Improvements in Apparatus for Treating Liquids with Gases and for other Purposes.
Year: 1899

page_text: Date of Application, 4th July, 1899
Complete Specification Left, 3rd May, 1900-Accepted, 4th Oct., 1900
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Treating Liquids with Gases and for
other Purposes.
I, PAUL NAEF, Ph. D., of 132, Woody Crest Avenue, near 165th Street, New
York, United States of America, Chemical Engineer, do hereby declare the
nature of this invention to be as follows:-
This invention relates to the construction of hollow cylinders for treating.
liquids with gases such as are referred to in Specification No. 13771 of 1899; the
said cylinders being also applicable to the treatment of various substances with
fluids.
According to my invention hollow cylinders are mounted' so as to revolve on
suitable rollers and are rotated in any suitable way.
In the interior the cylinders have pipes for cooling, which run through the
cylinders, and are connected at one end to a pipe for supplying a suitable cooling
fluid, and at the other end with an exit pipe for the fluid. There are further
arranged radial perforated partitions, which produce a fine distribution of liquor,
also longitudinal lifters, which lift the liquor and gradually empty it on to the
perforated partitions as the cylinders revolve. For the purpose of further increas-
ing the intimate contact of liquor and gas, there are arranged vertical cross-
partitions, with openings in such position, that the gas has to traverse the
revolving cylinder in a zig-zag way. The interior arrangement of the cylinder
is varied according to the use and according to the quantity of precipitate formed
in the apparatus.
In large plants, and if much precipitate is formed, it is of advantage to arrange
the longitudinal partitions in sections and to provide suitable manholes between
them, so as to give access for cleaning. By arranging a vertical partition at one
end of each section access can be had to all the longitudinal partitions through
the manholes without interfering with the vertical partitions.
To increase the efficiency of the perforated longitudinal partitions for the
purpose of lifting and showering the liquor, they have longitudinal rims and
also vertical rims. These rims prevent sudden flowing off, of the liquor from
the partitions without it passing through the perforations.
The longitudinal lifters can have the form of pipes having each a longitudinal
row of openings, or one slit running its length, and they may be fastened to the
partitions. They may be arranged running through the cylinder in one length
or in several longitudinal sections. Each pipe being closed at each end; fills
itself during the passage through the liquor. As the cylinder revolves the liquor
is gradually emptied on to the partitions. If the slit or openings are placed in
proper position liquor will be discharged from the lifters evenly during the whole
revolution. If the lifters and partitions are arranged in sections it is of advan-'
tage to arrange the sections radially offset, as in this way the intimate contact of
liquor and gas is further improved.

page_text: At each end the cylinders are closed by a stationary end plate, which has a flange
fitting loosely into the flange in the end of the cylinder. A suitable packing is
placed into the space between the two flanges and is tightened by a loose ring.
The stationary end-plate carries suitable gas and liquor pipes. Through the
centre of one end plate passes the cooling fluid inlet pipe, which is connected
to the cooling pipes by a connecting pipe and which is joined to a stationary
supply pipe by a suitable stuffing box.
If the cylinder is to be used for washing gases without the formation of
precipitate. such as the washing of waste gases resulting from the treatment of
brine with carbonic acid gas, it contains numerous vertical cross-partitions con-
structed of wire gauze, perforated wooden boards or other suitable material. At
intervals there are arranged non-perforated cross partitions having one or more
holes which are so arranged, that the gas has to pass through the cylinder in a
zig-zag way
The longitudinal lifters for the liquor are the same as described. They empty
the liquor in to the vertical partitions and as the gas has at the same time to
pass through the numerous perforations a most intimate contact is obtained. To
prevent the liquor flowing off too quickly from the vertical perforated partitions
rims can with advantage be arranged on them, which retard the flow. In this
form of apparatus the longitudinal partitions are not as important as in the
apparatus first described! If used they give the great advantage of showering
liquor in finest division on to the vertical partitions. This form of apparatus is
of great advantage for absorbing gases by liquor generally, where not much
precipitate is formed
Dated this 4th day of Anril 1900.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C..,
Agents for the Applicant.
Improvements in Apparatus for Treating Liquids with Gases and for
other Purposes.
I, PAUL NAEF, Ph.D., of 132, Woody Crest Avenue, near 165 Street, New
York, United States of America; Chemical Engineer, 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:-
This invention relates to the construction of 'hollow cylinders for treating liquids
with gases, such as are referred to in Specification No. 13771 of 1899.
According to my invention the hollow cylinders are mounted so as to be capable
of revolving and are provided internally with pipes which may be used for the
circulation of cooling or heating fluid There are further arranged within the
cylinders, radial longitudinal perforated partitions which produce a fine dis-
tribution of liquid in the cylinder; also longitudinal lifters which are adapted
to lift liquid aud gradually empty it on to the perforated partitions as the cylinder
revolves. For the purpose of further increasing the intimate contact of the sub-
stances in the cylinder. there may be arranged vertical cross partitions having
openings in such positions that the gas may be caused to traverse the revolving
.cylinder in a zig-zag path.
In large plants, and if much precipitate is to be formed in the cylinder, it is
of advantage to arrange the longitudinal partitions in sections and to provide
manholes between these sections so as to afford access for cleaning the cylinder.

