Improvements in the Manufacture of Sulphates of Soda and Potassa and in Apparatus therefor.
Year: 1886

page_text: Date of Application, 27th Apr., 1886.
Complete Left, 26th Jan., 1887.
Complete Accepted, 1st Mar., 1887.
Improvements in the Manufacture of Sulphates of Soda and Potassa
and in Apparatus therefor.
We, JAMES HARGREAVES Chemist, THOMAS ROBINSON Iron Founder, and Joun
HARGREAVES Chemist, all of Victoria Road Widnes in the County of Lancaster do
hereby declare the nature of the said invention to be as follows:-
The invention relates to improvements in the manufacture of sulphates of soda and
potassa by the direct action of sulphurous acid together with air and aqueous vapour
upon chlorides of sodium or potassium. The objects are to economise fuel, prevent
leakage of air and products of combustion into the apparatus increase the rate of
decomposition of the chlorides, obtain additional output, prevent the escape of noxious
gases into the atmosphere and simplify the construction of the apparatus.
As a means of economising fuel, to avoid leakage of air and products of combustion
into the cylinders and for increasing the rate of decomposition of chlorides of sodium
or potassium by means of sulphurous acid thereby giving an increased output of
sulphate of soda or potash from a given size of apparatus. We maintain the
sulphurous acid contained in the whole or part of the series of cylinders under
pressure by mechanical means or by suitable arrangements of injected highly heated
superheated steam. When mechanical means are employed we use an iron fan
inserted by preference in the pipe conveying the sulphurous acid gas from the pyrites
burners to the series of cylinders. In the part of the sulphurous acid gas pipe
where the fan is inserted we prefer to diminish by suitable means the area of the pipe
so as to facilitate the working of the fan. We arrange a connecting flue to the
sulphurous acid pipe so that when desired the sulphurous acid gas may pass direct from
the pyrites burners to any cylinder in the series without passing through the fan we
arrange a suitable valve or valves so that the connecting flue may be readily opened
or closed.
To place the sulphurous acid gas under pressure by means of steam we maintain the
steam under strong pressure and superheat the said steam previous to blowing it

page_text: amongst the sulphurous acid gas by means of a jet The said jet is inserted at the
month of a contracted throat fixed in the interior of the sulphurous acid gas pipe
conveying the gas from the pyrites burners to the series of cylinders any convenient
form of throat and jet may be used if capable of supporting sufficient pressure at the
exit of the throat whilst only a limited quantity of steam is used to maintain the
pressure. The amount of steam injected into the gas by means of the jet is that
theoretically necessary for the supply of aqueous vapour to the sulphurous acid for
the decomposition of the chlorides of sodium or potassium (which varies slightly
according to the strength of the gas) together with an additional amount of about
15 to 20 grains of aqueous vapour per cubic foot of the sulphurous acid gas calculated
at atmospheric temperature.
To economise the sulphate of soda and chloride of sodium contained in the residual
liquors occurring in extracting copper from pyrites by the wet process and also when
there is no objection to the presence of a small quantity of iron in the salt as in the
case where the sulphate is to be used for the manufacture of alkali the rapidity of the
decomposition of the chloride of sodium would be augmented by the small quantity of
iron contained in the residual liquors thereby increasing the amount of sulphate of
soda manufactured in a given size of apparatus with consequent economy of fuel used
in the said manufacture. Before the salt enters the drying oven we moisten it with
the residual liquors containing sulphate of soda and chlorides of sodium and iron
remaining after the precipitation of copper.
We use as above mentioned the residual liquors resulting from the precipitation of
copper from the liquors obtained from the first lixiviation of the vats containing the
roasted copper ore as such liquors are more concentrated and contain a large amount
of sulphate of soda and chloride of sodium together with iron in solution in a suitable
condition to mix with the salt whilst the amount of free acid contained in solution is
very small.
When it is desired to use a larger quantity of solution than is practicable for the
purpose of moistening the chlorides of sodium previous to making it into hard cakes
or when it is desirable to decrease the amount of iron which would ultimately find its
way into the resulting sulphate We evaporate all or part of the water contained in
the said saline solution and thereby cause to separate the crystals of sulphate of soda
and chloride of sodium and by preference leave in the mother liquor the greater part
of the salts of iron When. it is desired to evaporate the water contained in the said
solution by surface heat we use a pan which inay be made of cast iron and arrange the
working of the pan and the means of separating the mother liquor in a manner much
similar to the well known method used in the evaporation of alkaline liquors for
obtaining soda ash For the purpose of evaporating the said saline. solution containing
salts of soda and iron we prefer as far as possible to. use waste heat.
