IMPROVEMENTS MANUFACTURE OF THE PEROXIDES OF THE ALKALIES, ALKALINE IN THE AND HYDROGEN. EARTHS AND THE APPLICATION OF THE SAME FOR BLEACHING PROVISIONAL SPECIFICATIONTION FOR BLEACHING PURPOSES AS FAR AS REGARDS PEROXIDE OF
Year: 1882

page_text: LETTERS PATENT to Ludwig Mond of Winnington Hall Northwich in the
county of Chester Manufacturing Chemist, for an invention of "IMPROVEMENTS
MANUFACTURE OF THE PEROXIDES OF THE ALKALIES, ALKALINE
IN THE
AND HYDROGEN.
EARTHS
AND THE APPLICATION OF THE SAME FOR BLEACHING
PROVISIONAL SPECIFICATION left by the said Ludwig Mond at the Office
of the Commissioners of Patents on the 6th April 1882.
LUDWIG MOND of Winnington Hall Northwich in the county of Chester Manu-
facturing Chemist "IMPROVEMENTS IN THE MANUFACTURE OF THE PEROXIDES OF
THE ALKALIES, ALKALINE EARTHS AND HYDROGEN; AND THE APPLICATION OF THE
SAME FOR BLEACHING PURPOSES AS FAR AS REGARDS PEROXIDE OF CALCIUM."
Peroxide of hydrogen has been suggested repeatedly for bleaching purposes but
the difficulty experienced hitherto in manufacturing it cheapley has prevented its
adoption in any but a few very exceptional cases. Its liquid nature is also much
against its adoption for general bleaching purposes owing to its expense of
transport, and its liability to decomposition under certain circumstances.
I have however discovered that the peroxide of calcium is an almost equally
good bleaching agent and has the additional advantage of being solid. It is for
the application of this peroxide of calcium as a bleaching agent, and also for a
cheap method of manufacturing it, and the other alkaline, and alkaline earth
peroxides, and the peroxide of hydrogen, that this my invention is designed.
The method of manufacturing these peroxides which I propose to adopt may be
varied considerably. In all cases however I prefer to make the peroxide of barium
first and then form the peroxide of hydrogen and from this I produce the peroxides
of the alkalies or other alkaline earths by substitution. .
•
I take barium carbonate and make it into blocks with a small quantity of pitch
or other suitable material to agglutinate it and add carbon and saw dust or other

page_text: pure carbonaceous material to give it porosity and also add lime, strontia, magnesia,
or their carbonates to soak up the barium carbonate and to prevent it liquefying.
These blocks are heated to 1200 degrees centigrade in the upper part of a cupola,
or in one of the chambers of a continuous kiln as hereafter described by means of
gaseous fuel. Air heated to from 400 to 500 degrees centigrade is introduced at
or near the bottom of the cupola (or the chamber being for the time the last of a
continuous kiln). The mode of action will be evident by describing the cupola in
full operation.
Or the
The material supplied at the top of the cupola is heated by the escaping gases
till it reaches the combustion zone where it attains the heat of about 1200 degrees
centigrade through the combustion of the gaseous fuel, and the heated air coming
up from the bottom. Here the carbonate is changed into caustic baryta, and part
of the carbon burnt off; in the zone immediately below any excess of carbon is
burnt off at a heat still sufficiently high to prevent the Ba. O recombining with
the C. O., there formed descending still further and becoming gradually cooler
through meeting the ascending current of air the Ba. O attains the temperature of
about 400 to 500 degrees centigrade when it is still further oxidized and for the
most part becomes (Ba. O..) Small charges-from time to time are removed from
the bottom of the cupola. The mass is then lixiviated with water to remove the
Ba. O, and the insoluble portion treated with carbonic acid and water.
whole mass may be treated with CO₂ and water without previous lixiviation;
carbonate of barium, and peroxide of hydrogen are thus formed. The first is used
again to make fresh blocks for the process already described, the second is used to
make other peroxides or is separated from the water by freezing or by evaporation
at a very low temperature in vacuo. If pure peroxides of alkaline earths be
required the peroxide of hydrogen solution separated from the barium carbonate is
treated with the hydrates or oxides of the bases required, in this way calcium and
other peroxides are made, in the case of peroxide of calcium the most valuable and
useful of the lot milk of lime is used to decompose the peroxide of hydrogen. If
the peroxides of the alkalies are required the peroxide of barium is treated with a
solution of an alkaline carbonate, when carbonate of barium is formed and the
peroxide of the alkali is found in solution.
In using a continuous kiln with chambers worked in series instead of a cupola
each zone, namely the heating zone, oxydizing zone, complete combustion zone, and
second oxydizing zone of the cupola is represented by a separate chamber or a
number of separate chambers in the kiln, in other respects which ever apparatus
be used the various stages of the process remain the same.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Ludwig Mond in the Great Seal Patent Office on the
6th October 1882.
