IMPROVEMENTS IN THE MANUFACTURE OF CASTINGS FROM FURNACE SLAG
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I, HERBERT JOHN HADDAN, of the firm of Herbert and Company, Patent
Agents, of 67, Strand, in the City of Westminster, Civil Engineer, do hereby
declare the nature of said Invention for "IMPROVEMENTS IN THE MANUFACTURE
OF CASTINGS FROM FURNACE SLAG," a communication to me from abroad by Louis
Perin; of St Amand; France, to be as follows:-
This invention has for its object the devitrification of castings produced from
blast-furnace slag.
For this purpose the moulds representing the shape of the article to be cast are
filled with slag when leaving the blast furnace and are also completely covered
with or embedded into the molten slag.
This mass is then allowed to cool slowly, in order to remove the vitreous and
amorphous condition and obtain a crystalline texture which renders the product
similar to sandstone as regards appearance and hardness.
In order to retain the heat longer, the surface of the slag may be covered with
ashes.
In order to avoid the adhesion of the slag to the inside or outside of the mould,
the latter is coated with slip, and the mould is finally detached from the slag by
means of a hammer.
The moulds are preferably made of wrought or cast iron, but may be made of
otber materials capable of resisting high temperatures.
The improved process may be employed for casting pavement blocks, base plates
or stands for iron masts or posts, the said masts or posts being provided with holes
or notches and placed in the mould before the slag is allowed to run into the same,
so that after casting, the mast or post will be found firmly embedded into the slag.
Dated this 14th day of May 1884.

page_text: COMPLETE SPECIFICATION.
I, HERBERT JOHN HADDAN, of the firm of Herbert and Company, Patent
Agents, of 67, Strand, in the City of Westminster, Civil Engineer, do hereby
declare the nature of said Invention for IMPROVEMENTS IN THE MANUFACTURE OF
CASTINGS FROM FURNACE SLAG," a communication to me from abroad by Louis
Perin, of St. Amand, France, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement :-
This invention has for its object to obtain from furnace slag castings having the
texture of stone.
The improved process is performed as follows:
Moulds of suitable shape are filled with the slag direct from the blast furnace,
and are sunk in an excess of this material, which completely surrounds them.
The mass is allowed to cool slowly, which causes the vitreous and amorphous
slag to assume a crystalline and compact texture, making it rival the best stone-
ware in appearance and hardness.
The surface of the slag is covered with cinders, in order to retain the heat
longer.
To prevent the slag from adhering to the interior or exterior of the moulds, the
latter are smeared over with a coating of sandy clay, known under the name of
slip-slop, and a blow of the hammer suffices to separate the moulds from the
moulded objects and the surrounding mass which has served to maintain the heat
round the moulds.
The moulds are preferably made of cast iron, but may be made of any other
material possessing sufficient resistance, and capable of supporting a high degree of
temperature.
Uses of stony slag-
Castings of stony slag will serve for any purposes, for which the material is
suitable, for instance as paving-blocks, footings of fencing-posts, palisading of all
kinds. As this slag is very suitable for imbedding iron, it is only necessary to
imbed Tiron, pierced with a few holes, in the footing, when hot, in order to obtain
at little cost the well known fencing-post, the footings of which are made at present
of compressed concrete.
This post is illustrated in the annexed drawing by Figs. 1 to 5, while Figs 6 to 11
show two kinds of paving-blocks.
Fig. 6 is an elevation of a paving block.
Fig. 7. plan of Fig. 6.
Fig. 8. plan of another kind of paving block.
Fig. 9. Elevation of a paving block.
Fig. 10. Plan of Fig. 9.
11 Dlan South

page_text: Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is
The method of casting and devitrifying furnace slag, substantially as and for the
purposes described.