AN IMPROVED METHOD OF CARBONIZING CLAY, PLASTER, CHALK, POROUS STONE, AND OTHER LIKE POROUS MATERIALS.
Year: 1872

page_text: LETTERS PATENT to George Hand Smith, of the City and State of
New York, United States of America, now of No. 8, Southampton
Buildings, London, Gentleman, for the Invention of "AN IMPROVED
METHOD OF CARBONIZING CLAY, PLASTER, CHALK, POROUS STONE, AND OTHER
LIKE POROUS MATERIALS.'
Scaled the 4th March 1873, and dated the 24th December 1872.
PROVISIONAL SPECIFICATION left by the said George Hand Smith
at the Office of the Commissioners of Patents, with his Petition,
on the 24th December 1872.
I, GEORGE HAND SMITH, of the City and State of New York, United
States of America, now of No. 8, Southampton Buildings, London,
Gentleman, do hereby declare the nature of the said Invention for "AN
IMPROVED METHOD OF CARBONIZING CLAY, PLASTER, CHALK, POROUS STONE, AND
OTHER LIKE POROUS MATERIALS," to be as follows:→
My Invention relates to a novel treatment of porous materials, and
articles. or objects made thereof, whereby they are converted into
materials possessing properties altogether different to those peculiar to
them in their normal condition.

page_text: My said Invention consists in a process of treating the porous
materials by first causing them to absorb carbon from a liquid con-
taining the same, and then expelling the volatile portions of the carbon,
and the said Invention is applicable to the treatment of all substances
capable of absorbing and retaining the carbon, but I need only mention
a few well-known substances, and some of the purposes to which I adapt
them.
I take articles made of common clay or fire-clay, such as bricks,
crucibles, and the like, or of ordinary plaster of Paris, such as ornaments
for house decoration, statues, statuettes, or other works of art, and treat
them as follows:-The clay, plaster, or other article is first saturated by
immersion or otherwise with the carbonaceous material. I may use for
this purpose coal tar, coal oil, melted or dissolved mineral or vegetable
pitch, bitumen, or other similar material containing non-volatile carbon,
and from which the carbon can be caused by absorption to enter the
porcs of the material to be treated.
It will be generally found most convenient to saturate the porous
substances or articles with the carbonaceous or hydrocarbon liquid by
immersing them therein, but if desired the hydrocarbon may in some
cases be applied to statues and other articles or objects with a brush or
by other convenient means.
It will not be always necessary that the hydrocarbon fluid should
penetrate or pass through the article or object being treated. Sometimes
saturation to a slight depth only is desirable, it will be therefore
necessary to determine the proper depth of saturation and to withdraw
the statue or other article from the bath when this depth has been
reached.
The clay, plaster, or other article or material after being thus saturated
is subjected to the second part of my treatment, which consists in heating
the said article or material to drive off the volatile portions of carbon or
other volatile matter, so that only the solid and non-volatile portions of
the carbon will be retained in the pores of the said material. The
articles or materials to be heated are placed for that purpose in an oven
of any suitable form and construction, and are heated therein to the
proper degree, which will vary somewhat with the material used. They
are rotained in this oven until the whole of the volatile matters, or so
much of them as it is desirable to expel, are driven off. Then the said

page_text: articles or materials are allowed to cool; plaster of Paris and other
like substances must cool very slowly. After cooling the treatment is
finished and the articles or materials so treated are ready for use. If
they are found in any respect imperfect the saturation and heating may
be repeated..
Works of art, such as statues, statuettes, busts, decorative ornaments,
and the like, formed of ordinary plaster of Paris, are by my improved
treatment rendered much more hard and durable than in their original
condition, and they are made susceptible of a most brilliant polish, equal
if not superior to that of any stone or metal ordinarily used for like
purposes; they may moreover be rendered entirely free from any un-
pleasant odour.
Blocks or pieces of plaster may be first treated as above described,
then cut into any desired form and polished. Fire-bricks, fire-clay,
crucibles for metallurgical operations by this treatment have their
refractory or fire-resisting power increased, and many other substances
of a similar porous nature and capable of receiving and retaining the
carbon may by such treatment have their value greatly increased at a
very small cost.
Pulverized clay, plaster of Paris, chalk, and other similar porous
materials may be treated according to this Invention by mixing them
with a suitable quantity of coal tar, pitch, or other hydrocarbon liquid,
the compound thus formed being moulded or pressed into any required
shape and then subjected to heat as above described.
In treating substances of a very porous nature I may add to the
hydrocarbon liquid a small quantity of fire-clay, oxide of iron, or other
suitable material, which will remain in the pores of the said substance,
but care must be taken not to make the liquid so thick as to prevent or
retard the absorption of the carbon.
30 SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Hand Smith in the Great Seal Patent
Office on the 24th June 1878.