We utilize the iron contained in the mother liquor by any convenient method.
The crystals of sulphate of soda and chloride of sodium obtained from the evaporation
of the saline solution will invariably be found to have salts of iron associated with
them We mix the said salts of soda together with any salts of iron they may contain
with chloride of sodium used in the direct process for the manufacture of sulphates
of soda.
To avoid the escape of noxious gases into the atmosphere when a cylinder recently
finished is to be opened for the purpose of discharging the sulphate of soda we delay
opening the finishing cylinder until the preceding cylinder is nearly filled with raw
newly prepared salt, and after the doors are firmly closed at the bottom of the newly
charged cylinder withdraw the lid from the bottom discharging door of the finished
cylinder and by means of the valve in the circulating syphon which allows the gases to
pass from one cylinder to another, allow the noxious gasses to pass from the top of the
newly opened cylinder to the bottom of the cylinder newly charged with salt and
percolate through the mass of newly charged salt so as to filter and absorb noxious
gases the newly charged salt acting as a sponge for the absorption of the gas The
salt in the newly charged cylinder is thus readily heated by the air which will have
become very hot in passing from the bottom of the finished cylinder through the red

page_text: hot sulphate The said hot air is afterwards passed through the mass of salt contained
in the newly charged cylinder from the top of which the hot filtered air escapes into
the atmosphere or may be conveyed to the top of the upeast fire flue from which it
will be conducted to the chimney care being taken that the fire damper under the
cylinder leading to the chimney is opened and the doors of the fire place closed-or if
desired the hot air may be passed to the condenser by loosening the valve in the
circulating syphon, between the cylinder newly charged with salt and the preceding
cylinder.
As a means for externally heating the cylinders by means of fire-we use an
arrangement of flues and heating chambers with an iron pipe or brick flue in front of
two lines of cylinders which pipe or flue may be placed in the exterior of or inserted
in the mass of brickwork in front of the cylinders, we pass through the said pipe or
flue, combustible gases obtained by means of a suitable gas producer, which gases are
preferably ignited at the bottom of the upcast fire flue or flues when combustible gas
is used as a source of fuel for heating the cylinders we use two upeast fire flues,
passing up at each side of the fronts of the cylinders the heat being conveyed from the
top of each upcast flue to the fire chambers situated in the upper part of the front of
the cylinders a suitable arrangement of valves being made for turning the combustible
gas on and off We also prefer to arrange the pipe or flue conveying the combustible
gas along the side of the cylinders where the salt drying oven is situated in such a
manner that the said pipe or flue may also serve to supply combustible gas for the
heating of the salt drying oven In the case of cylinders of very large capacity when
necessary to heat the contents by means of fire we form a number of small iron tubes,
crossing the interior of the circulating syphons through which the gases necessary to
be heated pass from one cylinder to another and we pass through the tubes hot
products of combustion for the purpose of heating the circulating gases passing over
the exterior of the small tubes through which the products of combustion pass The
same tubes may also be used when necessary for cooling the circulating gases by
passing cold airs or other fluids through.
As up to the present every succeeding erection of cylinder apparatus seems to
demonstrate the economy and advisability of still further increasing the diameter of
the cylinders thereby decreasing the relative first cost of apparatus and also the cost of
fuel and labour per ton of sulphate of soda made, the practicability of such increase
of diameter of cylinders is greatly facilitated by the arrangements hereinafter
described.
One of the difficulties of increasing the diameter of the cylinders has been that of
adequately supporting the cover of the cylinder which is necessarily heavy. To
overcome this difficulty when cylinders of very large diameter are made we support
the cover from the interior by at least four cast iron columns placed in such a position
that one pillar stands beneath cach joint where the segments of the cover are joined
together by means of bolted flanges The number of pillars used will of course vary
with the number of pieces into which it is desirable to cast the cylinder cover caro
being taken that the foot of the pillar rests upon a part of the cylinder bottom whichi
rests firmly and securely upon solid masonry immediately under the point where the
pillar rests upon the cylinder bottom and also that each pillar shall serve as a sight
pipe being made hollow and sufficiently long to pass through the cover to about the
height of the working floor at the top of the cylinder thereby rendering the temperaturo
of each part of the sulphate through which the column or pillar passes visible.
