IMPROVEMENTS IN APPARATUS FOR BURNING OR CALCINING ORES AND MINERALS CONTAINING SULPHUR OR ARSENIC FOR THE MANUFACTURE OF SULPHURIC ACID OR ARSENIOUS ACID OR WHITE ARSENIC to be as follows
Year: 1885

page_text: of Sulphuric Acid, or Arsenious Acid, or White Arsenic.
We, ROBERT OXLAND of 32 Portland Square Plymouth in the County of
Devon, Consulting Chemist and CHARLES OXLAND of Greystoke, Crystal Palace
Park Road, Sydenham in the County of Surrey, Mining Engineer do hereby
declare the nature of our invention for "IMPROVEMENTS IN APPARATUS FOR
BURNING OR CALCINING ORES AND MINERALS CONTAINING SULPHUR OR ARSENIC
FOR THE MANUFACTURE OF SULPHURIC ACID OR ARSENIOUS ACID OR WHITE
ARSENIC to be as follows :-
"
In the specification of a Patent No 2950 granted to Robert Oxland and John
Hocking dated the 25th day of September 1868 is described the use of a revolving
cylinder lined with fire brick for calcining ores and minerals with a continuous
feed of ore into one end of the cylinder and continuous delivery of roasted ore at
the other end of the cylinder-and with a furnace at the delivery end the products
of combustion from which were led through the cylinder so that they were mixed
with the volatile products of calcination and passed off from the opposite end of
the cylinder to the flues communicating with the necessary condensers.
According to this invention we avoid the use of the fire place heretofore used
and in place thereof we employ at the delivery end a continuation of the cylinder
made of cast iron and heated externally either by gas or other fuel such as coal or
wood the products of combustion from which are led away by suitable flues and are
not allowed to enter the interior of the cylinder-in this way we avoid the
admission to the flues of the products of combustion of the fuel consumed in the
fire place and any other matters than the nitrogen and excess of atmospheric air.
required for the calcination of the ores.
The products of combustion resulting from the calcination or burning of the ores
are led away from the opposite end of the cylinder to chambers for condensation.
The ore in a powdered or divided state is introduced into this end of the
cylinder through a tube from a hopper or chamber in which the ore is contained.
The ore flows freely through the tube into the cylinder until the flow is obstructed
by the ore accumulating below its end and as the cylinder slowly rotates and
carries the accumulation of ore from below the end of the tube more ore flows

page_text: through the tube into the cylinder and so a continuous supply of the ore to be
burnt or calcined is maintained.
The calcined ore as it is delivered from the opposite end of the cylinder is
received into a wagon or receptacle placed within a closed chamber at that end-
at this end also apertures are provided through which air can be admitted for
sustaining the combustion of the pyrites or other ore in the cylinder and sight
openings through which the interior of the cylinder can be viewed to ascertain the
progress of the combustion of the ore within it.
In a similar manner if the furnace in which the ore is burnt or calcined is
composed of a series of shelves one below the other and the ore is raked in
succession along the shelves and so made to pass in succession from the upper to
the lower shelves we make provision for heating the lower shelves of the series by
making them hollow and carrying the products of combustion from a fire place or
furnace through their interior and so keep the ore heated to the required extent at
the delivery end of the furnace to carry on the calcining operation in an efficient
manner to the end and until the ore is delivered from the apparatus.
Dated thie 15th day of Tuna TOOK

page_text: of Sulphuric Acid, or Arsenious Acid, or White Arsenic.
We ROBERT OXLAND of 32 Portland Square Plymouth in the County of
Devon Consulting Chemist and CHARLES OXLAND of Greystoke Crystal Palace
Park Road Sydenham in the County of Surrey Mining Engineer 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:
In the Specification of a Patent N° 2950 granted to Robert Oxland and John
Hocking dated the 25th day of September 1868 is described the use of a revolving
cylinder lined with fire brick for calcining ores and minerals with a continuous
feed of ore into one end of the cylinder and continuous delivery of roasted ore at
the other end of the cylinder and with a furnace at the delivery end, the products
of combustion from which were led through the cylinder so that they were mixed
with the volatile products of calcination and passed off from the opposite end of the
cylinder to the flues communicated with the necessary condensers.
According to the present invention we avoid the use of a fireplace communicating
with the interior of the cylinder as heretofore used and in place thereof we employ
at the delivery end a continuation of the cylinder made of cast iron and heated
externally either by gas or other fuel such as coal or wood, the products of com-
bustion of which are led away by suitable flues and are not allowed to enter the
interior of the cylinder. In this way we avoid the admission to the flues of the
products of combustion of the fuel consumed in the fire place and of any other
matters than nitrogen and atmospheric air. The products of combustion resulting
from the calcination or burning of the ores are led away from the opposite end of
the cylinder to chambers for condensation.
The ore in a powdered or divided state is introduced into the end of the cylinder
through a tube from a hopper or chamber in which the raw ore is contained. The
ore flows freely through the tube into the cylinder until the flow is obstructed by
the ore accumulating below its end and as the cylinder which is slightly inclined
slowly rotates it carries the accumulation of ore from below the end of the tube
more ore flows through the tube into the cylinder and so a continuous supply of
the raw ore is maintained.
The inclination of the tube varies from half an inch to an inch in the foot
falling from the feeding to the delivering end.
The calcined ore as it is delivered from the end of the cast iron cylinder is
received into a wagon or receptacle placed within a close chamber.
In order that our said invention may be fully understood and readily carried into
effect we will proceed to describe the drawings hereunto annexed.

page_text: DESCRIPTION OF THE DRAWINGS.
Figure 1 is a side elevation partly in section of appartus constructed according
to our invention.
Figure 2 is a similar view but showing only a portion of the apparatus.
Figure 3 is an end elevation and Figure 4 is a transverse section.
a is the cylinder about 30 feet long lined with fire brick; it is supported on
rollers as the drawing indicates and it is slowly rotated by a worm a¹ engaging
with worm teeth on a ring a2 embracing the cylinder. bis a continuation of the
cylinder a; it is of thick cast iron. c is a fire place by which the part b, is heated
to a dull red heat; flues around the part b connect the fire place with the space-
This space has suitable partitions for the uniform distribution of the heat and
it communicates with the chimney d. e is the passage by which the ore descends
into the cylinder.
a' is the outlet at the fire end by which the calcined ore is delivered. a' is a
regulator for the admission of air. f is the gas passage leading from the cylinder
to a sulphuric acid chamber where the sulphurous acid gas is converted into
sulphuric acid.
In starting the apparatus the heat of the part b ignites the ore or it may be
otherwise ignited and it soon begins to burn from end to end of the cylinder which
is kept in continuous motion. After the starting a small fire will suffice; the
object then being to maintain an uniform combustion of the ore and to further
heat the spent ore as it reaches the part 6 to assist the separation of what remains
of the sulphur and arsenic. The arsenic passes into the sulphuric acid but by
known processes it is readily separated when it is necessary to do so.
The apparatus shown is capable of burning or calcining 13 or 14 tons of ore
per day.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is
Our improved apparatus for burning or calcining ores consisting of a revolving
cylinder with an interior lining and a continuation of cast iron which is heated
externally by the combustion of fuel; the whole so arranged that the ore admitted
at one end of the cylinder is delivered at the other through the heated cast iron
continuation whilst the gases separated pass off at the opposite end of the cylinder
without admixture with the products of combustion of the fuel substantially as
described.
Dh: 70th Jane of Mb 1004