Improvements relating to the Treatment of Blast Furnace Slag for the Manufacture therefrom of Hydraulic or similar Cement.
Year: 1887

page_text: Improvements relating to the Treatment of Blast Furnace Slag for
the Manufacture therefrom of Hydraulic or similar Cement.
I, THOMAS CHARLES HUTCHINSON, of Loftus Hall, Loftus, in the County of York,
Ironmaster, do hereby declare the nature of this invention to be as follows:-
My Invention relates to the treatment of Blast Furnace slag or scoria to be used
in the manufacture of bydraulic or similar cement, and has for its objects to effect
economy in the process of disintegrating the slag and. to improve the quality of
the slag sand by a more perfect elimination therefrom of the moisture absorbed
during immersion in water.
The ordinary process employed for disintegrating the slag or scoria of a Blast
Furnace is to plunge the slag or scoria as it flows from the furnace into water, from
which it is removed when cool and is afterwards exposed to heat to expel the moisture
absorbed during the immersion.
In carrying out my invention I take the slag from the Blast Furnace when
yielding it in a suitable condition, as for instance, when the furnace is burdened for
foundry iron, and immerse the slag in the hot state into water contained in a bosh or
other suitable vessel placed immediately below the slag runner, the size of the bosh or
vessel and its design or shape being varied as required to accomodate the stream of
slag supplied to it, the object being to cause the slag to flow with moderate force into
the bosh or other vessel so as to sink only a few inches into the water. The action of
the gases thereby liberated from the slag causes it to rise to the surface of the water
and float as a spongy or viscuous mass.
At this stage I lift the slag in a red hot state from the surface of the water by
means of a close grained gripe or shovel, or other suitable means, so that the slag
is thoroughly disintegrated by the action of a much smaller quantity of water than
that absorbed when the slag is left to cool in the water; added to which the moisture

page_text: is almost entirely expelled from the slag by the action of the initial heat retained in
the slag when removed from the water, and a slag sand of higher quality for the
manufacture of cement is produced by the ordinary operation of grinding under edge
runners or stones.
In some cases I accelerate the process of drying the disintegrated slag by removing
it from the water bosh to a drying kiln with air driven or drawn through it under
pressure and the air may be raised to a high temperature by hot blast stoves or other
means.

page_text: Improvements relating to the-Treatment of Blast Furnace Slag for
the Manufacture therefrom of Hydraulic or similar Cement.
I, THOMAS CHARLES HUTCHINSON, of Hilda House, Middlesbrough-on-Tees, in the
County of York, late of Loftus Hall, Loftus, in the same County, Ironmaster, 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:-
My Invention relates to the treatment of blast furnace slag or scoria of the kind
suitable to be used in the manufacture of hydraulic or similar cement, and has reference
to the process in which the disintegration is effected by immersion in water; the
objects in view being to effect economy in the process of disintegrating the slag, and
in the subsequent operation of expelling the moisture therefrom, and to obtain slag
sand of improved quality and more easily ground by the more perfect disintegration
of the slag.
In the ordinary process in use for disintegrating blast furnace slag by immersion
in water, the slag or scoria as it flows from the furnace is plunged into water with
sufficient force to sink below the surface to a depth at which it remains until cool, the
disintegration of the slag being effected by the action of the water which is absorbed
by the slag in large quantities, and is subsequently expelled by the application of
heat.
In carrying out my invention I take the slag from the blast furnace when yielding it in
the condition which is known to be suitable for the purpose, as for instance when
burdened with foundry iron by preference of No. 3 quality, and immerse, the slag
as it flows from the furnace in the hot state into water provided in a bosh or
other suitable vessel of any suitable design or shape, a bosh of 3 feet square and
18 inches deep being of sufficient capacity for the treatment of one stream of slag.
Instead of the slag being allowed to plunge into the water with a sufficient force to
sink to a depth at which it remains permanently below the surface according to
the process at present in use, I adjust the level of the surface of the water
according to the volumn of slag running into it so that the slag flows gently into
the water and sinks to a depth no greater than is sufficient to liberate the gases
generated by the hot slag coming in contact with the water, which in effecting
their escape cause the slag to rise to the surface of the water where it floats as a spongy and
viscuous mass of greatly increased bulk. At this stage and before the initial heat is
expended therefrom 1 lift the slag from the surface of the water by means of a
close grained gripe or shovel or other suitable means. By this mode of treatment
the slag is more perfectly disintegrated by the action of steam generated within the
pores or cells of the slag from water absorbed during immersion, with the result that
much less water is absorbed by the slag than when allowed to cool under water,
and consequently great economy is effected in the subsequent operation of expelling

page_text: the moisture from the slag and also in the grinding it to sand, which operation is
also accelerated by the action of the initial heat remaining in the slag at the time
of removal from the water. The process of expelling the moisture from the slag may
be completed by the application of heat according to the methods at present in use, or
in substitution of the usual methods of drying the disintegrated slag I avail myself of
the more porous and attenuated condition of the slag when disintegrated by my
improved process to complete the operation of expelling the moisture therefrom by
the application of air raised to. a high temperature by hot blast stoves or other
means which is passed through a drying kiln containing the slag. After the. slag is
dried it is reduced to slag sand of the requisite degree of fineness by edge runners or
other well known means.
Having now described the nature of my invention and in what way the same may
be carried into effect, what I claim is :-
•
Firstly The process for treating blast furnace slag or scoria to be used in the
manufacture of cement in which the slag is immersed in water so as to float to
the surface thereof and is removed therefrom before the initial heat is expended,
substantially as and for the purpose as herein before described.
メー
Secondly The means employed for drying the slag after immersion by the appli-
cation of air raised to a great temperature in combination with the initial heat of
the slag, substantially as and for the purpose as hercinbefore described.
Datad this 2nd day of July