Improvements in the Utilization of Slag for the Manufacture of Blooks, Slabs, Drain Pipes, or other Moulded Articles.
Year: 1891

page_text: Date of Application, 28th Oct., 1891
Complete Specification Left, 28th July, 1892-Accepted, 3rd Sept., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Utilization of Slag for the Manufacture of
Blooks, Slabs, Drain Pipes, or other Moulded Articles.
I, THOMAS ARNOLD, of 1, Stanley Terrace, West Hartlepool, in the County of
Durham, Cement Expert, do hereby declare the nature of this invention to be as
follows:-
My invention relates to the utilization of slag, such as the ordinary or slag
scoria obtained from blast-furnaces, and consists in reducing it to powder with an
admixture of Portland cement from which to manufacture paving blocks or slabs,
building blocks, drain pipes, garden edgings or the like articles which are usually
moulded to shape and afterwards brought to the requisite degree of hardness and
tenacity by some drying or setting process.
The object of my invention is to utilize blast-furnace slag which is obtainable in
unlimited quantities and at a small cost in the vicinity of blast-furnaces by manu-
facturing blocks, slabs, or the like articles in which this slag forms the principal
ingredient.
The following is a description of the nature of my invention.
The slag is first reduced to a state of powder and then powdered cement is added
thereto, or the slag and cement clinkers may be all ground together, this mixture
is then made to take its intended form, which may be that of a paving or building
block, a drain pipe or other mouldable article by being charged into moulds
designed for this purpose and subjected to great pressure. By exposure to the
atmosphere sufficient moisture is subsequently absorbed into the mixture to cause it
to set hard in the form to which it is moulded or it will set more readily by immersion
in water or in a silicate bath.
Where the slabs or blocks are exposed to much surface friction such as from
the feet of horses and transit of cart wheels, an extra hard surface can be
formed thereon by covering the mixture over with a layer of neat cement, say
inch in thickness before the pressure is applied in the process of moulding it
to its intended form.
Any suitable machinery or appliances may be used for reducing the slag to
the condition of powder, and for obtaining a proper mixture of slag and cement
as well as for discharging the ingredients into moulds, and applying the requisite
pressure thereto.
Dated this 27th day of October 1001
G. J. CLARKSON,
Stockton-on-Tees, Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Utilization of Slag for the Manufacture of
Blocks, Slabs, Drain Pipes, or other Moulded Articles.
I, THOMAS ARNOLD, of 1, Stanley Terrace, West Hartlepool, in the County of
Durham, Cement Expert, 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 utilization of slag such as the ordinary or slag scoria
obtained from blast furnaces, and consists in reducing it to powder with an
admixture of Portland cement from which to manufacture paving blocks or slabs,
877

page_text: building blocks, drain pipes, garden edgings, or the like articles which are usually
moulded to shape and afterwards brought to the requisite degree of hardness and
tenacity by some drying or setting process.
The object of my invention is to utilize blast furnace slag which is obtainable in
pratically unlimited quantities and at a small cost in the vicinity of blast furnaces
by manufacturing blocks, slabs, or the like mouldable articles in which this slag
forms the principal ingredient.
The following is a description of the nature of my invention and the manner
in which it is carried into effect. The slag is first reduced to powder which may
be done by passing it through crushers and then grinding it between ordinary
mill-stones. The cement to be mixed with it may then be added in the powdered
state, or cement clinkers may be mixed with the slag and all crushed and ground
up together. The amount of cement to be added to the slag varies according to
the proportion of lime present in the slag, as for instance, slags which contain a
high percentage of lime, such as the Cleveland slags, require a low percentage of
cement, and in cases where the slags contain 45 per cent. of lime an addition of
10 per cent. of cement is sufficient for the purposes of my invention. Slags from
the hematite and Spanish ores contain as low as 20 per cent. of lime and would
require an addition of 30 per cent. of cement. It will thus be seen that as the
utility of my invention depends mainly upon the small proportion of cement to be
added to consolidate the slag, my said invention can be more advantageously
applied to slags which are obtained from such ores as the Cleveland ores and which
are rich in lime than to slags obtained from hematite or Spanish ores which are
poor in lime. The mixture containing the requisite proportions of slag and cement
is made to take its intended form, which may be that of a paving or building block,
a drain pipe or other mouldable article, by being charged into moulds for this
purpose, which moulds may be constructed of wood, cast iron, or any suitable
material of sufficient toughness and rigidity to withstand the following process or
treatment of the mixture.
In order to obtain a hard and compact composition or material it is essential that
the mixture be thoroughly consolidated in the dry state; that is to say that the
particles should be brought together in the closest contact before water or moisture
is added, and any means which will conveniently effect this result may be employed
for the purposes of my invention, such as the application of intense pressure, or
what I prefer as equally effectual and generally more easily applied, that is to
subject each mould to a succession of blows or shocks until the mixture inside is
consolidated to a high state of density and usually corresponding to a reduction in
bulk of about 25 per cent. By exposure to the atmosphere sufficient moisture is
subsequently absorbed into the mixture to cause it to set hard in the form to which
it is moulded if sufficient time be allowed, but this result is accelerated by immersion
in water or in a silicate bath. As the means or machinery employed for applying
the succession of blows or shocks to the moulding boxes forms no part of this
invention, no detailed description of such machinery is necessary, and such machinery
can be readily designed, such for instance as by placing a series of moulds on a
hexagonal shaft, the rotary motion of which will impart to them a continuous
succession of shocks.
Where the slabs or blocks are exposed to much surface friction such as from
the feet of horses and transit of cart wheels, an extra hard surface can be formed
thereon by covering the mixture over with a layer of neat cement, say inch in
thickness before the pressure or shaking is applied in the process of consolidation,
and if desired the extra hard surface so formed may be moulded to a reticulated or
other pattern to roughen the surface.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
The manufacture of blocks, slabs, or the like mouldable articles by consolidating

page_text: a mixture of slag or blast furnace scoria with Portland cement, substantially in the
manner as herein before described.
1000
G. J. CLARKSON,
Stockton-on-Tees, Agent for the Applicant.
G. J. CLARKSON,
Stockton-on-Tees, Agent for the Applicant.