Improvements in the Reduction of Ores.
Year: 1890

page_text: Date of Application, 25th Nov., 1890-Accepted, 27th Dec., 1890
COMPLETE SPECIFICATION.
Improvements in the Reduction of Ores.
We, HOBACE WORTH LASH and JAMES JOHNSON, Metallurgists, residing at
Pittsburgh, in the County of Allegheny, State of Pennsylvania, and United States of
America, 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:-
The invention described herein relates to certain improvements in the production of
wash or carburized metal, and steel or wrought iron direct from ore. According to
the present practice this wash or carburized metal is reduced in the blast furnace, a
very effective apparatus, but expensive in construction and operation. The object of
this invention is to provide for the production of this class or kind of metal direct
from the ore in an ordinary cupola furnace.
In the practice of our invention ore and carbonaceous material such as coke, coal,
charcoal, etc., are ground up separately to a comparatively fine state of division. The
ground ore and carbonaceous material are then thoroughly mixed together and then
placed in a grinding pan or other suitable mill and subjected to a further grinding
operation. The percentage of carbonaceous material employed depends upon the degree
of carburization required in the metal to be produced, and varies from thirty to fifty
per cent. (30% to 50%) more or less, by weight of the ore, that is to say, thirty to
fifty pounds, more or less, of carbonaceous material for every hundred pounds of ore.
During the grinding of the ore and carbonaceous material together sufficient liquid
such as water or oil is added in sufficient quantity to form a comparatively thick self-
adherent paste or amalgam, and the grinding is continued until the materials are
pulverized and thoroughly ground into each other, so as to ensure in the subsequent
treatment of the amalgam, an equal and simultaneous heating of adjacent particles,
thereby preventing the combustion of the carbon before the ore has been sufficiently
heated to readily part with its oxygen.
In reducing this material, the cupola or like furnace is charged with lump coke or
other suitable fuel, to a height of twenty to twenty-four inches, more or less, above
the tuyeres, and the blast turned on until the coke has been raised to a state of
incandescence, forming a hot bottom for the subsequent charge. A fresh layer of
coke is then thrown in, and the pasty amalgam hereinbefore described as it comes
from the grinding pan, is loosely shovelled in on the charge. In charging the
amalgam, one shovelful of fuel, such as coke or charcoal is thrown in to about every
four shovelfuls, more or less, of amalgam, or sufficient to bear the burden and prevent
the amalgam from packing down and clogging the furnace. The amalgam and fuel
are charged in alternately as described until the mass rises to the furnace door. In
about fifteen minutes after charging, the blast being continued, the metal will
commence to come down and the charge gradually sink. From this stage, the process
is a continuous one, the ore being reduced and the molten metal tapped off as often as
necessary to prevent it from entering the tuyeres, and fresh amalgam and fuel being
shoveled in as the charge sinks down. As soon as the reduction is fairly under way,
the cupola will make as fast as two men can attend to the charging. The fuel added
not only serves to keep up the requisite heat, and prevent the clogging as before
stated, but also aids in the carburization of the metal. If desired, a flux, as
limestone, etc., may be added to the material during the preparation of the amalgam,
as hereinbefore described, the percentage of the flux to be added being determined by
the amount of silica to be reduced, and of sulphur to be overcome. Or, if preferred,
the flux may be charged with other materials into the cupola.
The molten metal may be charged by means of a ladle, or by a runner or spout
direct into an open hearth furnace, or other converting apparatus, and there used, as a

page_text: highly carburized molten bath, for the manufacture of steel, thus avoiding the great wear
and tear on an expensive furnace, incident to the usual method of melting the metal
for the bath in said furnace. And this method of charging molten metal direct into
the open hearth furnace, effects a great saving in time and consequently in out-put, as
one charge is being melted, while another is in process of reduction. Or the
carburized molten metal may be run into a puddling furnace and there worked in
the usual manner, or it may be run into pig-beds, as in the usual blast furnace
practice.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what
we claim is:
1. As an improvement in the art of producing metal direct from ore, the method
herein described, which consists in reducing the ore and carbonaceous material to a
pasty homogeneous amalgam, and then charging such amalgam and a carbonaceous
fuel into a cupola furnace, substantially as set forth.
2. As an improvement in the art of producing metal direct from ore, the method
herein described, which consists in reducing the ore, carbonaceous material and a flux
to a pasty homogeneous amalgam, and then charging such amalgam and a carbonaceous
fuel into the cupola furnace, substantially as set forth.
3. As an improvement in the art of reducing metal direct from ore, the method
herein described, which consists in reducing the ore, carbonaceous material and flux
to a pasty homogeneous amalgam, charging such amalgam and a carbonaceous fuel
into a cupola furnace, charging the reduced molten metal direct into a converting
furnace, and there treating the metal in the usual manner, substantially as set forth.
Signed at Pittsburgh. Pa.. U.S.A.. this Seventh day of October. A.D. 1890.
Witnesses,
DARWIN S. WOLCOTT.
R. H. WHITTLESEY.
HORACE WORTH LASH.
JAMES JOHNSON.