CERTAIN IMPROVEMENTS IN THE TREATMENT OF THE ALUM ROCK OR SCHIST, AND IN THE MANUFACTURE AND APPLICATION OF THE PRODUCTS DERIVED THEREFROM
Year: 1842

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PETER
KAGENBUSCH, of Wetter-on-Rhur, in Westphalia, in the Kingdom of Prussia,
Dyer, now residing in the Parish of Lyth, in the County of York, send
greeting.
WHEREAS Her most Excellent Majesty, by Her Letters Patent under the
Great Seal of the United Kingdom of Great Britain and Ireland, bearing date
at Westminster, the Thirteenth day of October, in the sixth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Peter Kagenbusch, my exors, adñors, and assigns, Her especial license, full
power, sole privilege and authority, that I, the said Peter Kagenbusch, my
exors, admors, and assigns, and such others as I, the said Peter Kagenbusch,
my exors, admors, and assigns, should at any time agree with, and no others,
from time to time and at all times hereafter during the term of years therein
expressed, should and lawfully might make, use, exercise, and vend, within
that part of the United Kingdom of Great Britain and Ireland called England,
and Her Majesty's Dominion of Wales, and Town of Berwick-upon-Tweed,
and all Her Majesty's Colonies and Plantations abroad, my Invention of
"CERTAIN IMPROVEMENTS IN THE TREATMENT OF THE ALUM ROCK OR SCHIST, AND
IN THE MANUFACTURE AND APPLICATION OF THE PRODUCTS DERIVED THEREFROM;"
in which Letters Patent there is contained a proviso, requiring that I, the
said Peter Kagenbusch, shall particularly describe and ascertain the nature of
iny said Invention, and in what manner the same is to be performed, by an
instrument in writing under my hand and seal, to be inrolled in Her said
Majesty's High Court of Chancery within six calendar months next and
immediately after the date of the now reciting Letters Patent.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Peter Kagenbusch, do hereby declare the nature of my said Invention, and

page_text: in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
My improvements in the treatment of the alum rock or schist consist, first, in
a method of preparing it for burning; and, secondly, in the method of burning.
I make a heap of the alum rock or schist, broken into small pieces of the
usual size for burning, moistening the heap continually with water during its
formation, and carefully covering up the top and sides with a plastering of
clay or mud, so as to prevent the escape of the gases arising from the decom-
position of the pyrites; care is to be taken to make and keep this covering as
tight as possible. The heap is to be kept in this state for a period varying
from three to eight months, acccording to the quality of the schist, that which
is richest in pyrites requiring to be left for the longest time, and generally the
longer the schist is left in the heap so covered up the better; after this process
it will be found that sulphate of alumina and other salts have been formed.
The schist so prepared may be lixiviated in the usual manner, but I prefer to
subject it to a process of burning in kilns or in heaps formed so as to act as
kilns in regulating the combustion. I construct a kiln of any convenient
dimensions, as from seven to eight feet in width, six feet in height, thirty-six
feet in length, or any other convenient length. In the bottom of the wall of
the kiln on all sides air holes are to be left at a distance of about every three
feet. Either wood or coal may be employed as fuel, but I have discovered
that turf or moorland parings is peculiarly economical and advantageous for
the purpose. This turf is laid on the floor of the kiln about a foot in thick-
ness, the turfs being set edgeways and
through the kiln. Upon the turf is
explained, to a depth of from two to
and the combustion is to be regulated by the air holes so as to be as slow
as possible. As the combustion goes on, the matter in the kiln sinks, and
gases may be perceived to escape; at this instant the kiln is be further filled
up. The further supply of prepared schist takes fire from that below and
becomes gradually kilned, so that again the gases may be perceived to escape.
This process is pursued until the kiln is filled up, when a covering of clay is
put on to prevent the escape of the gases, and the air holes are also stopped.
The combustion being thus stopped, the closed kiln remains for about three
days, and if, on opening it at any part, no gases escape, the process is completed,
and the burnt or kilned alum rock or schist is to be lixiviated and treated in
the usual manner, or according to the further improvement herein-after men-
tioned. It should be stated that the construction of the kiln may be varied;
and when of considerable height, like some lime kilns, the process may be
arranged so that the air may circulate
piled alum schist, prepared as before
three feet; the turf is then set fire to,

