Improvements in the Manufacture of Chlorine and Hydrochloric Acid, and in Apparatus or Plant Applicable therefor.
Year: 1888

page_text: Date of Application, 11th Aug., 1888
Complete Specification Left, 11th June, 1889-Accepted, 10th Aug., 1889
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Chlorine and Hydrochloric Acid,
and in Apparatus or Plant Applicable therefor.
I, DAVID GAMBLE, of St. Helens, in the County of Lancaster, Manufacturing
chemist, do hereby declare the nature of this invention to be as follows :-
This invention relates to the manufacture of Chlorine and Hydrochloric Acid from
Chloride of Magnesium.
I produce the decomposition of the solid substance obtained by the mixture of
Chloride of Magnesium and Oxide of Magnesium, in the Weldon-Pechiney, or other
process, by heating such substance in a revolving furnace similar to that well known
as the balling furnace in the manufacture of soda by the Leblanc method, or in several
such furnaces connected together in such manner that the same portion of air passes
through all of them in succession, such furnace or furnaces, and their contents, being
heated by the introduction of highly heated air produced by the Siemens-Cowper
stove or any other method, the mixed gases resulting from the operation being subjected
to any of the well known-methods for separating the hydrochloric acid from the
chlorine.
.
In one form of carrying out my invention, I take the solid substance above named,
and fill it into a revolving furnace. Heated air, preferably that used in the next step
of the process hereafter described, but reduced to a sufficiently low temperature, is
passed through the revolver until the substance is ready for the next step of the
process. The gases which escape are passed through a condenser or other well known
apparatus so as to eliminate the hydrochloric acid, which escapes during this dry
operation.
The dried material is now passed into a second revolver, where it is subjected to
intensely heated air such as that produced in the Siemens-Cowper stoves, and the
operation continued until the evolution of chlorine has practically ceased.
I may, with proper precautions for cooling the gases at the required point, carry
on the process continuously, but the plan which I at present prefer is to place the
drying revolver immediately above a second revolver, and the material after being
sufficiently dried, is passed at once into the second revolver. This revolver is divided
by a vertical transverse annular partition in the centre, and each end is alternately
charged from the drying revolver. The hot air in this case, is passed by means of
valves, first into the compartment of the lower revolver, which has been longest
charged, and then into the freshly charged one. The gases passing from these are
cooled in any desirable manner, but without admixture of fresh air, and are then
passed through the drying revolver.
In some cases, I may however, dry the material in any ordinary manner, and simply
finish it in the revolver, or I may do the drying in the revolver and finish the process
in an intensely heated stove or chamber.
It will be obvious that if air charged with steam be used, a much larger amount of
hydrochloric acid and much smaller amount of free chlorine will be liberated than if
absolutely dry air be used. When therefore, it is desirable to get as much chlorine as
possible, the air passed through the oxidising revolvers should be as free from moisture
as possible. But if hydrochloric acid be required, then the material should contain a
large amount of aqueous vapour.
The gases escaping from the revolvers are passed through a condenser so as to
condense the hydrochloric acid, and are then used for any purpose for which chlorine
diluted with air is applicable.
..
01
1
1000

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of Chlorine and Hydrochloric Acid,
and in Apparatus or Plant Applicable therefor.
I, DAVID GAMBLE of St. Helens in the County of Lancaster, Manufacturing
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:
This invention relates to the manufacture of chlorine and hydrochloric acid from
chloride of magnesium.
I produce the decomposition of the solid substance obtained by the mixture of
chloride of magnesium and oxide of magnesium, in the Weldon-Pechiney or other
process, by heating such substance in a cylindrical revolving furnace, similar to that
well known as the balling furnace in the manufacture of soda by the Le Blanc method,
or in several such furnaces connected together in such manner that the same portion
of air passes through all of them in succession, such furnace or furnaces and their
contents being heated by the introduction of highly-heated air, produced by the
Siemens or Cowper stove or any other method, the mixed gases resulting from the
operation being subjected to any of the well-known methods for separating the hydro-
chloric acid from the chlorine.
In one form of carrying out my invention, 1 take the solid substance above named,
and fill it into a revolving furnace. Heated air, preferably that which has already
been used, in the next step of the process hereafter described, but reduced to a suffi-
ciently low temperature, passed through the revolver until the substance is ready
for the next step of the process. The gases which escape are passed through a con-
densing arrangement or other well known apparatus, so as to eliminate the hydrochloric
acid which escapes during this drying operation. The dried material is now passed
into a second revolver, where it is subjected to heated air, such as that produced in
the Siemens or Cowper stove, and the operation continued until the evolution of
chlorine has practically ceased.
Another plan by which the invention may be carried out, is to place the drying
revolver above a second revolver, and the material, after being sufficiently dried, is
passed into the second revolver. This second revolver is divided by a vertical trans-.
verse annular partition in the centre, and each end is alternately charged from the
drying revolver by a door in the centre of each division, so arranged or placed that it
can be brought opposite a similar door in the drying revolver. The hot air, in this
case, is passed by means of valves, first into that compartment of the lower revolver
which has been longest charged, and thence through the annular partition into the
freshly charged one. The gases escaping from this last compartment are cooled to
any desirable extent, and are then passed through the drying revolver.
This plan of working is carried out in the apparatus shown in Figures 1, 2 and 3,
in which Figure 1 represents a sectional elevation, Figure 2 a plan, and Figure 3 an
end elevation. A is the heating revolver and B the drying revolver, both of which
are supported and driven in the customary manner. Cand are the charging doors
of the top revolver, which are also used for discharging, small doors c and c¹ being
provided for assisting in the discharging. D and D₁ serve the same purpose in the
heating revolver. E E are baffle plates for the distribution of the hot air, which,
issuing from the main pipe F, enters the pipes G G at alternate ends of the revolver.
The valves H H give the current of gases the direction desired. A portion of the
annular transverse partition can be seen at .J.
The plan, however, which I at present prefer, is a revolver about 40 feet long by
6 feet diameter inside, lined in the usual way with firebricks, and having a line of
breakers, projecting about a foot from the lining, so fixed as to form a helix of 4 or
more turns in the length of the revolver, but stopping short 3 feet from the end at
which the material is to be discharged. This revolver is charged by a door, such as
is generally used in black-ash revolvers, but placed near one end on the circumference

