Year: 1888

page_text: Date of Application. 18th Apr., 1883
Complete Specification Left, 18th Feb., 1889
Complete Specification Accepted, 6th Apr.. 1859
We, ARCHIBALD CAMPBELL PONTON of Viewfield Parkstone in the County of
Dorset Architect, BENJAMIN LEWIN MOSELF, of 36 Robertson Street, Hastings, in
the county of Sussex, Gentleman, and CROMPTON CHAMBERS, of The Gables, Ore,
Hastings, aforesaid, Solicitor, do hereby declare the nature of this invention to be as
follows:-
We employ as the matrix for our artificial marble granite or other stone the
following materials or one or more of them combined and in the form or state of an
impalpable natural or artificially produced powder viz: materials such as silicas,
silicates, fluor-spars, felspars, inicas, ground slag or glass, cryolite, tridymite or burnt
sand and that either alone (and with or without the addition of coloring matter as
required) or mixed with larger aggregates or coarser particles of materials such as
sands tridymite or burnt sands shingles or gravels granites or other stones natural or
artificial or other suitable earthy or mineral substances when required reduced to
pieces of suitable sizes.
The aforesaid materials are crystallized into a hard stone like mass by means of a
liquid siliceous cement averaging in quantity from half a gallon to one gallon containing
from 1 to 6 per cent of anhydrous silica, to each cubic foot of the fabricated hard stone
like substance. In order to explain a term hereinafter used we would state that colloidal
substances can exist in one of two states vis the liquid state soluble in water and the
gelatinous state only sparingly soluble. The soluble hydrate of a colloid is called a
hydrossol, and the gelatinous hydrate a hydrogel. The solubility of a hydrogel
diminishes with the quantity of water contained in it. We have found that a
hydrogel by long continued red-heat is converted into tridymite.
As the influence of the kiln heat is to be used subsequently, the amount of alkali in
the siliceous fluid is of very little moment, as the silica will be freed from its hydrous
and alkali bases when it is converted into tridymite.

page_text: To render the siliceous fluid cement more insoluble to the siliceous hot baths, we
sometimes mix along with the cement solutions of barium or strontium so as to obtain
more insoluble silicates than those produced from the crystallized siliceous hydrogels
or alkali silicates. To promote the vitrification in the kiln, we sometimes add hydro-
fluoric acid to the fluid siliceous cement and more especially in those cases where no
fluoride is used along with the matrix.
In connection with and before and even after the fabricated articles may have been
exposed to the heat of a kiln, we use hot or cold siliceous baths with or without pressure
to silt up the pores of the fabricated articles with silica, which subsequently we
crystallize by heat.
In this invention the aforesaid impalpable powder or powders with or without the
coarser aggregates are mixed with the fluid cement in a mixer or pug mill: it is
tamped rolled or compressed into moulds, and we use screw presses, or steam or
hydraulic presses and atmospheric or steam tamping tools.
We employ dry currents of air or ovens heated by steam or otherwise to crystallize
the silicas or silicates in the fluid cement; or the silicas or silicates which may be
introduced by means of baths into the fabricated articles.
We also employ kiln heat both for the purpose of converting any amorphous silicas
or crystallised silicas or silicates which may be in the fabricated articles, into tridymite.
As an example when we desire to manufacture artificial marble we use ground burnt
flint, or tridymite with about 2 per cent of cryolite for the matrix, and with or without
colouring powders that will stand kiln heat and 6 per cent of anhydrous silica in
solution for the cement.
:
These materials are well mixed in a pug mill or otherwise and then compressed into
a mould using a pressure of say from 50 to 1.40 tons to each cubic foot. The crystal-
lization of the cement is then effected in an oven or steam heated chamber. After the
crystallization we immerse the fabricated articles into a siliceous bath, until they are
thoroughly saturated having wiped the superfluous silica from the surface of each
article we carefully dry the same with currents of air or gentle heat. The fabricated
articles are then fired in a kiln until such time as may be required to convert all the
amorphous, or other silica or silicate into tridymite. If there is still porosity in the
fabricated articles we may again immerse them into a siliceous bath very free from
alkalies unto saturation and wipe and dry as before mentioned until crystallization
ensues. For another kind of Artificial Marble of courser grain we add to one part of
the matrix previously described 3 parts of coarser tridymite, and proceed as before
mentioned.
For producing Artificial Granite, we add to one part of the matrix previously
described 3 parts of any granite broken into suitable sizes and proceed as before
described.
For making Artificial Sandstone we add to one part of the matrix previously
described 3 parts of any sand which will stand kiln heat without permanent expansion.
By the above processes we obtain artificial stones of any required hygroscopic
properties that is to say hardened and waterproofed or with the pores filled up to any
desired extent and so as to withstand atmospheric and other deleterious influences.
The articles manufactured may be of any form that can be conveniently moulded or
compressed in moulds, and where made into the form of building stones we may cast
these with dovetail or other recesses and projections for binding them firmly
together thus partly or wholly obviating the use of mortar or other cementitious
binding material between them. This is of special value for submarine work for
which stones of a coarser and concrete like composition could be cheaply made and
efficiently employed.
The process is also very suitable for paving channel courses curbs ornamental
coloured or plain tile paving glazed or unglazed an improved stoneware of silica and
a siliceous fire stone of tridy mite also for balustrades, cornices, copings ashlar facings
and other architectural work, of a plain cheap character up to the finest work
including statuary.

