Improvements in Roasting Ovens or Furnaces for the Desulphuriza- tion of Volcanic Sulphur, Sulphurous Ores, and Ores Containing a greater or less Percentage of Sulphur.
Year: 1898

page_text: Date of Application, 12th Apr., 1898-Accepted, 16th July, 1898
Improvements in Roasting Ovens or Furnaces for the Desulphuriza-
tion of Volcanic Sulphur, Sulphurous Ores, and Ores Containing
a greater or less Percentage of Sulphur.
A communication by HOWARD HARLAND and SPOTTSWOOD DABNEY CRENSILAW, both
of Richmond, in the County of Henrico, and State of Virginia, United States
of America, Manufacturers.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of The Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both
in the County of Lancaster, 118, New Street, Birmingham, in the County of
Warwick, and 322, High Holborn, in the County of Middlesex, Civil 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 fol-
lowing statement:-
This invention relates to a roasting oven or furnace for the desulphurization
of volcanic sulphur, sulphurous ores, such as iron pyrites, sicilian sulphurets, and
other ores containing a greater or less percentage of sulphur.
The object of the invention is to provide a furnace that will permit the desul-
phurization to go on continuously without clogging, and to this end consists in
the construction and arrangement substantially as shown in the accompanying
drawings, in which—
Fig. 1, is an end view of a battery of furnaces, one being shown in section,
and
Fig. 2, is a detail perspective view of the air conduits.
"
It is well known that heat expels sulphur from the ores, the fumes being
carried off and condensed in lead chambers in the presence of nitric acid and
water, to form sulphuric acid of commerce, the residue is generally iron oxyde
which is ground to form a paint, or if containing copper it is matted" and the
copper separated by the electrolytic process. Heretofore in such operations there
has usually been a deficiency of oxygen to support combustion, and the reduction
is incomplete owing the clogging of the air ducts.
Generally a charge of ore requires sixty hours to become thoroughly desulphur-
ized.
"
Referring more specifically to the drawings, A represents a roasting furnace
of any suitable dimensions, the furnace being arranged in series, or battery'
the better to carry on the operation.
It has been found by experience that four foot cubes give the best results;
each furnace will contain when first charged about 3000 lbs., of ore, and every
twenty four hours a new charge of from 500, to 1000, lbs., of ore is added.
There are some ores that disintegrate rapidly under heat, and the residue falls
to the air inlets clogging them to such a degree that air is excluded and the
burning retarded.
The furnace is constructed with a series of bars A³, similar to grate bars to
admit air from the pit C. These bars have secured to them and support, air

page_text: conduits H, which are hollow, and perforated at their sides. They also open
downwardly to the pit C, and are carried up into the ore, separating it into divisions
so that in burning it will be divided and not have a tendency to fall into a com-
pact mass.
It will be observed from the construction shown, that air is not only admitted
between the bars A', but through the conduits H, and discharged through their
top openings h, and side openings h, and as the sulphurous acid is gradually
eliminated the residue falls down between the conduits and into the pit C. The
fumes pass off through the flue B, to the condensing chambers.
Each furnace is provided with a charging door K, having a peep hole g, and
a door or slide L, where a stirring rod can be introduced. The doors M, lead
to the pit C, and have openings N, for the admission of air. By means of this
construction and arrangement I am enabled to obtain a maximum of sulphurous
acid with least labor in re-charging, and least residuum of ore not properly de-
sulphurized are obtained.
These conduits may be of fire clay or any other suitable refractory material,
and they may be carried up into the ore body to a greater or less height as the
exigencies may require.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me by
my foreign correspondents, I declare that what I claim is:-
1st. In a roasting furnace of the nature described, a closed heating or roasting
chamber, bars underneath the same to support the ore and spaced apart to give
openings to admit air from below, an outlet flue at top for conducting the gas
to a condensing chamber, a series of hollow air conduits resting on the bars over
the openings, and consisting of vertical pyramidal shaped casings with smooth
sides provided with perforations, substantially as described. .
2nd. In a furnace of the nature described, having bars to support the ore,
and spaced apart to give openings from below, and a flue for conducting the gas
to a condensing chamber, hollow pyramidal conduits resting on the bars over
the openings extending vertically into said chamber, said conduits having smooth
sides, a longitudinal opening at top, and perforations in their sides whereby air
is admitted to the ore at top and sides of the conduits, substantially as described.
Dated this 7th day of April 1898.
WM. P. THOMPSON & Co.,
Agents.