IMPROVEMENTS IN THE MANUFACTURE OF BRICKS USED FOR BUILDING AND OTHER PURPOSES
Year: 1868

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at
the Office of the Commissioners of Patents, with his Petition, on
the 11th June 1868.-A communication from abroad by François
Fabre, Master Builder, of 13, Boulevart St. Martin, Paris.
I, ALEXANDER MELVILLE CLARK, of 53, Ohancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF BRICKS
USED FOR BUILDING AND OTHER PURPOSES," to be as follows:-
This Invention relates to improvements in the manufacture of bricks
or slabs suited to building purposes from the dross of blast furnaces
combined with hydraulic and other limes, cements, or plaster. Hitherto
all attempts to utilize the dross of blast furnaces for this purpose have
failed either from the defective nature of the products obtained or the
great expense incurred in producing good materials.
This Invention consists in a mode of reducing the dross to a fine
granular condition by plunging it into water while still in fusion and
incandescent, by which means the dross is reduced to a fine sand suited
to the purpose required. When the dross is removed from the cold
water in which it is immersed it presents a spongy appearance, is

page_text: very light, and has a rough and irregular form or appearance. The
sand so obtained I proceed to agglomerate with a small proportion of
hydraulic lime under the action of considerable pressure. Good results
are also obtainable even when inferior qualities of lime are employed.
I would here observe that the products obtained in the manner herein
described entirely differ from those made by the agglomeration of scoria
and scale with hydraulic lime, which are wanting in homogeneousness
and possess little durability, as they contain much earthy and even
calcareous matters which under the action of water soon cause the bricks
or paving tiles to crumble to pieces. By the mode, however, above
described of previously immersing the dross in water it is consequently
purified of all extraneous or liquefiable matters, which also increase its
weight. In this manner the sand produced is much lightened, is very
friable and easily compressed, and being intimately mixed with hydraulic
lime the agglomeration is readily effected.
The following is the method of manufacture:-The dross having been
converted into a coarse sand in the manner herein-before described and
while still wet, on leaving the troughs is immediately mixed with
hydraulic lime, the proportion of which varies according to the greater
or less hardness and impermeability to be imparted to the bricks or
slabs. I may however add that the proportions may be considerably
reduced for products of secondary quality without injuriously affecting
the agglomeration. The mixture of the sand and lime may be effected
either by hand or preferably in an ordinary mixing machine such as is
used for making motar, and after the materials have been sufficiently
mixed they are introduced into moulds of the form and dimensions
desired and subjected to a high pressure in any suitable manner in order
to produce bricks or slabs which on leaving the moulds are stacked for
the purpose of drying. The bricks in a few days' time acquire great
hardness, are as sound as those made of burnt clay, present a perfectly
homogeneous appearance when broken, possess great strength to resist
pressure, and are essentially impervious to moisture. These bricks may
further be readily shaped with a hammer, and
advantage for building purposes of being exceedingly light and also of
readily adhering to mortar, plaster, or cement.
possess the great