page_text: With proper moulds the surface of the artificial stone may be as smooth as glass.
The artificial stone made of a suitable density and homogeneity by compression
can be sawed and tooled as required or the tooling may in some cases be effected
before the final hardening.
ARCHIBALD CAMPBELL PONTON.
By Jensen & Son,
77, Chancery Lane, London, W.C.,
Patent Agents.
Improvements in the Manufacture of Artificial Stone.
We, ARCHIBALD CAMPBELL PONTON, of Viewfield, Parkstone, in the County of
Dorset, Architect; BENJAMIN LEWIN MOSELY, of 36 Robertson Street, Hastings, in
the County of Sussex, Gentleman; and CROMPTON CHAMBERS, of Town Hall Chambers
(formerly of Ore), Hastings, in the County of Sussex, Solicitor; 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 :-
This invention relates to the manufacture of artificial marble, and other stone.
The product is of a superior character, combining great strength with durability. It
can be made of a pure white. or of any required colour; it is mnouldable in any form;
it can be produced with a fine close grain, almost impermeable, or with any required
degree of porosity; and it has acid and fire resisting qualities.
The materials employed comprise silicas, silicates, burnt sand, burnt flint, and
similar substances. Certain colouring matter and fluxes for glazing may also be used
to suit special requirements. A siliceous cement is employed for binding the solid
particles together, which, when moulded into required forins, are exposed to the heat
of a kiln until crystallization in the tridymite state (or the normal state of silica
under extreme heat), has been attained.
For the finest grained products one or more of the solid forms of silica, such as
burnt flint or burnt sand, are reduced to an impalpable powder, and mixed with
enough of the siliceous cement (made as described hereinafter) to form a cohering or
plastic mass. For a coarser grained product, we employ one part of the impalpable
powder, as aforesaid, to two or three parts of coarser grained silica, such as burnt
sand or tridymnite. For stone of a still coarser quality, we mix variable proportions

