A NEW OR IMPROVED PROCESS OF AND APPARATUS FOR CALCINING BONES, PEAT AND OTHER SUBSTANCES CONTAINING A RICH PERCENTAGE OF CARBON, FOR OBTAINING THE BYE PRODUCTS AND FOR REVIVIFYING BONE-BLACK
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Benjamin Joseph Barnard Mills at
the Office of the Commissioners of Patents on the 24th October 1883.
Communicated to him from abroad by Abraham Zwillinger of Vienna in the
Empire of Austria.
BENJAMIN JOSEPH BARNARD MILLS of the firm of Harris and Mills of
23 Southampton Buildings in the County of Middlesex, Patent Agent, A NEW
OR IMPROVED PROCESS OF AND APPARATUS FOR CALCINING BONES, PEAT AND
OTHER SUBSTANCES CONTAINING A RICH PERCENTAGE OF CARBON, FOR OBTAINING
THE BYE PRODUCTS AND FOR REVIVIFYING BONE-BLACK A communication to me
from abroad by Abraham Zwillinger of Vienna in the Empire of Austria
The present invention relates to a new process, by means of which bones, peat
and other substances containing an abundant percentage of carbon are calcined and
bone-black is revivified not by means of white heat, as has generally been done
hitherto, but by means of super-heated steam.
I will now describe the said process in its application to the manufacture and
revivifying of bone-black, tho samo process boing applicable to other substances.
The calcining of the bones by means of this new process is effected as thoroughly
and at the same time in a more uniform way and bone-black is revivified by the
same as completely as by the ordinary bone-black-furnaces by performing this
calcination whether in kilns or in pots. This improved process offers besides, the
following particular advantages; the manufacture of the bone-black causes no
unpleasant smell, the bye products are obtained in a safe and easy manner and the
receiving of the formed gas does not occasion the least danger of fire or of explosion.
Generally speaking the new process is simpler, cheaper, safer, and more convenient
than the manipulations generally hitherto employed, by which a loss of bone-black
is often caused, in consequence of white-burning or red-burning the same, this
result being quite impossible with the present process, moreover the apparatus
devised for carrying the present process into practice is of a most simple
construction.
A large vessel of cast or wrought iron surrounded by some non conducting casing
and placed in brickwork of considerable thickness in order to prevent as far as
possible the loss of heat is employed for calcining the bones. It is filled with
bones up to the admission aperture of a tube at the upper part through which
super-heated steam is introduced into said vessel. The necessary steam may be
super-heated in any known manner, and by means of any known super-heating
apparatus.
The steam to be super-heated passes through a stop cock and pipe into
the super-heating apparatus; the calcining vessel having previously been shut.
The steam is only allowed gradually to enter the super-heater, and the stop cook or
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page_text: other contrivance employed for regulating the quantity of the admitted steam is
not opened completely until the worm lending down from the calcining vessel has
become hot and until an ammoniacal smell proceeds from a test tube.
The very hot steam containing ammoniacal vapours is then led through the
worm, where the greatest part of it is refrigerated; thence the said vapours pass
into the purifier (condensing or absorbing vessels) made of cast or wrought iron.
In the present instanco the first three of theso vessels are lined with lead-plates
and contain a mixture of water and sulphuric acid of equal parts, whilst the last
two vessels contain a solution of sulphate of iron. In the first three vessels &
solution of sulphate of ammonia is obtained, whilst the remaining small quantities
of cyanurets, having a strong characteristic odour, which have not been absorbed
by the sulphuric acid, are absorbed by the solution of sulphate of iron contained
in the last two vessels. The sulphate of ammonia can be obtained very easily and
without any odour by evaporating the liquid, and the solution containing the
cyanurets may serve for the manufacture of Prussian blue, or be sold as a manure,
the gas water obtained can also be advantageously sold for use in Soda-Ammonia-
Works.
The absorbing vessels absorb only the vaprous products of the distillation, whilst
the gaseous products pass into a line condenser, where they are freed from the
carbonic acid and being thus transformed into lighting gas or so called oil-gns, they
thence pass into the gas-holder. This gas yields an excellent bright white flame,
its illuminating power is four times as great as that of the ordinary coal-gas, it
contains no sulphur at all, and by simply passing through the lime solution it
becomes quite purified and may be forthwith employed for lighting purposes.
