Year: 1887

page_text: Date of Application, 1st Sept., 1887
Complete Left, 31st May, 1888
Complete Accepted, 6th July, 1888
1 GEORGE EDWARD DAVIS of 301 Great Clowes Street, Manchester in the County
of Lancaster, Consulting Chemist do hereby declare the nature of this invention to be
as follows: -
My invention relates to the more economical preparation of the alkalies than has
been possible hitherto, on account of the sulphur which is at present wasted being
recovered, a much smaller amount of labour being necessary to prepare the alkalies
by my process about to be described than by any existing process, less heat is
wasted in my process, and as all the products are utilized, there is no waste product
whatever.
In carrying out my invention, the first process or operation consists in placing,
salt, or other alkaline chlorides wrought into convenient forms, in a cylinder or series
of cylinders, or other suitable vessels, in which it is acted upon by a mixed current of
air, sulphurous acid gas & steam. Under the influence of heat, sulphate of the alkali
is formed & hydrochloric acid gas passes out of the apparatus with the residual gases,
to be condensed by any well known means.
The reactions which take place are as follows:-
When this part of the reaction is complete, & while the sulphate is still hot, the
second process or operation is commenced, by sending a current of hydrogen gas,
through the cylinders or other apparatus in which the sulphate is contained.
The hydrogen gas used in this portion of the operation, may be obtained by any
known process, or by any process found described in chemical or technological hand-
books, or, in place of it, any gas may be employed consisting largely of hydrogen,
such as coal-gas; debenzolated coal-gas; paraffin oil gas; shale oil gas; or coke oven
oil gas; or blast furnace oil gas; or the heated vapours of hydrocarbons; but for

page_text: economy & ease of working, and on account of the aid furnished to subsequent
processes, I prefer to employ the gaseous mixture obtained by passing steam through
red-hot coke, known technically as water-gas, and consisting substantially of equal
volumes of carbonic oxide and hydrogen.
Upon passing the mixture of carbonic oxide and hydrogen, through heated sulphates
of the alkalies, the carbonic oxide passes through unchanged, but the hydrogen
reduces the sulphate to the state of sulphide, producing water vapour at the same
time, after the manner of the following equation :-
(CO), + M₂SO¸ + H₁ = M₂S + (H₂O), + (CO)..
The water vapour passes from the apparatus, mixed with the carbonic oxido and
excess hydrogen. The two latter gases are collected and stored in a gas-holder for
future use, or passed directly into another portion of the apparatus, for employment
in the third process.
The third process or operation, consists in treating the sulphide of the alkali
already produced, in the vessel or other apparatus in which it is contained, with a
current of carbonic acid gas and water vapour, under the influence of which, the
sulphide becomes transformed into carbonate of the alkali, sulphuretted hydrogen
being liberated, which, when burned with air produces sulphurous acid, to be used
again in the first of the series of operations.
The reactions which take place may be represented as follows:-
The carbonic acid gas employed in this portion of the process may be procured by
any well known means, and providing that no free oxygen be present, or any other
body or bodies having an oxidising action upon the alkaline sulphides, any gaseous
mixtures containing a considerable percentage of carbonic acid gas, may be employed;
but I prefer to use a carbonic acid made by bringing a mixture of carbonic oxide gas
and water vapour, such as finds an exit from the apparatus in the second operation, in
contact with heated surfaces, which results in a mixture of carbonic acid gas and
hydrogen.
When this source of carbonic acid is employed, the effluent gases consist of a
mixture of hydrogen, & sulphuretted hydrogen, which when burned, form sulphurous
acid gas and water vapour so that the special addition of steam is not necessary when
this source of sulphurous acid gas is employed for the first operation.
The success of the processes herein before mentioned, depends to a large extent upon
the due & proper regulation of the temperatures at which the reactions are allowed to
take place. The first operation must be conducted at a gradually increasing red-heat;
but especial care must be taken that the contents of the cylinders or other apparatus
do not frit or flux together. In the second operation the heat must not be so high as
to volatilize the alkaline sulphide, nor to fuse it, while the third portion of the
operation takes place most efficiently at all temperatures between 150° C. and 250° C.
After the above cycle of operations has been completed, the cylinders, or other
vessels, or apparatus, are opened and the crude product, technically called "alkali'
in some parts of Great Britain, after withdrawal, is ready for sale. If a refined
product be desired, the crude carbonate or alkali is dissolved in water, the impurities
abstracted by well known means, and the purified liquor evaporated to dryness to
form a refined soda ash, or crystallized to produce soda crystals, or boiled down and
fished to produce a mono-hydrated carbonate.
The alkaline carbonate formed by this series of processes is transformed into caustic
sola by boiling with lime in the usual manner, or by heating the solid carbonate
with ferric oxide and afterwards dissolving in water & boiling down the resulting
solution.
In making the bicarbonates of the alkalies from the products of this, my process,

page_text: as before-described, the crude carbonates are saturated with moist carbonic acid gas,
or the soda crystals or the mono-hydrated carbonate, produced as before described are
saturated with carbonic acid gas, produced by the action of acids on carbonates, or by
the process already mentioned as relating to the aforesaid third process, namely, by
heating a mixture of carbonic oxide gas and water vapour.
I have also found that alkaline carbonates may be produced by employing the first
process as before described, and merging the second and third process into one, that
is to say, the heated sulphate produced in the first operation is treated with a current
of carbonic acid and hydrogen whereby the sulphide of the alkali is produced, and
carbonated as soon as it is formed, the mixture of carbonic acid and hydrogen being
preferably produced by heating a mixture of steam and water-gas, or a mixture of
steam with any of those gases specially named when treating of the second process
aforesaid; but unless the greatest care be taken in regulating the temperatures, it
will be found better to employ the three consecutive operations, already described.
Dated this 31st day of August 1887.