page_text: of the cylinder, and is emptied by a similar door placed near the opposite end of the
cylinder. The mixture of chloride of magnesium and oxide of magnesium is to be
charged into one of these doors at intervals of about an hour, and is to be discharged
from the other door at the same intervals. The furnace is heated by hot air produced
by Siemens' or Cowper's or similar hot air stoves, such as are used for blast furnaces
in the manufacture of iron, and the heat should be raised to 1200 degrees Fahrenheit,
or higher.
The object of the helix above mentioned is to move forward the contents of the
revolver slowly from the charging to the discharging end, a portion of the materials
continually falling back over the helical iine of breakers and being thereby more fully
exposed to the action of the heated air. The gaseous products of the decomposition
of the chloride pass out from the end of the furnace opposite to that at which the air
enters, through an earthenware pipe passing through a stuffing box in the axis of the
revolver. They are thence carried to the condensing arrangement, by which the
hydrochloric acid is separated from the chlorine, either directly, or after first passing
through another revolver placed above that just described, and being there used for
drying the material in the same manner as in the apparatus first indicated in this
specification. To prevent the air passing from the inlet to the outlet pipe in a direct
line, a baffle-plate is placed in front of the inlet pipe, so as to direct the current to the
circumference of the revolver. This baffle-plate is to be made of fire-clay and supported
by projections from the brick lining of the end of the revolver.
B is
The apparatus used in this mode of working is shown in Figures 4, 5 and 6, in
which Figure 4 represents a sectional elevation, Figure 5 a plan, and Figure 6 an end
elevation. A is the revolver, supported and driven in the customary manner.
the brick-lining and a portion of the helix is seen at C. D & E are doors E being
preferably the charging and D the discharging one, but by reversing the motion of
the revolver the functions of these doors can be reversed. The hot air enters the
revolver at F and is distributed by the baffle-plate G. The gases leave the apparatus
through an earthenware pipe H. J and K are cleaning doors, through which a rake
can be introduced, to assist in the charging and discharging.
In some cases, I may, however, dry the material in any ordinary manner, and simply
finish it in the revolver.
It is well known, that, if air charged with steam be used, a much larger amount of
hydrochloric acid and a much smaller amount of free chlorine will be liberated than if
absolutely dry air be used. When, therefore, it is desirable to get as much chlorine
as possible, the air passed through the revolvers should be as free from moisture as
possible. But if hydrochloric acid be required, then the air should contain a large
amount of aqueous vapour.
The gases escaping from the revolvers are passed through a condensing arrangement
so as to condense the hydrochloric acid, and are then used for any purpose for which
chlorine diluted with air is applicable.
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 :-
1. The improvement in the manufacture of chlorine and of hydrochloric acid
respectively, which consists in treating a mixture of chloride of magnesium and oxide
of magnesium by heated air or by heated air and steam in a revolving furnace or a
series of revolving furnaces, substantially as described.
2. In the treatment of a mixture of chloride and oxide of magnesium for the
purposes described, the application of one or more revolving furnaces fitted with a
helical line of breakers.
3. In the treatment of a mixture of chloride and oxide of magnesium for the purposes
described, the application of a series of revolving furnaces with or without vertical,
transverse, annular partitions, all these furnaces being connected together in such a
manner that the same portion of air passes through all of them in succession.

page_text: 4. In the manufacture of chlorine or hydrochloric acid from a mixture of chloride
and oxide of magnesium and heated air, the causing the solid materials to pass through
a revolving furnace in one direction and the air to pass through in the opposite
direction.
5. The use of the gases given off by the treatment, in a revolving furnace, of a dried
mixture of chloride and oxide of magnesium by highly heated air for the preliminary
drying of a fresh mixture of chloride and oxide of magnesium in the same or a separate
revolving furnace.
أيم
1
T
1000
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.