page_text: of America, now of No. 8, Southampton Buildings, London, Gentleman,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fourth day of December, in
the year of our Lord One thousand cight hundred and seventy-two, in |
the thirty-sixth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said George Hand Smith, Her
special licence that I, the said George Hand Smith, my executors,
administrators, and assigns, or such others as I, the said George Hand
Smith, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention
for "AN IMPROVED METHOD OF CARBONIZING CLAY, PLASTER, CHALK, POROUS
STONE, AND OTHER LIKE POROUS MATERIALS," upon the condition (amongst
others) that I, the said George Hand Smith, my executors or ad-
ministrators, by an instrument in writing under my, or their, or one
of their hands and seals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to be a
performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
•
NOW KNOW YE, that I, the said George Hand Smith, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement:-.
My said Invention relates to a novel treatment of porous or absorbent
materials and articles or objects made thereof whereby they are converted
into materials possessing properties altogether different to those peculiar
to them in their original condition.
My Invention consists in a process of treating the said porous or
absorbent materials by first causing them to absorb carbon from a liquid
'containing the same, and then expelling the volatile portions of the
carbon, and the said Invention is applicable to the treatment of all
substances capable of absorbing and retaining the carbon, but I need
only mention a few well known substances and some of the purposes to
which I adapt them?
"

page_text: -
Common chalk, all kinds of clay, and similar materials are well adapted
for treatment by my process and as by the said process they have their
commercial value enormously increased, they afford a very striking
illustration of the importance of my Invention and I have in the
following description more particularly referred to materials of this
class: In practising the said Invention I take common chalk as
quarried from the earth in picces of any desired shape or size, or common
clay or fire-clay in the form of bricks, crucibles, and the like, or articles or
objects made of ordinary plaster of Paris, such as ornaments for house
decoration, statues, statuettes, or other works of art, and treat them as
follows: The clay, plaster, chalk, or other material may be used in .
pieces or blocks which after the treatment herein described are turned or
cut to any desired form, or they may be cut or otherwise brought nearly
to the desired shape before being subjected to my process, so that there
will be no waste of the prepared material or substances used in its pre-
paration. The material or article to be treated is first saturated by
immersion or otherwise with the carbonaceous substance. I use for this
purpose coal tar, coal oil, melted or dissolved mineral or vegetable pitch,
bitumen, or other similar material containing non-volatile carbon and
from which the carbon can be caused by absorbtion to enter the pores of
the material to be treated.
It will be. generally found most convenient to saturate the porous
substances or articles with the carbonaceous or hydrocarbon liquid by
immersing them therein, but if desired the hydrocarbon may in some
cases be applied to statues and other articles or objects with a brush or
by other convenient means. If gas, tar, or pitch, or a mixture of both
is employed a film more or less dense will be deposited on the surface of
the article or material subjected to the above process, and many articles
such as works of art would have their finish and appearance thereby
greatly impaired. But I obviate this difficulty by continuing the boiling
in the bath or solution until the film no longer adheres to the surface of
the article, or by transferring the same to another bath of hot hydro-
carbon preferably coal tar less dense or more fluid than the first bath.
Care must be taken not to touch or handle the articles or pieces so
treated in removing them from the bath to the oven in which they are
heated according to the second part of my Invention, as herein-after
described.