page_text: To increase the efficiency of the perforated longitudinal partitions, they may be
provided with longitudinal ribs and also with cross ribs. These ribs may or may
not be curved and are adapted to prevent liquid from flowing off the partitions
without passing through the perforations in such partitions.
If the longitudinal perforated partitions are arranged in sections, it is of
advantage to arrange these sections in radially offset positions. that is to say with
the partitions of each section out of alignment with the partitions of the other
sections in order to obtain a more intimate contact of the substances treated.
In order that my invention may be clearly understood and readily carried into
effect I will proceed to describe the same more fully with reference to the accom-
panying drawings in which:-
Figure 1 is a longitudinal section of a suitable form of revolving cylinder
for treating liquid with gas.
Figures 2 and 3 are respectively sections on lines and y-y of Figure 1.
Figure 4 is a longitudinal section of a modified form of cylinder for treating
liquid with gas.
Figure 5 is a cross section of the cylinder shown in Figure 4.
Figure 6 is a longitudinal section of a suitable form of cylinder for the absorp-
tion of gas by liquid without the formation of precipitate.
Figure 7 is a cross section of the cylinder shown in Figure 6.
Referring to Figures 1, 2 and 3, 6 is the shell or outer casing of the cylinder.
2, 2, are the fluid circulating pipes for cooling or heating, which terminate at
each end of the cylinder in plates 61, 61. The pipes 2 may be secured to the
plates b', 6' by means of flanges or by the method usually employed in locomotive
boilers. There is an annular space between each of the plates 61. 6 and the end
plates b. 63 of the cylinder, with which spaces the pipes 2, 2 communicate. 3 is
the inlet to, and 4 is the outlet from the pipes 2, 2. 4* 4* are pipes respectively
connecting the pipes 3 and 4 with annular spaces between the plates b¹¹
and 62, 6 Fluid enters by the pipe 3, passes through the pipes 2, 2, and leaves
by the pipe 4, as indicated by the arrows. Each of the end plates 63 is provided
with a flange into which fits a stationary cover c provided with a rim.
suitable packing is placed between the flange and the cover c, which packing
is held in position by an adjustable ring r. Liquid enters the cylinder through
the pipe 19, and the liquid, with any precipitate it contains, leaves the opposite
end of the cylinder by the pipe 20. Gas enters the cylinder through the pipe 18
and leaves through the pipe 7. The cover c is preferably made larger at that
end of the cylinder at which the outlet 20 is situated.
A
The cylinder is rotated in any suitable manner and is supported by suitable
rollers 11, which run on hoops or bands attached to the cylinder.
The interior of the cylinder is divided into sections 63, 64, 65 provided with
perforated longitudinal partitions which may advantageously consist of plain .or
corrugated wire gauze, or of corrugated iron, or other suitable substance. Between
these sections are open spaces s which are accessible for cleaning purposes through
suitable manholes. The said longitudinal partitions of each section are preferably
arranged in radially offset positions, or at an angle to the longitudinal partitions
of the adjacent section or sections, in such manner that the longitudinal partitions
of section have the position shown in full line in Figure 2 while the longitu-
dinal partitions of the adjacent section 6 have the position shown in dotted lines
in Figure 2. The longitudinal partitions of section 65 can again have the position
of those of the section b³. This arrangement ensures a very intimate contact
of the liquid and gas in their passage through the cylinder. Vertical cross
partitions p, p, pª provided with openings o, o², o³, are arranged in such manner
as to cause the gas to pass through the cylinder in a zig-zag path.
'd, dare pipes provided with openings d, d. These pipes may be formed on
or attached to the longitudinal partitions, or they may be attached to the cylinder,
and are for the purpose of raising liquid and showering it on the perforated
longitudinal partitions as the cylinder revolves, The pipes d, d may extend

page_text: through the cylinder, or, if the cylinder is arranged in sections the said pipes
may also be formed in sections. The openings di are so arranged that liquid
enters the pipe through them when the said pipe is in its lowest position and' that
liquid is discharged through them on to the perforated longitudinal partitions
as the pipes d, d are raised during the revolution of the cylinder.
Referring to Figures 4 and 5, b is the shell or casing of the cylinder, 2 are the
cooling or heating pipes. 63, 6 are the end plates of the cylinder. The pipes 2, 2
pass through the end plates 3, 3, and the ends of said pipes communicate respec-
tively with annular pipes 66, 66. 3 is the cooling fluid inlet and 4 is the cooling
fluid outlet. 4*, 4* are pipes respectively connecting the pipes 3 and 4 with the
annular pipes 66, 6. The flanges f, rings r, and covers e, are arranged as described
with reference to the preceding figures. The liquid enters the cylinder through
the pipe 19 and leaves through the pipe 20. The gas enters the cylinder through
the pipe 20 and leaves through the pipe 7. This arrangement is of special
advantage if the liquid passes through several cylinders successively, as the
pipe 20 serves both for conveying the liquid from the upper to the lower cylinder
and for conveying gas from the lower to the upper cylinder. In the interior of
the cylinder there is a space at the charging end, and radial partitions e, e
running through the rest of the cylinder. These radial partitions e, e meet on
the axis of the cylinder and are provided with longitudinal ribs e', el which may or
may not be curved. The partitions, e and ribs e may be cast together. and are
both perforated; they may with advantage be made of wire gauze, or of corrugated
iron, or of wood. The ribs e" act as distributors of the liquid and prevent the
liquid from running off the partitions e, too quickly. It is often of advantage io
use corrugated wire gauze for the partitions & and to then omit the ribs e¹, the
corrugations being so formed as to effect a result similar to that effected by
the ribs' e'.
The pipes d, for showering the liquid are shown as forming part of the
partitions e. For the purpose of preventing the liquid from running through the
partitions too quickly. there are further arranged cross ribs on the partitions.e.
Usually also, perforated cross partitions such as described with reference to
Figures 1, 2 and 3 are employed. The ribs e and are only shown in part of the
cylinder; they may be omitted near the discharge end: It is usually of advan-
tage, however, to run the radial partitions e up. to the discharge end of the
cylinder as they assist in discharging solid material:
Referring to Figures 6 and 7. 6 is the cylinder shell or casing; 2. 2, are the
cooling or heating pipes; 66, 66 are the annular, pipes connecting the ends of
the cooling pipes; 63, are the cylinder ends: f, are the flanges; r, are the
rings and are the fixed covers; 3 is the cooling or heating fluid inlet;
4 is the cooling or heating fluid outlet; 4*, 4* are the pipes respectively con-
necting the cooling or heating fluid inlet and outlet. with the annular pipes 66;
as previously described. 8 is the liquid inlet, 11 is the liquid outlet. 9 is the gas
inlet and 10 is the gas outlet. In the interior of the cylinder are arranged a
number of perforated vertical cross partitions ³, p³ which usually consist of
wire gauze.
At suitable intervals there are also arranged vertical cross partitions which
are not perforated but are provided with openings o, o' which serve to cause the
gas to travel in a zig-zag patli in a similar manner to that described in Figures 1
2 and 3. For the purpose of cleaning the partitions 73 and also the spaces between
these partitions, doors bare provided. These doors permit a thorough cleaning
of the partitions without removing the latter. d, d are perforated pipes at the
periphery of the cylinder, for the purpose of lifting and showering the liquid
on to the partitions . As the pipes d,.d reach their lowest position, they fill
with liquid which they empty on to the partitions as the cylinder revolves.
It is often of advantage to use perforated radial longitudinal partitions
9, which
assist in raising the liquid and showering it over, the partitions p³.