THE
LUDWIG MOND of Winnington Hall, Northwich in the county of Chester,
Manufacturing Chemist. 'ÏMPROVEMENTS IN THE MANUFACTURE OF
PEROXIDES OF THE ALKALIES, ALKALINE EARTHS, AND HYDROGEN; AND
APPLICATION OF THE SAME FOR BLEACHING PURPOSES AS FAR AS REGARDS:
PEROXIDE OF CALCIUM,"
THE
Peroxide of hydrogen has been suggested repeatedly for bleaching purposes but
the difficulty experienced hitherto in manufacturing it cheaply its liability to
decomposition and the difficulty of transport have prevented its adoption in any
but a few exceptional cases, I have however discovered that the Peroxide of
Calcium is an almost equally good bleaching agent and has the great advantage of
being solid and perfectly stable. It is for the application of this Peroxide of
Calcium as a bleaching agent and also for a cheap method of manufacturing it and
the other alkaline, and alkaline earth Peroxides and the Peroxide of Hydrogen
that this my invention is designed.
The method of manufacturing these Peroxides which I propose to adopt may be
varied considerably. In all cases however I first make Peroxide of barium, and
then form Peroxide of Hydrogen and from this I produce the Peroxides of the
alkalies or alkaline earths by substitution.
I take Barium Carbonate and make it into blocks with a small quantity of pitch
or other suitable material preferably about 1. of pitch to 9. of Carbonate of Barium
and add carbon and Sawdust or other pure carbonaceous material and also some-
times add magnesia lime Strontia or their carbonates to make the blocks less
fusible at a high temperature. Of these earths magnesia gives the best results but
neither it nor the extra carbon are necessary as with care good results are obtained
from pitch and Carbonate of Baryta only. These blocks are heated to about
1200 degrees centigrade in the upper part of a cupola or in one of the chambers of
a continuous kiln as hereafter described. Air heated to from 400 to 500 degrees
centigrade is introduced at or near the bottom of the cupola or into a chamber
being for the time at or near the bottom of the cupola or into a chamber being for
the time at or near the tail-end of a continuous kiln. The mode of action will be
evident by describing the cupola in full operation.
The material supplied at the top of the cupola is heated by the escaping gases
and gradually descending is submitted to a heat of about 1200 degrees centigrade.
Here the carbonate is changed into Caustic Baryta and the greater part of the
Carbon is burnt off. In the zone immediately below any excess of carbon is burnt
off at a heat still sufficiently high to prevent the Caustic Baryta recombining with
the Carbonic acid there liberated. The heat required in this part of the process is
most conveniently obtained by introducing into the part of the kiln where the
Carbonic Acid is driven off gaseous fuel obtained from an ordinary gas producer
which coming into contact with the hot air introduced near the bottom of the kiln
and which has only been partially deprived of its oxygen produces a very high
temperature. Where a sufficient quantity of a pure carbonaceous material such as
Sawdust, coke from pitch or from oil residues et-cetera is available the use of.
gaseous fuel can be partially or entirely dispensed with by mixing these materials
into or with the blocks in sufficient quantity to produce the .required heat on
combustion. In both cases it will be necessary to regulate the amount of hot air
passing through the upper part of the kiln and for this purpose arrangements are
made which allow the withdrawal of part of the air introduced into the kiln

page_text: before it reaches the region where the carbon is burnt off. and which we call the
combustion zone. Descending further and becoming gradually cooler through
ineeting the ascending current of air the Caustic Baryta gradually cools down and
when a temperature of about 550 degrees centigrade is reached it commences to
absorb oxygen and continues to do so until it is cooler below 450 degrees
centigrade, becoming for the most part converted to Peroxide of Barium. When
his conversion is sufficiently advanced small charges are removed from time to
time from the bottom of the cupola. The introduction of steam into both the
upper and lower part of the cupola. will be found advantageous.
To more clearly explain this part of my invention I have appended a sectional
sketches of a cupola for use in forming Peroxide of Barium. Fig. 1 being an elevation
and Fig. 2 a plan. In these A B represent the interior of the cupola the part A
being parallel and of smaller diameter so as to enable the gases to thoroughly
permeate the materials, that part marked B is preferably conical as shown. C is a
hot air stove of any ordinary construction for heating the air to about 400 degrees.
centigrade. D, hot air flue passing round the cupola, and with pigeon holes at
intervals, admitting the air into the cupola, E gas generator also of any ordinary
construction F exit flue for discharging the excess of hot air provided with a
damper not shown in the drawing. G gas flue also passing round the cupola with
pigeon holes as in the air flue. H pipe carrying the hot waste gases from the cupola
to the air heating stove. I sloping hearth K door for extraction of the peroxidized
material.
In using a continuous kiln with chambers worked in series instead of a cupola,
each zone, namely the heating zone, combustion zone, and oxidizing zone of the
cupola is represented by a separate chamber, or a number of Separate Chambers in
the kiln, in other respects whichever apparatus be used the various stages of the
process remain the same.
