IMPROVEMENTS IN THE MANU- FACTURE AND PRODUCTION OF COMMON SALT, AND IN THE APPARATUS EMPLOYED PROVISIONAL SPECIFICATION left by the
Year: 1874

page_text: LETTERS PATENT to Frederick Bale, of Coventry Hospital, in the
Town of Droitwich, and County of Worcestershire, Government
Science Teacher, for the Invention of "IMPROVEMENTS IN THE MANU-
FACTURE AND PRODUCTION OF COMMON SALT, AND IN THE APPARATUS EMPLOYED
PROVISIONAL SPECIFICATION left by the said Frederick Balc at the
Office of the Commissioners of Patents, with his Petition, on the
10th February 1874.
I, FREDERICK BALE, of Coventry Hospital, in the Town of Droitwich,
and County of Worcestershire, Government Science Teacher, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN THE MANU-
FACTURE AND PRODUCTION OF COMMON SALT, AND IN THE APPARATUS EMPLOYED
THEREIN, to be as follows:-
"
This Invention has for its object improvements in the manufacture
and production of common salt whereby a great saving in time and
expense will be secured. This is accomplished by means of the property

page_text: of hydrochloric acid altering the solvent properties of water. This acid
having no chemical action upon the sodic chloride the salt upon being
precipitated from the brine by the acid and then dried becomes perfectly
pure, the acid being very volatile passes off on drying the salt. I pro-
pose for this purpose to introduce the sodic sulphate, known also as the
"salt cake" and "Glauber's salt manufacture," into the common salt
making districts.
The salt cake being made by the action of sulphuric acid upon sodic
chloride or common salt, and the hydrochloric acid evolved is passed by
the mannfacturer into water, where it is absorbed, forming the liquid
hydrochloric acid of commerce. But I propose by this Invention to pass
this gas into the brine, thus precipitating the sodic chloride and forming
also liquid hydrochloric acid and securing at the same time the
advantages of both manufactures; I would for this purpose employ
pans made of porcelain or other suitable material having say three pipes
or outlets, one to conduct the brine into the pan or pans, another to
conduct the acid, and a third (or others more or less as may be found
necessary in practice) to carry off the liquid bydrochloric acid after
having done its work in precipitating the salt. This liquid hydrochloric
acid may be converted into bleaching powder or otherwise treated as
follows:-Owing to the varying degrees of the strength of the brine and
of the sulphuric acid used in the salt cake manufacture, the actual
amount of common salt precipitated by the hydrochloric acid from the
brine varies from about forty to fifty per cent. by weight of the sodic
chloride used in the salt cake manufacture. The drying of the salt thus
made may be effected by the heat from the flues of the salt cake manu-
facture; the drying shed may be provided with suitable ventilators
connected with pipes dipping into tanks of water outside the building,
or other suitable means for the purpose may be employed.
By this Invention a very large saving of coal or other fuel that may
be employed will be effected, also a material saving in time, the salt
being precipitated almost instantaneously when the acid.cnters the brine.
The salt by this method being beautifully fine and much purer than that
made by evaporation.
For the purpose of obtaining a further supply of hydrochloric acid I
would debydrate the liquid hydrochloric acid by means of sulphuric acid
which would be at hand from the salt cake process. Concentrated

