufacturer, of Tracy-le-Mont, and ARMAND VIVIEN,
Chemical Expert, of St. Quentin, all in France, do hereby declare the nature of
our invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
The processes at present in use for the manufacture of sugar are so imperfect,
that seldom more than 75 per cent. of the saccharine matter is obtained in the
crystallized condition; the remainder is left in the state of molasses without much
commercial value.
We have attempted to discover a process, which would render a more complete
extraction possible by eliminating simultaneously almost the whole of the organic
impurities and the mineral matter, and we have found, that this double result can be
obtained by treating the saccharine solutions with fluosilicates of the metals (mole-
cular general formula Si Mu F, or equivalent general formula Si F, M F) in the
manner hereinafter described.
It has been proposed, to employ certain fluosilicates, such as those of ammonia,
of magnesia, and of alumina, for the purification of juices, and even experiments
have been made with fluosilicates of ammonia, but, as far as we know, without
success.
Previous inventors have worked with alkaline or neutral liquids or media, because
they feared the action of acids on the sugar. When they wished to use metallic
fluosilicates which have an acid reaction, they recommended the previous addition,
to the juice to be purified, of a base sufficient in quantity to obtain a neutral reaction
after the addition of the reagent or purifying agent.
We employ a fluosilicate having an acid reaction and allow it to act on the juice

page_text: in an acid condition for about half an hour, in order to precipitate the alkalis as
fluosilicates.
We avoid the action of the purifying compound in a neutral or alkaline
liquid, having found, that under these circumstances no satisfactory result can be
obtained.
FIRST MODE OF WORKING.
PURIFICATION OF THE JUICE OF BEETROOT, SUGAR-CANE, SUGAR MAPLE &c.
The juices, on leaving the extraction apparatus (such as diffusion apparatus,
presses and miils) are run into a gauged vat."
When the juices contain oxidizable substances, such as those contained in
beetroot, they are kept in the vat as long as possible, in order to oxidize the
organic substances and colouring matters. To promote this oxidizing action, air
may be injected into the liquid, or any other suitable oxidizing agent may be
employed.
An acid solution of a metallic fluosilicate (such as a fluosilicate of lead or
of iron) is then added to the juice in sufficient quantity to form insoluble
compounds with all the bases contained in the juice, such as potash, soda
and lime.
The mixing is effected either by blowing air through the liquid, or by means of
an agitator, acting as long as possible, half an hour being usually sufficient.
A copious precipitate is thereby produced, which may be separated by allowing the
acid liquid to flow off by decantation during several hours, or by filtering it through
a fabric sufficiently fine in texture to produce a very clear filtrate. This operation
is of some importance. The filtered liquid is acid and contains a slight excess of
metallic fluosilicate.
The liquid is collected in a vat and neutralized by a base, the mixing is repeated.
and the resulting precipitate again separated by decantation or filtration.
The solution treated in this manner is practically pure. It is, however, advisable,
in order that no traces of metal or silica may remain in it, to treat the solution
with a current of sulphuretted hydrogen, carbonic acid or sulphurous acid, or
to add to it sulphuric acid, phosphoric acid, or a suitable sulphide, sulphate,
phosphate, or any other reagent capable of precipitating the silica and the metal
in the condition of oxide or other compound; or we may reduce the lead to
the metallic state by boiling with iron turnings, file dust, zinc dust, or by
electrolysis.
We have found, that to attain very rapid purification the juice may be first
defecated or clarified by lime in the diffuser, which renders the juice issuing from
it slightly alkaline (alkalinity from one to ten ten thousandths) and very suitable
for "luation," as we call our treatment with fluosilicates.
But in this case, care must be taken, to add a large proportion of metallic
fluosilicate, for precipitating the free lime, and also the potash and soda, so as to
render the liquid acid.
1
With this important reservation, we may therefore if convenient, slighty defecate
or purify the juices, before the addition of fluosilicates.
We will now describe, by way of example, the application of our process to
beetroot juice.
