AN IMPROVED METHOD OF TREATING FLUID SLAG FROM IRON ORE SMELTING OR SO CALLED BLAST FURNACES
Year: 1881

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for an Invention of "AN IMPROVED
METHOD OF TREATING FLUID SLAG FROM IRON ORE SMELTING OR SO CALLED
BLAST FURNACES." A communication from abroad by Alexander Daniel
Elbers, of Hoboken, in the State of New Jersey, United States of America.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 12th July 1881.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "AN IMPROVED METHOD OF TREATING FLUID SLAG
FROM IRON ORE SMELTING OR SO CALLED BLAST FURNACES." [A communication
from abroad by Alexander Daniel Elbers, of Hoboken, in the State of New Jersey,
United States of America.]
This Invention has for its main object the rapid and cheap conversion of fluid
slag and its solidification into such shapes as to materially increase its utilization.
Slag from the modern large furnaces at which the Invention could be carried out
to greatest advantage generally contains rather less than more than forty per cent.
of silica, its glassy or vitreous character is therefore not so pronounced as to ensure
after solidification under ordinary treatment such a state of vitrifaction and com-
pactness as may be desirable. As slag is neither a compound especially concocted
with a view to its ultimate form or usefulness, nor of sufficient value to allow of
expensive treatment, such as reheating and annealing, its conversion into rather
primitive but still sufficiently uniform and suitable products for the utilization of
large masses has to contend with the disturbing influences well known to all metal
founders, almost simultaneous shrinkage of the still liquid and irregular contraction
in cooling of the solidified parts. Usually the slag is allowed to run from the
furnace through gutters or along a chute, and as it runs on the ground into furrows
it becomes quickly chilled on the surface, while from under the still liquid slag
runs onward and breaks out in new streams, which in their turn become crusted
over, or it is run into tubs or cars, allowed to cool therein, and then dumped on the
cinder banks.

page_text: In either case the slag is liable to solidify into irregular honey combed crumbling
pieces which disintegrate under exposure, and if used on road beds occasion con-
siderable dust; at best it assumes a somewhat denser and stone like appearance,
but even then has little strength or solidity. Aside from the influences of shrinkage
and contraction afore mentioned, these conditions are also owing to disturbances of
vitrifaction on account of the heat which is sent forth from the underlying and still
liquid mass to the already solidified portion above it, because the same quality of
slag may be made nearly as hard as flint glass if it is suddenly chilled in small
particles, as, for instance, the highly vitrified globules which are formed during the
conversion of the liquid slag into so. called mineral wool.
By this improved method and apparatus the action of the liquid on the solidifying
and solid parts is nearly reversed, as I will now proceed to explain.
The apparatus consists of an annular trough or gutter of suitable width and size
sustained by hangers from spider arms that are sustained on a post and fitted for
revolution by any suitable mechanism. I allow the fluid slag to spread swiftly in
the revolving gutter, which by preference is made in adjustable sections and of iron
or steel plates, into which it flows by a spout which by preference is made movable
so as to direct the course of the flow.
The apparatus to which the gutter is fastened in any convenient manner is best
constructed in the form of a so called carousal which can be quickly turned even
by hand power, and the necessary size of the apparatus depends on the quantity of
slag which is to be run into the gutter. After the apparatus is set in motion the
first layer of the slag as it flows from the trough into the revolving gutter will
almost instantly become chilled by contact cooling with the bottom and sides of
the gutter, while the subsequent layers have to be mainly solidified by the rapid
air circulation on their surface. As the liquid slag unites or welds readily with
the underlying already solidified but still very hot slag, a satisfactory weld of all
the layers as they accrue during rotation (the hotter strata always on top) is to be
expected, as well as a comparatively uniform contraction of the united mass.
material thus obtained by this new method is apt to be dense, comparatively proof
against disintegration, similar in tenacity and compactness to hard baked stoneware
or pottery, more or less vitrified, and of glazed appearance where it has been in
contact with the gutter surface or facings.
The
As to its utilisation, one of its most extensive applications may be for railroad
ballast under and between ties; if it is cast into the shape of gutters or troughs
these may be used in culverts and in underground telegraph and steam heating
constructions. As a material for jetties, dams, and similar work where the filling
in of a large volume at a minimum weight may be desirable, the slag can be run
in small streams into the rapidly revolving gutter so as to form fascicular bulky
masses of irregularly shaped threads highly vitrified, which may also be used for
filtering beds in water reservoirs, &c. The shape of the material may therefore be
that of solid blocks, of slabs, sticks, hollows, or of any other forms which can be
obtained in the revolving gutter by indentations, projections, and other well known
contrivances which are used in casting and removing casts. The gutter itself may
consist of different and many pieces which may be put together or taken out as
occasion may require; or several gutters alongside of each other or arranged in such
a manner in the circumference of the apparatus as to receive the slag from a
movable trough or from other channels may be provided without affecting the
result otherwise than in degree.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the
12th January 1882.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "AN IMPROVED METHOD OF TREATING FLUID SLAG
FROM IRON ORE SMELTING OR SO CALLED BLAST FURNACES." A communication
from abroad by Alexander Daniel Elbers, of Hoboken, in the State of New Jersey,
United States of America.
This Invention has for its main object the rapid and cheap conversion of fluid
slag and its solidification into such shapes as to materially increase its utilisation.
Slag from the modern large furnaces at which this Invention could be carried out
to greatest advantage generally contains rather less than more than 40 per cent. of
silica, its glassy or vitreous character is therefore not so pronounced as to ensure
after solidification under ordinary treatment such a state of vitrifaction and com-
pactness as may be desirable, and as slag is not of sufficient value to allow of
expensive treatment, such as reheating and annealing, its conversion into rather
primitive but still sufficiently uniform and suitable products for the utilisation of
large masses has to contend with the disturbing influences well known to all metal
founders, as hereinafter described. Usually the slag is allowed to run from the
furnace through gutters or along a chute on the ground into furrows; it becomes
quickly chilled on the surface, while from under the still liquid slag runs onward
and breaks out in new streams which in their turn become crusted over until the
flowing supply becomes exhausted, when also the cores of the slag streams solidify.
As slag yields its heat very readily or chills quickly, the irregular contraction in
cooling of the already solidified crust, while the core of the piece is still changing
from liquid to solid, is apt to cause tension or strain in and give irregular or hap-
hazard shape to the slag, and that hardness and vitrifaction which can be obtained.
by sudden cooling are lessened by the radiation or conduction of heat from the
underlying and still liquid mass to the already solidified portion above it, because
the same quality of slag may be made nearly as hard as flint glass if it is suddenly
chilled in small particles, as, for instance, the highly vitrified globules which are
formed during the conversion of liquid slag into so called silicate cotton or slag
wool.
By the improved method of this Invention the action of the liquid on the
solidifying and solid parts is nearly reversed, as I will now proceed to explain.
In the accompanying Drawings Figure 1 is a side elevation; Figure 2, a vertical
section; and Figure 3, a horizontal section of an apparatus suitable for carrying out
the Invention. Similar letters of reference indicate corresponding parts.
A is an annular trough or gutter of suitable width and size sustained by hangers a
from spider arms b that are sustained on a post c and fitted for revolution by any
suitable mechanism; d is a spout for supply of slag to trough A.
I allow the fluid slag to spread swiftly in the revolving gutter A, which by
preference is made in adjustable sections and of iron or steel plates, into which it
flows by a spout d which by preferènce is made movable so as to direct the course
of the flow.
The apparatus to which the gutter A is fastened in any convenient manner is
best constructed in the form of a so called "carrousel" which can be quickly
turned even by hand power, and the necessary size of. the apparatus depends on
the quantity of slag which is to be run into the gutter A. After the apparatus is
set in motion the first layer of the slag as it flows from the trough d into the
revolving gutter A will almost instantly become chilled by contact cooling with

