IMPROVEMENTS IN THE PROCESS FOR TREATING ZINC-ORES
Year: 1883

page_text: LETTERS PATENT to Friedrich Carl Glaser, of Berlin, in the Kingdom of
"
Prussia and Empire of Germany, Engineer and Patent Solicitor, for an
Invention of "IMPROVEMENTS IN THE PROCESS FOR TREATING ZINC-ORES
communicated to him by the firm of G. v. Kramsta'sche Erben and Rudolf
PROVISIONAL SPECIFICATION left by the said Friedrich Carl Glaser at
the Office of the Commissioners of Patents on the 28th December 1883.
FRIEDRICH CARL GLASER, of Berlin, in the Kingdom of Prussia, and Empire of
Germany, Engineer and Patent Solicitor, "IMPROVEMENTS IN THE PROCESS FOR
TREATING ZINC ORES" A. Communication to me by the Firm of G. v. Kramsta'sche
Erben and Rudolf Wiester both residing at Kattowitz in the Kingdom of Prussia
and German Empire
The method at present in vogue of smelting zinc ores in the cupola furnace
requires such a large expenditure of fuel that in the case of ores poor in zinc
Sinelting appears to be no longer profitable. By means of the process hereinafter
described a considerably smaller consumption of fuel is arrived at and through
limiting the use of the refractory distilling vessels the result of the smelting
operation is generally more advantageous, especially as regards the more perfect
extraction of the zinc contained in the ores, and thus the smelting of poor ores
which is unprofitable by the present methods, is rendered practicable.
This improved process is carried out substantially as follows:-
The zinc ores-oxide ores such as calamine, silicious zinc ore, franklinite, or
roasted zinc blende are mixed with the necessary quantity of reducing material,
coke for example, arranged in a cupola like shaft furnace and there subjected to a
temperature raised to a white glowing heat until the escape of zinc vapours from
the heap ceases and the residues are wholly, or it may be only to a relatively
small extent, freed from zinc. The zinc vapors generated in the furnace burn
again to oxide immediately as they are evolved upon contact with the
atmospheric air.
A furnace of this kind is shewn in the accompanying Drawing by way of
example.

page_text: It consists of a furnace shaft A, which is closed by floor plates B, B, provided
with counter weights and turning on their axes. These floor plates are protected
from injury by the heat by means of a layer of sand. The side walls of the
furnace, which are of refractory material, are pierced with one or more rows of
openings serving as nozzles or tuyeres through which air, either cold or heated, is
supplied to the furnace. Apertures may be provided in the upper part of the
furnace through which to observe the evolved zinc flames, these being carried off
through the passage C. The furnace is erected either on arches or on iron columns
so that iron trucks may be brought underneath it for the reception after the
process is finished of the residues which are caused to fall down by opening the
floor plates.
As before stated the formed zinc oxide escapes with the gases of combustion
through the passage C and is carried through a passage in connection with the tuyeres
to dust chambers the capacity of which is sufficient so to retard the outflowing
gases that the zinc oxide has time and opportunity to fall down and collect on the
floors of the chambers. For the more ready clearing out of the chambers it is
advisable that their floors should consist of a system of hoppers through the
openings of which the oxide obtained may be removed

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Friedrich Carl Glaser in the Patent Office on the 10th June 1884.
FRIEDRICH CARL GLASER of Berlin in the Kingdom of Prussia and Empire of
Germany, Engineer and Patent Solicitor, "IMPROVEMENTS IN THE PROCESS For
TREATING ZINC ORES" A Communication to me by the firm of G. v. Kramsta'sche
Erben and Rudolf Wiester both residing at Kattowitz in the Kingdom of Prussia
and German Empire
The method at present in vogue of smelting zinc ores in the cupola furnace
requires such a large expenditure of fuel that in the case of ores poor in zinc
smelting appears to be no longer profitable. By means of the process hereinafter
described a considerably smaller consumption of fuel is arrived at, and, through
limiting the use of the refractory distilling vessels, the result of the smelting
operation is generally more advantageous, especially as regards the more perfect
extraction of the zinc contained in the ores, and thus the smelting of poor ores,
which is unprofitable by the present methods, is rendered practicable.
This improved process is carried out substantially as follows :--
The zinc ores-oxide ores such as Calamine, Silicious Zinc Ore, Franklinite, or
roasted Zinc Blende-are mixed with the necessary quantity of reducing material,
coke for example, arranged in a cupola like shaft furnace and there subjected to
a temperature raised to a white glowing heat until the escape of zinc vapours
from the heap ceases and the residues are wholly, or it may be only to a relatively
small extent, freed from zinc. The zinc vapours generated in the furnace
burn again to oxide immediately as they are evolved upon contact with the
atmospheric air.
A furnace of this kind is shewn in the accompanying Drawing by way of
example.
It consists of a furnace shaft A, which is closed by floor plates B, B, provided
with counterweights and turning on their axes. These floor plates are protected
from injury by the heat by means of a layer of sand. The side walls of the
furnace, which are of refractory material, are pierced with one or more rows of
openings serving as nozzles or tuyeres, through which air, either cold or heated, is
supplied to the furnace. Apertures may be provided in the upper part of the
furnace through which to observe the evolved zinc flames, these being carried off
through the passage C. The furnace is erected either on arches or on iron columns,
so that iron trucks may be brought underneath it for the reception, after the
process is finished, of the residues which are caused to fall down by opening the
floor plates.
As before stated, the formed zinc oxide escapes with the gases of combustion
through the passage C, and is carried through a passage in connection with the
tuyeres to dust chambers, the capacity of which is sufficient so to retard the
outflowing gases that the zinc oxide has time and opportunity to fall down and
collect on the floors of the chambers. For the more ready cleaning out of the
chambers it is advisable that their floors should consist of a system of hoppers
through the openings of which the oxide obtained may be removed.
Having now described and ascertained the nature of the invention communi-
cated to me as aforesaid and in what manner the same is or may be performed
I Claim as secured to me by the hereinbefore in part recited Letters Patent :-
The process for reducing zinc ores, especially Calamine, Silicious Ore, Franklinite,
as also Zinc Blende, under mixture with reducing material in a shaft furnace
constructed in the form of a cupola furnace of circular or oval cross section, which
•

page_text: is fed through a number of nozzles, arranged at one or different heights, with
compressed cold or hot air, and then intercepting, in suitable chambers, the zinc
oxide immediately resulting from the zinc vapours upon contact with the
atmospheric air substantially as hereinbefore described.
In Witness whereof I the said Friedrich Carl Glaser have hereunto set my
hand and Seal this twenty sixth day of May in the year of Our Lord One thousand
Eight hundred and Eighty four.
FRIEDRICH CARL GLASER (L.S.)