page_text: made continuous by drawing from time to time from below, as it is found in
practise that the lower portion of the schist under process is stopped in its
combustion, notwithstanding the upper part is burning.
The advantages derived from the above process of kiln burning of previously
prepared schist, and the use of turf or moorland parings may be partially
obtained by forming small heaps of turf and schist covered with clay or other
material, leaving passages for the air, so that the combustion may be regulated
as desired. I am aware that it has been long known that some description of
alum schist, when moistened and exposed to the atmosphere, becomes partially
decomposed and disintegrated, and this I mention for the purpose of stating
that the alum schist, whether so prepared by exposure to the atmosphere
or by the artificial means of covered heaps, as aforesaid, is to be treated
according to my method of kilning.
And what I claim as of my Invention is,-
First, the mode of treating the alum rock or schist by subjecting it to a
process of decomposition in closed heaps.
-
Secondly, the burning the alum schist in the state of decomposition and
preparation above described, in kilns or heaps formed to act as kilns, as above
described.
And, thirdly, I claim as of my Invention the improvement in the treating of
the alum rock or schist by burning it in kilns, as above described, with turf or
moorland parings.
Another of my said improvements in the treatment of the alum rock or
schist, and in the application of one of its products, consists in lixiviating the
alum schist, together with such an admixture of kelp as will furnish the alkaline
base. For this purpose the alum rock or schist, treated according to my im-
proved method, as before-mentioned, or treated in the usual manner, is put
into pits with the kelp of commerce, broken small and spread over the pit and
lixiviated together; also, the raw liquor of the rock or schist, however treated,
may be applied to lixiviate the kelp, to extract therefrom the alkaline base of
the alum. If the kelp be of good quality and perfectly lixiviated, about three-
fourths of a ton of kelp is sufficient for the quantity of schist required to make.
a ton of alum; but as the kelp of commerce varies in quality, the proper pro-
portion in each particular case can only be ascertained by trial.. The alum
rock or schist so treated as the requisite alkaline base, and the liquor is to be
drawn off and settled and evaporated in the same manner as the raw liquor is
now usually treated.
Another of my said improvements in the application of the products derived
from the alum rock or schist, is the application of the rock or shale from which

page_text: the alum has been extracted for the manufacture of artificial pouzzolana and
hydraulic cement. The exhausted or refuse rock or schist is to be broken into
small pieces, such as will pass a sieve with meshes one quarter of an inch, and
calcined on a red hot plate, being freely exposed to the air during the process
of calcination, which is known to be complete by the schist becoming porous
and friable, and of a pale red color. The calcined schist is to be ground to
a fine powder and used as pouzzolana. For the purpose of making an hydraulic
cement, the exhausted or refuse schist is to be mixed with lime, either burnt
or unburnt (but I prefer the former), in proportions depending on the greater
or less richness of the limestone, but proportions of lime varying from forty to
seventy per cent., with schist varying from sixty to thirty per cent., will be
found to answer well. The schist and lime being ground together by edge
stones or other suitable means, bricks or balls are to be formed, thorouglily
dried and burnt as bricks, or in a lime kiln, or the mixture may be calcined
directly on red-hot iron plates. Carè must be take to regulate the heat so that
no vitrification of the cement bricks or the mixture may take place. Care must
also be taken to burn the cement bricks or the mixture sufficiently, which may
be ascertained by taking a brick or the mixture, grinding it to an impalpable
powder, and testing its properties as a cement.
In witness whereof I have hereunto set my hand and sool this Tonth