A NEW AND USEFUL PROCESS OF REMOVING BOTH IRON AND MANGANESE FROM CERTAIN SOLUTIONS
Year: 1882

page_text: LETTERS PATENT to Conrad Semper of the City and County of Philadelphia
in the State of Pennsylvania United States of America, for an Invention of
"A NEW AND USEFUL PROCESS OF REMOVING BOTH IRON AND MANGANESE
FROM CERTAIN SOLUTIONS "
e
COMPLETE SPECIFICATION filed by the said Conrad Semper at the Office
of the Commissioners of Patents on the 19th September 1882.
CONRAD SEMPER of the City and County of Philadelphia, in the State of
Pennsylvania United States of America "A NEW AND USEFUL PROCESS OF
REMOVING BOTH IRON AND MANGANESE FROM CERTAIN SOLUTIONS
"
The object of my Invention is to remove both the iron and manganese at one
operation where both are present in certain solutions.
I have discovered that if a ferruginous solution of such salts as are not decomposed
by the per-manganate used in the operation of the process and which contain
manganese, is treated with a per-manganate that not only the manganese is
precipitated by such treatment but that the manganic-dioxide attracts the per-
oxide of iron, forming a chemical combination, and is precipitated jointly, leaving
the solution, if the proper proportion should have been employed free or almost free
from both iron and manganese. If such a ferruginous solution should originally
not contain any or not contain a sufficient quantity of manganous salt, to give the
proper reaction, a certain quantity of manganous salt must be added sufficient to
jointly precipitate all or nearly all the iron with the manganic-dioxide. In case
the iron in the said solutions is present as ferrous-oxide part of the per-manganate
added for its removal will be consumed in its oxidation to ferric oxide, as the iron
can only be precipitated by this process in this form.
The relative quantity of per-manganate necessary to be used can be readily
calculated by testing the amount of the manganic-dioxide and iron present. I do
not confine myself to any specific proportions, but care must be taken that enough

page_text: manganese is present to precipitate the iron. In order to prevent any of the
manganese or iron from remaining in solution, the solution must be as neutral as
possible; and if it should be basic or slightly basic, it will be of advantage.. A
ferruginous solution containing manganese may be thus treated either before or
after the impurities other than organic impurities have been removed, as for instance
a solution of sulphate of alumina need not have the silica or undecomposed raw
material removed beforehand.
It is necessary that sufficient manganous salt, be used so as to form when
oxidized with the per-manganate, a manganic-dioxide in the proportion of about 3
to 1, of the ferric oxide present in the solution.
I will now describe the process in detail taking a ferruginous solution of sulphate
of alumina for convenience of explanation: although the process is the same in
solutions of other salts not decomposed by a per-manganate such as solutions of
salts of zinc, nickel, magnesia, soda &. After the sulphuric acid and the aluminous
raw material have acted upon each other, and the action ceases, a sufficient quantity
of water or mother liquor from a previous operation is added to keep the solution
from hardening. It is now tested to see whether the sulphate of alumina is
neutral or not too sour, and if the latter is the case the necessary steps are taken
to bring it to as nearly a neutral or basic state as possible. Then provided there
should not already be sufficient manganese present a small but sufficient quantity
of a manganous salt preferably manganous sulphate is added. The whole mass is
now well stirred, and if the temperature is not sufficiently high for the chemical
reaction to take place promptly it is heated by means of a steam coil or direct
steam or by any other suitable means until this action begins. Then a portion
of the per-manganate solution is added, the mass kept in agitation, and after some-
time, say five or ten minutes, a sample is drawn, if the sample thus drawn shows
iron or manganese in any considerable quantity another portion of per-manganate
is added, and the mass again stirred, and another sample drawn, and so on until a
sample shows no iron or manganese, or only a small quantity of either or both.
If a slight excess of per-manganate should have been added, which can be readily
seen by its color it is only necessary to add a little more manganous salt, in which
case the same action takes place and both the manganese and iron are finally
precipitated.
The liquor is now ready for further treatment after the subsiding of the insoluble
parts or removal of the same by any of the well known means. The residue con-
sisting of silica, undecomposed raw material, manganic dioxide, and ferric oxide,
has to be washed and the weak solution of sulphate of aluinina obtained thereby
utilized in this next operation to prevent hardening of the solution of the sulphate
of alumina. The silica and undecomposed raw material, mixed with the manganic-
dioxide and ferric oxide from the above treatment can perhaps profitably be
employed as a pigment, the sediment which I have obtained having a beautiful
brown color. It will only be necessary after washing it, to subject it to a floating
process, by which all the coarse particles are removed and to dry the fine particles
collected therefrom.
•
The clear solution of sulphate of alumina which contains no iron or manganese
or only a small quantity of them, is now boiled down and run out to cool into a
cake or it can be utilized for crystal alum or for any other purpose it may be
desired,
Having thus described the nature and objects of my Inventions what I claim
herein as new and desire to secure by Letters Patent is:
First. The process of removing both the iron and manganese by a single operation
from ferruginous solutions, (of such salts as are not decomposed in the operation of
the process) containing manganous salts by treating them with a per-manganate,
and subjecting them to heat, substantially as described.
Second. The addition to a ferruginous solution of any salt of the alkalies,
alkaline earths or metallic bases, not decomposed by treatment with a per-
manganate, of a sufficient amount of manganous salt, if such was not previously
w

page_text: present to jointly precipitate the iron with the manganese by treating such
solution with a per-manganate and subjecting it to heat; substantially as
described;
.
:
In witness whereof I the said Conrad Semper have hereunto set my hand
and seal this Thirty first day of July in the year of our Lord one thousand eight
hundred and eighty two.
CONRAD SEMPER. (L.S.)