page_text: sulphuric acid added to strong hydrochloric acid liberates the gaseous
hydrochloric and becomes itself a dilute sulphuric acid, in which state it
may be used in the salt cake manufacture. The expelled hydrochloric
acid would again be used to precipitate the common salt.
In practice it would perhaps be found necessary to again pass the
gaseous hydrochloric acid into the liquid acid which has done its work
in precipitating the salt. Complete precipitation would thus be ensured
and after being strengthened in this way the liquid acid may be again
used to precipitate an additional quantity of salt, or in other cases the
brine may be decomposed, causing soda and hydrochloric acid to be
liberated. By either of these methods a sufficient supply of hydrochloric
acid would be obtained to precipitate the common salt in sufficient
quantities to supply the salt cake manufacture and for other uses.
Another method may be employed by using what is known in
chemistry as an "aspirator," or other similar or suitable vessel, and
connecting it with the salt pans in a suitable manner, and then by
applying heat thereto the liquid contents become evaporated and pass
through the "aspirator" or other vessel in which a current of water is
caused to descend or circulate, and so becomes condensed, creating a
partial vacuum, or may be otherwise treated to effect the desired object;
the amount of heat requiried would by this means be greatly lessened in
producing the salt and consequently considerable economy effected.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Frederick Bale in the Great Seal Patent Office on
the 10th August 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
BALE, of Coventry Hospital, in the Town of Droitwich, and County of
Worcestershire, Government Science Teacher, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of February, in the year
of our Lord One thousand eight hundred and seventy-four, in the
year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Frederick Bale, Her special
licence that I, the said Frederick Bale, my executors, administrators, and

page_text: assigns, or such others as I, the said Frederick Bale, 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
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THE MANUFACTURE AND PRODUCTION OF COMMON SALT, AND IN THE APPARATUS
EMPLOYED THEREIN," upon the condition (amongst others) that I, the said
Frederick Bale, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should 1
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 Frederick Bale, do hereby declare the 1
nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement and accompanying Drawings:-
This Invention has for its object, as aforesaid, improvements in the
manufacture and production of common salt, whereby a great saving in
time and expense will be secured. This I propose to accomplish by
means of the property which hydrochloric acid possesses of altering the
solvent properties of water. This acid having no chemical action upon
the sodic chloride the salt upon being precipitated from the brine by the
acid and then dried becomes perfectly pure. The acid being very
volatile passes off on drying the salt. For this purpose I would introduce
thic sodic sulphate, known also as the salt cake and “Glauber's salt"
manufacture, into the common salt making districts.
The salt cake is at present made by the action of sulphuric acid upon
common salt, the following equation expressing the final results of the
reaction-2 Na Cl + SO2 Ho2 = SO2 Nao2 + 2 H Cl.
The hydro-
chloric acid evolved is ordinarily passed, as at present, by the manu-
facturers into water, where it is absorbed, forming the liquid hydrochloric
acid of commerce. But what I propose by this Invention is to pass the
hydrochloric acid gas as it comes from the salt cake furnace into the a
brine after conveying it through an arrangement or series of cooling
pipes and purifiers if necessary, or other suitable arrangements. Sodic

page_text: chloride would thus be precipitated, and liquid hydrochloric acid formed
at the same time. I should by this means thus secure the advan-
tages of both manufactures at about the cost of one. The reaction
may be regarded as one of displacement, according to the equation,―
3 OH2 Na Cl + HCl = 3 OH2, H Cl + Na Cl
Hydrochloric acid gas.
Brine.
"
Agneous acid. Precipitated salt. 1
The precipitated salt may now be washed from the acid by agitating
it with the brine, and afterwards drying, when it may be used for salt
cake purposes or for other uses. I would propose for this purpose to
employ pans made of porcelain or other suitable material or materials,
having, say, three or more pipes, one to conduct the brine, another to
conduct the gaseous acid, and a third (or others, more or less, as may
be found necessary in practice) to carry off the liquid hydrochloric acid
after having done its work in precipitating the salt. The liquid hydro-
chloric acid may then afterwards be converted into bleaching powder,
or treated as follows:-The pans I would prefer to employ should if
necessary have lids or covers fitting air and gas-tight, and arranged in
a series one above the other. These pans I would connect by suitable
tubes on the principle of a series of what is known to chemists as
"Woulf's bottles, so that whatever gas was not condensed in the first
or lowest pan may pass on to the second, or third, or other pan or
chamber. The precipitation of the salt from the brine would thus be
carried on chiefly in the first pan of the series. The brine in the other
pans being used for condensing any gas that may pass over from the
first pan, and also for washing the salt precipitated in the first from the
acid. The size of these pans should be so arranged that the complete
precipitation of the salt from the brine in the pan should occur as near
as possible at the time of the complete decomposition of the salt in the
salt cake furnace, and that the charging of the furnace and the emptying
of the pan or pans should go on at the same time. I would diffuse the
gascous hydrochloric acid (as it came from the furnace) through the
brine in the salt pans by passing it through a suitable tube or tubes
having a suitable number of holes or jets. This tube or tubes may be
connected with the pipe or pipes conveying into the brine pan or pans
the hydrochloric acid and may be removed at pleasure for cleaning. If
necessary I would connect the upper pan of each of such series as the
above with a "Gossage tower" or other suitable means, so as to obtain
complete condensation, and thus comply with the requirements of the
Alkali Act.