The bottoms of the pillars being radiated around the discharging hole in the bottom
in such a manner as not to impede the tool of the workman when working through the
front door nor to impede the laying of the grids or movable wrought iron bars for
supporting the salt.
The rate of decomposition of chlorides of sodium or potassium by means of sulphurous
acid is greatly augmented as the temperature of the chlorides is increased thereby
increasing the amount of sulphate capable of being manufactured in an apparatus of
given size in a given time and also reducing the amount of fuel required per ton of
sulphate. manufactured In the internal arrangement of the cylinders as at present

page_text: used care is necessary that the temperature of the chlorides be not raised so high as io
soften the texture of the chlorides as in that case, the chloride near the bottom and
more particularly towards the centre of the cylinders (where the heat generated by
chemical action is necessarily greatest being pressed by the weight of the chlorides
above (the height of which it is always desirable to maintain for economical working)
is consequently liable to become soft thereby impeding the passage of the sulphurous
acid gas and causing inconvenience in discharging the contents of the cylinders.
To obtain a more equal temperature when heating the chloride for the purpose of
increasing the output of sulphate to a higher temperature than is now convenient to
work at whilst undergoing decomposition by means of sulphurous acid and to avoid
any softening of the lower strata of the chloride we place an intermediate grid or table
above the falso floor now used to support the chlorides this intermediate grid or
floor is preferably fixed a few feet above the centre of the false floor and preferably
covers about one half of the area of the cylinder bottom and is arranged with a hole in
the centre of the grid or table so that the under portion may be conveniently charged
with chlorides when the cylinder is being filled; and the facilities for discharging the
cylinder are increased. We arrange the table so as to form two or more grids fixed
upon cast iron or brick supports the said grids having hinges or equivalent arrange-
ments so that when the movable supports holding the grids in position are removed
the grids shall assume a vertical, instead of the horizontal position maintained when
the cylinder is at work or the grids may romain in the horizontal position until the
sulphate is discharged and then raised into vertical position to facilitate the filling of
the cylinder with salt The movable grid may be hinged either from the centre or
the extremity.
In the case of apparatus to be erected for purposes of economy in erecting apparatus
and to cheapen and facilitate manufacture of sulphate we increase the cylinders to a
greater height and greater diaineter than at present adopted and divide, the whole
diameter of the cylinder into two or more series of grids forming false bottoms the
said grids being fixed upon strong girder like supports extending across the cylinder
and supported by cast iron pillars extending from the bottom to the top of the
cylinder the said pillars preferably acting as supports for the cover of the cylinder
The centre portion of the grids extending from the door to near the back of the
cylinder is formed of long wrought iron bars capable of being easily removed from the
door. We arrange one working door opposite to each grid or false floor.
With the exception of the bottom grids and also excepting the wrought iron bars
opposite the doors the table or false floors existing between the bottom and cover of
cylinder are formed of cast iron grids so arranged that they can be raised into vertical
positions by means of hooks inserted from the top of the cylinders. After the sulphate
in a cylinder has been discharged and it is desirable to refill the cylinder with chloride
the said grids are raised into vertical position so as to allow the salt charged in at the
top of the cylinder to fall freely to the bottom or intermediate false floors-as each
stratum of chloride is charged into the cylinders the grids of the false floor next above
it are by means of lowering the hook from the top supporting the girders allowed to
fall into the horizontal position and to form the false floor supporting the next higher
stratum of chloride to be charged into the cylinder.
When it is inconvenient to work with movable hinged grids, we arrange the upper
false floors with the wrought iron bars as above described in the centre part of the
cylinder opposite and about the same width as the door and we form the sides of the
false floors of permanent grids arranged with large open spaces between the grids so
that the stratum beneath the grid could be easily filled from the tops of the cylinders
without moving the grids. The salt in falling through the spaces would leave
convenient channels or spaces beneath the grids for the free intermixing of the gases
as they descend to the lower stratum. To further aid the free passage and intermixing
of the descending gases we fix the long narrow permanent grids at right angles to the
centre wrought iron grids so that whilst a gas space of at least 6 inches deep and of
large area would extend underneath the wrought iron bars channels for the passage
of and mixing of the gases will be formed extending the whole length of the passage

page_text: beneath the grids and connecting directly with the large area of gas space beneath the
wrought iron bars.