page_text: Having now particularly described and ascertained the nature of my sail
invention and in what manner the same is to be performed, I declare that what
I claim in apparatus for treating liquor is:-
1. A hollow rotary cylinder provided with longitudinal radial perforated parti-
tions arranged substantially as and for the purpose specified.
2. A hollow rotary cylinder provided with longitudinal radial perforated parti-
tions arranged in offset sections substantially as and for the purpose specified.
3. A hollow rotary cylinder provided with longitudinal radial perforated parti-
tions provided with ribs substantially as and for the purpose specified!
4. A hollow rotary cylinder provided with vertical cross partitions having
openings for directing the flow of fluid through the cylinder, substantially as
described
5. A hollow rotary cylinder provided with perforated longitudinal partitions and
means for lifting liquid and showering it on said partitions, substantially as
described.
6. A hollow rotary cylinder provided with perforated longitudinal radial parti-
tions, and vertical cross partitions having openings for directing the flow of fluid
through the cylinder, substantially as described.
7. A hollow rotary cylinder provided with vertical perforated partitions and
vertical cross partitions having openings for directing the flow of fluid through
the cylinder, substantially as described.
8. A hollow rotary cylinder provided with vertical perforated partitions and
means for lifting liquid and' showering it on said partitions, substantially as
described.
9. A hollow rotary cylinder provided with a series of internal pipes for the
circulation of fluid, and means for lifting and showering liquid in the cylinder.
substantially as described.
10. A rotary cylinder constructed arranged and operating substantially as
described with reference to any of the examples illustrated in the accompanying
drawings for the purposes specified.
Dated this 3rd day of May 1900.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, WC.
Agents for the Applicant.

page_text: Date of Application; 4th July, 1899
Complete Specification Left; 4th May, 1900-Accepted, 4th Oct., 1900
Method and Apparatus for Producing Alkali and Chlorine.
PAUL NAEF, Ph. D., Chemical Engineer, of Woody Crest Avenue, near 165th
Street, New York, U.S.A., do hereby declare the nature of this invention to
be as follows:-
This invention refers to the manufacture of alkali products and chlorine from
chloride of sodium.
The improvements are in connection with the so called. ammonia-soda process.
Objects of the invention are:
To recover the chlorine, which is at present usually lost in ammonia-soda
works;
To reduce the large loss of salt, which takes place in the ammonia-soda-process
at present;
To avoid the enormous amount of waste liquor produced at present;
To reduce the amount of steam used and the power required for carrying out
the ammonia-soda-process;
To reduce the loss of ammonia and the volume of waste gases;
To reduce the loss of lime in the process and produce cement instead ;
To avoid pumping of gas under high pressure.
The method furnishes a continuous production of bicarbonate of soda and
chlorine gas and consists of the following steps:
1) Saturating brine with ammonia gas obtained in a later step of the process;
2) Treating the saturated liquor with carbonic-acid gas for the production of
bicarbonate of soda, a solution of chloride of ammonia being simultaneously
produced;
3) Cooling the ammonium chloride solution for the separation of solid chloride
and returning the remaining solution to step, 1, after saturating the same with
Bolid salt;
4) Separating ammonia from the solid ammonium chloride by heating it with
an oxide, preferably magnesium oxide and returning the ammonia gas to step 1.
5) Decomposing the mixture of magnesium oxide and chloride obtained by
step 4, by means of heated air, returning the oxide to step 4, and utilizing the
chlorine gas obtained by the decomposition for the manufacture of bleaching
powder.
The drawing shows the general arrangement of the plant.
The process is
carried out in revolving cylinders, mounted on suitable rollers 1 and rotated
in any suitable way.
In the interior the cylinders have pipes 2 for cooling, which run through the
cylinders, and are connected at one end to a pipe (3) for supplying a suitable
cooling fluid 3, at the other end with an exit pipe for the fluid 4. There are
further arranged radial perforated partitions, which produce a fine distribution

page_text: "
of liquor, also longitudinal lifters, which lift the liquor and gradually empty
it on to the perforated partitions as the cylinders revolves. For the purpose of
further increasing the intimate contact of liquor and gas, there are arranged
vertical cross-partitious, with openings in such position, that the gas has to
traverse the revolving cylinder in a zig-zag way.
At each end the cylinders are closed by a stationary end plate, which has a
flange fitting loosely into the flange in the end of the cylinder. A suitable pack-
ing is placed into the space between the two flanges and is tightened by a loose
ring. The stationary end-plate carries suitable gas and liquor pipes. Through
its centre passes the pipe. 3, which is in connection with the cooling pipes 2
by a connecting pipe 4 and which is joined to a stationary supply pipe by a
suitable stuffing box.
The brine used in the process is saturated with ammonia by passing it first
through washer A' and afterwards through saturator A.
The latter is con-
structed as described; the former being used for washing the waste gases result-
ing after the treatment of the brine with carbonic acid gas, is constructed some-
what differently. It contains numerous perforated vertical cross-partitions con-
structed of wire gauze, perforated wooden boards or other suitable material. At
intervals there are arranged non-perforated cross partitions, having one or more
holes, which are so arranged, that the gas hias to pass through the cylinder in
in a zig zag way.
The. fresh brine runs continually into A through pipe 5 and the waste gas
leaves perfectly free from ammonia through pipe 6. The waste-gas enters A'
from 13 through pipe 7, and the brine leaves the same apparatus through pipe 8
which delivers it to A.
Ammonia gas from the 4th step of the process, which is carried out in cylinder D,
enters this saturator A, continuously through pipe 9. The gas, which leaves
through pipe 10, is returned to D, as later on described.
The brine saturated with ammonia leaves A, through pipe 11, and passes
through settling tank 12, for removal of any lime or other, impurity precipitated
from the brine.
The saturated brine is treated with carbonic acid gas in the cylinders. B. and B¹
for the precipitation of bicarbonate of soda. This operation is carried out with
as efficient cooling as possible. This cooling is partly effected by circulating
water or another cooling fluid through the pipe system in the cylinders B
and B. As the pipes get gradually covered with scale, which reduces their
efficiency, more thorough cooling is effected by cooling the carbonic acid gas
used in the process. This gas comes from a suitable kiln, to be later on described,
through pipe 13, and passes through a suitable washer 14, to remove dust and
other impurities. It enters through pipe 14 a suitable gas cooler B3, in which
it is cooled to low temperature.
The cold gas leaves the cooler through pipe 16. and is in cylinder B, brought
into intimate contact with liquor flowing to it from pipe 17. The unabsorbed
gas leaves B through pipe 15 and enters cooler B here it is again cooled,
leaves through pipe 18, through which it enters cylinder B' leaving the latter
practically free of carbonic acid through pipe 7, by which it is conducted to
washer A, as described. The brine saturated with ammonia enters cylinder B¹
through pipe 19; from settling tank 12, and leaves B¹, by pipe 20." It flows
through settling tank 21, and 22, to settle bicarbonate; it then enters cylinder B
through 17. From B pipe 23 conducts it through the settling tanks 24 and 25,
in which most of the bicarbonate settles, which is withdrawn from, the conical
bottom. The system for treating the liquors with carbonic acid gas described
gives a most intimate contact of gas and liquor, and very efficient cooling, and
can be used for very dilute gases: It requires very little gas pressure, which
may be supplied by a suitable fan. The coolers B, and B3, may be of any suit-
able construction. They can be constructed on the principle of the locomotive
boiler and any, suitable fluid can be used for cooling. As no liquor passes
through these gas coolers they need no cleaning, and do not loose their efficiency.

