Process for Revivifying Boneblack or Animal Charcoal.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
Process for Revivifying Boneblack or Animal Charcoal.
I, JASPER WETTER, Patent Agent, of 433, Strand, London, do hereby declare
the nature of this invention, a communication from Moriz Weinrich, Manufac-
turer, of 1746 Waverly Place, St. Louis in the State of Missouri, United States of
America, to be as follows:-
The object of this invention is, to free boneblack through oxidation, from
organic matters and also from certain inorganic matters such as iron and sulphides
absorbed by the boneblack during the filtration of sugar solutions or other solu-
tions or liquids; or from any excess of carbon and of iron sulphides accumulated
through continuous revivifying in kilns.
As known to those versed in the art, the present mode of revivifying boneblack
consists in converting by destructive distillation, the organic matters absorbed
during the filtration, into carbon in retorts at a red heat under careful exclusion
of air. This carbon accumulates gradually and chokes the pores of the bone
black, thus impairing more and more its efficiency, until its use has to be
discontinued.
Certain inorganic matters, especially iron and sulphide of calcium, which are
very injurious to sugar solutions, accumulate likewise by this way of revivifying,
and sometimes to such a degree that the boneblack is no longer fit for use in
sugar refineries and has to be discarded for this reason alone.
My process avoids these serious disadvantages, besides being cheaper in its
operation than the ordinary kiln work. It is carried out in the following way.
The boneblack to be revivified, coming from the filters, is first deprived, through
drying, of more or less of its moisture. It then enters through some controllable
feeding device into a suitable apparatus, preferably a revolving drum provided
inside with projecting ribs which move the boneblack slowly to the discharge end,
as shown in my specification to Letters Patent No. 4354 of 1894. The apparatus
may, however, be constructed as follows.
A stationary drum or vessel having a slight incline towards its discharge end,
is provided with a shaft extending through its whole length, to which shaft
paddles are fastened, which, when set in motion, will lift and drop the boneblack
continuously moving it from the upper end to the discharge end. The vessel or
drum is surrounded by a brick wall: between the wall and the vessel a space is
left of about 6 inches in width. In this space are admitted hot gases coming from
a furnace or other outside source of heat; the object being to heat the vessel from
its outer side and thereby also the boneblack which is inside the vessel, to the
desired temperature. The gases enter this space at the discharge end of the drum,
surround it and heat it continuously in its whole length, and are drawn off either
by a chimney or a fau at its feed end.
Both ends of the vessel are provided with suitable devices in the shape of
sliding shutters or dampers, their object being to admit atmospheric air at the
discharge end and to discharge it at the feed end, thus procuring a continuous
and easily controllable draught of air through the vessel.

page_text: As soon as the apparatus is heated to the desired degree, the boneblack enters
in a regulated stream at its upper end, is there heated at once and lifted and
dropped continuously by the ribs or paddles, or other suitable means arranged in
the vessel. Any moisture retained by the boneblack will quickly evaporate and
will escape with the draught of air. At the same time the boneblack is slowly
moved to the discharge end of the vessel, and every particle of it is exposed in a
heated state repeatedly to the air which passes through the apparatus. The
oxygen of the air is thereby enabled to enter the very finest pores of every grain.
It will in this way gradually oxidize the organic matters and the iron and sulphides
taken up during its last use, and these are deposited as a thin coat on the carbon,
which itself covers the mineral frame work of the boneblack.
My correspondent has found, that if sufficient air be admitted, most of the
organic matters will oxidize at a temperature of between 250 and 300° F., and
that the rest can be removed at a temperature of outside 400° F. to which degree
the boneblack has to be exposed for a few minutes only, at the discharge end of
the apparatus, where it is the hottest, because the heated gases enter beneath the
vessel or drum at this end.
By a proper regulation of the temperature, of the draught of air, and of the
feed of the boneblack, and also of the velocity at which it is moved by the
revolving ribs or paddles, or other means through the vessel, the organic matters,
the iron and sulphides, can be oxidized without removing any of the carbon which
is lying underneath these constituents. My correspondent has found, that it
requires a temperature of over 400° F. before any of this carbon will oxidize, so
that by a proper use of the described means, a line can easily be drawn where the
revivification is completed, before any of the underlying carbon is removed. The
boneblack revivified in this way falls at the discharge end into a suitable cooling
device, and after being cooled, is again ready for use.
