CERTAIN IMPROVE. MENTS IN EMPLOYING THE RESIDUE ARISING FROM THE LIXIVIATION OF CRUDE SODAS
Year: 1855

page_text: LETTERS PATENT to Pierre Antoine Favre, Professor of Chemistry, à la
Faculté des Sciences at Marseille, in the Empire of France, and of
4. South Street, Finsbury, London, for the Invention of "CERTAIN IM-
Scaled the 16th November 1855, and dated the 7th June 1855.
PROVISIONAL SPECIFICATION left by the said Pierre Antoine Favre at
the Office of the Commissioners of Patents, with his Petition, on the
7th June 1855.
I, PIERRE ANTOINE FAVRE, Professor of Chemistry, à la Faculté des Sciences
at Marseilles, in the Empire of France, & of 4, South Street, Finsbury,
London, do hereby declare the nature of the Invention of "CERTAIN IMPROVE.
MENTS IN EMPLOYING THE RESIDUE ARISING FROM THE LIXIVIATION OF CRUDE SODAS,"
to be as follows, that is to say:-
My Invention consists in the utilising the residues obtained in the lixiviation
of crude sodas. My process is based on the employment of the muriatic
acid produced in the soda manufacture itself in such quantities as almost
always to constitute an encumbrance.
The following are the principles on which I carry out the treatment of the
residues of lixiviation of crude soda :-The sulphuret of calcium contained in
these residues is mixed with water, & then submitted to the action of the
muriatic acid envolved from the kilns in which the sulphate of soda is manu-
factured._
of bringing the aid-in-its caseous-state: T-treat the oxuculahuicts

page_text: "
according to circumstances, with muriatic acid condensed to the liquid state in
water, or in saline solutions contained in the condensing apparatus. As may
be imagined, this latter mode is to be preferred in factories where the marine
salt solution is precipitated by muriatic acid. The muriatic acid with the lime
and the sulphuret of calcium forms a soluble chloride of calcium, and at the
same time throws off gaseous hydrosulphuric acid containing all the sulphur
of the sulphuret. The sides of the apparatus in which this reaction is operated
should be formed of silicious stones, or, as a general rule, of material inalter-
able by the acids employed.. Having thus disengaged the sulphur in the form
of hydrosulphuric acid, I employ either, of the two following processes for the
utilisation of the sulphur.
FIRST PROCEss.
I prepare a saturated solution of sulphurous acid by passing the products
arising from the combustion of sulphur pyrites or hydrosulphuric acid through
water contained in an apparatus hereafter described. I then pass through this
solution the hydrosulphuric-gas: The reaction commences; and précipitation
of sulphur takes places; one equivalent of sulphurous acid and two equivalents
of hydrosulphuric acid give, rise to three equivalents, of sulphur precipitated;
arrangements being made so as to have several apparatus for the sulphurous
acid solution. The sulphurous acid once destroyed by the chemical reaction
in the first apparatus, I can prevent the arrival of the hydrosulphuric acid, and
direct it to the second sulphurous acid apparatus where the action recommences,
during which time I pass a new quantity of sulphurous acid to saturate the
water in the apparatus from which I had shut off the hydrosulphuric acid.
As to the means destined to favor or accelerate the reaction of the sulphurous
and hydrosulphuric gases with the water, I employ one of the following arrange-
ments:-I pass the hydrosulphuric gas (sulphuretted hydrogen) into a chamber
containing sulphurous acid, which has been put in solution by a feeble pressure
of a few centimètres of water. This sulphurous acid is previously passed into
'the water, which it ought to saturate, drawing it off as formed either by
suction or decantation, employing for this purpose the means already known.
I do not immerse in the liquid the orifices of the conduits which 'conduct
either of the gases, but I dispose across the chamber a series of parallel partitions
passing from the upper part of the chamber, and terminating within a certain
distance of the bottom. The lower edge of each partition is immersed to a
certain extent in the water intended to operate the solution. By this means the
gas can only pass from one partition to another after having traversed the depth
of the liquid column which corresponds to the part of the immersed partition.
Instead of this method, 'I can suppress the partitions, and substitute for the
.