page_text: If ammoniated brine is treated in the way described it is noticed; that little
bicarbonate is formed in the beginning and also towards the end of the treat-
ment. Most of the precipitation takes place during a middle period. It is of
advantage to treat the liquor during this period in an apparatus, which allows,
very easy removal of the bicarbonate and can easily be cleaned without inter-
fering with the general run of the process. Apparatus 12 is so arranged. It
consists of a vertical cylinder having a suitable filling, which gives no resistanco
and can be quickly removed, or cleaned by steaming. A continuous flow of liquor
is sent into the top of the apparatus through pipe 27, and a suitable pump 28.
During its passage it meets a current of cold strong carbonic acid gas. Much
of the bicarbonate settles in the conical bottom of 132, from which it is with-
drawn. The liquor flows into settling tank 22 and afterwards into cylinder B, in
which the last traces of bicarbonate are precipitated. It will be noticed, that
no, attempt is made to get a complete absorption of the carbonic acid in 13º.
The object is to throw down as much bicarbonate as possible with an excess of
gas and leave the complete absorption of the gas to an apparatus more suitable
for that purpose.
The gas is circulated through B, by means of a suitable
fan 29, which draws carbonic acid from pipe 14b through cooler B, delivers
it into B, through pipe 15, and returns it to pipe 14, which conducts it to
carbonator B.
The ärrangement chosen for treating the brine with carbonic acid gas will
depend greatly on the percentage of carbonic acid in the gas. In some cases
it may be sufficient to pass the ammoniated brine through B¹ and B. For the
purpose of further facilitating the treatment with carbonic acid and to enable
a large production in very small plants. I produce a carbonic acid gas con-
taining very little nitrogen. For this purpose I calcine limestone or other
materials by means of heated carbonic acid gas. The carbonic acid is heated
again, after it has been in contact with limestone until its temperature is
reduced so that the reaction progresses slowly. The limestone kiln B5, consisto
of a shaft with suitable arrangements for continuously charging limestone
on top, consisting of a hopper 30 and a conveyor 31. It is supported on
columns 31, and has a conical bottom with doors 32. Some distance from
the bottom it has gas ducts 33 and an annular channel 34, and at a higher
level, but a considerable distance from the top, gas-off-takes 35, and an annular
channel 36.
The annular channel 34 is in connection with the bottom of the gas lieater B
by means of pipe 37. The annular channel 36 is connected to B6, by means
of pipe 38. By means of fan 39 a continuous circulation of hot gas is kept
up between heater B, and kiln B³, in such a way, that highly heated carbonic
acid enters B, through the ducts 33, acts on the limestone in B5 until its
temperature is reduced (below the temperature of reaction), leaves through off-
takes 35, and again enters the heater through pipe 38. The carbonic acid
produced by the action of the hot gas passes through the fresh limestone in the
upper part of B³, and leaves in cool condition through pipe 13.
As the gas
thus obtained contains practically no nitrogen (instead of 60-70% in lime kiln
gas) the absorption apparatus can be of small size and the chief point is to
supply sufficient cooling so as to get a complete precipitation of the bicarbonate.
Settling tanks 21, 22, 24, 25, are with advantage fitted with agitators in the
conical bottom. The bicarbonate is withdrawn from these vessels in form of a
thick sludge and is washed in a filter or in a centrifugal apparatus. The liquor
which leaves settling tank 25, consists of a solution of chloride of ammonium,hold-
ing some chloride of sodium. It is subjected to a low. temperature in, cylinder C,
for the separation of solid chloride of ammonium. This vessel is constructed
as cylinder B and B¹. It has a system of cooling pipes in the interior, through
which a cooling fluid circulates. It is further in connection with a gan
cooler C, consisting of a cylinder containing a system of pipes 40. The space.