It will be evident that some of the arrangements described as suitable when a new
apparatus is to be erected are also applicable to existing apparatus When the
sulphurous acid is forced through the cylinders as herein before described and when it
is desired to cool the contents of a cylinder having intermediate grids as described for
the purpose of cooling the contents of the cylinder instead of the arrangement of
cooling pipes usually employed we use pipes extending to the spaces underneath the
grids and above the strata of salt which it is desired to cool and pass through the pipes
steam or cold air under pressure.
In filling pieces of dried salt into cylinders of great depth we avoid the formation of
dust by lowering the pieces of salt into the cylinders by means of a deep circular.
wrought iron bucket or box of such diameter as to easily pass through the charging
holes in the cover of the cylinder. The pieces of salt are filled through the charging
holes in the usual way but instead of falling to the bottom of the cylinder they fall
into the box which is suspended nearly to the height of the top of the cylinder when
the box becomes filled it is lowered to the bottom of the cylinder by convenient
means.
The bottom of the box is hinged to the lower part of the body of the box and so
arranged that by means of a chain reaching to the top of the cylinder the bottom can
be readily detached and allow the pieces of salt to be discharged through the bottom of
the box.
The spaces between the grids forming each series are so arranged as to be directly
beneath the charging holes in the cover of the cylinder so as to allow of the box being
readily lowered to each strata of grids.

page_text: Improvements in the Manufacture of Sulphates of Soda and Potassa
and in Apparatus therefor.
We JAMES HARGREAVES of Peel House Lane, Farnworth Chemist, THOMAS
ROBINSON, of Hope House, Farnworth Iron founder, and JOHN HARGREAVES of
Albert Road Widnes Chemist, all in the County of Lancaster 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 :-
The invention relates to improvements in the manufacture of Sulphates of Soda and
potassa by the direct action of sulphurous acid together with air and aqueous vapour
upon chlorides of sodium or potassium-The objects are to economise fuel, prevent
leakage of air and products of combustion into the apparatus, increase the rate of
decomposition of the chlorides, obtain additional output, prevent the escape of noxious
gases into the atmosphere and simplify the construction of the apparatus.
As a means of economising fuel, to avoid leakage of air and products of combustion
into the cylinders and for increasing the rate of decomposition of chlorides of sodium
or potassium by means of sulphurous acid, thereby giving an increased output of
Sulphate of Soda, or potash from a given size of apparatus. We maintain the sulphurous
acid contained in the whole or part of the series of cylinders under pressure by
mechanical means or by suitable arrangements of injected highly heated superheated
steam. When mechanical means are employed we use an iron fan inserted by
preference in the pipe conveying the sulphurous acid gas from the pyrites burners to
the series of cylinders. In the part of the sulphurous acid gas pipe where the fan is
inserted, we prefer to diminish by suitable means the area of the pipe so as to
facilitate the working of the fan. We arrange a connecting flue to the sulphurous
acid pipe, so that when desired the sulphurous acid gas may pass direct from the
pyrites burners to any cylinder in the series without passing through the fan. We
arrange a suitable valve or valves so that the connecting flue may be readily opened
or closed.
To place the sulphurous acid gas under pressure by means of steam, we maintain
the steam under strong pressure and superheat the said steam previous to blowing it
amongst the sulphurous acid gas by means of a jet. The said jet is inserted in the
mouth of a contracted throat fixed in the interior of the sulphurous acid gas pipe
conveying the gas from the pyrites burners to the series of cylinders. Any convenient
form of throat and jet may be used if capable of supporting sufficient pressure at the
exit of the throat, whilst only a limited quantity of steam is used to maintain the
pressure. The amount of Steam injected into the gas by means of the jet is that
theoretically necessary for the supply of aqueous vapour to the sulphurous acid for the
decomposition of the chlorides of Sodium or potassium (which varies slightly according
to the strength of the gas) together with an additional amount of about 15 to 20 grains
of aqueous vapour per cubic foot of the sulphurous acid gas calculated at atmospheric
temperature.

page_text: To economise the sulphate of soda and chloride of sodium contained in the residual
liquors, occurring in extracting copper from pyrites by the wet process and also when
there is no objection to the presence of a small quantity of iron in the salt, as in the
case where the sulphate is to be used for the manufacture of alkali, the rapidity of the
decomposition of the chloride of sodium would be augmented by the small quantity of
iron contained in the residual liquors thereby increasing the amount of sulphate of
soda manufactured in a given size of apparatus with consequent economy of fuel used
in the said manufacture-Before the salt enters the drying oven we moisten it with
the residual liquors containing Sulphate of Soda and chlorides of sodium and iron
remaining after the precipitation of copper.