We employ chiefly two metallic fluosilicates, namely the Luosilicate of lead,
(molecular formula: Si Pb F, or equivalent formula: Si F, Pb F) and the fluo-
silicate or iron (molecular formula Si Fe Fe, or equivalent formula Si F, Fe F) which
are acid to test paper and contain one equivalent of metal to three equivalents of
fluorine.
We may indiscriminately take the one or the other, the fluosilicate of iron being,
of course, chosen, where the use of lead for the preparation of food is prohibited
by law.
We pour into the saccharine liquid the fluosilicate solution in proportions
calculated according to the concentration of the latter and the composition of the

page_text: liquid; the treated liquid is then oxidized or mixed for some time. The precipitate
thus formed contains the organic impurities and the major portion of the mineral
matter in the shape of insoluble compounds; the liquid is then carefully filtered,
so as to obtain a very limpid filtrate, which is rendered slightly alkaline by the
addition of milk of lime (or other suitable alkaline-earthy base) in order to
precipitate the excess of reagent and to completely decolourize the liquid.
Subsequently the liquid is again filtered.
If fluosilicate of lead has been employed, any traces of lead, which may still
remain in solution, are removed by a current of sulphurous acid gas, or better
still, by means of phosphoric acid or an acid phosphate, in order to precipitate all
traces of lead and of silica. Finally, a slight excess of lime, potash, baryta or
other suitable base is added, to impart a very slight alkalinity to the juices, so as to
ensure their keeping during the subsequent operations, such as filtering over bone
black, evaporation, and boiling down.
If fluosilicate of iron has been employed, we remove the traces of iron and of
sulphates by neutralizing the juice with lime, subsequently adding baryta or (and
preferably) sulphide of barium or of strontium, which precipates at the same time
the iron and the sulphuric acid; afterwards we render the liquid slightly alkaline
with a very slight excess of lime. We may also employ baryta or strontia at any
convenient stage of the operation, in order to get rid of the sulphuric acid, in
cases where lead cannot be used.
The juices are so well purified, that they may be kept for several days, even
when they are in a neutral condition, without undergoing any alteration.
The juices purified as has just been explained, follow the chain of processes
usual in the manufacture of sugar, for transforming them into concentrated syrup
and finally into raw sugar, or directly into refined sugar. The sediments collected
by means of filtration contain the bases in the condition of fluosilicates and most
of the acids, both mineral and organic, in the state of metallic salts.
The purification is very perfect, only the minutest quantities of the organic and
mineral substances which constitute impurities, remaining behind in the solutions.
The sediments are subsequently treated for obtaining the bases, the hydro-
fluosilicic acid, the metal, and various other substances, which they may contain,
such as nitrogen, phosphorus, &c.
We have not mentioned, while describing the preceding series of reactions, what
are the temperatures, at which they ought to be conducted. We generally prefer,
to operate at the lowest temperatures possible; however, there are certain
circumstances under which we have found it necessary, to employ heat; what these
circumstances are, may be readily ascertained by a few comparative trials, the
composition of the sugar solutions to be treated being known.
Generally speaking, the process is conducted in the cold, to avoid any alteration
of the sugar and the loss of heat which usually occurs in sugar refineries, where all
purifying operations are carried out at a high temperature.
The purified juice may be employed for condensing purposes in the evaporation
and concentration apparatus at present in use. For this purpose, we employ two
condensers of large tubular surface, the cold and pure juice entering at the
bottom of the condensers and emerging at the top at the temperature of
about 60° C.
Saavn MADE OF WORKING
PURIFICATION OF SYRUPS (INCLUDING DRAINAGE FROM SUGAR LOAVES),
OR MOLASSES.
In order to purify raw sugar, syrups, (including the liquid drained from
crystalline sugar) or molasses, in the refining, the process may be conducted in
the same way as for the juices, or it may be divided into two stages and conducted
as follows:
5
The saccharine solution or syrup is brought to a density ranging between 1.2 5

page_text: and 13, that is to say, about 25° to 35° Beaumé. A quantity of the reagent, of
fluosilicate of lead, for example, sufficient to saturate all the bases, is then added.
The acid liquor is then filtered, and subsequently saturated with lime, or with the
double sucrate of lead and of lime, and again filtered. A fresh quantity of the.
reagent is then added, and the saturation effected at once in a manner similar to
that described above. The deposit is then separated.
