and Bye Products therefrom.
Year: 1884

page_text: and Bye Products therefrom.
I, FRANCIS BOLTON, Knight, Colonel in Her Majesty's Army, Civil Engineer,
of 4 The Sanctuary, Westminster in the county of Middlesex do hereby declare
the nature of my said invention for " IMPROVEMENTS IN THE MANUFACTURE OF
CAUSTIC SODA AND POTASH AND BYE PRODUCTS THEREFROM" to be as follows :-
:-
My invention consists in an improved method of converting chloride of sodium
or potassium into caustic soda or potash without the use of sulphuric acid; while,
at the same time, Hydrochloric acid is obtained as a bye-product.
In order to effect this, I intimately mix salt and finely powdered natural
sulphate of Strontia or Baryta together, or, preferably, salt and precipitated
sulphate of either of the bases, in equivalent proportions but with an excess of
the sulphate.
This mixture I heat either in a furnace, retort or kiln, and either as a powder
or made into blocks of suitable shape by compression with or without a binding
material added to it. When sufficiently heated, I cause steam, superheated to the
same or to a greater temperature to pass through and permeate the mixture. A
double decomposition takes placo, liberating the chlorine of the chloride of sodium,
and this chlorine, combining with the hydrogen of the steam goes off as hydrochloric
acid which can be condensed and collected in the usual manner.
The oxygen of the steam combines with the bases or one of them and the
mixture of salt and sulphate of Baryta or Strontia, is converted into a mixture or
combination of Sodium and strontium or Barium with an equivalent of oxygen
and an equivalent of SO. The mixture also contains undecomposed salt and
sulphate..
This mixture yields on lixiviation with water, a solution of caustic soda containing
more or less chloride of sodium and a precipitato or deposit of sulphate of strontia
or Baryta.
This precipitate is separated from the solution by decantation or filtration, or
both, and after being washed can be used over again.
The solution of caustic soda is concentrated in the usual way.
The wash waters from the sulphate may be used for lixiviating the next charge
from the furnace. The hydrochloric acid given off during the first operation is
much purer than that usually obtained by decomposing salt with sulphuric acid.
The same process may be applied to Chloride of Potassium.

page_text: :
Improvements in the Manufacture of Caustic Soda and Potasḥ
and Bye-products therefrom.
I, FRANCIS BOLTON, Knight, Colonel in Her Majesty's Army, Civil Engineer, of
The Sanctuary, Westminster in the County of Middlesex, do hereby declaro
the nature of my invention for "IMPROVEMENTS IN THE MANUFACTURE OF
CAUSTIC SODA AND POTASH AND BYE-PRODUCTS THEREFROM" and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement ——
My invention consists in an improved method of converting chloride of sodium
or potassium into caustic soda or potash without the use of sulphuric acid, while
at the same time hydrochloric acid is obtained as a bye-product.
L
In order to effect this I intimately mix salt and finely powdered natural ||
sulphate of Strontia or Baryta together or preferably salt and precipitated sulphate
of either of the bases, in equivalent proportions, but with an excess of the
sulphate.
This mixture I heat either in a furnace retort or kiln, and either as a powder or
made into blocks of suitable shape by compression, with or without a binding
material added to it. When sufficiently heated, I cause steam superheated to the
same or to a greater temperature, to pass through and permeate the mixture; a
double decomposition takes place with the result of liberating the chlorine of the
chloride of sodium which combines with the hydrogen of the steam and goes off
as hydrochloric acid, which can be condensed and collected in the usual manner.
The oxygen of the steam combines with the bases or one of them and the
mixture of salt and sulphate of baryta or strontia is converted into a mixture of
sodium and strontium (or barium) with an equivalent of oxygen and an equivalent
of SO,, though in what manner these are combined I am unable to say.
The mixture also contains undecomposed salt and sulphate.
This mixture yields, on lixiviation with water, a solution of caustic soda
containing more or less chloride of sodium and a precipitate or deposit of sulphate
of strontium (or baryta).
This precipitate is separated from the solution by decantation or filtration, or
both, and after being washed is used over again.
The solution of caustic soda is concentrated in the usual way.
The wash waters from the sulphate may be used for lixiviating the next charge
from the furnace.
The same process may be applied to chloride of potassium.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. The process of manufacturing caustic soda or potash by treating chloride of
Bodium.or potassium with sulphate of strontia or baryta, treating the heated mass
with superheated steam and extracting the caustic by lixiviation,

page_text: 2. The manufacture of hydrochloric acid by decomposing a heated mixture of
chloride of sodium or potassium and sulphate of strontia or baryta by means of
superheated steam,
3. In combination with the processes referred to in the preceding claims, the
repeated or continuous use of the sulphate of strontia or baryta as described.
Dnted thi. 9th Jan 1005
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.