IMPROVEMENTS IN OBTAINING SULPHATE OF SODA, HYDROCHLORIC ACID, CHLORINE, AND OTHER PRODUCTS
Year: 1871

page_text: LETTERS PATENT to Emil Königs, Manufacturing Chemist, of West-
hofen, in Westphalia, but at present residing at Maryhill, in the
County of Lanark, North Britain, and James Henderson, Chemist,
of Glasgow, in the same County, for the Invention of "IMPROVEMENTS
IN OBTAINING SULPHATE OF SODA, HYDROCHLORIC ACID, CHLORINE, AND OTHER
PRODUCTS."
Sealed the 19th December 1871, and dated the 22nd June 1871.
PROVISIONAL SPECIFICATION left by the said Emil Königs and James
Henderson at the Office of the Commissioners of Patents, with
their Petition, on the 22nd June 1871.
We, EMIL KÖNIGS, Manufacturing Chemist, of Westhofen, in West-
phalia, but at present residing at Maryhill, in the County of Lanark,
North Britain, and JAMES HENDERSON, Chemist, of Glasgow, in the
same County, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN OBTAINING SULPHATE OF SODA, HYDROCHLORIC ACID, CHLORINE,
AND OTHER PRODUCTS," to be as follows, that is to say :—
This Invention has principally for its object the production of sulphate-
of soda, hydrochloric acid, and chlorine from common salt without using

page_text: vitriol chambers and nitre for first making sulphuric acid, whilst at
the same time hydrochloric acid or chlorine is obtained without using
manganese.
In carrying out the Invention. according to one modification an
intimate mixture of about one part by weight of common salt and about
three parts peroxide of iron, both in coarse powder, is placed in a muffle
furnace or in a revolving tube or retort lined with fire-brick and heated
preferably to dull redness. Over the heated mixture sulphurous acid is
passed and dry air, these mixed gases being heated by preference by
passing them through flues or chambers kept at a dull red heat before
being admitted to the muffle furnace or revolving retort. By the reaction
which takes place the common salt is gradually converted into sulphate
of soda, whilst chlorine is given off mixed with small quantities of
sulphurous acid, some sublimed metallic chloride, and sometimes sulphuric
and hydrochloric acids. If muffle furnaces are used they must be such
as allow of raking, and they may be worked in sets of three or four, and
gases passed over a furnace newly charged may be passed through a
second one which is more advanced, and again through a third which is
nearly finished, whilst the fourth is discharging and recharging, and
thereafter becomes the first of the series.
There is often a small quantity of other gases besides nitrogen and air
mixed with the chlorine, and to insure their removal or conversion they
are passed through a regenerative chamber filled with bricks formed of
oxide of iron and salt, clay being added when necessary to enable them
to keep their shape. The bricks are heated by external heat, or by
heated air, or heated air and combustible gases. The sulphurous and
sulphuric acids, if any, are absorbed by the bricks, producing sulphate
of soda and chlorine. The remaining gases are finally cooled and the
chlorine is absorbed by lime or an alkali in a well-known way.
By a second modification the oxide of iron and salt is formed into
bricks, and these are arranged and heated in kilns or furnaces adapted
for burning bricks heated either from the outside or by heating the
mixture of sulphurous acid and air that is to be passed over them as in
the first modification. The resulting gases are treated and utilised as in
the first modification.
When hydrochloric acid is wanted a mixture of air and steam is used
instead of the dry air herein-before referred to, and in proceeding
otherwise as in either the first or second modification.