Should the said gas be utilised for heating purposes instead of for lighting
purposes, it may be led forthwith, without previously purifying it, under the
steam-boiler. 100 kilogrammes of bones containing as a minimum 2 per cent.
of nitrogen, yield about 10 kilogrammes of gas-water and 15 cubic metres of
purified gas.
In a modified construction of the bono calcining apparatus that may also serve
for revivifying bone-black in sugar refineries the speut bone-black does not need
to be previously dried but can be immediately introduced in a very wet condition
into the iron calcining vessels or cylinders; all the moisture being driven out from
the bone-black in a few minutes by the super-heated steam. Within about two
hours one vessel's charge; say from 10 to 15 metrical quintals (of 100 kilogrammes
onchi) of bone-black is completely revivified.
Thus
When working with 5 such vessels during 12 hours from 250 to 375 metrical
quintals (of 100 kilogrammes each) of bone-black can be revivified and furthermore
by this new process the bone-black is treated in a very economic manner.
this new process allows of dispensing with a considerable expenditure of hand
labour, as well as with the great number of large and costly heating furnaces and
of proventing the rapid wear of the bone-black and the retorts, not to speak of
the great positive advantages resulting from it. For all these reasons the said
improved process becomes quite indispensable in sugar refineries for the
revivifycation of spent bone-black.
As steam of ordinary tension can easily be superheated by means of hot fire
gases to a temperature of 500 degrees Centigrade and as by a pressure of two
atmospheres its volume is reduced to about one half of the original one, and at the
saine time the temperature raised to 1000 degrees Centigrade it is easy to give
solid bodies a temperature of several hundred degrees: To this end the steam
coining from the boiler is made to pass through heated cast-iron pipes and is
thereby superheated. The steam coming from the boiler and having a tension of
from 1 to not more than 2 atmospheres, enters the system of heated pipes made of
rather strong cast iron tubes connected with each other by means of semi-circular
connecting pieces fastened in the brickwork and not exposed to the direct action
of the flame; the joints of these tubes are made steam-tight by means of asbestos
packing.

page_text: In order to prevent the burning through of those parts of the cast iron pipes,
which are exposed to the direct action of the flame, these parts of the pipes are
coated several times, before said apparatus is put together, with a mixture of two
parts by weight of clay and one part by weight of fossil meal, mixed up into a
very thin watery syrup, whereby a thin coating ensues, closely adhering to the
pipe and protecting it from the influence of the flame.
The interior side of the said pipes is in the course of time lined with a closely
adhering layer of crystallized oxide of iron, whereby a further damaging of the
iron is prevented.
By means of the new process any desired temperature (from 525 up to
1000 degrees Centigrade) that ought to be given to the body which is to be
calcined, can be maintained constantly and very easily, which cannot be obtained
with the ordinary furnaces.
This new means for providing caloric has therefore two advantages: Firstly;
a very rich source of caloric is obtained: Secondly: the temperature between the
desired limits is enabled to be maintained. The first circumstance has an influence
upon the rapidity of the operation whilst the latter circumstance is of considerablo
value as enabling the temperature to be varied according to the nature of the body
that is to be calcined.
The process of manufacturing bone-black and of rovivifying spent bone-black,
when the last described apparatus is employed is as follows:
The bones as well as the spent bone-black may be worked up according to the
improved method in ordinary steaming vessels or in filters; these vessels being
clad with a bad conductor of heat and provided with the necessary conducting
pipes and stop-cocks..
The pressure of the steam in the boiler ought to be maintained constantly at
only about two atmospheres oqual to 120, 64 degroes Centigrade whilst the worm
of the super-heater is to be heated to a dark red heat. As soon as the cylindrical
steaming vessels or filters are filled with bones or with spent bone-black and shut
steam-tight the lower or the upper cock is opened according to whether the steam
is to be introduced through the lower pipe or through the upper one, and at the
same time the steam valve of the boiler is successively opened.
The steam in passing through the pipes heated to dark red heat becomes super-
heated and reaches a temperature of from 525 to 700 degrees Centigrade which,
temperature is quite sufficient either for the manufacture of bone-black or for the
revivification of the same after it has been once employed.
