IMPROVEMENTS IN THE MANUFACTURE OF REFRACTORY BRICKS AND FUR- NACE LININGS
Year: 1879

page_text: LETTERS PATENT to Sidney Gilchrist Thomas, of 3, Queen's Road Villas,
Queen's Road, Battersea Park, in the County of Surrey, for the Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF REFRACTORY BRICKS AND FUR-
NACE LININGS."
Sealed the 18th April 1879, and dated the 22nd January 1879.
PROVISIONAL SPECIFICATION left by the said Sidney Gilchrist Thomas at
the Office of the Commissioners of Patents on the 22nd January 1879.
SIDNEY GILCHRIST THOMAS, of 3, Queen's Road Villas, Queen's Road, Battersea
Park, in the County of Surrey. "IMPROVEMENTS IN THE MANUFACTURE OF
REFRACTORY BRICKS AND FURNACE LININGS."
My Invention relates to the manufacture of improved basic linings and bricks,
especially suitable for use in iron and steel furnaces where it is desired to produce
calcareous basic slags. For this purpose I take lime (preferably that which has
been burnt at a high temperature) containing either a large amount of magnesia
and less than five per cent. of silica and alumina together, which I prefer, or if a
highly magnesian stone is not readily available, a less magnesian stone, or even a
non magnesian stone may be used, but in this case it is desirable to have a con-
siderable amount of silica and alumina present. I mix this lime with liquid tar so
as to moisten it and render it somewhat plastic. When the silica and alumina is low
a little oxide of iron may be mixed with the lime before adding the tar, the oxide of
iron acting as a binding material. I use these mixtures either to ram the interior
of converters or other iron and steel furnaces, particularly their bottoms, or I make
it into bricks and twyers under very great pressure. These bricks prefer to fire
at an intense and prolonged heat. I also use this mixture when made rather liquid
as a cement for calcareous bricks; crude creosote may be substituted for tar when
it is readily obtainable.
I also use a mixture of very bighly fired hard shrunk lime made from the silico
aluutinous magnesian limestones (such as described in my Specification, No. 908,
in the year 1878) with crude petroleum or similar cheap oils as a material to use

page_text: for rammed linings, particularly bottoms and hearths, and also to make bricks of.
In all cases when using this mixture of petroleum and highly fired shrunk lime I
expose the linings and bricks (after the linings are in position or the bricks made)
to a further very intense and prolonged firing. This mixture also may be used as
a cement for basic bricks
5
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Sidney Gilchrist Thomas in the Great Seal Patent Office on the 22nd
July 1879.
SIDNEY GILCHRIST THOMAS, of 3, Queen's Road Villas, Queen's Road, Battersea
Park, in the County of Surrey. "IMPROVEMENTS IN THE MANUFACTURE OF
REFRACTORY BRICKS AND FURNACE LININGS."
My Invention relates to the manufacture of bricks and furnace-linings from crude
petroleum, crude naptha, heavy tar-oil, and other cheap oils in combination with
the hard, very highly fired, shrunk lime produced by calcining alumino-silicious
dolomite, or equivalent artificial mixtures, as described in my Specifications Nos.
908 and 4063, and 3975 in the year 1878. For my present purpose I prefer the
use of limestone containing from three (3) to five (5) per cent. of silica and about
four (4) or five (5) per cent. of alumina and oxide of iron together, and over twenty-
seven (27) per cent. of carbonate of magnesia for burning to hard shrunk lime.
I consider five (5) per cent. of silica, alumina, and oxide of iron together to repre-
sent the minimum proportion which must be present in the unburnt material. The
limestone may be burnt preferably in pieces not more than three inches thick, in
any convenient kiln in which a white heat can be obtained. This white heat
should be maintained for at least 36 hours. A gas-furnace may be economically
used for the calcination, and a large quantity may be burnt at once. Any imperfect
bricks produced in the manufacture of my basic bricks, as described in my Specifi-
cations Nos. 4063 and 908, before referred to, may be also conveniently ground up
and utilised for the purpose of my present Invention.
I grind these hard lime blocks or bricks (not too finely) in a mortar-mill, with
enough crude petroleum, crude naptha, heavy tar-oil, or other similar cheap oil to
moisten the mass, less than ten (10) per cent. boing generally enough. I sometimes
mix with the oil a little tar or ground pitch to give greater plasticity. A mixture
of two-thirds (1) oil and one third tar may be used.
I also sometimes mix a small amount of ordinary magnesian lime or finely ground
unburnt limestone with the hard shrunk lime, while one (1) or two (2) per cent. of
oxide of iron may be added if the oxide of iron and alumina in the burnt mixture
are under seven (7) per cent. The mixture thus prepared may be used to ram fur-
naces with, particularly converter bottoms, but I prefer to mould it under con-
siderable pressure into bricks and twyers.
These bricks or twyers I fire in kilns with a strong draft and very large fire-
places, gradually raising the kiln to a very intense white heat, much superior to that
used in burning fire-bricks, which intense heat must be maintained for at least
twenty-four (24) hours.

page_text: This firing at a heat superior to that used for burning fire-bricks is absolutely
essential for the manufacture of good bricks.
The kilns are cooled slowly and the bricks are then ready for use.
I do not claim as my present Invention the manufacture of hard shrunk lime, and
I do not claim the use of ordinary burnt lime mixed with petroleum or other oils
for the manufacture of furnace-linings, nor the production of bricks or twyers from
such a mixture by moulding them from such mixture and burning them in the
ordinary way; but I claim the manufacture of refractory bricks and furnace-linings
from the mixture of hard shrunk, highly fired magnesian lime and crude petroleum
or other oils, as herein described.
In witness whereof, I, the said Sidney Gilchrist Thomas, have hereunto set
my hand and seal, this Twenty-first day of July, in the year of our Lord
1879.
SIDNEY GILCHRIST THOMAS. (L.S.)