page_text: pressure produced by them on the gases the effect of a shower of water falling
from the upper part, or the effect of mechanical agitation of the liquid to
favor the solution of the sulphurous gas; introduced without pressure, and the
subsequent reaction of the two gases., I nevertheless: give preference.to the
employment of the partitioned, chamber. It is understood. that the sides of
the apparatus in which the reaction takes places' are lined either with lead,
silicious stone, or other material resisting the action of the reagents to beşin
contact with it:
****
After several successive operations, and a sufficient quantity of, sulphur has
been precipitated; I separate, it from the liquid in which, it is held in suspen->
sion: This liquid, which has become slightly acidulated by a, certain: portion
of sulphuric acid, the formation of which it is impossible, to prevent, may be
preserved for use in future operations.
SECOND PROCESS.
The difference between this, process and the first arises from the hydro-,
sulphuric acid being entirely submitted to combustion, so as to decompose it.
into water and sulphurous acid. To this end I pass the gaseous hydrosulphuric
acid into sulphur. or pyrites kilns, according as it is formed. The gas is there
burned, and the resulting sulphurous acid mingles with that arising from the
combustion of the sulphur, or pyrites,
1
J.
the
I
is ..
In the manufactories, where the sulphurous acid passed into the chambers is
formed. by the combustion of pyrites, I lead the hydrosulphuric gas across the
fragments of pyrites in combustion, where it inflames, after having traversed,
the incandescent mass. can, also burn, the bydrosulphuric acid by lighting,
the gas, and leading it directly into the leaden chambers, then supplied, simply
with sulphurous acid from the combustion of the hydrosulphuric acid. The,
running off of the hydrosulphuric acid may be regulated and gauged by, a,
gasometer, through which the gas would pass towards the points where the
combustion should take place.
5
ان
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed.
by the said Pierre Antoine Favre in the Great Seal Patent Office on the

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of June, in the year of our Lord One
thousand eight hundred and fifty-five, in the eighteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Pierre Antoine Favre, Her special license that I, the said Pierre Antoine
Favre, my executors, administrators, and assigns, or such others as I, the said
Pierre Antoine Favre, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times there-
after during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention of "CERTAIN IMPROVE-
MENTS IN EMPLOYING THE RESIDUE ARISING FROM THE LIXIVIATION OF CRUDE SODAS,"
upon the condition (amongst others) that I, the said Pierre Antoine Favre,
by an instrument in writing under my hand and seal, should particularly
describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said Pierre Antoine Favre, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:
My Invention consists in the lixiviation of crude sodas, ball soda, or British
barilla. It is well known that these residues are composed essentially of
oxysulphuret of calcium (Ca O, 2. CaS), which theorically ought to contain
thirty-two per cent. of sulphur. Analyses of these residues have proved to me
that the average proportion of sulphur to be looked for ranges from nineteen
to twenty-two per cent. of material simply dried in the open air. The sulphur
thus contained in these residues is entirely lost. Each year the soda manu-
factories accumulate enormous masses of this product, the "caput mortuum,"
as it were, of fabrication; and it is easy to estimate the annual loss in cach
manufactory by the corresponding value of sulphur bought for manufacturing
purposes. To restore a valuable portion of the sulphur thus wasted is the basis
my Invention.
of
'11
I make use of the chlorhydric acid, produced in the manufacture of soda in
such quantities as almost to constitute always an encumbrance, and even at
times becomes a source of expense in the payment of indemnities for
.damages.
The following is the principle on which I carry out the treatment of the

page_text: residues of lixiviation of crude sodas:
The sulphuret of calcium contained
in these residues is put in suspension with water, and then submitted to the
action of the chlorhydric acid evolved from the kilns in which the sulphate of
soda is manufactured. Instead of bringing the acid in the gaseous state on
the sulphured substances, I treat, according to circumstances, the oxysulphurets
by means of muriatic acid condensed in water to the liquid state, or in a saline
solution contained in the condensing apparatus. As may be imagined, this
latter mode is to be preferred in manufactories where the marine salt solution
is precipitated by chlorhydric acid. This acid, with the lime and sulphuret
of calcium, forms a soluble chloride of calcium, and at the same time throws
off gaseous hydrosulphuric acid containing all the sulphur of the sulphuret..
The sides of the apparatus in which reaction is taking place should be formed.
of silicious stones, or, as a general rule, of material inalterable by the acids
employed. Having thus disengaged the sulphur in the form of a hydro-
sulphuric acid, I employ either of the two following processes for the utilisation
of the sulphur
I prepare a saturated solution of sulphurous acid by passing through the
water contained in an apparatus herein-after described the products arising
from the combustion of sulphur, pyrites, or of hydrosulphuric acid; I then
pass through this solution the hydrosulphuric gas. The reaction commences,
and precipitation of sulphur takes places. One equivalent of sulphurous
acid, and two equivalents of hydrosulphuric acid, give rise to three equivalents
of sulphur precipitated. Arrangements can be made so as to have several
apparatus for the sulphurous acid solution. The sulphurous acid once destroyed
by the chemical reaction in the first apparatus, I prevent the arrival of the
hydrosulphuric acid, and direct it to the second sulphurous acid apparatus,
where the action recommences, during which time I bring a new quantity of.
sulphurous acid to saturate the water in the apparatus from which I had shut.
off the hydrosulphuric acid.
As to the means destined to favor or accelerate the reaction of sulphurous
acid and hydrosulphuric gases with the water being present, .I.employ one of
the two following arrangements :-I cause the bydrosulphuric gas to arrive into
a chamber containing sulphuric acid in a state of solution, by.a feeble pressure
of about one inch and a half of water. This sulphurous acid is previously
passed into the water it ought to saturate, drawing it off as formed either by
suction or pression, employing for this purpose the means already known. I
do not immerse in the liquid the orifices of the conducts which bring either