I will briefly enumerate the great advantages of this new way of revivifying
boneblack over the old system.
1. The boneblack is kept always at its best and no granular char has ever to be
discarded. The pores always remain open and no shrinking of the mineral
framework will take place, because of the mild heat applied during the
revivification.
2. The revivifying is done in about 20 minutes and will require only about
fifty per cent. of the fuel now needed with the ordinary kiln-work.
3. The washing of the boneblack may be discontinued as soon as the salts are
washed out, as it is time saving and cheaper to oxidize the remaining organic
matter than to wash it out.
4. The valuable carbonate of lime contained in the boneblack, which is
generally too much reduced by excessive washing with boiling water, will be
kept, by less washing, nearer to its original percentage.
5. By the regular and often repented exposure of all the particles of the bone-
black in a heated state to the air, the percentage of iron and sulphides will be
kept at low figures through oxidation.
I mentioned above, that by the present existing system of revivification of
boneblack the percentage of carbon and also of iron and sulphides accumulates
gradually and renders it thereby more and more unfit for filtration purposes.
Users of boneblack who retain this system, are enabled, by adopting the new
process as an auxiliary, to remove this accumulation of carbon, of iron and of
sulphides as often as desired, and can do this without any extra expense. In this
case, the boneblack coming from the filters is treated in substantially the same
way as herein before described.
But as, besides the organic matters, iron and sulphides, and also a certain
amount of carbon have to be removed, the means and devices for attaining this
object must be regulated accordingly.
The amount of boneblack fed into the apparatus has to be diminished, while
the temperature and the draught of air have to be increased, and in doing this

page_text: properly, the desired amount of carbon can be burned off to a nicety in a very
uniform way, thus restoring the boneblack to its original porosity and efficiency.
This combined treatment of revivifying and decarbonizing boneblack will not
requne any more fuel and attendence, than by simply revivifying it in kilns.
It is advisable to repeat this operation as often as the carbon has increased
about 2 (two) per cent. over its original percentage. If the amount of carbon to
be removed does not exceed 5 (five) per cent. of the weight of the boneblack, it
can be done in one operation at a maximum temperature of about 500° F. and by
admitting plenty of air into the apparatus. If old boueblack containing an excess
of over 5 (five) per cent. of carhon shall be reduced to its original percentage of
carbon, the temperature may be raised to such a degree, that the boneblack is
brought at the discharge cud to a dull red heat, admitting at the same time
sufficient air to ensure the desired degree of oxidation.
If the boneblack which shall have become decarbonized has been before deprived
of its organic foreign matters by burning it in the ordinary kilns, then the
treatment is substantially the same as described above. In this case a somewhat
larger quantity can be run through the apparatus in a given time, than when the
organic fereign matters and some moisture have to be removed in the same
peration.
Dated this First day of September 1896.
FAIRFAX & WETTER,
, Strand, London, Agents.
Process for Revivifying Boneblack or Animal Charcoal.
I, JASPER WETTER, Patent Agent, of 433, Strand, London, do hereby declare
the nature of this invention, a communication from Moriz Weinrich, Manufac-
turer, of 1746 Waverly Place, St. Louis in the State of Missouri, United States of
America, to be particularly described and ascertained in and by the following
statement: -
The specification of my British patent No. 1354, dated 1st March 1894, describes
an apparatus for decarbonizing and for revivifying boneblack without charring
the same.
I will now set forth a process by which carbon or other organic matter, and
also certain inorganic matters, can be removed from boneblack through oxidation,
either by means of the said apparatus, or by any other suitable device having
means for controllable admission and controllable discharge of atmospheric air,
for receiving and for discharging the matérial, and some means for admitting the
required heat to such apparatus or device.
