IMPROVEMENTS IN THE MANUFACTURE OF MAGNESIUM, AND IN THE PRE- PARATION OF ITS ANHYDROUS CHLORIDE
Year: 1869

page_text: LETTERS PATENT to Henry Larkin, of No. 6, Torriano Cottages,
Leighton Road, and William White, of No. 30, Thurlow Road,
Hampstead, both in the County of Middlesex, for the Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF MAGNESIUM, AND IN THE PRE-
PARATION OF ITS ANHYDROUS CHLORIDE."
Sealed the 16th November 1869, and dated the 2nd June 1869.
PROVISIONAL SPECIFICATION left by the said Henry Larkin and
William White at the Office of the Commissioners of Patents, with.
their Petition, on the 2nd June 1869.
WC, HENRY LARKIN, of No. 6, Torriano Cottages, Leighton Road,
and WILLIAM WHITE, of No. 30, Thurlow Road, Hampstead, both in
the County of Middlesex, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF MAGNESIUM, AND IN
THE PREPARATION OF ITS ANHYDROUS CHLORIDE," to be as follows:--
This Invention has for its object improvements in the manufacturo
of magnesium, and in the preparation of its anhydrous chloride.

page_text: Magnesium is obtained by the reaction of sodium on the anhydrous
chloride of magnesium, and the chloride of magnesium is prepared by
dissolving the carbonate in hydrochloric acid. We use or add acid in
such proportions that in the solution obtained it shall be considerably in
excess. We then partially dry the acid solution in thin layers in covered
dishes, taking care that there shall be sufficient aperture for the ready
escape of the heated acid vapor. The vessels used may be of glazed
earthenware or porcelain. When the acid solution is thus made as dry
as can conveniently be done we remove the residue from the evaporating
dishes and place it in plumbago or other suitable crucibles or vessels, in
which we rapidly fuse it at a red heat under as close cover as is prac-
ticable. The partial drying of the dissolved chloride and its subsequent
igneous fusion may be very rapidly accomplished by passing streams of
hydrochloric acid gas over the material, first at a moderate heat and
then fusing as quickly as possible at a red heat. These operations may
be readily carried on upon an enormous scale at the various soda works,
by utilizing the almost waste fumes of hydrochloric acid gas as they pass
from the salt cake furnaces in the production of sulphate of sodium from
common salt. We also obtain chloride of magnesium by dissolving its
oxide in an aqueous solution of chloride of ammonium, using the latter
somewhat in excess of their respective equivalents. The two materials
are thoroughly mixed in a covered vessel and exposed to a gradually
increasing heat, which, however, must not be carried too high. As
soon as the materials are thus mixed chemical action between them
commences and increases with the heat, the chlorine combining with
the magnesium of the oxide to form magnesic chloride, which remains
in the vessel while the ammonia volatilizes off and is condensed in
proper
receivers. By this process we substitute the oxide of magnesium for the
lime commonly used in the manufacture of ammonia from sal ammoniac;
or carbonate of magnesium may be substituted for chalk in the pro-
duction of carbonate of ammonium. By such substitutions we obtain as
a kind of bye-product magnesic chloride in a highly dried condition,
instead of the ordinary calcic chloride for which there is but little com-
mercial demand. When the material thus obtained is sufficiently dried,
which may be known by the gradual cessation of the ammonia fumes, it
is removed into a plumbago crucible and fused under as close cover as
possible at a red heat. In this latter opération, as in the former, a
condensing apparatus is attached to collect the fumes given off at the
greatly increased heat.