page_text: of the gases, but I arrange across the chamber a series of parallel partitions
passing from the upper part of the chamber, and terminating within a certain
distance from the bottom. The lower edge of each partition is immersed to
a certain extent in the water which is to be employed for the solution. By
this means the gas can only pass from one partition to another after having
traversed the depth of the liquid column which corresponds to the part of the
immersed partition. Instead of this method, I can suppress the partitions; and
substitute for the pressure produced by them on the gases the effect of a
shower of water falling from the upper part, or the effect of mechanical agita-
tion of the liquid to favor the solution of the sulphurous gas introduced without
pressure; and the subsequent reaction of the two gases. I nevertheless give
preference to the employment of the partitioned chamber.
"After successive operations, and when a sufficient quantity of sulphur has
been precipitated, I separate that body from the liquid where it is found in a
state of suspension. This liquid, slightly acid on account of a certain quantity
of sulphuric acid, the formation of which cannot be prevented, can be pre-
served, to be again introduced into the apparatus, and serve for further opera-
tions. It is understood that the sides of the apparatus in which the reaction
takes place are lined either with lead or with silicious stones or other materials
resisting the action of the agents in contact with it.
SECOND PROCESS.
The difference between this second process and the first arises from the
hydrosulphuric acid having entirely disappeared by combustion, so as to decom-
pose
it in water, and sulphurous acid. For this purpose I direct the gaseous
hydrosulphuric acid as soon as produced in the kilns for consuming the
sulphur and pyrites. In the kilns the gas, is burnt, and the sulphurous acid.so
obtained is added to that arising from the direct combustion of sulphur. and
pyrites. In manufactories where the sulphurous acid having passed into the
chambers is formed by the combustion of pyrites, I lead the, hydrosulphuric
acid gas across the fragments of pyrites in combustion, where it inflames after
having. traversed the incandescent mass. I can also burn the hydrosulphuric
acid by lighting the gas, and leading it directly into the leaden chamber, then
entirely supplied with sulphurous acid from the combustion of the hydro-
sulphuric acid. But as irregularities might arise in the disengagement, and
the temperature become lowered, a sufficiently continuous combustion could
not be depended on. The running off of the hydrosulphuric acid may be
regulated and gauged by a gasometer; through which this gas would pass before
being sent towards the point where its combustion should take place. An

page_text: objection might be raised on the ground of the possibility of disengaging
carbonic acid at the same moment as the hydrosulphuric acid, in treating the
oxysulphuret by muriatic acid, but this could have no real value if the residues
of lixiviation of crude sodas are treated shortly after the lixiviation; for the
proportions of material employed and experience proves that the quantity of
free lime in the matter withdrawn from the kilns is extremely feeble, and con-
sequently this lime has not produced a sufficient amount of carbonate of
lime for disengaging the carbonic acid in quantity capable for destroying the
reactions.
I will now give an estimate of the proportions of sulphur which may be
procured from the residues:-Two equivalents of hydrochloric acid correspond
theoretically to the production of two equivalents of carbonate of soda. This
carbonate of soda in its formation has left in the residue two equivalents of
sulphur in the state of oxysulphuret, containing one equivalent of lime and
two equivalents of sulphuret of calcium; one equivalent of oxysulphuret of
calcium requires, therefore, more hydrochloric acid for its decomposition than
the quantity set free by the first reaction. Theoretically, according to the
composition 2 CaS, Ca O, only two-thirds of the sulphur could be utilised. In
practice, the half may be recovered without difficulty.
And having now described the nature of my Invention, and the best mode
of putting the same into execution, I wish it to be understood that I do not
confine myself to the precise details or modus operandi I have described, pro-
vided the principle of my Invention be preserved; but what I claim is, the
utilisation of the sulphur wasted in the lixiviation of crude soda, (British
barilla), by employing in the treatment of these residues the muriatic acid
evolved from the sulphate of soda kilns, as herein-before described.
In witness whereof, I, the said Pierre Antoine Favre, have hereunto
set my hand and seal, this Fourthi day of December, in the year of our
Lord One thousand eight hunred and fifty-five.
PIERRE ANTOINE FAVRE. (L.S.)