In the drawing I have shown a simple means for practising this invention,
Fig. 1 being partly a longitudinal section and partly a side view, aud Fig. 2
being a plan. A indicates a drum or vessel adapted to treat the boneblack; B is
a means for regulating the admission of air; C a means for controlling its
discharge a means for admitting and regulating the heat for heating the
vessel; E a casing around the vessel, and a means for regulating the feed of
the boneblack; G is a revolving shaft with paddles; H a means for discharging
the heating gases: I a discharging mouth; and K a pipe to any draught or
suction fan, while the bridge-wall L serves not only to support the stationary
cylinder at its centre, but it also forces the gases to properly surround the vessel
or drum.
The object of the present process is, to free boneblack through oxidation from

page_text: ciganic matters and also fram certain inorganic matters, such as iron and
sulphides absorbed by the boneblack during the filtration of sugar solutions or
other solutions or liquids; or from any excess of carbon and of iron and sulphides
accumulated through continuous revivifying in kilns.
As known to those versed in the art, the present mode of revivifying boneblack
consists in converting by destructive distillation, the organic matters absorbed
during the filtration, into carbon, in retorts at a red heat and under careful
exclusion of air. This carbon gradually accumulates and chokes the pores of the
boneblack, thus impairing its efficiency more and more, until its use has to be
discontinued.
Certain inorganic matters, especially iron and sulphide of calcium, which are
very injurious to sugar solutions, accumulate likewise by this way of revivifying,
and sometimes to such a degree, that the boneblack is no longer fit for use in
sugar refineries, and has to be discarded for this reason aloue.
The present process avoids these serious disadvantages, besides being cheaper
in its operation, than the ordinary kiln work. It is carried out in the following
way: The boneblack to be revivified coming from the filters, is deprived first,
through drying, of more or less of its moisture. It then enters through some
controllable feeding device into a suitable apparatus, as mentioned above. I
generally prefer the use of a revolving drum provided inside with projecting ribs
which move the boueblack slowly to the discharge pipe end, as shown in my
patent specification No. 454 of 1894. The apparatus may, however, be con-
structed in different ways, for instance, as shown in the drawings, as a stationary
drum or vessel having a slight incline towards its discharge end, and provided
with a shaft extending through its whole length, to which shaft paddles are
fastened, which when set in motion, will lift and drop the boneblack, continuously
moving it from the upper end to the discharge end. The vessel or drum is
surrounded by a brick wall; between the wall and the vessel a space is left, of
about six inches in width. Into this space hot gases coming from a furnace or
other outside source of heat are admitted: the object being to heat the vessel
from its outer side, and thereby also the boneblack which is inside, to the desired
temperature. The gases enter this space at the discharge end of the drum,
surround and heat it continuously in its whole length, and are drawn off either
by a chimney or a fan at its feed end.
Both ends of the vessel are provided with suitable devices in the shape of
sliding shutters or dampers, their object being to admit atmospheric air at the
discharge end and to discharge it at the feed end, thus securing a continuous
and easily controlled draught of air through the vessel.
As soon as the apparatus is heated to the desired degree, the boneblack enters
in a regulated stream at the upper end, is there heated at once and lifted and
dropped continuously by the ribs or paddles or other suitabl means arranged in
the vessel. Any moisture retained by the boneblack will quickly evaporate, and
will e-cape in the draught of air. At the same time the boneblack is slowly
moved towards the discharge end of the vessel, and every part of it is exposed in
a heated state repeatedly to the air which passes through the apparatus. The
oxygen of the air is thereby enabled to enter the very finest pores of every grain.
It will in this way gradually oxidise the organic matters and the iron and sulphides
taken up during its last use, and which are deposited as a thin coat on top of the
carbon, which itself covers the mineral frame work of the boneblack.
I have found, that if sufficient air be admitted, most of the organic matters will
oxidise at a temperature of between 300 and 350 degrees Fal. and that the rest
can be removed at a temperature of about 400 degrees Fah., to which temperature
the boneblack has to be exposed only for a few minutes at the discharge end of
the apparatus where it is the hottest, becauso the heated gases outer beneath the
drum or vessel at this end.
By a proper regulation of the temperature, of the draught of air, and of the
feed of the boneblack and of the velocity at which it is moved by the revolving

page_text: ribs or paddles or other means through the vessel, the organic matters, the iron
and sulphides can be oxidized without removing any of the carbon which is lying
under these constituents. I have found, that it requires a temperature much
above 400 degrees Fah. before any of this carbon will oxidize, so that by a proper
use of the described means, a line can be easily drawn, where the revivification is
completed, before any of the underlying carbon is removed.