We use as above mentioned the residual liquors resulting from the precipitation of
copper from the liquors obtained from the first lixiviation of the vats containing the
roasted copper ore, as such liquors are more concentrated and contain a large amount
of sulphate of Soda and chloride of sodium together with iron in solution in a suitable
condition to mix with the salt, whilst the amount of freed acid contained in solution is
very small.
When it is desired to use a larger quantity of solution than is practicable for the
purpose of moistening the chloride of sodium previous to making it into hard cakes or
when it is desirable to decrease the amount of iron, which would ultimately find its
way into the resulting sulphate, we evaporate all or part of the water contained in the
said saline solution and thereby cause to separate the chrystals of sulphate of soda and
chlorine of sodium and by preference leave in the mother liquors the greater part of
the salts of iron. When it is desired to evaporate the water contained in the said
solution by surface heat, we use a pan which may be made of cast iron and arrange
the working of the pan and the means of separating the mother liquor in a manner
much similar to the well known method used in the evaporation of alkaline liquors for
obtaining soda ash. For the purpose of evaporating the said saline solution containing
Salts of soda and iron, we prefer as far possible to use waste heat.
We utilize the iron contained in the mother liquor, by any convenient method.
The chrystals of sulphate of Soda and chloride of sodium obtained from the evaporation
of the saline solution will invariably be found to have salts of iron associated with
them. We mix the said salts of soda together with any salts of iron they may contain
with chloride of sodium used in the direct process for the manufacture of sulphates
of Soda.
To avoid the escape of noxious gases into the atmosphere when a cylinder recently
finished is to be opened for the purpose of discharging the sulphate of soda-we
delay opening the finishing cylinder until the preceding cylinder is nearly filled with
raw newly prepared salt and after the doors are firmly closed at the bottom of the
newly charged cylinder, withdraw the lid from the bottom discharging door of the
finished cylinder and by means of the valve in the circulating syphon which allows the
gases to pass from one cylinder to another, allow the noxious gases to pass from
the top of the newly opened cylinder to the bottom of the cylinder newly charged with
salt and percolate through the mass of newly charged salt so as to filter and absorb
noxious gases. The newly charged salt acting as a sponge for the absorption of the
gas the salt in the newly charged cylinder is thus readily heated by the air which
will have become very hot in passing from the bottom of the finished cylinder through
the red hot sulphate. The said hot air is afterwards passed through the mass of salt
contained in the newly charged cylinder, from the top of which the hot filtered air
escapes into the atmosphere or may be conveyed to the top of the upcast fire flue from
which it will be conducted to the chimney, care being taken that the fire damper under
the cylinder leading to the chimney, is opened and the doors of the fireplace closed-
or if desired the hot air may be passed to the condenser by loosening the valve in the
circulating syphon between the cylinder newly charged with salt and the preceding
cylinder.
As a means for internally heating the cylinders by means of fire, we use an
arrangement of flues and heating chambers with an iron pipe or brick flue in front of
two lines of cylinders which pipe or flue may be placed in the exterior of, or inserted

page_text: in the mass of brickwork in front of the cylinders, we pass through the said pipe or
flue, combustible gases obtained by means of a suitable gas producer, which gases are
preferably ignited at the bottom of the upcast fire flue, or flues. When combustible
gas is used as a source of fuel for heating the cylinders, we use two upeast fire flues,
passing up at each side of the fronts of the cylinders, the heat being conveyed from
the top of each upcast flue to the fire chambers, situated in the upper part of the front
of the cylinders a suitable arrangement of valves being made for turning the
combustible gas on and off. We also prefer to arrange the pipe or fluc conveying
the combustible gas along the side of the cylinders where the salt drying oven is
situated in such a manner that the said pipe or flue may also serve to supply
combustible gas for the heating of the salt drying oven. In the case of cylinders of
very large capacity, when necessary to heat the contents by means of fire we form a
number of small iron tubes crossing the interior of the circulating syphons through
which the gases necessary to be heated pass from one cylinder to another and we pass
through the tubes, hot products of combustion for the purpose of heating the
circulating gases passing over the exterior of the small tubes through which the
products of combustion pass. The saune tubes may also be used when necessary for
cooling the circulating gases by passing cold air or other fluids through.
