Improvement in Method of Refining Kaolin and other Earths.
Year: 1895

page_text: Date of Application, 23rd July, 1895-Accepted, 24th Aug., 1895
[Communicated from abroad by DAVID HANNAH CHAMBERS, of Pittsburg, in the
County of Allegheny and State of Pennsylvania, United States of America,
Manufacturer.]
Improvement in Method of Refining Kaolin and other Earths.
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane in the
County of London, Chartered Patent Agent, 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:-
My invention relates to the refining or separation, from kaolin ochre or similar
earths, of the gritty or other deleterious constituents contained therein, and is
designed to attain a cheaper, more expeditious and more effective method than
those heretofore employed.
The common method of separation previously used consisted in mixing the
kaolin up with water and allowing the gritty matter to settle, an expensive, slow
and inefficient method in which the impurities were not thoroughly separated.
In carrying out my invention in its preferred form, I first dry the earth at least
partially either by air drying or other means. I then disintegrate the earth by the
use of any well known disintegrator, such as the double cylinder machine, in which,
however, the gritty particles are not ground up but are merely separated from the
earth which is reduced to a powdered condition therein. I then take the resulting
powder and pass it through a combined heater and drier, preferably a steam-
jacketted cylinder, in which the powder is not only dried but heated so that it will
not absorb moisture on its way to the screens. From the heater and drier I pass
the powder to a "scalper," which consists of a rotating cylindrical screen through
which the earth and fine gritty particles pass, while the larger particles of
deleterious matters are left therein. From this scalper the powder passes to the
sieves, which in the case of kaolin are preferably of very fine bolting cloth, of such
fine mesh that the earth will not pass therethrough unless it is perfectly dry. The
heating forms an important part of the process, as the powder, which is a great
absorber of moisture, is thereby prevented from absorbing moisture before it
reaches the bolting cloth through which it would not pass unless perfectly dry,
and the earth may be heated before the disintegrating operation for this purpose;
if desired, the earth being made up into bricks and dried before disintegrating.
The earth may also be separated from the heavier deleterious particles by directing
a blast of air upon it and collecting the earth by a dust-collector. In either case,
if thoroughly dried, a complete separation will be effected, the larger and heavier
particles of gritty and other deleterious matters being entirely removed. With the
use of bolting cloth it is also found that the surface clays which seep down and
intermingle with and discolour the kaolin, are also removed.
Many variations may be made in the form of the apparatus employed, and in the
final step without departure from my invention, since I consider myself the first to
disintegrate and dry the earth in order to effect easy separation of the silica and
other contained impurities.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1 The method of refining kaolin or similar earths, consisting in disintegrating

page_text: and drying the same without reducing the size of the gritty particles, and then
mechanically separating the particles of the silica and other impurities from the
dried powder; substantially as described.
2. The method of refining kaolin and similar earths, consisting in disintegrating
and drying the same, heating them to prevent their absorbing moisture, and then
separating the larger particles of silica and other impurities from the powder;
substantially as described.
3. The method of refining kaolin and similar earths, consisting in disintegrating
and drying the same, passing them through a heater and drier, and then screening
to remove the larger particles of silica and other impurities; substantially as
described.
ABEL & IMRAY,
Agents for the Applicant.