page_text: below the pipes is in connection with one end of C by means of pipe 41; the
space above the pipes 40, communicates with the other end of C by pipe 42.
Fan 43 causes a continuous circulation of gas through C, and C, in such a way,
that gas cooled to very low temperature enters C, through pipe 41; cools the
liquor and thus precipitates chloride during its passage through C, and after-
wards reenters cooler through pipe 42. The gas is cooled in C by circulating
a cooling fluid through the space surrounding pipes 40, which enters at 44 and
leaves at 45. As the liquor is brought into intimate contact with the cold gas
in cylinder C, the precipitation of ammonium chloride is rapid and the apparatus
has a large capacity. The liquor holding chloride in suspension leaves C,
through pipe 46 and runs through settling tank 47, which may be fitted with
an agitator. The chloride is drawn into a suitable filter 48, where it is washed.
The liquor flowing from settling tank 47, consists mostly of a solution of salt
and is returned to the process through pipe 5 to washer A¹ after being saturated
with solid, salt. All the salt is thus utilized in the process: The solid
ammonium chloride from filter 48 is treated with magnesium oxide for the
evolution of ammonia
2NH Cl + MgO
=
MgCl, + H;O + 2NH,
This reaction takes place in cylinder D, which is constructed of cast iron in a
similar way as B¹. If a pipe system is used in the interior of D, it is used for
heating instead of cooling. The use of such pipes is not absolutely necessary
with my system and I prefer to supply all the heat for the reaction by means of
a heated inert gas. The mixture of oxide of magnesium and chloride of
ammonium is simultaneously agitated and a rapid and complete elimination of
ammonia is effected. The mixture of chloride and oxide is produced by dis-
charging the former continuously from hopper 49, and the latter from hopper 50.
The mixture passes through D, and a mixture of chloride and oxide of magnesium
free from ammonia is discharged into hopper 51.
A hot inert gas enters D from a heater D, through pipe 52 anu leaves contain-
ing much ammonia gas through pipe 9, which conducts to absorber A. After
removal of ammonia the gas is conducted back to the heater D', by means of
pipe 10. The fan 53 effects a continuous circulation through heater D!, cylinder D,
and absorber A, as described'.
The mixture of chloride and oxide of magnesium is now treated for the pro-
duction of chlorine in furnaces E and E¹.
These furnaces consist of iron cylinders supported and rotated in any con-
venient way. At each end they have stationary plates connected to the furnace
by means of a stuffing box similar to the one used on the other cylinders B etc.
The interior arrangement of the cylinders can be the same as described in my
previous Patent 30496/97.
The solid material enters E, continuously through conveyor 52, descends
from E to E, through pipe 53, from which it discharges itself into hopper 54.
From this hopper it is raised to hopper 50 by means of elevator 55, and con-
veyor 56, and is as it consists of practically pure magnesium oxide used over
again in the process.
The air which affects the decomposition of the magnesium chloride enters
heater E, through pipe 57 and in passing through the same is brought to high
temperature. It then enters E¹. through pipe 58. Dilute chlorine gas leaves
this furnace through pipe 59 and after being reheated by passing through
heater E, it enters furnace E by means of pine 60. From cylinder E concen-
trated chlorine gas is conducted through pipe 61 to suitable absorbers (not shown)
for the production of bleaching powder. Suitable fans (not shown) can be used
for the purpose of assisting the passage of the gas through heater E and E³,
and furnaces E and E
The method and apparatus described is continuous and of large canactiy. It
gives no waste liquor or other waste material. All the chlorine and alkali is

page_text: recovered from the salt. No pressure pumps are required for pumping carbonio
acid. As no line is required in the process cement or hydraulic lime can with
advantage be produced as a bye-product.
92nd Lung 00
PAUL NAEF, Ph.D.,
Applicant.
New York, U.S.A., Woody Crest Avenue, near 165th Street.
COMPLETE SPECIFICATION.
Method and Apparatus for Producing Alkali and Chlorine.
I, PAUL NAEF, Ph. D., of 132, Woody Crest Avenue, near 165th Street, New
York, United States of America, Chemical Engineer, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be particu-
larly described and ascertained in and by the following statement:-
This invention refers to the manufacture of alkali products and chlorine from
chloride of sodium.
"
The improvements are in connection with the so called ammonia-soda""
process.
The objects of the invention are: To recover the chlorine, which has hitherto
usually been lost in ammonia-soda works to reduce the large loss of salt which
has hitherto taken place, and to avoid the enormous amount of waste liquor
heretofore produced in the "ammonia-soda" process; to reduce the amount of
steam used and the power required for carrying out the "ammonia-soda " process;
to reduce the loss of ammonia and the volume of waste gases; to avoid the use
of lime in the process and produce cement instead; and to avoid the pumping
of gas under high pressure.
The method furnishes-a-continuous production of bicarbonate of soda and
chlorine gas and consists of the following steps;
1. Saturating brine with ammonia-gas obtained in a later step of the process:
2. Treating the saturated liquor with carbonic acid gas for the production of
bicarbonate of soda, a solution of chloride of ammonium being simultaneously
produced;
3. Cooling the ammonium chloride solution for the separation of solid chloride
and returning the remaining solution to step 1, after saturating the same with
solid' salt;
4. Separating ammonia from the solid ammonium chloride by heating it with
an oxide, (preferably magnesium oxide), and returning the ammonia-gas to
step 1.
5. Decomposing the mixture of magnesium oxide and chloride obtained by
step 4, by means of heated air. returning the oxide to step 4, and utilizing the
chlorine gas obtained by the decomposition for the manufacture of bleaching
powder or other purpose.
In order that my invention may be clearly understood and' readily carried into
effect, I will describe the same more fully with reference to the accompanying
drawing which shows the general arrangement of the plant.
The process is carried out in revolving cylinders A, A, B, B, C. D, E and E¹,
mounted on suitable rollers 1. 1. and rotated' in any convenient manner.
In the interior of the cylinders A, B'. B and C for treating the liquor, there
are cooling pines 2 which run through the cylinders and are connected at one
end to a pipe 3 for supplying a suitable cooling fluid; and at the other end with
an exit pipe 4 for the said fluid. There are further arranged within the cylinders.
radial perforated partitions, which agitate and produce a fine distribution of
liquor, also longitudinal lifters, which lift the liquor and gradually shower if in
a finely divided state on to the perforated partitions as the cylinders revolve. For