As up to the present every succeeding crection of cylinder apparatus seems to
demonstrate the economy and advisability of still further increasing the diameter of
the cylinders, thereby decreasing the relative first cost of apparatus and also the cost
of fuel and labour per ton of sulphate of soda made, the practicability of such increase
of diameter of cylinder is greatly facilitated by the arrangements hereinafter
described.
One of the difficulties of increasing the diameter of the cylinders has been that of
adequately supporting the cover of the cylinder which is necessarily heavy.-To
overcome this difficulty when cylinders of very large diameter are made, we support
the cover from the interior by at least four cast iron columns placed in such a position,
that one pillar stands beneath each joint, where the segments of the cover are joined
together by means of bolted flanges; the number of pillars used will of course vary
with the number of pieces into which it is desirable to cast the cylinder cover, care
being taken that the foot of the pillar rests upon a part of the cylinder bottom, which
rests firmly and securely upon solid masonry immediately under the point where the
pillar rests upon the cylinder bottom and also that each pillar shall serve as a sight
pipe, being made hollow and sufficiently long to pass through the cover to about the
height of the working floor at the top of the cylinder thereby rendering the temperature
of each part of the sulphate through which the column or pillar passes visible.
The bottoms of the pillars being radiated around the discharging hole in the bottom
in such a manner as not to impede the tool of the workman when working through
the front door, nor to impede the laying of the grids, or movable wrought iron bars
for supporting the salt.
The rate of decomposition of chloride of sodium or potassium by means of sulphurous
acid is greatly augmented as the temperature of the chlorides is increased, thereby
increasing the amount of sulphate capable of being manufactured in an apparatus of
given size in a given time and also reducing the amount of fuel required per ton of
sulphate manufactured.
In the internal arrangement of the cylinders as at present used, care is necessary
that the temperature of the chlorides be not raised so high as to soften the texture of
the chlorides, as in that case the chloride near the bottom and more particularly
towards the centre of the cylinders (when the heat generated by chemical action is
necessarily greater) being pressed by the weight of the chlorides above-(the height
of which it is always desirable to maintain for economical working) is consequently
liable to become soft thereby impeding the passage of the sulphurous acid gas and
causing inconvenience in discharging the contents of the cylinders.
To obtain a more equal temperature when treating the chloride for the purpose
of increasing the output of sulphate to a higher temperature than is now convenient
to work at whilst undergoing decomposition by means of sulphurous acid and to avoid

page_text: any softening of the lower strata of chloride we place an intermediate grid, or table
above the false floor, now used to support the chlorides, this intermediate grid or floor
is preferably fixed a few feet above the centre of the false floor and preferably covers
about one half of the area of the cylinder bottom and is arranged with a hole in the
centre of the grid, or table, so that the under portion may be conveniently charged
with chlorides when the cylinder is being filled and the facilities for discharging the
cylinder are increased. We arrange the table so as to form two or more grids fixed
upon cast iron or brick supports, the said grids having hinges or equivalent arrange-
ments so that when the movable supports holding the grids in position are removed,
the grids shall assume a vertical, instead of the horizontal position maintained when
the cylinder is at work-or the grids may remain in the horizontal position until the
sulphate is discharged and then raised into vertical position to facilitate the filling of
the cylinder with salt.-The movable grid may be hinged either from the center or
the extremity.
In the case of apparatus to be erected from purposes of economy in erecting
apparatus and to cheapen and facilitate manufacture of sulphate, we increase the
cylinders to a greater height and greater diameter than at present adopted and divide
the whole diameter of the cylinder into two or more series of grids forming false
bottoms the said grids being fixed upon strong girders like support extending across
the cylinder and supported by cast iron pillars extending from the bottom to the top
of the cylinder, the said pillars preferably acting as supports for the cover of the
cylinder. The center portion of the grids extending from the door to near the back
of the cylinder is formed of long wrought iron bars capable of being easily removed
from the door we arrange one working door opposite to each grid or false floor.
With the exception of the bottom grids and also excepting the wrought iron bars
opposite the doors, the table or false floors existing between the bottom and cover of
cylinder, are formed of cast iron grids so arranged that they can be raised into vertical
positions by means of hooks inserted from the top of the cylinders. After the sulphate
in cylinder has been discharged and it is desirable to refill the cylinder with chloride,
the said grids are raised into vertical position so as to allow the salt charged in at the
top of the cylinder to fall freely to the bottom or intermediate false floor-As each
stratum of chloride is charged into the cylinders the grids of the false floor next above
it are by means of lowering the hook from the tops upporting the grids allowed to fall
into the horizontal position and to form the false floor supporting the next higher
stratum of chloride to be charged into the cylinder.