The liquid which flows through, is comparatively pure, but it still contains small
quantities of the salts of lead; these are got rid of by boiling with zinc dust,
sulphurous acid, the derivatives of phosphorus, or by means of the methods which
have been pointed out above.
The first operation should be performed at a low temperature, not exceeding
about 30°, to avoid the action of the acids on the sugar.
After neutralization, however, the temperature may be raised to the boiling
point if the saccharine liquid treated does not contain any glucose; otherwise the
heating must be less in proportion to the glucose contained in the liquid, and in
this case a temperature of 70° C. is sufficient.
To obtain the sugar therefrom, the purified solution is treated by the ordinary
processes.* The sediments which contain the saline and organic impurities
combined with hydro-fluosilicic acid and with lead or iron, are worked up, as will
be hereafter described, with a view to recovering their constituents including the
precipitated bases.
1
THIRD MODE OF WORKING.
ELIMINATION OF ORGANIC IMPURITIES AND COLOURING MATTERS.
Let us suppose, that work is being done in the refinery. The saccharine
solutions, syrups or molasses, are to be treated with the reagent in sufficient
quantity, to obtain the maximum of decolouration and removal of organic
impurities. The cold liquid is filtered and immediately saturated with lime or
with double sucrate of lead and of lime. The temperature is then raised to
between 60° and 100° C., depending on the amount of glucose contained in the
liquid, as has just been stated with regard to the second mode of working, and
the solution is filtered. The liquid which runs through, is freed from the lead or
from the lime which it contains, by the means which we have already described.
The solution thus purified and decolourized, is further treated in the ordinary
way. The sediments are collected, and treated for the purpose of recovering the
alkaline salts, the hydro-fluosilicic acid, and the lead or the iron,, if considered
advantageous.
All the operations mentioned in the instances we have given of this method of
treatment, may be carried out with the apparatus and materials usually employed
in the sugar industry, such as vata, mixers, and filter presses. It is advisable,
however, to protect the apparatus employed for the acid liquors, by a lining of
gutta-percha, india-rubber, paraffin, or by a double sheet of lead foil.
If fluosilicate of iron is employed as a reagent, we may use the ordinary recep-
tacles, without providing them with any protective coating.
QUANTITY OF REAGENTS TO BE EMPLOYED.
The quantity or proportion of the reagents to be employed varies with the
quality of the saccharine liquid; as a rule, we ascertain the quantity of ash
contained in the saccharine liquids, express this quantity in carbonate of potash
and ascertain by calculation the quantity of fluosilicate which corresponds (or is
equivalent) to the contents of the ash.
Theoretically we require for saturating one kilogramme of carbonate of potash,
and consequently one kilogramme of ash
2.536 kilos of anhydrous fluosilicate of lead

page_text: we should destroy by the washing the effect of the purification previously obtained,
inasmuch as
the fluosilicate of potash dissolves in
833 parts of water
620
"
"
of rubidium in
"
of calcium in
"
of sodium in
"
"
"
166 "
"
"
153 "
وو
"
"
Thus, in the example described above, instead of washing with four litres of
water per kilo. of frothy sediment, we may wash with or ½, or or 10 that
quantity of water.
If we wish to employ of the quantity, that is half a litre, for the washing, and
if the filter press contains 10,000 kilos. of the froth, we employ a vat of 40 hectolitres
divided into eight compartments of 5 hectolitres each.
When the
The five first hectolitres running out of the filter press are again used in the
process and are replaced by purified juice; each of the five hectolitres of washing
water which follows, is placed into one of the compartments from 1 to 7.
seventh compartment is full, the washing of the froth has been completed.
For washing the subsequent charges of the filter-press, we force by means of a
pump consecutively the washing water contained in the compartments from 1 to 7,
the first 5 hectolitres running out of the press, are again used in the process, and
the others are consecutively placed into the compartments from one to six; lastly,
we take 5 hectolitres from the eighth compartment and force them back into the
filter-press. The liquid which runs out will again fill the seventh compartment,
and so on. In this way, the washing liquids are used in the order of decreasing
density, and finally we end with pure water.
