Improvements in the Manufacture of Chlorine.
Year: 1893

page_text: Date of Application, 6th June, 1893
Complete Specification Left, 1st Mar., 1894-Accepted, 7th Apr., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Chlorine.
I, ARCHIBALD BRAND Chemist 20 Talgarth Road West Kensington London W.
do hereby declare the nature of this invention to be as follows :-
--
My invention consists in a continuous process for the manufacture of chlorine by
treating a mixture of nitric acid & hydrochloric acid (aqueous) commonly called
aqua regia with gaseous hydrochloric acid. I am aware that by heating aqua regia,
chlorine & nitrosyl chloride gases are evolved but the yield of these gases is too
small to make this a profitable means of manufacturing chlorine. I am also aware
that a mixture of sulphuric acid & aqua regia has been made with a view of increasing
the volume of these gases by the sulphuric acid absorbing the water of the aqua regia
as well as that made during the reaction.
My method differs from those & is as follows-I produce gaseous hydrochloric
acid by adding aqueous hydrochloric acid to either hot or cold sulphuric acid. This
gaseous hydrochloric acid I introduce into one, two, or more vessels containing
aqueous hydrochloric & nitric acids (aqua regia) which vessels are called decomposers
& may or may not but preferably are heated by a steam coil or other suitable
means. In this way chlorine & nitrosyl chloride are evolved these gases I then pass
through a series of towers containing sulphuric acid to arrest the nitrogen compounds
the sulphuric acid being converted into nitrous vitriol & lastly through a water
tower to arrest any hydrochloric acid. The gas is now pure chlorine & ready for
the manufacture of bleaching powder &c. I continue to pass gaseous hydrochloric
acid into the decomposers as long as any nitrogen compounds exist in the liquor
under treatment. When no more nitrogen compounds exist the liquor is aqueous
hydrochloric acid but the volume has increased through the water of the nitric acid
as well as that chemically made during the reaction having absorbed portion of the
gaseous hydrochloric acid. This increased amount when withdrawn from the
decomposer is utilized together with additional aqueous hydrochloric acid for the
production of gaseous hydrochloric acid as before & a fresh quantity of nitric acid is
added to restore the remainder to aqua regia. In using more than one decomposer it
will readily be seen that the aqua regia in the first one is deprived of its nitric acid
more quickly than the aqua regia in the second one & so on in order of priority. The
decomposers are made interchangable by means of connections so that when No. I
has lost its nitric acid No. II becomes No. I & so on in order of priority. The
sulphuric acid used as a dehydrator for the production of gaseous hydrochloric acid
is reconcentrated.
The sulphuric acid in the absorbing towers when sufficiently saturated with nitrogen
compounds as to become strong nitrous vitriol is denitrated by any of the well
known methods. The water of the wash tower eventually becomes aqueous hydro-
chloric acid so there is no loss of the material used & by a suitable arrangement of
pipes & vessels the process is continuous.
Deted this 5th day of June 1893.

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of Chlorine.
I, ARCHIBALD BRAND of 20 Talgarth Road West Kensington Chemist do
hereby declare the nature of this invention 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 a continuous process for the manufacture of chlorine by
treating a mixture of nitric acid and hydrochloric acid (aqueous) commonly called
aqua regia with gaseous hydrochloric acid. I am aware that by heating aqua regia
chlorine and nitrosyl chloride gases are evolved but the yield of these gases is too
small to make this a profitable means of manufacturing chlorine. I am also aware
that a mixture of sulphuric acid and aqua regia has been made with a view of
increasing the volume of these gases by the sulphuric acid absorbing the water of
the aqua regia as well as that made during the reaction.
My method differs from those and is as follows-I produce gaseous hydrochloric
acid by adding aqueous hydrochloric acid to hot or cold sulphuric acid. This gaseous
hydrochloric acid while still hot I introduce into one, two or more vessels containing
aqueous hydrochloric and nitric acids which vessels are called decomposers and may
or may not but preferably are heated by a steam coil or other suitable means.
In this way chlorine and nitrosyl chloride are evolved these gases I then pass
through a series of towers containing sulphuric acid to arrest the nitrogen compounds
the sulphuric acid being converted into nitrous vitriol and lastly through a water
tower to arrest any hydrochloric acid. The gas is now pure chlorine and ready for
the manufacture of bleaching powder &c. I continue to pass gaseous hydrochloric
into the decomposers as long as any nitrogen compounds exist in the liquor under
treatment. When no more nitrogen compounds exist the liquor is aqueous hydro-
chloric acid but the volume has increased through the water of the nitric acid as
well as that chemically made during the reaction having absorbed portion of the.
gaseous hydrochloric acid. This increased amount when withdrawn from the
decomposer is utilized together with additional aqueous hydrochloric acid for
the production of gaseous hydrochloric acid as before and a fresh quantity of nitric
acid is added to the balance to restore it to aqua regia. In using more than one
decomposer it will be readily seen that the aqua regia in the first one is deprived of
its nitric acid more quickly than the aqua regia in the second one and so on in order
of priority. The decomposers are made interchangable by means of connections so
that when No. I has lost its nitric acid No. II becomes No. I and so on.
sulphuric acid used as a dehydrator for the production of gaseous hydrochloric
acid is reconcentrated.
The
The sulphuric acid in the absorbing towers when sufficiently saturated with
nitrogen compounds as to become strong nitrous vitriol is denitrated by any of the
well known methods.
The water of the wash tower eventually becomes aqueous hydrochloric acid so
there is no loss of the material used and by a suitable arrangement of pipes and
vessels the process is continuous.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is.
The introduction of hot gaseous hydrochloric acid into a mixture of aqueous
hydrochloric acid and nitric acid as a means of obtaining chlorine as herein
substantially described.
Datel Mah 1004
ARCHIBALD BRAND.