In five hours the operation is finished, when raw bones are calcined, and in 'tho
case when bone-black is to be revivified, two and a half hours are quite sufficient,
in either case the quantity of the material placed in each of the steaming vessels
or filters being from 12 to 15 metrical quintals. The super-heated steam ought
not to be completely hindered in its passage through the bones, but it should be
allowed to pass in such manner that tho manometer of the boiler is never allowed
to mark a pressure exceeding two atmospheres. (one atmosphere additional
pressure.)
As soon as the operation of the charring is terminated, which is manifested by
the steam emanating from the little test tube being no longer inflammable, the
bone-black is placed in coolers and worked up in the usual manner. If non-super-
heated steam is introduced from the boiler directly into the said steaming vessels
or filters, for which purpose a direct communication ought to be established between
the boiler and said vessels, and if this non-super-healod steam is allowed to
escape for about five minutes the bone-black can be loaded directly from the said
vessels into iron trucks and spread out in thin layers, without undergoing “a”
previous cooling.
For revivifying bone black the superheated steam is introduced directly into the
first steaming vessel or filter preferably by opening the cock in the bottom part of
this vessel; it passes upwards, penetrates the bone-black contained in said vessel,
passes through a short tubo arranged near the top-lid of this vessel into the second

page_text: vessel, leaves this vessel at its bottom in order to pass into the third vessel. It
passes equally through the last named vessel and through a tube into a pipe and
thence immediately escapes into the air. From the above description it becomes
manifest that the steam coming from the first vessel ought to pass through three
other vessels before leaving the apparatus and it thereby loses all its heat, which
it gives to the bone-black contained in these vessels.
By means of the described process the bone-black contained in the first vessel, is
thus completely revivified in the course of two hours, and the bone-black contained
in the second and third vessols is considerably heated.
The first vessel is then shut out which is effectuated by shutting a cock on the
steam pipe. Cocks leading steam into second vessel, being then opened and the
cocks connecting the first and second vessels at top and bottom being shut, the
super-heated steam is made to pass immediately into the second vessel and thence
into the third and fourth vessels. In the meantime the first vessel is emptied and
filled with fresh bone-black and by that time the bone-black contained in the
second vessel is equally revivified; this second vessel is then also shut out by
shutting the steam cuck at the bottom of said vessel. On opening a cock at
bottom of said vessel the super-heated steam passes into the third vessel and
thence through the upper tube into the fourth vessel which communicates by means
of a connecting pipe with the first vessel; from the fourth vessel the steain thus
passes back again into the first vessel and thence it escapes through the opened
cock into the air.
Then the second vessel is emptied and filled anew and again inserted in the
apparatus as hereinbefore described. This mode of operation may be carried on
uninterruptly in the manner described.
The communication of the four cylindrical vessels is established by means of a
pipe, communicating both with the steam boiler and with the superheating coil and
provided with lateral tubes by means of which this pipe communicates with said
cylindrical vessels. These vessels are provided at their top with tubes commu-
nicating with one common pipe.
When the apparatus is employed for the manufacture of fresh bone-black said
pipe may be brought into coinmunication with the apparatus herein first described
serving for obtaining the accessory products of the operation.
When the cocks fitted in the said steam and escape pipes are conveniently
opened, the steam may be made to enter the cylindrical vessels from below through
the said steam pipe and thence to escape through the upper tubes and the escape
pipe, either into the said apparatus for obtaining the accessory products, or, when
the apparatus is employed only for the revivification of spent bone black, into the
outer air.
In order to allow of the admission of fresh steam into the cylindrical vessels not
from below, as before described, but from above, a steain pipe is fitted above the
apparatus; this steam pipe communicates by means of a valve with the super-
heating coil and by means of connecting tubes with each separate cylinder; thus
all other valves or cocks of the apparatus being suitably disposed, the fresh steam
may be admitted successively into the vessels from above so as to enter one vessel
after the other, and the steam let out from the last vessel may be educted through
tubes at the lower end thereof either into the apparatus serving to obtain the
accessory products or, as the case may be, into the outer air.
The arrangement of the described series of vessels should be adapted to local
circumstances; instead of being placed in a row, they may be arranged polygonally
or otherwise. In this case the admission and the eduction of the steam and of
the products of carbonization are modified in a suitable manner.