page_text: the bottom and sides of the gutter, while the subsequent layers have to be mainly
solidified by the rapid air circulation on their surface. As the liquid slag unites or
welds readily with the underlying already solidified but still very hot slag, a
satisfactory weld of all the layers as they accrue during rotation (the hotter strata
always on top) is to be expected, as well as a comparatively uniform contraction of
the united mass.
The material thus, obtained by this method is dense, comparatively proof against
disintegration, similar in tenacity and compactness to hard baked stoneware or
pottery, more or less vitrified, and of glazed appearance where it has been in
contact with the gutter surface or facings. As to its utilisation, one of its most
extensive applications may be for railroad ballast under and between ties; if it is
cast into the shape of gutters or troughs, these may be used in culverts and in
underground telegraph and steam heating constructions. As a material for jetties,
dams, and similar work where the filling in of a large volume at a minimum weight
may be desirable, the slag can be run in small streams into the rapidly revolving
gutter so as to form fascicular bulky masses of irregularly shaped threads highly
vitrified, which may also be used for filtering beds in water reservoirs, &c. The
shape of the material may therefore be that of solid blocks, of slabs, sticks, hollows,
or of any forms which can be obtained in the revolving gutter by indentations,
projections, and other well known contrivances which are used in casting and in
removing casts. The slag may while accumulating in the gutter be subjected to
the action of steam, water, or air blasts, or granulated slag, ashes, or other materials
may be allowed to run into the revolving gutter so as to mix with the liquid slag,
and thereby form conglomerate products. The gutter itself may consist of
different and many pieces which may be put together or taken out as occasion may
require, and instead of being fastened to a carrousel or revolving spider the gutter
may be placed on a turn table, or several gutters alongside of each other (or
arranged in such manner in the circumference of the apparatus as to receive the
slag from a movable trough or from other channels) may be provided without
affecting the result otherwise than in degree.
I
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein before in part recited Letters Patent is,-
The hereinbefore described method of treating liquid slag, which consists in
casting it in cumulative layers, substantially as specified.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my band and seal, this Fifth day of January, A.D. 1882.
A. M. CLARK. (L.S.)