page_text: Having by such method or methods prepared anhydrous chloride of
magnesium, we proceed to obtain the metal from the same by placing the
said chloride with a proper equivalent of sodium in a plumbago or other
suitable crucible or retort, the retort being constructed with a neck
having a stopper accurately fitted into it, but capable of being casily
removed. The sodium and magnesic chloride having been secured in
the retort the whole is submitted to a full red heat until the reaction of
the contents is completed. The stopper is then quickly removed and a
condenser fitted on to the neck of the retort, when all is thus arranged
the heat is increased until the metallic magnesium is distilled off and
received into the condenser. Or the condenser may be connected with
the retort at the commencement of the operation, and at the proper time
the stopper be drawn up by means of an iron rod connected with it and
passing through the condenser. The residue after the distillation of the
magnesium, and consisting chiefly of chloride of sodium in a highly
fused condition, may then be poured out of the retort, which will thus
be emptied for another charge. This method of direct distillation would
also be applicable to the separation of magnesium from any other
preparation of its anhydrous chloride.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Larkin and William White in the Great
Seal Patent Office on the 2nd December 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, HENRY
LARKIN, of No. 6, Torriano Cottages, Leighton Road, and WILLIAM
WHITE, of No. 30, Thurlow Road, Hampstead, both in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria,, by. Her
Letters Patent, bearing date the Second day of June, in the year of
our Lord One thousand eight hundred and sixty-nine, in the thirty-second
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto us, the said Henry Larkin and William White, Her special
licence that we, the said Henry Larkin and William White, our exe-
cutors, administrators, and assigns, or such others as we, the said
Henry Larkin and William White, our executors, administrators, and
assigns, should at any time agree with, and no others, from time to

page_text: time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN THE MANUFACTURE
OF MAGNESIUM, AND IN THE PREPARATION OF ITS ANHYDROUS CHLORIDE," upon
the condition (amongst others) that we, the said Henry Larkin and
William White, our executors or administrators, by an instrument in
writing under our or their hands and scals, or under the hand and scal
of one of us or them, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Oflice within six calendar mouths next and immediately after the dato
of the said Letters Patent.
NOW KNOW YE, that we, the said Henry Larkin and William
White, do hereby declare the nature of the said Invention, and in
what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement thereof, that is to
Бау:-
This Invention has for its object improvements in the manufacture
of magnesium and in the preparation of its anhydrous chloride.
Magnesium is obtained by the reaction of sodium on the anhydrous
chloride of magnesium, and the chloride of magnesium is prepared
by dissolving the carbonate in commercial hydrochloric acid. We
according to our Invention use or add the hydrochloric acid in such
proportion relatively to the carbonate of magnesia that in the solution
obtained the acid shall be considerably in excess. We then partially
dry the acid solution in thin layers in covered dishes at a temperature
of about 110° centigrade, taking care that there shall be sufficient
aperture for the ready escape of the heated acid vapour. The vessels
used may be of glazed earthenware or porcelain. When the neid solution
is thus made as dry as can conveniently be done at such temperaturo
we remove the residue from the evaporating dishes and place it in
plumbago or other suitable crucibles or vessels, in which we rapidly
fuse it at a red heat under as close cover as is practicable. The partial
drying of the dissolved chloride and its subsequent igneous fusion may
be very rapidly accomplished by passing copious streams of hydrochloric
acid gas over the acid solution, first at a moderate heat and then fusing
the salt as quickly as possible at a red heat. These operations may

page_text: be readily carried on upon an enormous scale at the various soda works
by utilizing the almost waste fumes of hydrochloric acid gas as they
pass from the salt cake furnaces in the production of sulphate of
sodium from common salt. It would be quite unnecessary to take any
extremo precaution to render the gas perfectly dry, hydrochloric acid
as it passes from the salt cake furnace in the production of sulphate.
of soda being sufficiently dry for practical purposes.
The process above described may be varied by using in place of
carbonate of magnesium the hydrated chloride of magnesium of com-
merce in which case the chloride is dissolved in commercial hydrochloric
acid, and from this point the process is conducted as before.
We claim as respects this part of our Invention, the manufacture of
anhydrous chloride of magnesium by drying a solution containing.
an excess of hydrochloric acid, and afterwards rapidly fusing the salt.
We also according to our Invention obtain chloride of magnesium.
by dissolving its oxide in an aqueous solution of chloride of ammonium,
using the latter somewhat in excess of their respective equivalents.
The two materials are thoroughly mixed in a covered vessel and ex-
posed to a gradually increasing heat, which however should not be
carried higher that 130 centigrade. As soon as the materials are thus
mixed chemical action between them commences and increases with
the heat. The chlorine combines with the magnesium of the oxide to
form magnesie chloride which remains in the vessel while the ammonia
volatilizes off and is condensed in proper receivers. Thus by this process
we substitute the oxide of magnesium for the lime commonly used
in the manufacture of ammonia from sal ainmoniac which process is
familiarly known to manufacturing chemists. We use by preference
a saturated solution of chloride of ammonium. Carbonate of mag-
nesium may in a similar way be substituted for the chalk used in the
production of carbonate of ammonium. By such substitutions we obtain
a kind of bye-product, magnesic chloride, in a highly dried condition.
instead of the ordinary calcic chloride for which there is but little
commercial demand. When the material thus obtained is sufficiently.
dried, which may be known by the gradual cessation of the ammonia
fumes, it is removed into a plumbago crucible and fused under as close
cover as possible at a red heat. In this latter operation as in the
former a condensing apparatus is attached to collect the fumes given
off at the greatly increased heat, and which consist principally of