The boneblack revivified in this way falls at the discharge end into a suitable
cooling device, and, after being cooled, is again ready for use.
1 will enumerate briefly the great advantages of this new way of revivifying
boneblack over the old system.
1. The boneblack is kept always at its best, and no granular char has ever to be
discarded. The pores always remain open, and no shrinking of the mineral
framework will take place, because of the mild heat applied during the
revivification.
2. The revivitying is done in about 25 minutes, and will require only about
fifty per cent. of the fuel now needed with the ordinary kilu work."
3. The usual washing of the boneblack with boiling water in the filters after its
use, may be discontinued as soon as the salts are washed out, as it is timesaving
and cheaper to oxidize the remaining organic matter, than to wash it out.
4. The invaluable carbonate of lime contained in the boneblack, which is
generally too much reduced by excessive washing with boiling water, will be
kept, by less washing, nearer its original percentage.
6. By the regular and oft repeated exposure of all the particles of the boneblack
in a heated state to the air, the percentage of iron and sulphides will be kept at
low figures through oxidation.
It was mentioned above, that by the present existing system of revivifying
boneblack, the percentage of carbon and also of iron and sulphides accumulates
gradually and renders it thereby more and more unfit for filtration purposes.
Users of boueblack who retain this system are enabled, by adopting this
process as an auxiliary, to remove as often as desired, this accumulated excess
of carbon, of iron and of sulphides, and can do this without any extra expense.
In this case the boneblack coming from the filters is treated in substantially
the same way as hereinbefore described; but as, besides the organic matters, iron
and sulphides and also a certain amount of carbon have to be removed, the means
for attaining this object must be regulated accordingly.
The amount of boneblack fed into the apparatus has to be diminished, while
the temperature and the draught of air have to be increased, and by doing this
properly, the desired amount of carbon can be burned off to a nicety in a very
uniform way, thus restoring the boneblack to its original porosity and efficiency.
This combined treatment of revivifying and decarbonizing boneblack will not
require any more fuel and attendance than by simply revivifying it in kilns.
It is advisable, to repeat this operation as often as the carbon has increased
about two (2) per cent. over its original percentage. If the amount of carbon to
be removed does not exceed five (5) per cent. of the weight of the boneblack, it
can be done in one operation at a maximum temperature of about 600 degrees Fab.
and by admitting plenty of air into the apparatus. If old boneblack containing
an excess of over five (5) per cent. of carbon shall he reduced to its original
percentage of carbon, the temperature may be raised to such a degree, that the
boneblack is brought at the discharge end to a dull red heat, admitting at the same
time sufficient air to ensure the desired degree of oxidation.
The same object can be attained by treating the boneblack twice or three times
at a lower temperature thau red heat, removing by each operation from two to
three per cent. of carbon.
This method of treating boueblack can be applied also with great advantage to
other carbonaceous filtering materials which are employed in granular or
dust-like form.
If the boneblack which is to be decarbonized, has been before deprived of its

page_text: organic foreign matters by burning it in the ordinary kilns, then the treatment
is substantially the same as described above. In this case a somewhat larger
quantity can be run through the apparatus in a given time, than when the
foreign organic matters and some moisture have to be removed in the same
operation.
Having now particularly described and ascertained the nature of my said In-
vention and in what manner the same is to be performed, I declare that what I
claim is:
1. The herein described process for revivifying boneblack or other carbonaceous
filtering materials through oxidation, which consists in exposing the boneblack
in a heated state to a regulated draught of atmospheric air and to a regulated
temperature and under a regulated feed of the boneblack.
2. The herein described process for revivifying boneblack or other carbonaceous
filtering materials, which consists in removing from it through oxidation all the
organic impurities and certain inorganic impurities and also any excess of carbon,
by exposing the boneblack in a heated state, and while being transported in a
suitable device, to a regular draught of atmospheric air and to à regulated
temperature and under a regulated feed of the boneblack.
Dated this 27th day of May 1897.
FAIRFAX & WETTER,
37 & 39, Essex Street, Strand, London, Agents.