IMPROVEMENTS IN THE MANUFACTURE OR PRODUCTION OF ARTIFICIAL OXIDE OF MANGANESE
Year: 1855

page_text: LETTERS PATENT to Charles Tennant Dunlop, of Glasgow, in the County
of Lanark, North Britain, Chemist, for the Invention of "IMPROVEMENTS
IN THE MANUFACTURE OR PRODUCTION OF ARTIFICIAL OXIDE OF MANGANESE."
Sealed the 22nd February 1856, and dated the 22nd November 1855.
PROVISIONAL SPECIFICATION left by the said Charles Tennant Dunlop
at the Office of the Commissioners of Patents, with his Petition, on the
22nd November 1855.
I, CHARLES TENNANT DUNLOP, of Glasgow, in the County of Lanark, North
Britain, Chemist, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MANUFACTURE OR PRODUCTION OF ARTIFICIAL OXIDE OF
MANGANESE" to be as follows, that is to say:
This Invention relates to the application & treatment of the residuum of
the chlorine manufacture, commonly consisting of the chloride of manganese,
for the obtainment of oxide of manganese therefrom, the manganese being
produced in the state of a carbonate by heating the residuum with carbonate
of lime. The chloride of calcium resulting from this decomposition is washed
out of the carbonate of manganese, and by gently heating this carbonate in
contact with the atmosphere, in the manner already referred to in the Pro-
visional Specification of an Invention, for which British Letters Patent, dated:
on or about the Thirtieth day of May last, have been granted to Mr. Dunlop,
an oxide of manganese suitable for chlorine and glass makers & for other
purposes is obtained.
The carbonate of lime used for this purpose is prepared by burning common
limestone in an ordinary kiln, and retransforming this limestone iuto carbonate

page_text: by bringing it in contact with the carbonic acid evolved from the kiln. The
carbonate of lime may be prepared in this way when a sufficiently soft and
easily decomposable natural carbonate of lime cannot be obtained for the
decomposition of the chloride of manganese.
Another convenient means of obtaining the carbonate of lime for the pro-
duction of carbonate of manganese consists in decomposing the chloride of
calcium once obtained by gaswork liquors. A muriate of ammonia is thus
produced, & a very finely divided carbonate of lime, which readily decom-
poses the chloride of manganese; chloride of calcium is thus obtained, and this
can again decompose the gas liquors, and so on.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Tennant Dunlop in the. Great Seal Patent Office
on the 21st May 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
TENNANT DUNLOP, of Glasgow, in the County of Lanark, North Britain,
Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of November, in the year of our
Lord One thousand eight hundred and fifty-five, in the nineteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Charles Tennant Dunlop, Her special license that I, the said Charles
Tennant Dunlop, my exccutors, administrators, and assigns, or such others.
as I, the said Charles Tennant Dunlop, my executors, administrators, or
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 Inven-
tion for "IMPROVEMENTS IN THE MANUFACTURE OR PRODUCTION OF ARTIFICIAL
OXIDE OF MANGANESE," upon the condition (amongst others) that I, the said
Charles Tennant Dunlop, by an instrument in writing under my hand and
seal, should particularly describe and ascertain the nature of the said Inven-
tion, 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 I, the said Charles Tennant Dunlop, do hereby
declare the nature of my said Invention, and in what manner the same is

page_text: to be performed, to be particularly described and ascertained in and by the
following statement in writing, that is to say:-
My said Invention relates to the application and treatment of the residuum
of the chlorine manufacture, commonly consisting of chloride of manganese,
for the obtainment of peroxide of manganese therefrom, and consists in using
carbonate of limo to convert the chloride of manganese into carbonate of
manganese, and in subsequently converting this carbonato of manganese into
peroxide of manganese.
And in order that my said Invention may be properly understood, I shall
now proceed to describe in detail the various processes practised in carrying it
into effect. It is first necessary to free the solution of manganese from the
various impuritics with which it is contaminated as it is received from the
stills of the chlorine manufacture. The solution usually contains more or less
free acid, together with chloride of iron and other impurities, and the whole
of these are effectually removed from it by the addition of either bydrate or
carbonate of lime, after which there remains a clear solution containing
chloride of manganese and chlorido of calcium. This solution is transferred
to a strong cylindrical boiler or other suitable vessel, into which is also intro-
duced a sufficient quantity of carbonate of lime to effect the decomposition of
the chloride of manganese. This decomposition is brought about by the
application of heat, which I prefer to carry into effect by blowing steam
through the materials, this causing at the same time the necessary agitation of
such materials. The introduction of steam is continued for about four hours,
or longer, if necessary, after the materials have been brought to a temperature
of from 260 to 280 degrees Fahrenheit, more or less, a sufficient steam pres-
sure being maintained within the boiler or vessel for that purpose. When a.
sample taken from the boiler shows that all the carbonate of lime is dissolved,
and that only carbonato of manganese remains undissolved, this portion of the
operation may be considered as terminated. The carbonate of manganese is
subsequently freed from adhering chloride of calcium by washing with water,
and after being dried is heated or gently calcined in a furnace, oven, or kiln
in contact with atmospheric air, the carbonate thus treated parting with its
carbonic acid and absorbing oxygen from the atmosphere. When the operation
is successfully conducted, a peroxide of manganese, containing eighty or ninety
per centum of peroxide, is thus obtainable.
According to another modification of my improved process, the chloride of
manganese is decomposed by simple boiling without the aid of extra pressure,
by using a carbonate of lime prepared artificially by passing carbonic acid into
hydrate of lime, or by using a carbonate of lime prepared by precipitation of

page_text: a lime salt by an alkaline carbonate. In this way gas liquors or the waste
liquors from gas works may be used to produce a carbonate of lime for the
purposes of my Invention, the liquor being mixed with chloride of calcium,
which also produces a muriate of ammonia. The muriate of ammonia thus
prepared may be disposed of, whilst the carbonate of lime may be used for
precipitating chloride of manganese, in which operation chloride of calcium
is again produced, and may be again used in decomposing gas liquor.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I may observe, in conclusion, that I do not confine or restrict
myself to the precise details or arrangements which I have had occasion to
describe or refer to; as many variations may be made therefrom without
deviating from the principles or main features of my Invention; but what
I consider to be novel and original, and therefore claim as the Invention secured
to me by the herein-before in part recited Letters Patent, is,―
First, the general process of manufacturing an artificial oxide of manganese
from the residuum of the chlorino manufacture, as herein-before described.
Second, the system or mode of producing peroxide of manganese, by gentle
calcination of carbonate of manganese, prepared from chloride of manganèse by
precipitation with carbonate of lime, as herein-before described..
.
Third, the system or mode of preparing carbonato of manganese from the
residuum of the chlorine manufacture, by boiling it under a high or low pressure;
with carbonate of lime, as herein-before described.
I
Fourth, the system or mode of preparing carbonate of manganese from
chloride of manganese, by precipitation with carbonato, of limo artificially.
prepared, in the manner herein-before described.
Fifth, the system or mode of preparing carbonate of manganese from chloride
of manganese, by precipitation with carbonate of lime, formed by the pre-
cipitation of a lime salt, such as chloride of calcium, with an alkaline carbonate,
such as gas liquor, as herein-before described.
In witness whereof, I, the said Charles Tennant Dunlop, have hereunto-
set my hand and seal, this Seventeenth day of May, One thousand-
eight hundred and fifty-six.
CHAS TENNANT DUNLOP. (L.S.)