page_text: ammonia and of the excess of san antoniae used in
mixture.
We claim as respects this part of our Invention the manufacture of
anhydrous chloride of magnesium by acting with an aqueous solution
of chloride of ammonium on magnesia, or on carbonate of magnesium
and fusing the solid residuo which remains when the ammonia has for
the most part escaped.
Another part of our Invention relates to the manufacture of
magnesium from anhydrous chloride of magnesium. We proceed by
placing the said chloride with a proper equivalent of sodium in a plum-
bago iron or other suitable crucible or retort, the retort is constructed
with a neck having a stopper accurately fitted into it but capable of
being easily removed. The sodium and magnesic chloride having been
secured in the retort the whole is submitted to a full red heat until the
reaction of the contents is completed. The stopper is then quickly
removed and a condenser fitted on to the neck of the retort. When all
is thus arranged the heat is increased until the metallic magnesium is
distilled off and received into the condenser. Or the condenser may
be connected with the retort at the commencement of the operation
and at the proper time the stopper be withdrawn by means of an iron
rod connected with it and passing through the condenser. The residue
after the distillation of the magnesium, and consisting chiefly of chloride
of sodium in a fused condition, may then be poured out of the retort,
which will thus be emptied for another charge. In carrying on this
operation the retorts may be made of any convenient size, in form like
a mercury bottle with a neck attached. They are received into a furnace
from which however they can be removed for emptying in a slightly
inclined position, so that the materials when fused may not run into the
neck, the mouth of which projects from the furnace. Into the neck a
screw or other plug is fitted to close it until it is desired that the dis-
tillation should commence. The neck also receives the condenser upon
it so as to project from its end, it may be attached by screw clips or in
any other convenient way. The condensor wo employ is an iron
cylinder of about one-third the size of the retort, its surface is exposed
to the air and so is sufficiently cooled. It is a close vessel except that
there is a hole in its end for the passage of a rod which is formed or
fixed on the plug by which the retort is closed. This rod is used for
removing the plug when it is desired that the distillation should

page_text: commence. The rod loosely fits the hole in the condenser and no
special care is required to make a tight joint at this place. In con-
ducting the process the retort with the materials enclosed within it is
first heated to the degree required for the reduction of the metal, and this
licat is continued for a sufficient time just as is usual in the reduction
of magnesium, but when the reduction is complete in place of cooling
the retort or crucible and removing the crude metal in the solid state
as heretofore the plug is removed from the mouth of the retort, and
the heat increased, so as to distil the magnesium over into the condenser.
When the distillation is complete the condenser is detached from the
retort and the metal is removed from it. The retort also is removed
from the furnace and its contents poured out.
We claim as respects this part of our Invention the distillation of
metallic magnesium out of the retort or vessel in which it has been
reduced from the anhydrous chloride in place of, as heretofore, cooling
such vessel and removing the reduced metal in the solid form.
In witness whereof, we, the said Henry Larkin and William
White, have hereunto set our hands and seals, this Second
day of December, in the year of our Lord One thousand eight
hundred and sixty-nine.
HENRY LARKIN.
(L.S.)
WILLIAM WHITE. (L.S.)