page_text: When the salt in the lower or bottom pan or chamber has been
completely precipitated the liquid acid may be allowed to pass off, and
upon the tap between the pans being opened the brine in the upper pan
may be allowed to pass into the lower and the precipitated salt thus
washed from the acid by agitation with the brine.
Owing to the varying degrees of strength of the brine the amount of
common salt precipitated from the brine by the hydrochloric acid
evolved from the salt cake decomposing pan will vary from about say
40 to 50 per cent. by weight of the sodic chloride used in the salt cake
process according to the equation 2 Na Cl + SO2 Ho2 = SO2 Na
Ho" Na Cl + HCl.
In the roaster of the furnace the remaining or other portion of the
hydrochloric acid is expelled at the higher temperature according to the
equation SO2 Na Ho" + Na Cl SO2 Nao2+ HCl, that is to say, the
hydrochloric acid evolved precipitates salt in about sufficient quantity to
carry on the salt cake manufacture, which may be introduced into the
common salt districts according to this Invention.
In this manufacture an enormous amount of common salt is annually
decomposed in Great Britain and elsewhere. The coal required to make
this amount of salt by the present method may be saved by this
Invention by means of the acid evolved directly from the salt cake
manufacture, as herein described. But for the purpose of obtaining a
further supply of gaseous hydrochloric acid than that derived imme-
diately from the salt cake manufacture I would propose to dehydrate
the liquid hydrochloric acid formed in the salt pans according to this
Invention, and thus expel the acid in the gaseous state. This I would
propose to effect by the aid of the sulphuric acid manufacture, which
would be at hand for the salt cake process, which might be accomplished
by two methods as follows:-Firstly, I would add the sulphuric acid
from the vitriol chambers to the liquid hydrochloric acid from the salt
pans, or the latter to the former, whichever may be most convenient.
The gaseous hydrochloric acid would thus be expelled and may again be
conducted into the brine for a further precipitation of common salt, as
by the following equation:-SO2 HO2 + HCl 3 OH2 = SO2 H02,
3 OH2 + HCl. The dilute sulphuric acid may be restrengthened by
returning it again to the vitriol chamber. Or, secondly, the floor of the
vitriol chamber could be covered with the liquid hydrochloric acid from