page_text: the purpose of further increasing the intimate contact of liquor and gas; there
are arranged vertical cross-partitious, with openings in such position that the gas
has to traverse the revolving cylinder in a zig-zag path.
W
At each end the cylinders are closed by a stationary end plate, which has a
flange fitting loosely into a flange in the end of the cylinder. A suitable pack-
ing is placed in the space between the two flanges and is tightened by a loose
ring. The stationary. end-plates carry suitable gas and liquor pipes. Through
the centre of the plate at one end of each cylinder passes the pipe 3.
pipe is connected to the cooling pipes 2 by a pipe 4, and is also joined to a
stationary cooling fluid supply pipe by a suitable stuffing box.
This
The brine used in the process is saturated with ammonia by passing it first
through the cylinder A which serves as a washer for waste gases, and after-
wards through the cylinder A. which constitutes a saturator. The washer A'
is used for washing the waste gases resulting after the treatment of 'the brine with
carbonic acid gas in the next step of the process, and contains.numerous perforated
vertical cross-partitions constructed of wire gauze, perforated wooden boards or
other suitable material. At intervals there are arranged also within this wash-
ing cylinder, non-perforated cross partitions having one or more holes which
are so arranged that the waste gas is caused to pass through the cylinder in a
zig-zag path.
The cylinders A', A, B, B and C are constructed in the manner described in
Specification No: 13771 of 1899:
PA
Fresh brine runs continually into the cylinder A' through a pipe 5, and
waste gas leaves (perfectly free from ammonia) through a pipe 6. The waste
gas from the cylinder B enters the cylinder A through a pipe 7, and the brine
leaves the same apparatus through a pipe 8 which delivers the said brine to
the cylinder A.
Ammonia gas from the 4th step of the process, which is carried out in
cylinder D, enters the cylinder A continuously through a pipe '9.. The gas,
which leaves the cylinder A through-a pipe 10 is returned to the cylinder D' as
hereinafter described.
5.
The brine saturated with ammonia; leaves the cylinder A through a pipe 11
and passes through a settling tank 12 for the removal of any lime or other
impurity precipitated from the brine.
I
The saturated brine is treated with carbonic acid gas in the cylinders Band B, 3
for the precipitation of bicarbonate of soda. This operation is carried out with
as efficient cooling as possible. This cooling is partly effected by circulating
water or another cooling fluid through the pipe system in the cylinders B
and B. As the cooling pipes get gradually covered with scale, which reduces
their efficiency, thorough cooling of the brine is effected by cooling the carbonic
acid gas used in the process. This carbonic acid gas comes from a suitable
kiln (hereinafter described) through' a pipe 13, and passes through a suitable
washer 14; for the removal of dust and other impurities. It then enters, through
a pipe 14, a suitable gas cooler B³ in which it is cooled to a low temperature.
The cold carbonic acid gas leaves the cooler B3 through a pipe 16, and enters 4
the cylinder B, where it is brought into intimate contact with liquor flowing
into, the said cylinder from a pipe 17. The unabsorbed carbonic acid gas leaves
the cylinder B through a pipe 15 and enters a cooler 13. In the cooler B4 the
said gas is again cooled, and then leaves through a pipe 18 by which it is con-
ducted into the cylinder B. The gas leaves the cylinder B practically free 5
of carbonic acid and is conducted by a pipe 7 to the cylinder A' as above described.
The brine saturated with ammonia enters the cylinder B from the settling
tank 12 through a pipe 19; and leaves the cylinder B by a pipe 20. It 'flows
through the settling tanks 21, B. and 22 to settle bicarbonate of soda; and then
enters the cylinder B through the pipe 17. From the cylinder B a pipe 23 5
conducts it througli settling tanks 24 and 25 provided with conical bottoms in
which the bicarbonate of soda settles.
T

page_text: .. The above described system of treating the liquor with carbonic acid gas,
produces a most intimato contact of gas and liquor with very efficient cooling,
and can be used with very dilute gases. The said system requires very little
gas-pressure which may be supplied by a suitable fan.
"
.!
The. coolers. I and B3 may be of any suitable construction: They can be
constructed on the principle of the locomotive boiler and any suitable fluid can
be used for cooling. As no liquor passes through these gas coolers they need
no cleaning, and do not lose their efficiency.
J'
If ammoniated brine is treated with carbonic acid in the manner described;
it is noticed that but little bicarbonate of soda is formed at the beginning and
also towards the end of the treatment, but that most of the precipitation of bi-
carbonate of soda takes place during the middle period of the treatment. It is
generally of advantage. therefore to treat the liquor during mis middle period
in an apparatus which is adapted for the ready removal or the bicarbonate of
soda and which can be easily cleaned without interfering with the general run
of the process. Apparatus 133 is so arranged, it consists of a vertical cylinder
having a suitable filling which gives no resistance and can be quickly removed
and cleansed by steaming. A continuous flow of liquor is-sent into the top of
the, apparatus 12 from the tank 21 through a pipe 27 by a suitable pump 28.
Much of the..bicarbonate of soda settles in the conical bottom of the tank Ba
from which it is withdrawn. The liquor flows from the tank 133 into the settling
tank 22 and afterwards into the cylinder B in which the last traces of bicarbonate
of soda are precipitated. 137 is a gas cooler connected to the tank 13 by pipes 15*
and 15 29. is a fan for maintaining a continuous circulation of gas. -14° is
a pipe connecting the pipe 14 to the pipe 15b. 14 is a pipe connecting the
tank B to the pipe, 14. 15, 15%, and 15° are valves: 16 is a fan in the
pipe 14ª
r
"
When the valve: 15° is closed, and the valves 15 and 15° are open, a current
of cold strong carbonic acid gas is circulated by the fan 29 from the washer 14
through the cooler B',. thence through the pipe 15ª to the tank B³ and back by
the pipe, 15b; the fan 15 at the same time drawing carbonic acid gas from the
tank B to the gas cooler B³. It will thus be seen that, during its passage
through the tank B2 the liquor meets a current of cold strong carbonic acid
gas,
h
It will be noticed, that no attempt is made to get a complete absorption of
the carbonic acid in the tank 12. The object is to throw down as much bi
carbonate of soda as possible with an excess of carbonic acid gas and to leave
the complete absorption of the said gas to an apparatus more suitable for that
purpose.
1
The arrangement chosen for treating the brine with carbonic acid gas will
depend greatly on the percentage of carbonic acid in the gas. In some cases it
may be sufficient to pass the ammoniated brine through the cylinders B and B³.
In this case the valves 15d and 15° are closed, and the valve 15° is opened. The
fan 15 then draws the carbonic acid gas directly from the washer 14 to the
cooler B³.
The carbonic acid gas is cooled in the coolers B³, 1 and B3 below the tem-
perature of the reaction producing the bicarbonate, to such an extent as to remove
part of the heat produced by said reaction.
For the purpose of further facilitating the treatment of the ammoniated brine
with carbonic acid and to enable a large production of bicarbonate of soda to
be made in a small apparatus, I produce a carbonic acid gas containing very
little nitrogen. For this purpose I calcine limestone or other suitable material
by means of heated carbonic acid gas. After the carbonic acid has passed
through the limestone, it is re-heated and passed through the limestone again,
as often as required.
The limestone kiln B5 consists of a shaft with a hopper 30 and a conveyor 31
for continuously charging limestone into it from the top. It is supported on