The flues which carry the hot air and the producer gases to the kiln and which
take the excess of hot air and the products of combustion away from the kiln must
all four be connected with all the various chambers of the kiln so that each
chamber in rotation can be put into communication with one or more of these four
flues as may for the time be.required.
The material withdrawn from the cupola or kiln is mainly composed of Peroxide
of Barium, Caustic Baryta, and carbonate of Baryta. This mass is lixiviated with
water to remove the remaining Caustic Baryta the insoluble portion is then treated
with carbonic acid and water, or the whole mass removed from the cupola may be
treated with carbonic acid and water, without previous lixiviation. This operation
is preferably performed by mixing or grinding the mass containing the Peroxide
of Barium with a small quantity of water, and then forcing from time to time
small quantities of this mixture into a vessel filled with water through which a
current of Carbonic Acid gas (which may be obtained from a lime kiln) is passed
under pressure. This vessel must be provided with efficient cooling appliances,
such as worms or mantles through which water circulates, so as to prevent any rise
of temperature. Carbonate of Baryta and a solution of Peroxide of Hydrogen are
thus formed. The first is separated by settling or filtration preferably by a filter
press and after washing and drying it is used over again to make fresh blocks for use
in the first part of the process. To obtain a good yield of Peroxide of Hydrogen by
the described operation it is absolutely necessary to avoid the presence of oxidizable
or disoxidizable oxides, such as the oxides of iron manganese et-cetera. Very
ninute quantities of which cause the decomposition of a large proportion of the
Peroxide of Hydrogen in course of formation. For this reason the repeated use
of the carbonate of Baryta regenerated by the process itself and which is quite
free from these oxides, is of the greatest importance for the successful working
of my invention. The solution of Peroxide of Hydrogen so obtained can be'
directly employed as a bleaching agent, or for any other purpose for which
such a solution can be used, but I prefer to use it for the manufacture of
other Peroxides.

page_text: The Peroxide of Calcium Strontium and Barium I produce by treating the
Peroxide of Hydrogen solution with the oxides required. In the case of the
Peroxide of Calcium the cheapest and at the same time the most valuable of these
substances as it contains the largest amount of useful Oxygen, milk of lime may
be used to decompose, the Peroxide of Hydrogen, but lime water also answers the
purpose. The hydrated Peroxide of Calcium which is very insoluble in water is
thus formed and is separated by filtration preferably by a filter press. It may be
brought into the market in the moist state as obtained by the press, or it may be
dried at a low temperature, or if desired it may be converted into the anhydrous
Peroxide of Calcium by exposing it to a temperature of 100 degrees centigrade
before it is sent out. All these products contain a large amount of useful oxygen
and compare in this respect favourably with Bleaching Powder. Peroxide of
Calcium can be used for bleaching oxidizing or disinfecting purposes by mixing it
up with water and adding the mixture direct to the substances to be bleached,
oxidized or disinfected warming the whole if required to expedite the action, but
generally it will be preferable to treat the Peroxide of Calcium with an acid
(Carbonic Acid will be the cheapest) or with a Solution of Chloride of Magnesium
or Sulphate of Magnesia, so as to obtain Peroxide of Hydrogen in Solution, or the
Peroxide of Calciuin may be treated with a solution of the Carbonate of Potass or
Soda, when the Peroxide of Potass or Soda is obtained in solution. These Peroxides
of Potass or Soda may also be made by treating with a solution of their carbonates
the Peroxide of Barium as it is left after lixiviation of the mass withdrawn from
the cupola or kiln, when the alkaline Peroxide is found in solution and Carbonate
of Baryta is formed and thus regenerated.
Having now described my invention and the best mode known to me of carrying
it into effect I wish it to be understood that I do not claim as my invention the
manufacture of Barium Peroxide by treating Caustic Baryta with air at from
400 to 500 degrees centigrade, nor the Subsequent obtaining of Peroxide of
Hydrogen by treating the Peroxide of Barium with Carbonic Acid, but what I do
believe to be new and desire to claim under the Letters Patent is-
1st. The manufacture of Barium Peroxide from Carbonate of Baryta in a cupola
or continuous kiln in one part of which the material is exposed to great heat so as
to reduce it to Caustic Baryta and in another to the action of hot air to produce
the Barium Peroxide substantially as described.
2nd. The continuous process of manufacturing Peroxide of Barium in which hot
air passing among the material successively (1) converts Caustic Baryta into
Peroxide (2) burns the excess of carbon (3) assists in producing the heat necessary
for driving off the Carbonic Acid from the Carbonate of Baryta and (4) in the form
of products of combustion and decomposition heats up the mixture, or blocks of
Carbonate of Baryta and Carbon.
3rd. The combination of the various operations whereby Carbonate of Baryta is
employed in the manufacture of Peroxide of Hydrogen, is regenerated, and is used
over and over again substantially as described.
4th. The application of Peroxide of Calcium for bleaching purposes substantially
as described.
In witness whereof, I the said Ludwig Mond have hereunto set my hand
and seal this twenty eighth, day of September in the year of our Lord
LUDWIG MOND (L.S.)