Year: 1887

page_text: I, GEORGE FREDERICK MARSHALL, of Church Road, Battersea, in the county of
Surrey, Manufacturer, do hereby declare the nature of this invention to be as
follows:
This invention relates to the manufacture of an improved carbon suitable for filtering
and decolorizing purposes.
In manufacturing my improved carbon I take a given quantity of carded Asbestos
(Canadian Asbestos for choice) and soak it for about forty eight hours or more in a
strong solution of lime in water, whereby the material reduced to a friable condition,
and it is then well washed in several waters and then dried in a muffle furnace.
It is then taken out and mixed with powdered coal pitch in the proportion of about
one part of the powdered coal pitch to about four parts of the treated Asbestos and
packed into Crucibles in a muffle kiln where it is raised to a white heat.
When cold it is drawn from the kiln to be rubbed through sieves of different meshes
and sorted into the various grains and is then in a fit state to be used for filtering and
decolorizing purposes.
G. F. REDFERN,
4, South Street, Finsbury, London,
Agent for the Applicant.

page_text: The Manufacture of an Improved Carbon for Filtering and
Decolorizing Purposes.
I, GEORGE FREDERICK MARSHALL, of Church Road, Battersea, in the County of
Surrey, Manufacturer, 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 an improved carbon suitable for filtering
and decolorizing purposes.
In manufacturing my improved carbon I take a quantity of carded Asbestos
(Canadian Asbestos for choice) and soak it for about forty eight hours or more in a
strong solution of lime, whereby the material is reduced to a friable condition, and it
is then well washed in several waters and then dried in a muffle furnace. It is then
taken out and mixed with powdered coal pitch in the proportion of about one part of
the powdered coal pitch to about four parts of the treated Asbestos and packed
into Crucibles in a muffle kiln where it is raised to a white heat.
'
When cold it is drawn from the kiln to be rubbed through sioves of different meshes
and sorted into the various grades and is then in a fit state to be used for filtering and
decolorizing purposes.
I sometimes modify the process in the following manner, that is to say, instead of
soaking the asbestos in a solution of lime to remove the dress I boil it in water and
instead of drying it in a muffle 1 burn it in an open kiln. Further, instead of placing
the pitch in the crucibles with the asbestos, I may place the asbestos in crucibles having
perforated bottoms and pass the fumes of coal pitch through the said crucibles so as to act
on their contents, the said fumes being produced in the muffle or introduced thereinto
any suitable manner.
in
When these modifications are employed I prefer to rub the asbestos through sieves
after it is removed from the open kiln and before introducing it into the perforated,
crucibles.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. The manufacture of an improved carbon which consists essentially in soaking or
boiling carded asbestos to remove the dress therefrom and render it friable; subjecting
the same to heat in a muffle furnace or kiln and then allowing it to cool; and
then subjecting the material to the action of coal pitch in a furnace, substantially
as described.
2. The improved process first hereinbefore described of carbonizing asbestos.
3. The modified process hereinbefore described for the manufacture of carbonized
asbestos:
4. The use for filtering and decolorizing purposes of the improved carbon hereinbefore
described.