page_text: This may be done
the salt pans, instead of as now with water. The sulphuric anhydride
(SO3) formed in the vitriol chamber would thus fall into the liquid
hydrochloric acid, expelling the latter as a gas according to the equation
SO2 + HƠI 3 OH2 = S02 Ho2 2 OH2 + HCl. The gaseous hydro-
chloric acid thus formed could be separated from the other gases of the
vitriol chamber and conducted again into the brine.
by passing the gases as is now done as they issue from the exit tube or
tubes of the chamber into concentrated sulphuric acid where the nitric
oxide (N2 O2) would be absorbed and the nitrogen and hydrochloric acid
may be passed into the brine, the latter precipitating common salt,
the former passing off by the "Gossage chimney" or other suitable
exit. A small amount of hydrochloric acid (HCI) may thus be made to
do a repeated or almost endless amount of work in precipitating sodic
chloride from the brine on the principle of expelling it again and again
from its aqueous solution. But practically this would be limited by the
amount of sulphuric acid manufacture carried on in the common salt
district.
I would also use the gaseous hydrochloric acid for raising the brine
from depths which are not beyond the influence of the atmospheric
pressure. This may be done by condensing the gas in a strong vessel
capable of resisting the pressure of the atmosphere and of being made
air-tight.
IN THE ACCOMPANYING DRAWING
Fig. No. 1 exhibits, for example, three vessels or pans A, B, C, (although
a greater number may be employed) arranged at different levels, having,
as before described, lids or covers fitting gas or air-tight. In each of
these vessels or pans suitable apertures are provided having pipes con-
nected thereto, in which on the pan A a represents the pipe conveying
the brine from the brine springs or reservoirs; b, the pipe conveying the
hydrochloric acid gas from the salt cake process; c, the exit pipe for the
liquid hydrochloric acid. The pan B is connected with the pan A by
means of the pipe d and pipe e, the former coming from the top of the
pan A into the top of pan B, and passing to its bottom for the purpose
of condensing what gas might pass over the latter pipe e, allowing the
brine in pan B to descend into A for the purpose of washing the precipi-
tated salt. In the upper pan C the pipe fis connected with it and with
the pan B in a similar way to the pipe d with the pans B and A, and

page_text: pipe g with the pans C and B similar to the pipe e with the pans B and
A. At the end of the upper pan of the series I provide a pipe and
connection as at 7 in the pan C, which may be led to or connected with
a Gossage tower," if found necessary, for the purpose of complete
condensation of the hydrochloric acid gas, and so as to comply with the
Alkali Act.
65
Fig. No. 2 is a plan I propose to employ in some cases for raising the
brine or other liquid from depths which are not beyond the influence of
the atmospheric pressure (as herein referred to), in which a tube A may
be suitably connected with the hydrochloric acid tube from the salt cake
furnace into a strong vessel of suitable material capable of resisting the
pressure of the atmosphere, and of being made air tight. Also having
connected thereto a tube B connected with the brine shaft. On opening
the stop-cock C, having a funnel above it containing a requisite quantity
of water, which being allowed to descend would condense, the gaseous
contents and the brine would be caused to rush up the tube B and into
the vessel, and led off as may be required by any suitable connection,
such as shown at H.
It may be found necessary to provide a relief or safety valve against
the destruction of the vessel by atmospheric pressure, which may be
effected by keeping the stop-cock or tap D open while the brine is being
delivered through the tap and connection. A current of gas would thus
be pouring in from the tube arranged as at F, and the condensation
would thus be gradual.
It may be found necessary to provide for the free ingress of the acid
into the brine which might be obstructed by the tube or tubes being
blocked up by the salt. I would for this purpose propose to employ a
floating chamber or vessel as indicated at B, Fig. 3, so arranged as to rise
and fall in the salt pan A with the level of the brine, into which the acid
is led by the pipe as at b, suitably connected by means of a vulcanised
india-rubber tube or other connection, and caused to diffuse into and
through the brine by means of the tubes c in its under side, a suitable
number of tubes being employed as may be found necessary, and the
tubes or openings may be formed "bell shaped" or of other suitable
form with a view to prevent the accumulation of salt upon their ends.
Having thus described the nature of my said Invention, and in what
manner the same is or may be performed or carried into effect, I wish it

page_text: to be understood that I do not confine myself to the exact arrangement
or form of apparatus shown in the Drawing herewith, nor in the precise
details herein described, but what I claim is, "Improvements in the
Manufacture and Production of Common Salt, and in the Apparatus
Employed therein," substantially as herein described and set forth.
In witness whereof, I, the said Frederick Bale, have hereunto set
my hand and seal, this Seventh day of August, in the year of
our Lord One thousand eight hundred and seventy-four.
Witness,
J. S. JEACOCK,
National School,
Droitwich.
FRED. BALE. (L.S.)
Coventry Hospital,
Droitwich.