page_text: By a third modification the proportion of oxide of iron in the mixture
may be reduced and pyrites in coarse powder may be substituted yielding
the required sulphurous acid, the mixture being heated and acted on by
dry air or by air and steam and yielding the same products as in the
other modifications.
The sulphate of soda is extracted from the burned powders, burned
and ground bricks, or the like, by washing with warm or hot water, and
separating it from the resulting solution by crystallising, salting out,
or evaporating to dryness. The hydrochloric acid is condensed in the
usual way.
The application of the Invention is not restricted to oxide of iron, iron
pyrites, or similar compounds free from other or more valuable metals
such as copper. Thus burnt cupreous pyrites may be used instead of
mere oxide of iron, allowance being made for the proportion of sulphur
usually remaining in it. Unburnt pyrites containing copper may also
be used.
When copper and similar metals occur, instead of trying to obtain all
the copper in solution with the sulphate of soda the mixture is heated
until all or nearly all the copper or iron present is rendered insoluble in
water. If after continued heating there is still a small amount of metal
soluble it is made insoluble during the extraction of the sulphate of soda
by the addition of lime or other suitable base. Then after the separation
of the sulphate of soda the metal may be dissolved by the aid of acid
and be subsequently precipitated by iron, as is well understood. A great
advantage of this mode of rendering the copper insoluble is that the
lixiviation for the sulphate of soda can be conducted in iron vessels, and
that the resulting salt is free from iron.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Emil Königs and James Henderson in the Great
Seal Patent Office on the 21st December 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, EMIL
KÖNIGS, Manufacturing Chemist, of Westhofen, in Westphalia, but at
present residing at Maryhill, in the County of Lanark, North Britain,
and-JAMES HENDERSON, Chemist, of Glasgow, in the same County, send
greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-second day of June, in the year
of our Lord One thousand eight hundred and seventy-one, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto us, the said Emil Königs and James Henderson, Her |
special licence that we, the said Emil Königs and James Henderson, our
executors, administrators, and assigns, or such others as we, the said.
Emil Königs and James Henderson, our executors, administrators, and
assigns, should at any time agree with, and no others, from time to
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 OBTAINING SULPHATE OF
SODA, HYDROCHLORIC ACID, CHLORINE, AND OTHER PRODUCTS," upon the condition
(amongst others) that we, the said Emil Königs and James Henderson,
our executors or administrators, by an instrument in writing under our,
or their, or one of their hands and seals, 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 Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that we, the said Emil Königs and James Henderson,
do hereby declare the nature of our said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement in writing, that is to say :-
Our said Invention has principally for its object the production of
sulphate of soda, hydrochloric acid, and chlorine from common salt,
without using vitriol chambers and nitre for first making sulphuric acid,
whilst at the same time hydrochloric acid or chlorine is obtained without
using manganese.
Our improved process is also equally applicable for obtaining the
hydrochloric acid or chlorine when chloride of potassium is substituted
for common salt, sulphate of potash being in that case obtained instead
of sulphate of soda.
In carrying out our said Invention, according to one modification an
intimate mixture of about one part by weight of common salt and
about three parts of any kind of peroxide of iron, both in coarse powder,
is placed in a muffle furnace or in a revolving tube or retort lined

page_text: with fire-brick and heated preferably to dull redness. Over the heated
mixture gaseous sulphurous acid is passed and dry air either successively
or together, these gases being heated by preference by passing them
through flues, pipes, or chambers kept at a dull red heat before being
admitted to the furnace or retort. By the reaction which takes place,
and in which the oxygen of the air takes part, the common salt is
gradually converted into sulphate of soda, whilst chlorine is given off,
mixed with small quantities of sulphurous acid, some sublimed metallic
chlorides, and sometimes sulphuric and hydrochloric acids.
If the
sulphurous acid is derived from burning pyrites, or other sulphur com-
pounds, or even sulphur, it will be mixed with more or less nearly
exhausted air, which air may be got rid of by passing the mixed gases
through flues, chambers, retorts, or spaces containing sulphur or sulphur
compounds and heated to dull redness if necessary, so that sulphurous
acid may be formed with any remaining oxygen. The resulting gases
then consisting almost exclusively of sulphurous acid and nitrogen are
passed over the heated mixture of iron oxide and salt, the sulphurous
acid being absorbed and the nitrogen passing onwards to the chimney.
After the mixture ceases to absorb sulphurous acid dry atmospheric air
heated sufficiently to maintain active decomposition in the mixture, but
without any approach to fusion, is allowed to act on it, when chlorine
is evolved with a minimum admixture of nitrogen, and is passed on to
the apparatus for making bleaching powder or other chlorine compound.
If muffle furnaces are used they must be such as allow of raking, and
are by preference worked in combined sets of two or more, the gases
passing from a newly charged furnace being passed through a second
which is more advanced, and if necessary or desirable again through a
third, which is nearly finished, whilst a fourth may be discharging and .
recharging in readiness to be made first of the series.
There is often a small quantity of other gases besides nitrogen and
air mixed with the chlorine, and to insure their removal or conversion
they are passed through a regenerative chamber filled with bricks, balls,
or blocks of any convenient form made up of iron oxide and salt with
clay added if necessary to enable them to keep their shape; or the iron
oxide and salt may be in the form of a mixed powder and the gases
be passed over them. The iron oxide and salt are heated by external
heat, or by heated air, or by heated air and combustible gases; and when
the mixed gases are--passed-over them the sulphurous and sulphuric
acids, if any, are absorbed, producing sulphate of soda and chlorine.

