Improved Process for Roasting Mixed Sulphide Ores.
Year: 1899

page_text: Date of Application, 15th June, 1899-Accepted, 28th Oct., 1899
COMPLETE SPECIFICATION.
Improved Process for Roasting Mixed Sulphide Ores.
We, ERNST CHRISTIAN HERMANN PAPE, Engineer, of Hohe Bleichen 36, II,
Hamburg, Germany, and CARL AUGUST LOUIS WILHELM WITTER, Metallurgist,
of Hühnerposten 10, Hamburg, Germany, 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:
-
This invention relates to an improved process for roasting mixed sulphide ores
wherein the roasting is carried out in such a manner that one part of the metallic
oxides produced is caused to pass away simultaneously with the furnace gases
from the roasting chamber, while the other part is directly precipitated in such
chamber.
For this purpose the mixed sulphide ores are reduced to as fine a state of sub-
division as possible, and are then fed in the form of a fine powder into a com-
bustion chamber, the walls of which have been previously heated to a high degree,
and into which, previously heated air currents are introduced at suitable points
so that as intimate a contact as possible is effected between the hot air and the
separate particles of ore.
The sulphide ore is by this means oxidised instantaneously as it falls on to
the hearth of the furnace.
If the ore contains sufficient sulphur, no further addition of fuel is requisite
during the working; should this not be the case, the temperature is maintained
at the required high degree by the introduction of fuel.
While the non-metallic constituents of the ore fall together with the greater
part of the oxides of lead, silver, iron, copper &c., on to the bed of the furnace
chamber, the greater part of the zinc oxide, together with a portion of the lead
oxide, silver oxide &c. will escape with the furnace gases.
With the roasting furnace are combined chambers into which the escaping
combustion gases are led and cooled down, and are thus made to deposit the
greater part of the metallic oxides carried along with them. The remainder of
the metallic oxides carried by the gases are precipitated therefrom by bringing
them in contact with water or other suitable liquids in suitable chambers or
vessels. In this process sulphates are produced by the combination of the oxides
and the sulphurous acid contained in the gases, together with air.
Various forms of apparatus for operating as described may be employed; the
accompanying drawing is a vertical section of one form, given by way of example.
From a hopper a the finely subdivided ore descends in a broad thin stream b
while a current of heated air supplied by a flue c is directed on the stream
deflecting it towards the outlet g. At the zone 1 sulphurous acid is formed and
oxides of the non volatile metals which fall on the sloping floor e whence they
can from time to time be removed by opening the door h. In the zone 2 the
volatile metals separated from the sulphur exist in a state of vapour, which
becomes oxidised in the zone 3, some of the oxides falling into the chamber f
whilst some pass with the fumes through the outlet g leading to chambers or
flues in which they are collected in the usual way.

page_text: Having now particularly described and ascertained the nature of this
invention and in what manner the same is to be performed, we declare that what
we claim is:
Process for roasting mixed sulphide ores, wherein the finely divided mixed
ores are fed into a combustion chamber supplied with previously heated air, a
portion of the produced oxides being thereby made to pass off with the furnace
gases from the combustion chamber, in order to be collected in chambers or
receptacles separately from the oxides that are precipitated in the combustion
chamber, substantially as described.
Dated this 15th da
1000
ABEL & IMRAY,
Agents for the Applicants.