IMPROVEMENTS IN THE MANUFACTURE OF SODA CRYSTALS
Year: 1869

page_text: LETTERS PATENT to William Spence, of 8, Quality Court, Chancery
Lane, in the County of Middlesex, Patent Agent, for the Inven-
tion of "IMPROVEMENTS IN THE MANUFACTURE OF SODA CRYSTALS." -A
communication from abroad by Messieurs Perret, Brothers, and
Olivier, of Paris, in the Empire of France, Manufacturers.
Sealed the 27th May 1870, and dated the 1st December 1869.
PROVISIONAL SPECIFICATION left by the said William Spence at the
Office of the Commissioners of Patents, with his Petition, on the
1st December 1869.
I, WILLIAM SPENCE, of 8, Quality Court, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF SODA
CRYSTALS," (being a communication from abroad by Messieurs Perret,
Brothers, and Olivier, of Paris, in the Empire of France, Manufacturers,)
to be as follows:-
Carbonic acid (CO) although applied to the carbonating of the lyes
of soda, has not hitherto been applied usefully to the manufacture and

page_text: production of soda crystals by reason of its impurity as it proceeds
from a limekiln.
Now this Invention consists in the use of carbonic acid gas rendered
pure as required by means of washings, by which means it is adapted
to produce soda crystals of the requisite whiteness for commerce. The
usual amber tint which is communicated to the crystals when produced
by the use of carbonic acid gas in its usual condition is prevented by
such process of washing from being so communicated.
The liquors
thus prepared are ultimately concentrated in order to obtain the degree
suitable for crystallization. Some precautions require to be observed
with respect to the temperature of this evaporation.
The advantages of the foregoing process are considerable. By means
of it is avoided the evaporation to dryness of the lyes of soda and the
ultimate dissolving of the salt thus dried. Moreover there is con-
siderable economy in the consumption of fuel required for the manu-
facture of the soda.
The apparatus required for producing the carbonic acid gas, washing
it, and introducing it into the liquor consists, in the first place, of a lime-
kiln in which the air is introduced by means of a suitable pump, either
under pressure or by an exhaust; secondly, of one or several washing
vessels or apparatus containing fresh or renewed water over which the
gas naturally rises; and thirdly, of a vase with a double bottom pierced
with holes under which the washed gas passes and becomes by this
means divided and permeated through the whole mass of soda lyes con-
tained in the said vase. But this apparatus and precise mode of washing
may be varied and are not intended to be claimed as forming part or
parts of the present Invention.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Spence in the Great Seal Patent Office on
the 31st May 1870..
TO ALL TO WHOM THESE PRESENTS SHALL COME,, I,, WILLIAM
SPENCE, of 8, Quality Court, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of December, in the year

page_text: of our Lord One thousand eight hundred and sixty-nine, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said William Spence, Her special licence, that I,
the said William Spence, my executors, administrators, and assigns, or
such others as I, the said William Spence, my executors, administrators,
and assigns, should at any time agree with, and no others, from time to
time and at all times thereafter during the term therein expressed, should
and lawfully might make, use, exercise, and vond, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle
of Man, an Invention for "IMPROVEMENTS IN THE MANUFACTURE OF SODA
CRYSTALS," being a communication to me from abroad by Messieurs Perret,
Brothers, and Olivier, of Paris, in the Empire of France, Manufacturers,
upon the condition (amongst others) that I, the said William Spence,
my executors or administrators, by an instrument in writing under my,
or their, or one of their hands and seals, 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 William Spence, do hereby declare
the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by
the following statement (that is to say):-
1
This Invention of "Improvements in the Manufacture of Soda
Crystals," consists in the use of the process or processes, for the purpose
herein-after described. The direct application of carbonic acid to the
carbonating of the lyes of soda has not hitherto been applied usefully for
the manufacture and production of soda crystals. And it has been found
by experiments that pure carbonic acid is adapted for the purpose, that
is to say, when purified by means of washing the impure carbonic acid
gas proceeding from a lime furnace. By the use of such pure carbonic
acid crystals of soda have been obtained white and suitable as an article
of commerce. The said washings appear to prevent the formation of
carburets, and the impurities resulting from the decarbonating of the
lime which give to the sodaic liquors an amber tint, which tint is com-
municated to the crystals when the gas is employed directly on its issue
from the apparatus in which it is produced. The liquors thus prepared
should be ultimately concentrated in order to obtain the degree suitable

page_text: for crystallisation. Some precautions require to be observed with regard
to the temperature of this evaporation. The carbonating by the aid
of carbonic acid washed and purified does not always get rid of the.
sulphur, the consequence of which is that the crystals are found to have
impurities which are always deleterious in however small a proportion
they may exist. In order to obviate this inconvenience a first crystal-
lisation rather thick or snowy is effected. The snowy crystals quickly
dried by means of a mechanical airing and drying apparatus allow the
sulphurous mother liquor to escape. After this operation a second
crystallisation is effected, which yields crystals completely free from
sulphur. The same effect may be produced by chemical instead of
by mechanical means as above stated. It will thus be seen that white
crystals are obtained at the first crystallisation by purifying the lye by
the aid of a metallic salt which precipitates the sulphurs. Sulphate of
zinc, for instance, is eminently useful for this purpose. The advantages
of this method are considerable. The evaporation to dryness of the lyes
of soda is avoided, and thereby an economy of nearly one-half in the fuel
required for the manufacture of soda by the ordinary processes.
The apparatus for producing the carbonic acid gas for washing it and
introducing it into the liquor is composed of the following parts:
First. Of a lime furnace into which air is forced under pressure or by
exhaust by means of an air pump or exhaust apparatus.
Secondly. Of one or several washing vessels containing water fresh
or renewed across which the gas naturally rises.
Thirdly. Of a vase with a double bottom pierced with holes under
which the washed gas passes, and becomes by this means divided and
permeated through the whole mass of soda lyes contained in the said
vase.
Fourthly. Of apparatus in which the first snowy crystallisation is
produced.
Fifthly. Of a mechanical airing apparatus for drying the snowy
crystals to extract from them the sulphurous water.
And, sixthly. Of apparatus for the last crystallisation of the purified
matter.
Having thus described the nature of the said Invention, and in what
manner the same is to be performed, I hereby declare that what I claim as
of the said Invention communicated to me from abroad as aforesaid is,—

page_text: The use of the process herein-before described consisting of,-
First. The washing of the carbonic acid before causing it to act on
the lyes of soda.
Secondly. The first snowy crystallisation.
Thirdly. The drying apparatus for separating the sulphurous water.
Fourthly. The definitive crystallisation of the matter arrived at the
degree of purification desired.
I also claim suitable modifications of the washing and other apparatus
herein-before referred to so long as such apparatus is used for purifying
carbonic acid for the purpose described.
In witness whereof, I, the said William Spence, have hereunto set
my hand and seal, the Thirty-first day of May, in the year of
our Lord One thousand eight hundred and seventy.
15 Witness,
W. A. JACKSON,
8, Quality Court,
Chancery Lane, W.C.
WILLIAM SPENCE. (L.S.)