page_text: The gases are finally cooled in chambers, pipes, or spaces allowing
volatile matters to be deposited, and hydrochloric acid or moisture, if
present, is removed by well-known means; after which the chlorine is
absorbed by lime or an alkali in the well-known way.
By a second modification the iron oxide and salt mixture is formed 5
into bricks, balls, or blocks of any convenient shape, and these are
arranged and heated in kilns or furnaces adapted for burning bricks,
lented either from the outside or by heating the sulphurous acid and
air that are to be passed over them, as in the first modification. The
-resulting gases are treated and utilised as in the first modification.
1
When hydrochloric acid is wanted a mixture of air and steam is used
instead of the dry air herein-before referred to, and in proceeding
otherwise the process is the same as in either the first or second modi-
fication.
By a third modification the proportion of iron oxide in the mixture 1
may be reduced and pyrites in coarse powder substituted to yield the
required sulphurous acid, the mixture being heated and acted upon by
dry air or by air and steam, and yielding the same products as in our
other modifications.
The sulphate of soda is extracted from the burned powders, burned 2
and ground bricks, or the like, preferably by washing with warm or hot
water, and separating it from the resulting solution by crystallising,
salting out, or evaporating to dryness. The hydrochloric acid is con-
densed in the usual way.
The application of our Invention is not restricted to iron oxide, iron 2
pyrites, or similar compounds free from other or more valuable metals,
such as copper. Thus burnt cupreous pyrites may be used instead of
mere iron oxide, allowance being made for the proportion of sulphur
usually remaining in it. Unburnt pyrites containing copper may also
be used.
3
When copper and similar metals occur, instead of trying to obtain all
the copper in solution with the sulphate of soda, the mixture is heated
until all or nearly all the copper or iron present is rendered insoluble
in water. If after continued heating there is still a small amount of
metal soluble it is made insoluble during the extraction of the sulphate 3
of soda by the addition of lime or other suitable base. Then after the
separation of the sulphate of soda the metal may be dissolved by the
aid of acid, and be subsequently precipitated by iron, as is well

page_text: understood. A great advantage of this mode of rendering the copper
insoluble is that the lixiviation for the sulphate of soda can be conducted
in iron vessels, and that the resulting salt is free from iron.
Having thus particularly described our said Invention, and the manner
of performing the same, we have to state that we do not restrict our-
selves to the precise details herein-before referred to; but that what
we believe to be novel and original, and claim as the Invention secured
to us by the herein-before in part recited Letters Patent is,-
1. The herein-before described processes wherein iron oxide, salt, sul-
phurous acid, and air, or air and steam are made to react to produce
sulphate of soda, hydrochloric acid, chlorine, and other products.
2. The exhausting of any surplus oxygen gas mixed with the sul-
phurous acid as first formed (when the sulphurous acid is to be used
separately), in the manner and for the purposes herein-before described.
3. The purifying of the chlorine or hydrochloric acid from sulphurous
or sulphuric acid by passing the mixed gases through the so-called
regenerative chamber or furnace, as herein-before described.
4. The applying of lime or other base when lixiviating the burnt or
calcined materials, so as to obtain the sulphate of soda or of potash
unmixed with metals and the subsequent utilising of any metals present,
as herein-before described.
In witness whereof, I, the said James Henderson, on behalf of the
said Emil Königs and myself, have hereunto set my hand and
seal, this Nineteenth day of December, in the year of our Lord
One thousand eight hundred and seventy-one.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
JAMES HENDERSON. (L.S.)