The washing water is charged with salts, and we extract from the press cakes
the sugar which they contain, without eliminating from them the salts and causing
the latter to re-enter the process.
The metallic fluosilicates are but little known, and the text books contain only
We have been obliged to study
very meagre information regarding these bodies.
them, in order to practise our process of purification, and we will therefore complete
the present description by stating how the reagent is to be prepared and revivified
or recovered.
6
The fluosilicate of iron may be prepared by causing fluosilicic acid to act upon
metallic iron, when ferrous fluosilicate Si Fe F is formed. This is neutralized by
adding sulphide of iron, in order to obtain a well defined salt. Ferric fluosilicate,
Si, Fе, F, may be prepared by saturating fluosilicic acid by means of hydrated
sesquioxide of iron.
The fluosilicate of lead, Si Pb F is prepared by dissolving lead, in the form of
thin sheets, or of powder or granules, or better still, an oxide or a silicate of lead, in
hydro-fluosilicic acid. In the first case, an evolution of hydrogen takes place,
which is collected for the purpose of utilizing it in the "revivification" furnaces.
In the other instances, water, which remains in the reagent, is formed, and silica
which is precipitated.
In preparing the fluosilicate of lead, of 35° Beaumé strength, by means of an
oxide of lead (red lead or litharge, for example), it is advisable, to conduct the
If it is
reaction with a solution of hydro-fluosilicic acid of about 20° Beaumé.
desired, to prevent all decomposition of the reagent and to avoid even partial
precipitation of silica, hydro-fluosilicic acid which contains a very small quantity
of free hydro-fluoric acid is employed, and in this case, the operation may be
conducted with acid of more than 20° Beaumé. The addition of metal above the
amount corresponding to the molecular formula Si Pb F, must be avoided; it is
better, to take less than this amount, to avoid decomposition.

page_text: If oxide of lead is first added to the juice, in the manner which we have pointed
out above, the reagent is prepared with a quantity of lead reduced in proportion to
the lead added to the juice. This method of conducting the operation acts very
well, and the fluosilicate of lead is formed and decomposed in the body of the
liquid which has to be purified.
Lime
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The amount of the reagent to be employed varies according to the purity of the
juice at the commencement; under average conditions 5 per cent. of the reagent is
the maximum employed. We have obtained a very satisfactory purification by
employing 4 per cent. with a juice, the purity of which on leaving the diffuser
We may even go below this point, and it will be understood, that the
nature of the precipitate or sediment varies according to the proportion of the
reagent employed.
was 85.
First method. The residues are treated with sulphuric acid; fluoride of silicon
escapes, which on being collected in water decomposes, and produces gelatinous
silica, which may be employed for the manufacture of dynamite; hydro-fluosilicic
acid is also formed.
There remains a mixture of sulphates, which are lixiviated, to obtain the soluble
sulphates of potash and other bases separate from the insoluble sulphates, such as
that of lead.
If it is desired, to recover the sulphuric acid, the sulphates are calcined with
silica, the sulphuric acid is distilled off; there remain soluble alkaline silicates and
silicate of lead, which, when dissolved in hydro-fluosilicic acid, leaves the silica
behind in the form of gelatinous silica.
By this process, the fluosilicate is "reconstituted" and the alkaline bases (potash
and soda) are obtained in the form of sulphates.
Second method.--The dried residues are heated in a retort, or in a shaft furnace,
after having been mixed with coal, coke, or any other suitable fuel. The lead
reduced to the metallic state melts and is collected, as are also the liquid fluorides.
The silicon fluoride, phosphorus, and the gases produced by the decomposition of
organic substances distil over. These gaseous products pass through a tube or
chamber heated to redness and are converted into nitrogen, carbonic acid &c., and
escape from the water which serves to collect the silicon fluoride and the
phosphorus, or, if oxidation has taken place, the phosphoric acid.
A current of air may also be introduced into the top of the retort or blast
furnace, in order to effect the combustion of the greater part of the organic matter,
and the process may be conducted in such a manner, as to produce an oxidizing
atmosphere at the top, and a neutral or reducing atmosphere at the bottom, if it be
desired to recover the lead in the metallic state; or the atmosphere may be kept
oxidizing throughout, if it be desired to produce litharge.
