An Improved Process for Freeing Chalk, Clay or similar Material from Flints, Stones, or Gritty Substances.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
An Improved Process for Freeing Chalk, Clay or similar Material
from Flints, Stones, or Gritty Substances.
I, CHARLES THEODORE HENNIG, of 18, Park Place, London, S.E., Chemist, do
hereby declare the nature of this invention to be as follows:-
The object of my process is to free chalk, clay and similar material from
gritty substances.
I first calcine or dry the crude chalk or other material with its contained flints
or other hard substances in a rotary or other suitable furnace. I then tumble
it about in a suitable tumbling chamber to loosen the chalk or other material
adhering to the flints or other substances; and to break it up into fine particles.
The finely divided chalk or other material is blown from the tumbler, while
it is in operation, by a blast of air and is separated from the smaller particles of
the gritty substances either by a suitable screen placed over the exit, or by
gravity after it is outside.
It will be readily understood that the heavy flints and hard substances of con-
siderable size will remain in the tumbler and that they will there assist in
breaking up new material, and that any finer particles blown out with the fine,
dry chalk, clay or similar material being of greater specific gravity will settle
before it does and thus naturally separate from it.
Foreign substances may be introduced into the tumbler to assist in the breaking
up of the chalk or other material, if necessary: and the tumbling chamber
should be made so that the accumulating flints and other substances may be
removed when desirable.
Thabad with In- of Cantambor 1899
An Improved Process for Freeing Chalk, Clay, or similar Material
from Flints, Stones, or Gritty Substances.
.
CHARLES THEODORE HENNIG, Engineer, 18, Park Place, London, S.E., 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:-
The removal of flints and other hard substances found in chalk, clay and
similar materials now entails considerable labor and expense. In the manu-
facture of whiting, for instance, the flints are separated from the crude chalk,

page_text: as follows:
The chalk as it comes from the quarry is put into a bath of water
and agitated therein until it disintegrates and becomes suspended in the water,
the contained flints separating and falling to the bottom of the bath. Then the
water holding the chalk is run into pans and evaporated, the remaining chalk
being afterwards dried or calcined. This process requires considerable time and
labor and necessitates the evaporation of the large quantity of added water.
My new process for freeing chalk, clay and similar materials from flints and
like substances is more expeditious and less expensive.
I first calcine or dry the crude chalk (or similar material), with its contained
flints or other hard substances, in a rotary or other suitable furnace. When
the moisture in the crude material is completely driven off, the material naturally
crumbles to a greater or less extent and falls away from the flints or other
hard substances.
To complete the disengagement, I put the crude but dried material into any
suitable tumbling chamber, and tumble it about.
During the tumbling the hard flints or similar substances naturally clean each
other of all adhering particles of the dry, soft material and thoroughly pulverize
it.
I then separate the pulverized, dry material from the hard substances in any
suitable way such as by causing a blast of air, to blow through the tumbling
chamber, to carry out the light, pulverized material.
I thus use the flints or other hard substances naturally present in the, crude
materials to good purpose in my process of separation; and I entirely avoid the
considerable expense of evaporating the large quantity of, added water used in
the wet method of separation above referred to.
In carrying out my process only known apparatus is required. The drying
of the crude material can be effected in the rotary or other suitable furnace.
And any suitable tumbling-chamber may be used. A horizontal revolving one,
irregular (say hexagonal) in shape, with tapering ends with suitable openings
in one end for the admission of the crude material and a blast of air, and in the
other end for the escape of the powdered separated material--and provided with
a door in the intermediate portion to enable the accumulated flints, etc. to be
removed from time to time, will be found well-adapted for the purpose in view.
If desired a screen may be placed over the discharge end of such a chamber
to intercept any fine particles of the hard substances that may be carried by the
air along with the powdered material, but a screen will not be found to be
absolutely necessary for if such fine particles should be blown out of the chamber
with the powdered material they will naturally separate from said material when
outside, by gravity, as the material, being lighter, will be blown farther away.
Should the flints or hard substances contained in the crude material not be
sufficient to cause a complete and ready pulverization of the material in the
tumbling chamber, hard foreign substances may be added without departing
from the spirit of my invention.
My invention is essentially a process, and it differs radically from the process
at present employed for effecting the same purpose.
Mine is a dry process.
Instead of disintegrating the crude material in water and thus separating the
flints, etc., I first dry the crude material and then, by simple attrition of its
component substances, disengage one from the other and then separate them.
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 hereinbefore described process for freeing chalk, clay and similar
material from flints, stones and gritty substances which consists in drying the
crude material, disengaging the chalk or similar material from the flints or other
hard substances by attrition, and in separating the one from the other.
2. The hereinbefore described process for freeing chalk, clay and similar

page_text: material from flints, stones and gritty substances which consists in first drying
the crude material, in then tumbling it about in a suitable tumbling-chamber
until the chalk or other material is completely disengaged and pulverized, and
in then separating it from the 'flints or other hard substances by means of a
blast of air, substantially as described.
Dated this Nineteenth day of June 1900.
CHARLES THEODORE HENNIG.