Improvements in and relating to the Roasting and Calcining of Minerals and the like substances.
Year: 1897

page_text: Date of Application, 4th May, 1897
Complete Specification Left, 3rd May, 1898-Accepted, 23rd Apr., 1898
Improvements in and relating to the Roasting and Calcining of
Minerals and the like substances.
I, GEORGE HENRY BLENKINSOP, of Melbourne Place, Swansea, in the County of
Glamorgan, Mining Engineer and Metallurgist, do hereby declare the nature of
this invention to be as follows:--
My invention relates to an improved method of roasting or calcining minerals
and other substances whereby the oxidation or volatilisation of certain inorganic
impurities is effected more economically and efficiently than has hitherto been
possible.
In the following specification I have set forth my invention as applied to the
treatment of ores containing small percentages of sulphur or of arsenic, by way of
example; it is, however, obvious that the same is equally applicable to the treat-
ment of other compounds, natural or artificial containing sulphur or arsenic: also
that the invention might be applied for the separation of other bodies in like
manner, such for instance as selenium or thallium.
By means of my improved method of treatment, I am able to extract practically
the whole of the small percentage of sulphur which contaminates certain iron ores,
and thus add considerably to the value of said ores, and I am also able to manu-
facture sulphuric acid from ores and substances which are not at present considered
commercially suitable for such purpose. I am also able to extract arsenic from
ores and compounds to greater commercial advantage than at present.
In carrying my invention into effect I charge the ore under treatment into a
closed revolving or stationary vessel, and subject the same to the action of air
heated to a given temperature and at a determined pressure whereby the oxygen
of the air is caused to combine with the sulphur and arsenic present and to form
sulphurous and arsenious acids respectively which may be afterwards dealt with
in the wellknown manner. If heated air be merely passed over ores and substances
containing sulphur and arsenic in the ordinary way the resultant gases are too
weak to be of commercial value or in some cases so much heat is generated as to
fuse the substances under treatment, but by employing a vessel closed at the inlet
and outlet the supply of air can be so regulated as to produce a gas or gases con-
taining a high percentage of sulphurous and arsenious acids and the effectual
oxidation of the substances under treatment results.
When the substances under treatment contain only a small or comparatively
small percentage of sulphur or arsenic it may be advantageous to heat them by one
of the well known methods before they are subjected to the action of hot air under
pressure and this preliminary heating may be done in the same vessel by opening
the inlet and outlet.
The vessel in which the calcination is effected can be fitted with means for
indicating and controlling the temperature and pressure and the temperature of

page_text: the air and the internal pressure can be regulated in accordance with the nature of
the substances under treatment.
100K 2
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C.,
Patent Agents for the Applicant.
Improvements in and relating to the Roasting and Calcining of
Minerals and the like substances.
I, GEORGE HENRY BLENKINSOP, of Melbourne Place, Swansea, in the County of
Glamorgan, Mining Engineer and Metallurgist, 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:-
My invention relates to an improved method of roasting or calcining minerals
and other substances whereby the oxidation or volatilisation of certain inorganic
impurities is effected more economically and efficiently than has hitherto been
possible.
In the following specification I have set forth my invention as applied to the
treatment of ores containing small percentages of sulphur or of arsenic, by way of
example; it is, however, obvious that the same is equally applicable to the treat-
ment of other compounds, natural or artificial, containing sulphur or arsenic:
also that the invention might be applied for the separation of other bodies in like
manner, such for instance as selenium or thallium, namely by volatilisation from a
closed vessel in a heated air-current.
By means of my improved method of treatment, I am able to extract practically.
the whole of the small percentage of sulphur which contaminates certain iron ores,
and thus add considerably to the value of said ores, and I am also able to manu-
facture sulphuric acid from ores and substances which are not at present considered
commercially suitable for such purpose. I am also able to extract arsenic from
ores and compounds to greater commercial advantage than at present.
In carrying my invention into effect I charge the ore under treatment into a
closed revolving or stationary vessel, and subject the same to the action of air
heated to a given temperature and at a determined pressure whereby the oxygen
of the air is caused to combine with the sulphur and arsenic present and to form
sulphurous and arsenious acids respectively which may be afterwards dealt with
in the well known manner. If heated air be merely passed over ores and substances
containing sulphur and arsenic in the ordinary way, the resultant gases are too
weak to be of commercial value, or in some cases so much heat is generated as to.
fuse the substances under treatment, but by employing a vessel closed at the inlet
and outlet the supply of air can be so regulated as to produce a gas or gases con-
taining a high percentage of sulphurous and arsenious acids and the effectual
oxidation of the substances under treatment results.
When the substances under treatment contain only a small or comparatively
small percentage of sulphur or arsenic it may be advantageous to heat them by one
of the well known methods before they are subjected to the action of hot air under
pressure and this preliminary heating may be done in the same vessel by opening
the inlet and outlet.
The vessel in which the calcination is effected can be fitted with means for
indicating and controlling the temperature and pressure and the temperature of

page_text: the air and the internal pressure can be regulated in accordance with the nature of
the substances under treatment.
In order to make my invention and the mode of carrying the same into effect
more clear I will now proceed to describe the same in connection with the accompany-
ing drawing, but I desire it to be understood that I make no claim to this specific
construction of apparatus shewn here by way of example only, nor do I limit my
invention to use with apparatus constructed as shewn, because it is obvious that
considerable variations may be made in the apparatus to meet the requirements
of special cases without departing from the principle of the invention.
In this drawing A indicated a revolving furnace more or less cylindrical in
shape. B is the inlet for the hot air, and C the out-let for the escape gases; both
these tubes are controlled by suitable valves. The materials are supplied to the
interior of the furnace from the hopper or hoppers D through manholes a, and
the roasted products are discharged through corresponding manholes.a¹, a¹ below
into trolleys or the like which run beneath the furnace. The apparatus may be
conveniently mounted upon gear-wheels in the manner shewn in the drawing, and
can be readily rotated by the same means if found requisite.
The construction of the furnace shewn diagrammatically in the drawing bears
some resemblance to the apparatus known in the alkali trade as the revolving
black-ash furnace, but in the black-ash furnace the air admitted to its interior
passes in along with the furnace gases and combustion products; whereas by my
improved process pure heated air at the requisite temperature is alone injected and
in contra-distinction to other processes for treating similar ores there is no outside
heating applied to the materials during the roasting process, the amount of caloric
necessary being supplied from the heated air current.
As an example of the temperature and pressure which may be requisite in the
carrying out of my process on an industrial scale I have found that when the material
under treatment is a dense magnetic iron ore it is necessary to heat the
air to a temperature of one thousand degrees Fahrenheit, and to employ a pressure.
of ten pounds per square inch. When operating, however, on a less dense material,
such as a mono-sulphide, a temperature of seven hundred degrees Fahrenheit and a
pressure of three pounds only per square inch will be sufficient.
Other materials of varying density and conductivity will require different
temperatures and pressures, the exact amount of each being determinable by experi-
ment in the usual manner.
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:-
The improved process for calcining substances containing relatively small per-
centages of elements capable of being oxidised to the gaseous state, consisting in
subjecting the substances with or without previous heating, to a current of undiluted
air at a given temperature and pressure without outside heating of the furnace,
and removal of the gaseous products, substantially as described.
Dated this 2nd day in
LXYX
Dated this 2nd dox
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester, and Birmingham,
Patent Agents for the Applicant.
X
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester, and Birmingham,
Patent Agents for the Applicant.