We have observed, that our residues may be easily fused by heat, after the
organic matter has been burned away.

page_text: In this calcination process, the lead, whether oxidized or not, flows to the
bottom of the hearth, as also do some of the fluorides and silicates, and the fluoride
of silicon escapes as in the preceding case and is collected, as has been described.
Three tap-holes are arranged one above the other, the lead flows out through the
lowest, the fluorides from the one in the middle, and the silicious "gangue" from
the highest hole.
The melted products are decomposed by sulphuric acid in closed vessels and in
the presence of silica; silicon fluoride is set free, causing the regeneration of the
hydro-fluosilicic acid, while sulphates of lime, lead, potash &c. remain behind, and
are treated with silica, as we have described, when it is desired to recover the
sulphuric acid, or the insoluble sulphate of lead is separated and reduced by
charcoal, in order to obtain metallic lead and sulphurous acid, which is employed in
the process of purifying the juices.
If a current of steam be introduced into the lower part of the retort, or even if
small drops of water be injected into it, the fluorine escapes in the form of
hydrofluosilicic acid. It is advisable, in this case, to add silica, in order that
the hydrofluosilicic acid may be completey formed (i.e. that all the fluorine may
be got into this condition). It is condensed by cooling, in order to obtain it in the
concentrated form.
Third method. The first precipitate produced by the treatment of the juice,
contains large quantities of alkaline fluosilicates, decomposable by heat into
fluoride of potassium, of sodium, &c. and into fluoride of silicon; if it be desired
to recover the alkalies, which it contains, in the caustic state, the alkaline
fluorides are heated with an excess of lime; silicate of lime is formed, together with
fluoride of calcium, caustic potash or soda &c. which remain dissolved in the liquid.
The fluoride of calcium and the silicate remaining in combination with the other
fluorides, are treated as we have just described, in order to obtain the hydro-
fluosilicic acid.
Fourth method. The residues are calcined, in order to get rid of the organic
matter, and to recover the fluoride of silicon arising from the decomposition of the
alkaline fluosilicates. The atmosphere is rendered oxidizing at the top of the
furnace by an addition of air, and reducing at the lower part by injecting carbon
monoxide or the fluorides of potassium, sodium, calcium, &c.
The lead is separated, and the fluorides, &c. recovered by means of liquidation.
The alkaline fluorides, crushed and dissolved in water, are treated with lime,
fluoride of calcium is precipitated, and caustic soda and potash obtained.
By this means, the alkaline fluorides are converted into insoluble fluoride of
calcium which is treated as follows:-
The crushed calcium fluoride is mixed with a powdered felspar, for instance
domite, which is rich in potash, and calcined; silicon fluoride is produced which,
when received in the water, is decomposed into silica and hydrofluosilicic acid; if
the employment of aqueous vapour be resorted to, hydrofluosilicic acid distills over
directly. A mixture of lime and potash remains behind; in this way we extract
from the domite in the first case potash, and in addition gelatinous silica-two
products which are of value and cover the expenses of revivification.
By this method, all expense for sulphuric acid for the purpose of decomposing
the fluorides may be avoided and the potash extracted from the beetroot juice, as
well as from the domite.
If it be desired, to obtain from the silicates soda, instead of potash, rocks rich in
the felspar having soda for a base are selected, such as the albite of Finbo, which
according to the analysis of M. Mené contains 10 to 50 per cent. of soda, and
48 to 70 per cent. of silica.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is:

page_text: fluosilicates, which consists in using fluosilicates having an acid reaction by causing
them to act on the sugar in an acid condition or in an acid medium, substantially as
described.
2. The purification of saccharine liquids by means of a fluosilicate of iron or of
lead in the manner substantially as described.
3. The special method of washing the sediments or precipitates produced by
treating saccharine liquids with fluosilicates, substantially as described.
4. The processes or methods of preparing the reagents, substantially as described.
5. The four methods or processes of revivification taken separately or in com-
bination, substantially as described.