page_text: of burnt coarse siliceous material with the burnt sand and impalpable powder. The
proportion of the cement used to the amount of the powdered, granular or coarse
material employed will necessarily vary according to the relative sizes of the particles
and proportions of the several grades of material to each other; but in general, one
gallon of the siliceous cement suffices to bind together from one to two hundred
pounds of powdered and granular material.
The siliceous cement used for binding the aforesaid particles together is composed
of a solution of silicate of soda, or of potash, or combinations thereof, with or. with-
out the addition of free silica ; and it is desirable that the amount of alkali contained
therein should not exceed five per cent. of the weight of the moulded article before
burning. If this proportion is exceeded, the alkali should be neutralized, as stated
hereafter.
The powdered and granular materials, already named, alone, or in combination with
burnt coarse siliceous material, are mixed with a sufficient amount of the liquid
siliceous cement aforesaid in a suitable mixing apparatus, to form a cohering or
plastic mass. The mass is then moulded in suitable moulds, and we preferably use
a high pressure to compress the material in the mould. Subsequently, the moulded
articles are removed from the moulds and placed in a porcelain or other suitable kiln,
and exposed to red or white heat until all, or nearly all, of the contained silica has
been converted into the tridymite form of crystallization. The articles are then
removed from the kiln, and stacked ready for use.
If, however, the articles are too porous for a desired purpose, they are immersed
(before or after the firing just mentioned) in a siliceous bath until saturated, then
wiped, dried, and fired until crystallization has been attained; in the manner already
stated. The bath is composed of one part of silicate of soda, or of potash, or combi-
nations thereof, with two or three parts of freshly prepared silicic acid dissolved therein.
The silicic acid is only required when it is necessary to neutralize the alkali to the
required amount and a larger proportion of silicic acid may sometimes be used.
Where glazing is required, the glazes or fluxes usually employed in the ceramic art
may be added to the siliceous cement, in the first instance; or combined with the
articles in the kiln at the last firing.
We make, for example, an artificial or imitation marble, by taking ground burnt
flint or burnt sand, (otherwise tridymite), about one third of which should be in the
form of an impalpable powder mixing the same thoroughly with the siliceous cement,
aforesaid, into a coherent mass. This is tamped or compressed in moulds, and subse-
quently burnt in a porcelain, or other suitable kiln, until the tridy mite state or
condition of crystallization has been attained throughout the mass. To give greater
density to the product, the moulded articles are soaked in the siliceous bath aforesaid,
preferably after the moulded articles have been dried, but before being fired in the
kiln. If the marble is required to be white, care must be taken to use such sands
only as will burn white in the kiln.
Other sands than those just named may be employed (with or without the same,
or other forms of silica reduced to powder), in the making of artificial sandstone,
exactly in the manner described for marble; it being noted that the sands or other
forms of silica should be burnt, and that the fineness of the grain depends upon the
proportionate amount of powdered material used. Other varieties of product are
obtainable by mixing variable quantities of burnt coarse aggregates with the other
ingredients. For example, we may add three parts of burnt quartz, broken into suitable
sizes, to the other ingredients, and proceed as before described.
The nature of the product is very different from stone hitherto made, inasmuch as
the treatment by heat is carried further than ever before, until tridymite crystalliza-
tion (or the normal state of silica under extreme heat) has been effected throughout
the mass, and the product is capable of withstan ling fire without permanent expansion
or contraction. Furthermore, the said stone will withstand the action of such acids
or agents as sulphuric acid, nitric acid, hydrochloric acid, aqua regia and ammonia.
If pure materials only are used, (those which burn white in the kiln), the product is
a beautiful lustrous substance resembling the finest white marble, the grain of which

page_text: depends upon the proportionate amount and fineness of granular material combined
with the powdered material.
It is to be noted that we have used the term "Tridymite." in this specification to
indicate a certain state or condition of silica. We apply the term not only to loose
burnt sand and burnt flint, but also to a compacted or moulded mass of material after
it has been fired in a kiln in which case it includes the contained silica that was
previously in a state of solution. So little is known, at present, of tridymite, or of
silica in its most stable form, that hereafter it may be found our references are not
absolutely correct, although intended to be so. But so far as we can ascertain, the
characteristic feature to be relied upon is the specific gravity, which, in the powdered
materials, is about 2.22, while the finished product may be 1.98 or less, on account
of its porosity.
We also desire to call attention to other specifications filed by us, and relating to
silica or siliceous materials, and to stages in the manufacture of artificial stone as
practiced by us; being No. 15, 256, dated 23rd October 1888; No. 2718, dated
15th February 1889; No. 2719, dated 15th February 1889; No. 2780, dated 16th
February 1889; and No. 2781, dated 16th February 1889.
Having now particularly described and ascertained the nature of our said
Invention, and in what manner the same is to be performed, we declare that what we
claim is:
1. An artificial stone composed of tridymite crystals of silica; substantially as
described.
2. In the manufacture of artificial stone, the combination of ground burnt flint
in the tridymite state, with an alkaline silicate; substantially as described.
3. In the manufacture of artificial stone. the combination of burnt sand in the
tridymite state, with an alkaline silicate; substantially as described.
4. In the manufacture of artificial stone, the combination of an alkaline silicate
with ground burnt flint and burnt sand (or tridymite); substantially as described.
5. The manufacture of artificial stone by the combination of silica in solution with
burnt powdered or granular siliceous substances, with or without burnt coarse aggre-
gates, and the exposure of the same in the form of moulded articles to kiln heat until
tridymite crystallization has been effected; substantially as described.
6. In the manufacture of artificial stone, the treatment of moulded articles, composed
of silica in the tridymite form, by immersion in a siliceous bath; substantially as and
for the purpose described.
בז
11
101
T1900
FAIRFAX & WETTER,
433, Strand, London,
Agents for the Applicants.