page_text: columns 31 and has a conical bottom with doors 32. Some distance from the
bottom it has gas ducts 33 and an annular channel 34, and at a high level, but
a considerable distance from the top, there are gas-off-takes 35 and an annular
channel 36. The annular channel 34 is connected with the bottom of a gas
heater B by a pipe 37. The annular channel 36 is connected to the gas heater B
by a pipe 38. By means of a fan 39 a continuous circulation of hot-
gas is kept up between the gas heater B and the kiln B, in such manner that
highly heated carbonic acid enters the kiln B through the ducts 33, there acts
on the limestone in the kiln until the temperature of the said gas is reduced
(below the temperature of the reaction), leaves through off-takes 35, and again
enters the heater through the pipe 38. The carbonic acid produced by the
action of the hot gas upon the limestone, passes through the fresh limestone
in the upper part of the kiln and leaves in a cool condition through the pipe 13.
As the gas thus obtained contains practically no nitrogen (instead of from 60
to 70 per cent. as is usual in ordinary lime kiln gas) the absorption apparatus
can be of small size; the chief point with respect to the absorption apparatus,
being to cool the carbonic acid gas sufficiently to get a complete precipitation
of the bicarbonate of soda.
The settling tanks 21, 22, 24, and 25 may with advantage be fitted with
agitators in their conical bottoms. The bicarbonate of soda is withdrawn from
these vessels in the form of a thick sludge and is subsequently washed in a
filter or in a centrifugal apparatus.
The liquor, which leaves the settling tank 25 consists of a solution of chloride
of ammonium containing some chloride of sodium. This liquor is subjected to
a low temperature in the cylinder C, for the separation of solid chloride of
ammonium. The vessel C is constructed in the same manner as the cylinders B
and B'; having a system of cooling pipes in the interior, through which a
cooling fluid circulates. The cylinder C. is further connected with a gas
cooler C, which latter consists of a cylinder containing a system of pipes 40.
The space below the pipes 40 is connected with one end of the cylinder C by
a pipe 41; and the space above the pipes 40 communicates with the other end
of the cylinder C through a pipe 42. A fan 43 causes a continuous circulation
of air or inert gas through the cylinder C, and the cooler C, in such manner
that the air or inert gas cooled to very low temperature enters the cylinder
through the pipe 41, cools the liquor and thus precipitates chloride of ammonia
during its passage through the cylinder C and afterwards re-enters the cooler C¹
through the pipe 42. The air or inert gas is cooled in the cooler C by circulating
a cooling fluid through the space surrounding the pipes 40, the cooling fluid
entering the cooler Cat 44 and leaving at 45.
As the ammonium chloride liquor is brought into intimate contact with the
cold air or inert gas in the cylinder C, the precipitation of ammonium chloride
is rapid and the apparatus has a large capacity. The liquor holding the
ammonium chloride in suspension, leaves the cylinder C through the pipe 46
and runs through a settling tank 47, which may be fitted with an agitator. The
ammonium chloride is drawn into a suitable filter 48, where it is washed:
liquor flowing from the settling tank 47 consists mostly of a solution of sodium
chloride and is returned to the process through the pipe 5, to the cylinder A¹
after being saturated with solid sodium chloride. All the sodium chloride is
thus utilized in the process.
The
The solid ammonium chloride from the filter 48 is treated with magnesium
oxide for the evolution of ammonia according to the following reaction:-
NHCI + MgO = MgCl2 + 11,0 + 2NH
This reaction takes place in the cylinder D, which is constructed of cast iron
in a similar way to the cylinder B. If a pipe system is used in the interior
of the cylinder D, such pipe system is used for heating instead of cooling. The

page_text: use of such heating pipes is not absolutely necessary with my system however,
as I prefer to supply all the heat for the reaction by means of a heated inert
gas. The mixture of oxide of magnesium and chloride of ammonium is simul-
taneously heated and agitated and a rapid and complete elimination of ammonia
is effected. The mixture of chloride of ammonium and oxide of magnesium is
produced by discharging the former continuously from a hopper 49, and the
fatter from a hopper 50 into the cylinder D. The mixture passes through the
cylinder D and a mixture of chloride and oxide of magnesium free from ammonia
is discharged into a hopper 51. A hot inert gas enters the cylinder D from
a gas heater D through a pipe 52. This gas, containing much ammonia gas,
leaves the said cylinder through a pipe 9, which leads to the cylinder A.
the absorption of ammonia by the brine in the cylinder A. the gas is conducted
back to the heater D' by a pipe 10. The fan 53 effects a continuous circulation
through the heater D and the cylinders D and A, as described!
After
The mixture of chloride and oxide of magnesium resulting from the heat-
ing of the ammonium chloride with the magnesium oxide, is now treated for the
production of chloride in furnaces E and E¹.
These furnaces consist of iron cylinders supported and rotated in any con-
venient manner. At each end they have stationary plates connected to the
furnace by means of a stuffing box similar to those used on the above described
cylinders. The interior arrangement of the cylinders E and E¹ can be the same
as described in the Specification of my previous Patent No. 30496 of 1897.
The solid material enters the furnace E continuously through a conveyor 52,
descends from the furnace E to the furnace E¹ through a pipe 53 and is dis-
charged from the furnace E¹ into a hopper 54. The material discharged from
the hopper 54 consists of practically pure magnesium oxide which is raised to
hopper 50 by an elevator 55 and a conveyor 56, and is used over again in the
process.
The air which effects the decomposition of the magnesium chloride enters a
gas heater through a pipe 57 and in passing through the said heater is
brought to a high temperature. This heated air then enters the furnace E'
through a pipe 58. Dilute chlorine gas leaves the furnace E through a pipe 59
and after being re-heated by passing through a gas heater 13, enters the furnace I
by a pipe 60. From the furnace E, concentrated chlorine gas is conducted
through a pipe 61 to suitable absorbers (not shown) for the production of bleach-
ing powder. Suitable fans (not shown) can be used for the purpose of assist-
ing the passage of the gas through the heaters and E3 and the furnaces E
and E!.
The method and apparatus described is continuous and of large capacity. It
gives no waste liquor or other waste material. All the chlorine and alkali is
recovered from the salt. No pressure pumps are required for pumping carbonic
.acid. As no lime is required in the process cement or hydraulic lime can with
advantage be produced as a bye-product by charging suitable cement forming
substance into the kiln B in place of limestone and raising the temperature
to a suitable degree.
In regard to the absorption vessel B² it may be continually used by itself for
the production of bicarbonate. For this purpose and also for giving the said
vessel a large capacity it is of advantage to circulate the gas at great velocity
in such a way that the same gas passes repeatedly through the apparatus. It
is also of advantage for the purpose of throwing down a large amount of bi-
carbonate of soda in the vessel B2, to circulate the ammoniated brine liquor at
a great velocity and return the same liquor several times to the absorption vessel.
In this way a most intimate contact of gas and liquor is obtained.
Instead of revolving cylinders, vessels which are fitted with shafts and
agitators can be used, but the efficiency of these latter vessels is usually smaller
than that of the revolving cylinders and their use is associated with mechanical
difficulties,