When it is inconvenient to work with movable hinged grids, we arrange the upper
false floors with the wrought iron bars as above described in the center part of the
cylinder opposite and about the same width as the door and we form the sides of the
false floors of permanent grids arranged with large open spaces between the grids so
that the stratum beneath the grid could be easily filled from the tops of the cylinders
without moving the grids The salt in falling through the spaces would leave
convenient spaces or channels beneath the grids for the free intermixing of the gases
as they descend to the lower stratum. To further aid the free passage and intermixing
of the descending gases, we fix the long narrow permanent grids at right angles to the
center wrought iron grids so that whilst a gas space of at least 6 inches deep and of
large area would extend underneath the wrought iron bars, channels for the passage of
and mixing of the gases will be formed, extending the whole length of the passage
beneath the grids and connecting directly with the large area of gas space beneath the
wrought iron bars.
It will be evident that some of the arrangements described as suitable when a new
apparatus is to be erected, are also applicable to existing apparatus.
When the sulphurous acid is forced through the cylinders as herein before described
and when it is desired to cool the contents of a cylinder having intermediate grids as
described for the purpose of cooling the contents of the cylinder instead of the
arrangement of cooling pipes usually employed, we use pipes extending to the spaces
underneath the grids and above the strata of salt which it is desired to cool and pass
through the pipes steam or cold air pressure.

page_text: In filling pieces of dried salt into cylinders of great depth we avoid the formation
of dust by lowering the pieces of salt into the cylinders by means of a deep circular
wrought iron bucket or box of such diameter as to easily pass through the charging
holes in the cover of the cylinder. The pieces of Salt are filled through the charging
holes in the usual way but instead of falling to the bottom of the cylinder they fall
into the box which is suspended nearly to the height of the top of the cylinder, when
the box becomes filled, it is lowered to the bottom of the cylinder by convenient means.
The bottom of the box is hinged to the lower part of the body of the box and so
arranged that by means of a chain reaching to the top of the cylinder, the bottom can
be readily unfastened and allow the pieces of salt to be discharged through the bottom
of the box.
The spaces between the grids forming each series are so arranged as to directly
beneath the charging holes in the cover of the cylinder so as to allow of the box being
readily lowered to the desired grids.
Having now particularly described and ascertained the nature of, this invention and
in what manner the same is to be performed we declare that what we claim is:-
1st Maintaining sulphurous acid under pressure in the first cylinder of the series in
the manner substantially as described.
2nd A separate bye flue for the passage of Sulphurous acid gas between the
pyrites burners and cylinder, when pressure is not employed, substantially as and for
the purpose set forth."
3rd Increasing the rate of decomposition of chloride of sodium in cylinders and at
the same time recovering the Soda Salts by adding iron liquors from copper
precipitation tanks to the chloride of sodium before it is formed into lumps substantially
as described.
4th Avoiding escape of sulphurous acid gas from the finished cylinder of a series
into the atmosphere by passing such gas and air through a newly charged cylinder
ensuring thereby absorption of the sulphur and subsequently withdrawing the air
substantially as described.
5th Heating cylinders by means of combustible gas with iron pipes .or flues
arranged in the manner, substantially as described.
6th Heating or cooling gases in the syphons between the cylinders by means of a
hollow grid iron, substantially as set forth.
7th Supporting the covers of the cylinders in the manner and for the purpose
substantially as described.
8th Avoiding excessive pressure upon the lower portion of the Salt contained in a
cylinder by the use of two or more superposed grids for bearing the Salt substantially
as described.
9th Two or more discharging doors placed in front of each cylinder for the
purpose substantially as described.
10th Arranging grids to ensure easy charging of Salt into and discharging
sulphate from the cylinders, substantially as described.
11th So arranging the grids that there is a space left under each one, for the
purpose of mixing the descending gases substantially as described.
12th Cooling the contents of a sulphate converting cylinder by means of Steam or
air under pressure amongst the contained mass, substantially as described.
13th Avoiding formation of dust in charging a cylinder with Salt by means of
charging buckets substantially and for the purpose described.
JAMES JOHNSON,
Patent Office,
4, Clayton Square, Liverpool,
Agent.