IMPROVEMENTS IN THE MANUFACTURE OF CHLORINE AND HYDROCHLORIC ACID
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I WALTER WELDON, of Rede Hall, Burstow, in the County of Surrey, Fellow
of the Royal Society, President of the Society of Chemical Industry, do hereby
declare the nature of the said Invention for IMPROVEMENTS IN THE MANUFACTURE
OF CHLORINE AND HYDROCHLORIC ACID to be as follows:-
This invention relates to the manufacture of chlorine and hydrochloric acid from
chloride of magnesium.
The chloride of magnesium available for the manufacture of chlorine and hydro-
chloric acid therefrom will usually be in the state of either aqueous solution, or of
hydrated crystals or other solid masses containing water. When it is in the state
of aqueous solution, the first step must be to evaporate that aqueous solution to or
nearly to the point at which if its evaporation were further continued there would
begin to be evolved vapour of hydrochloric acid.
The present invention consists in treating chloride of magnesium associated with
water by two successive operations, the first of which operations shall drive off
some of its chlorine as hydrochloric acid, and the second of which operations shall
drive off the remainder or a portion of the remainder of its chlorine in the free
state.
The first of the said two operations consists in heating chloride of magnesium
associated with water as aforesaid in vessels of the nature of retorts or muffle-
furnaces to such temperature that reaction shall be caused to take place between a
portion of the chloride of magnesium and a portion of the water at first present
therewith, that reaction producing magnesia and vapour of hydrochloric acid.
The dispositions must be such (as will be well understood) that the vapour of
hydrochloric acid shall be conveyed away as it is evolved from the apparatus
in which the operation is performed into apparatus in which it shall be condensed
or otherwise dealt with. The magnesia which is the other product of the
reaction taking place in the first operation may be regarded as forming with the
chloride of magnesium remaining undecomposed the compound which may be called
oxychloride of magnesium.

page_text: The second of the said two operations consists in heating the said residual
oxychloride of magnesium of the first operation in a current of air. In this
operation the chlorine of the residue of the first operation is driven off, partly as
vapour of hydrochloric acid but largely in the free state.
The first of the two said operations may be performed in any one of many kinds
of apparatus, and I do not confine myself to any particular kind of apparatus in
which to perform it; but I may indicate that a suitable apparatus in which to
perform it is that which is known to manufacturers of sulphate of soda as a
"close roaster."
The second operation may also be performed in any one of many kinds of apparatus,
such apparatus being either of the nature of a muffle furnace, and either cold or
previously heated air being admitted into it during the operation, or apparatus
which is not heated externally, but the contents of which are heated by highly
heated air being sent among and through them; but while not confining myself
to any particular kind of apparatus in which to perform the said second operation,
I believe it may best be performed in and by means of a new apparatus an
application for a patent for which will be deposited at the Patent Office on the
same day as the present specification, the said other application being for a patent
for an invention of: "Improvements in Furnaces for heating Solid Substances out
of Contact with the Products of Combustion of the Fuel-Employed."
What is new in the present invention consists in treating choride of magnesium
associated with water as aforesaid by two successive operations, the first of the said
two operations consisting in treating chloride of magnesium so associated with
water by heat, in close vessels from which vapour of hydrochloric acid can be
conducted away, and thereby decomposing some of the chloride of magnesium and
some of the water into magnesia and vapour of hydrochloric acid, and the second
operation consisting in heating the solid residue of the first operation in contact
with air, and so obtaining a part of its chlorine in the free state.
Titel 1001

page_text: I WALTER WELDON, of Redo Hall, Burstow, in the County of Surrey, Fellow
of the Royal Society, do hereby declare the nature of the said Invention for
IMPROVEMENTS IN THE MANUFACTURE OF CHLORINE AND HYDROCHLORIC ACID,
and in what manner the same is to be perforined, to be particularly described
and ascertained in and by the following statement:-
This invention relates to the manufacture of chlorine and hydrochloric acid from
chloride of magnesium).
The chloride of magnesium available for the manufacture of chlorine and
hydrochloric acid therefrom will usually be in the state of either aqueous solution,
or of hydrated crystals or other solid masses containing wator. When it is in the
state of aqueous solution, the first step must be to evaporate that aqueous solution
to or nearly to the point at which if its evaporation were further continued there
would begin to be evolved vapour of hydrochloric acid.
The present invention consists in treating chloride of magnesium associated with
water by two successivo operations, the first of which operation shall drive off
some of its chlorine as hydrochloric acid, and the second of which operations shall
drive off the remainder or a portion of tho remaindor of its chlorine in the
free state.
The first of the said two operations consists in heating chloride of magnesium
associated with water as aforesaid in vessels of the nature of retorts or muffle-
furnaces to such temperature that reaction shall be caused to take place between a
portion of the chloride of magnesium and a portion of the water at first present
therewith, that reaction producing magnesia and vapour of hydrochloric acid.
The dispositions must be such (as will be well understood) that the vapour of
hydrochloric acid shall be conveyed away as it is evolved from the apparatus in
which the operation is performed into apparatus in which it shall be condensed or
otherwise dealt with.
The second of the said two operations consists in beating the solid residual
product of the first operation in a current of air: In this second operation the.
chlorine of the solid residual product of the first operation is driven off, partly as
vapour of hydrochloric acid but largely in the free state.
The first of the two said operations may be performed in any one of many kinds
of apparatus, and I do not confine myself to any particular kind of apparatus in
which to perform it; but I may indicate that it may be performed, for example, in
what are known as "close roasters." In performing it in apparatus of that kind,
the bed of the close furnace employed should preferably be kept covered with solid
residual product of the decomposition of chloride of inagnesium, and fresh chlorido
of magnesium be charged thereonto in successive small quantities, either in the state
of strong aqueous solution, or in that of hydrated crystals, or in that of other solid
masses containing magnesium chloride and water, as will be well understood.
The second operation may also be performed in any one of many kinds of
apparatus, such apparatus being either of the nature of a muffle furnace, and either

page_text: cold or previously heated air being admitted into it during the operation, or being
apparatus which is not heated externally, but the contents of which are heated by
highly beated air being sent among and through them; but while not confining
myself to any particular kind of apparatus in which to perform the said second
operation, I believe it may best be performed in and by means of a new.apparatus,
invented by Messieurs Pechiney et Compagnie, of Salindres, for which the
patent No 9304, of 23rd. June, 1884, has been granted to me under the title of:
"Improvements in Furnaces for Heating Solid Substances out of Contact with the
Products of Combustion of the Fuel Employed."
It will be obvious, however, that it is not essential that the first of the two
operations together constituting the present invention should be performed in one
apparatus, and the second of the said two operations in another apparatus, but that
both may be performed, if desired, in one and the same apparatus, as, for example,
in a close furnace, or other appliance of that nature,-that apparatus being kept as
far as possible closed during the first operation, but a current of air being admitted
into it during the second operation.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed, I declare that what
I claim is
Treating magnesium chloride associated with water by two successive operations,
in the first of which two operations the said magnesium chloride is simply heated
with little or no access of air, yielding vapour of hydrochloric acid and a residual
solid product containing both magnesia and magnesium chloride, and in the second
of which two operations the said solid residual product of the first operation is
heated in a current of air, and a portion of its chlorine thereby driven off in the
free state.