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. In the production of alkali products and chlorine, the method of bringing
a liquid and a gas into intimate contact by passing them simultaneously and
preferably in opposite directions through a revolving cylinder constructed with
perforated partitions substantially as described.
2. In the production of alkali products and chlorine, the method of conduct-
ing a gas cooled below the temperature of the reaction through a liquid and
simultaneously cooling and agitating the liquid and the gas during the reaction,
substantially as described.
3. In the production of alkali products and chlorine the method of crystallising
a solid from a liquid by cooling the liquid while passing it through a revolving
cylinder, substantially as described.
4. In the production of alkali products and chlorine the method of passing
and re-passing cooled carbonic acid gas through and in contact with a solution
of sodium chloride and ammonia, and re-cooling the said gas in a separate
apparatus after each passage through the said solution, substantially as and
for the purpose specified.
5. In the production of alkali products and chlorine, the method of precipi-
taling bicarbonate of soda from a solution of sodium chloride and ammonia in
successive stages by treatment with carbonic acid gas, substantially as and for
the purpose specified.
6. In the production of alkali products and chlorine, the method of crystal-
lizing ammonium chloride from a solution by passing a cold inert gas through
the said solution, substantially as described.
7.The continuous process for obtaining alkali products and chlorine, which
consists in cooling a solution of sodium chloride and simultaneously saturating
the same with ammonia, repeatedly treating this saturated solution with cooled
carbonic acid gas to produce bicarbonate of soda and a solution of ammonium
chloride, settling the bicarbonate of soda from said solution of ammonium chloride
and removing the bicarbonate in successive stages of the process. cooling the
solution of ammonium chloride to thereby obtain solid ammonium chloride from
said solution, heating the solid ammonium chloride together will an oxide to
produce ammonia gas and a chloride, passing said ammonia gas into and through a
fresh charge of sodium chloride solution to saturate the same, and decomposing
the said chloride by heated air to produce chlorine and an oxide. substantially
as described.
8. The continuous process for obtaining alkali products and chlorine, which
consists in cooling a solution of sodium chloride and simultaneously saturating
the same with ammonia, passing cooled carbonic acid gas repeatedly into and
through this saturated solution of sodium chloride to obtain bicarbonate of soda
and a solution of ammonium chloride, agitating and showering the saturated
solution in the presence of the cooled carbonic acid gas to effect a fine sub-
division of said solution and bring it into intimate contact with said gas for
obtaining a rapid and complete precipitation of the bicarbonate of soda, removing
the bicarbonate in successive stages of the process. cooling the solution of
ammonium chloride to thereby obtain solid ammonium chloride, heating the
solid ammonium chloride together with an oxide to produce ammonia gas and a
chloride causing said ammonia gas to circulate through a fresh charge of sodium
chloride solution to saturate the same, and decomposing the said chloride by
heated air to produce chlorine and an oxide, substantially as described:
9. The continuous process for obtaining alkali products and chlorine, which
consists in cooling a solution of sodium chloride and simultaneously saturating
the same with ammonia, repeatedly treating this saturated solution with cooled
carbonic acid gas by alternately cooling said gas and passing it into and through
the ammonia saturated solution of sodium chloride and in intimate contact

page_text: therewith to obtain bicarbonate of soda and a solution of ammonium chloride,
passing a current of cooled air or inert gas through the solution of ammonium
chloride to obtain solid ammonium chloride therefrom, returning the residual
liquor to be again saturated with ammonia, and heating the solid ammonium
chloride with an oxide to obtain ammonia gas and a chloride, passing saiil'
ammonia gas into and through said returned residual liquor and a fresh charge
of sodium chloride to saturate said solution, and decomposing said chloride
by heated air to produce chlorine and an oxide, substantially as described
10. The continuous process for obtaining alkali products and chlorine which
consists in cooling a solution of sodium chloride and simultaneously saturating
the same with ammonia, obtaining bicarbonate of soda and ammonium chloride
from the solution of sodium chloride and ammonia by treating the latter solution
with cooled carbonic acid gas repeatedly, and with an excess of the acid, said
gas being alternately cooled and passed into said solution, passing the waste
gas from these carbonating operations into and through a fresh charge of sodium
chloride solution, obtaining solid ammonium chloride from the solution of
ammonium chloride by continuously circulating a current of cooled air or
inert gas through said solution, returning the residual liquor to the fresh charge
of sodium chloride solution, heating the solid ammonium chloride with magnesium
oxide or other suitable oxide to obtain ammonia gas and a chloride, causing
said ammonia gas to circulate continuously through a fresh charge of sodium
chloride solution for saturating the same, decomposing the said chloride by
heated air to obtain chlorine and an oxide and returning this oxide to be again
treated with ammonium chloride and heat substantially as described.
11. The continuous process for obtaining alkali products and chlorine, which
consists in cooling a solution of sodium chloride and simultaneously saturating
the same with ammonia, treating this saturated solution with cold carbonic
acid gas by repeatedly cooling said gas and passing it into and through said
solution to obtain bicarbonate of soda and a solution of ammonium cliloride,
meanwhile lifting and showering the solution to bring it into a state of fine
subdivision and in intimate contact with said gas, settling the bicarbonate of
soda from said solution of ammonium chloride and removing the bicarbonate
in separate quantities and during successive stages of the process, cooling the
solution of ammonium chloride to thereby obtain solid ammonium chloride from
said solution, heating the solid ammonium chloride together with an oxide to
produce ammonia gas and a chloride, continuously passing said ammonia gas
into and through a fresh charge of sodium chloride solution to saturate the
same, and decomposing the said chloride by heated air to produce clilorine and
an oxide substantially as described:
12: In the production of alkali products and chlorine, continuously passing
and re-passing heated carbonic acid gas through limestone in a kiln, and re-
heating the gas passed through the limestone after every passage through the
limestone. substantially as and for the purpose described.
13. In the production of alkali products and chlorine, a rotary cylinder through
which liquor and a cooled gas are continuously passed, and means for re-cooling
the gas during the reaction, substantially as described.
14. Apparatus having its parts constructed and arranged to operate substan-
tially as described with reference to the accompanying drawings, for the purpose
specified.
HASELTINE, LAKE & Co.,
45, Southampton Buildings. London, W.C., Agents for the Applicant.