page_text: fluid should penetrate or pass through the article or object being treated.
Sometimes saturation to a slight depth only is desirable; it will be
therefore necessary to determine the proper depth of saturation, and to
withdraw the statue or other article from the bath when this depth has
been reached. The article or object being treated, especially if made of
plaster or clay, should first be thoroughly dried and heated and after
immersion in the hydrocarbon liquid should be taken to the aforesaid
oven without being allowed to cool, and any film on the surface of the
said article or object will be absorbed into the material.
The clay, plaster, or other article or material after being thus satu-
rated is subjected to the second part of my process, which consists in
heating the said article or material to drive off the volatile portions of
carbon or other volatile matter, so that only the solid and non-volatilo
portions of the carbon will be retained in the porcs of the said material.
The articles or materials to be heated are placed for that purpose in an
oven properly constructed to carry off the volatile matters, which may
be condensed by suitable apparatus, and utilized for various purposes.
The degree of heat to which the articles are subjected in the said oven
will vary somewhat with the material used and the precise result sought
to be obtained. They are retained in this oven until the whole of the
volatile matters, or so much of them as it is desirable to expel, are
driven off, then the said articles or materials are allowed to cool. The
heating and cooling should be gradual. The proper heat is usually
indicated by the loss of odour and the hardening of the article or material
thus treated.
If the bath consists entirely or nearly so of pitch, it may be heated to
a very high temperature, and in some instances no after heating of the
porous material in the oven will be necessary, as the heat imparted to
the said material in the bath is so great that in cooling, after immersion
in the aforesaid bath, sufficient volatile matter will be driven off.
Plaster of Paris and other like substances should cool very slowly.
After cooling the treatment is finished, and the articles or materials so
treated are ready for use. If the articles or objects are to be heated to
redness, they must be enclosed in seggars to prevent the combustion of
the carbon.
Works of art, such as statues, statuettes, busts, decorative ornaments,
and the like, formed of ordinary plaster of Paris, are by my improved
treatment rendered much more hard and durable than in their original

page_text: condition, and if left unpolished they will have a peculiar and beautiful
appearance, unlike that of any other known material, while at the same
time they are susceptible of a most brilliant polish, equal if not superior
to that of any stone or metal ordinarily used for like purposes; they are
moreover entirely free from any unpleasant odour.
Blocks or pieces of plaster or chalk may be first treated as above
described, then cut into any desired form and polished. Fire-bricks,
fire-clay, and crucibles for metallurgical operations by this treatment
have their refractory or fire-resisting power increased, and many other
substances of a similar porous nature, and capable of receiving and
retaining the carbon, may by such treatment have their value greatly
increased at a very small cost.
Pulverized common clay, fire-clay, plaster of Paris, chalk, and other
similar porous materials may be treated according to this Invention by
mixing them with a suitable quantity of coal tar, pitch, or other hydro-
carbon liquid, and pressing or moulding the compound thus formed into
any required shape, and then subjecting it to heat as above described.
Various articles, such as bricks, drain pipes, and the like may be
manufactured by first thoroughly drying or baking powdered clay, or
drying chalk and mixing the same intimately with a small quantity of
coal tar, pitch, resin, or other hydrocarbon in a liquid state, or in such a
condition that they are capable of being made liquid by heat or other-
wise in a close vessel, in which the vapour generated is kept under
pressure before escaping; this mixture may then be worked into the
desired forms by pressure or otherwise while hot. The high degree of
heat to which these materials or articles are subjected will cause enough
of the volatile matter to pass off while they are cooling. The bricks or
other articles may be coloured by using light coloured hydrocarbon, such
as gum resin, with clay containing metallic oxide.
In treating some substances I may add to the hydrocarbon liquid a
small quantity of fine clay, oxide of iron, or other suitable material which
will remain in the pores of the said substance, but care must be taken
not to make the liquid so thick as to prevent or retard the absorbtion of
the carbon.
Having thus fully described my said Invention, and the manner of
performing the same, I wish it understood that I claim, the herein
described process of carbonizing porous or absorbent materials, that is to

page_text: say, first causing them to absorb carbon, and then partially or entirely
expelling the volatile portions of the same in such a manner that the
carbon retained in the said materials is incorporated with them, and
changes their condition and appearance in the manner herein set forth.
In witness whereof, I, the said George Hand Smith have here-
unto set my hand and seal, this Twenty-fourth day of June, in
the year of our Lord One thousand eight hundred and seventy-
throo
Witness,
W. ROB. LAKE.
GEORGE HAND SMITH. (L.S.)