IMPROVEMENTS IN THE MANUFACTURE OF HYDROCHLORIC ACID AND SODIUM CARBONATE FROM SODIUM CHLORIDE
Year: 1884

page_text: We EUSTACE CAREY, HOLBROOK GASKELL the younger and FERDINAND HURTER
all of Widnes in the County of Lancaster do hereby declare the nature of said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF HYDROCHLORIC ACID AND
SODIUM CARBONATE FROM SODIUM CHLORIDE to be as follows:-
According to our Invention we heat to redness in suitable vessels a mixture of
Sodium chloride and hydrogen sodium sulphate obtained as hereinafter described.
Hydrochloric acid is given off and neutral sulphate of Soda formed.
The hydrochloric acid gas we may utilise for any purpose in any well known
manner.
The neutral sulphate of soda we dissolve in water and render the solution
alkaline by means of a little carbonate of Soda to precipitate iron, lime or the like.
Into the clear solution we pass ammonia and carbonic acid gas (which may be
obtained from a lime kiln) keeping the solution cool and agitating it. Bicarbonate
of Soda is formed and precipitated whilst sulphate of Ammonia and sulphate of
Soda remains in solution.
We separate the Bicarbonate of Soda from the solution by filtration, wash it, dry
it, and calcine it in suitable apparatus. Carbonic acid is given off and utilised in
the above operation. The calcined carbonate of Soda may then be utilised in any
manner.
The solution of Sulphate of Ammonia and sulphate of Soda is evaporated and
any ammonia given off during the evaporation condensed by a solution of sulphate
of Soda or by water. The dry mass of salts is mixed if necessary with so much
sulphate of Soda that there shall be one or more than one equivalent of Sulphate
of Soda for each equivalent of Sulphate of Ammonia. This mixture of the dry salt
is then heated in suitable iron vessels in an atmosphere of steam when the sulphate
of Ammonia decomposes giving off free ammonia, whilst the sulphuric acid
combines with the sulphate of Soda to form hydrogen sodium sulphate.
The free ammonia is utilised again in the process of converting sulphate of Soda
into bicarbonate.
The hydrogen sodium sulphate is used for decomposing sodium chloride as above
described.

page_text: "
We EUSTACE CAREY, HOLBROOK GASKELL the Younger and FERDINAND HURTER
all of Widnes in the County of Lancaster Alkali Manufacturers do hereby declare
the nature of said invention for IMPROVEMENTS IN THE MANUFACTURE OF
HYDROCHLORIC ACID AND SODIUM CARBONATE FROM SODIUM CHLORIDE" and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
In manufacturing Hydrochloric acid and Sodium Carbonate from sodium
Chloride according to our Invention we heat to redness in suitable vessels a
mixture of Sodium Chloride and Hydrogen Sodium Sulphate or bisulphate of Soda,
the latter being obtained as hereinafter described-Hydrochloric Acid is given off
and neutral Sulphate of Soda is formed. The apparatus we employ for effecting
this portion of the process according to our Invention may be similar to that
employed in the manufacture of Sodium Sulphate from Sodium. Chloride and
Sulphuric Acid or from Sodium Chloride and Nitre Cake (Hydrogen Sodium
Sulphate or bisulphate of Soda obtained in the manufacture of Nitric Acid) as is
well understood.
The Hydrochloric Acid Gas obtained as aforesaid may be utilized in any well
known manner for any of the purposes for which Hydrochloric Acid Gas may be
wanted, as is also well understood.
We dissolve the neutral sulphate of Soda in water and render the solution
alkaline by means of Carbonate of soda or by means of Caustic Lime in order to
precipitate iron and other Foreign matters that may be present. The iron and
other precipitated impurities are then separated by filtration or by settling. This
operation may be advantageously performed in apparatus similar to that described
in the Specification of an Invention for which Letters Patent were granted to
Eustace Carey and Ferdinand Hurter Numbered 5712 of One thousand eight
hundred and eighty three and illustrated in sectional elevation in Figure 1 of the
drawings accompanying that Specification.
Into the clear solution we pass Ammonia Gas (which may be obtained as
hereafter described) and Carbonic Acid Gas (which may be obtained from a Lime
Kiln) keeping the solution cool and agitated by any convenient means-Bicarbonate
of Soda is formed and precipitated whilst sulphate of Ammonia and Sulphate of
Soda remain in solution with some Bicarbonate of Ammonia.
The operation of charging the solution with Ammonia Gas and Carbonic Acid
Gas we carry out under the conditions and precautions as to temperature and
pressure described in the Specification of the aforesaid Patent N° 5712 of One
thousand eight hundred and eighty three. The apparatus we find it advantageous
to employ is in details similar to the apparatus therein described, except that we
construct the carbonating and absorbing vessels V 1 to V 6 shewn at Figure 2 of
the drawings accompanying the said Specification of cast iron instead of wrought
iron, cast iron being less acted upon by the Ammoniacal Solutions than wrought
iron. We have also found it better to place the saturators M' and M2 shewn in
the said drawings at such an elevation that the ammoniacal Sulphate of Soda
Solution may flow by gravitation into the Carbonating vessels and we pump the
contents of the Carbonating and absorbing vessels V 5 and V 6 there shewn into
the saturating vessels. In every other respect the mode of operating and the
apparatus may be the same as described in the before mentioned Specification Or
we add to the clear solution of Sulphate of Soda Bicarbonate of Ammonia previously

page_text: prepared in order to precipitate Bicarbonate of Soda; Sulphate of Ammonia
remaining in solution.
We separate the Bicarbonate of Soda from the solution by filtration, wash, dry,
and calcine it in suitable apparatus as is well understood. Ammonia in small
quantity and Carbonic Acid are given off and utilized in these last mentioned
operations. The calcined carbonate of Soda may then be utilized for any purpose
for which it is required. The solution containing sulphate of Ammonia, Sulphate
of Soda, and Bicarbonate of Ammonia, is heated in Stills and the Ammonia which
is given off condensed and absorbed by fresh solution of sulphate of Soda in the
saturating vessels.
The solution thus deprived of all free Ammonia is then evaporated in open pans,
sufficient sulphate of Soda being added either to the solution or to the salt obtained
by evaporation to secure at least one equivalent of sulphate of Soda for every
equivalent of Sulphate of Ammonia. The salts thus obtained are then heated in
suitable cast iron vessels in an atmosphere of Steam when the sulphate of Ammonia
decomposes, giving off free Ammonia whilst the Sulphuric acid combines with the
Sulphate of soda and forms Hydrogen Sodium Sulphate.
This operation may advantageously be carried out in apparatus described in and
with attention to the precautions set-forth in the Specification of the Patent
Numbered 2118 of One thousand eight hundred and eighty four of even date
herewith.
The Ammonia Gas is used again in conjunction with Carbonic Acid for the
precipitation of Bicarbonate of Soda from solutions of sulphate of soda, or is first
converted into Bicarbonate of Ammonia and then used for precipitating Bicarbonate
of S da as before mentioned.
The Hydrogen Sodium Sulphate may be used for decomposing sodium Chloride
as above described.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed We declare that
what We claim is:-
The manufacture of Hydrochloric acid and of Sodium Carbonates (meaning
thereby Carbonates and Bicarbonates of Soda) from Sodium Chloride by the
employment of Sodium Hydrogen Sulphate (meaning thereby Bisulphate of Soda)
Ammonia and Carbonic Acid in such manner as that Sodium Hydrogen Sulphate
and the Ammonia are recovered and utilized, substantially as herein before
described.