IMPROVEMENTS IN MAKING SILICA BRICKS
Year: 1883

page_text: LETTERS PATENT to Archibald Hendry Dunnachie, of Glasgow, in the County
of Lanark, North Britain, Chemist, for an Invention of "IMPROVEMENTS IN
MAKING SILICA BRICKS
"
PROVISIONAL SPECIFICATION left by the said Archibald Hendry Dunnachie
at the Office of the Commissioners of Patents on the 11th January 1883.
ARCHIBALD HENDRY DUNNACHIE, of Glasgow, in the County of Lanark, North
Britain, Chemist, "IMPROVEMENTS IN MAKING SILICA BRICKS"
This Invention has for its object the making of bricks of certain kinds of siliceous
materials so as to have a high percentage of silica and so as to make them better
suited for certain well known uses.
The difficulty hitherto experienced has been to find a substance to combine with
the pulverised silica or siliceous materials in order to render it sufficiently adhesive
without its being necessary to use such a quantity of that substanco as will
materially affect the properties of the finished bricks; and the present Invention
consists in employing a special kind of fireclay, or fireclay in a particular condition,
by using which in the proportion of about ten per centum or even less the practical
difficulty referred to is completely overcome.
Fireclay of a suitable kind and in a suitable condition is obtainable at Glenboig
and other places, and consists of a naturally plastic fireclay which differs from
fireclay that is freshly excavated, mined, or uncovered in having been brought to a
plastic condition in which moisturo is very intimately combined with it, by
weathering or the long continued action of rain and other atmospheric agencies.
A plastic fireclay artificially brought to the same condition in any suitable manner
from raw or freshly excavated fireclay may also be used.
The plastic fireclay may be mixed or combined with the silica or pulverised sand
or siliceous matter in any convenient way; but the fireclay is by preference first
worked by grinding apparatus into a cream of homogeneous consistency with
sufficient water and the silica is then added in a roughly ground state, and ground
down along with the fireclay. The bricks are afterwards moulded, dried, and fired
in the ordinary way.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Archibald Hendry Dunnachie in the Great Seal Patent Office
on the 3rd July 1883.
ARCHIBALD HENDRY DUNNACHIE, of Glasgow, in the County of Lanark, North
Britain, Chemist, "IMPROVEMENTS IN MAKING SILICA BRICKS
"
My said Invention has for its object the making of bricks of certain kinds of
siliceous materials so as to have a high percentage of silica and so as to make them
better suited for certain well known uses.
The practical difficulty hitherto experienced has been to find a substance to
combine with the pulverised silica or siliceous material in order to render it
sufficiently adhesive without its being necessary to use such a quantity of that
substanco as will materially affect the properties of the finished bricks. Silica
bricks of the kind which it is the object of the present Invention to produce in an
improved manner, are principally used in the construction of furnaces or furnace
linings which are to be subjected to very intense heats; and such bricks are more
refractory and better able to withstand high temperatures the greater the per-
centage of silica in their composition. It is however found necessary to combino
some other substance with the silica so that the bricks after being fired may be
sufficiently coherent and rigid and capable of withstanding the wear and tear to
which they have to be subjected.
My Invention consists in employing a special kind of fireclay or fireclay in a
particular condition, as the adhesivo constituent of the silica bricks; and by using
this constituent in the proportion of about ten per centum or even less the practical
difficulty herein before referred to is completely overcome.
Fireclay of a suitable kind and in a suitable condition is obtainable at Glenboig
and other places and consists of a naturally plastic fireclay which differs from
fireclay that is freshly excavated, mined, or uncovered, in having been brought to a
plastic condition in which moisture is very intimately combined with it, by
weathering, or the long continued action of rain and other atmospheric agencies.
A plastic fireclay artificially brought to the same condition in any suitable manner
from raw or freshly excavated fireclay may be used. Thus the raw fireclay may
be finely ground and agitated in water so that its finer particles may become
suspended in the water, which water may be allowed to flow into tanks or ponds
where the suspended fireclay may be slowly deposited in a plastic condition suitable
for the purposes of my Invention.
The plastic fireclay may be mixed or combined with the silica or pulverised sand
or siliceous material in any convenient way; but in the mode which I prefer to
adopt in practice the fireclay is first worked by grinding apparatus into a cream of
homogeneous consistency with sufficient water, and the silica is then added in a
roughly ground state, and ground down along with the fireclay. The bricks are
afterwards moulded, dried, and fired in the ordinary way.
Silica bricks made according to my Invention are rigid and tough, and are not
easily broken or crumbled, whilst the proportion of the adhesive constituent used
in making them is so small as not to materially interfere with or appreciably
diminish the refractory or fire resisting properties which render them so useful and
valuable in metallurgical and other manufacturing process in which very intense
heats are employed.
Having thus particularly described my said Invention and the manner of
performing the same I have to state that I do not restrict myself to the preciso
details herein before described but that what I believe to be novel and original and

page_text: claim as the Invention secured to me by and in terms of the hereinbefore in part
recited Letters Patent is:-
The employment of a naturally plastic or weathered fireclay in the manufacture
of silica bricks, such plastic fireclay being produced and applied substantially in
the manner herein before described.
In Witness whereof I, the said Archibald Hendry Dunnachie, have hereunto
set my hand and seal this twenty-eighth day of April in the year of our
Lord One thousand eight hundred and eighty-three.
Witness
EDMUND HUNT
Patent Agent
Glasgow.)
AH DUNNACHIE (L.s.)