page_text: An Improved Method of Manufacturing Alkalies.
I, GEORGE EDWARD DAVIS of 301 Great Clowes Street, Manchester, in the County
of Lancaster, Chemical Engineer and Consulting Chemist, 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 :-
My invention relates to the more economical preparation of carbonates of the
alkalies than has been possible hitherto, on account of the sulphur which is at present
wasted being recovered, a much smaller amount of labour being necessary to prepare
the carbonates of the alkalies by my process to be described than by any existing
process, less heat is wasted in this process and as all the products are utilised there is
no waste product whatever.
In carrying out my invention the first process or operation consists in placing salt
or other alkaline chloride in convenient forms in a cylinder, a series of cylinders, or
other suitable vessels and acted upon by a current of air, sulphurous acid gas and
steam. Under the influence of heat, sulphate of the alkali is formed and hydrochloric
acid gas passes out of the apparatus with the residual gases.
The reaction which takes place being as follows:-
2 CM CD + SO. + 0 + H OM SO +27FC
When this part of the reaction is complete and while the sulphate is still hot, the
second process or operation is commenced by sending a current of hydrogen gas
through the cylinders or other vessels in which it is contained. The hydrogen gas
may be obtained by any known process described in chemical or technological hand-
books, or in place of it any gas may be employed consisting largely of hydrogen,
such as coal gas, paraffin or shale oil gas or coke oven oil gas, or the heated vapours
of hydrocarbons, but for economy and ease of working, and on account of the aid
furnished to subsequent processes I prefer to employ the gas obtained by passing
steam through red hot coke, known technically as water-gas, and consisting substan-
tially of equal volumes of carbonic oxide and hydrogen. Upon passing this mixture
of carbonic oxide and hydrogen through heated sulphates of the alkalies the carbonic
oxide passes through unchanged but the hydrogen reduces the sulphate to the state of
sulphide, producing water vapour at the same time, after the manner of the following
equation:

page_text: transformed into carbonate of the alkali, sulphuretted hydrogen being liberated which
when burned with air produces SO, and may be used again in the first of the series
of operations.
The reactions which take place may be represented as follows:-
M, S + CO2 + H2O = M, CO₂ + H₂S.
The carbonic acid used in this portion of the process may be procured by any well
known means, and providing no free oxygen is prosent or any other compound having
an oxidising action on sulphides of the alkalies, any gaseous mixture containing a
considerable percentage of CO₂ may be employed but I prefer to use a carbonic acid
made by bringing a mixture of carbonic oxide gas and water vapour, such as finds its
exit from the apparatus in the second operation, in contact with heated surfaces, which
results in a mixture of carbonic acid and hydrogen. When this source of carbonic
acid is employed the effluent gas consists of a mixture of H, S and H, which when
burned form sulphurous acid gas and water vapour, so that the special addition of
steam is not necessary, when the source of SO, is used for the first operation.
The success of the process deponds to a large extent upon the due and proper
regulation of the temperatures employed, the first operation must be conducted at a
red heat but special care must be taken that the contents of the cylinders do not frit
or flux together. In the second operation the heat must not be so high as to volatilize
the alkaline sulphide nor to fuse it, while the third portion of the operation takes
place easily at all temperatures between 150° C. and 250° C.
After the above cycle of operations the cylinders or other vessels or apparatus are
opened and the carbonates of the alkalies withdrawn for sale, or if a refined product
be required the crude carbonate is dissolved in water, the impurities abstracted by
well known means, and the purified liquor evaporated to dryness in the case of soda
to form soda ash or crystallised to form soda crystals, or boiled down and fished
to produce the mono-hydrated carbonate.
If it is not convenient to transform the sulphide of the alkali into carbonate by the
passage of a current of carbonic acid gas in the vessel or vessels in which it has been
produced, the sulphide of the alkali may be removed from the vessel or vessels and
made into a solution by dissolving in water and the solution thus obtained treated
with a current of carbonic acid gas, yields sulphuretted hydrogen which should be
collected and made to serve again in the first operation, while a solution of a carbonate
of the alkali is formed at the same time. The carbonic acid gas described in the main
process hereinbefore described, or in this the alternative process of carbonation may
be obtained from any known source whatsoever, such as by the action of strong acids
on carbonates; or by the absorption of carbonic acid gas from its mixture with other
gases by carbonates, and evolving this gas again in a concentrated form by means of
agitation and beat; or from the burning of limestone or cement; or from the waste
gases evolved during the process of working up ammoniacal water from gas works or
from shale or bone distilleries; or from the fermentation of saccharine bodies; or
from the action of hot contact surfaces upon a mixture of steam and carbonaceous
substances; or from the combustion of carbon, or carbonic oxide, or carbonaceous
substances either in air or oxygen, whether having previously been used as fuel or
otherwise.
If the carbonic acid gas employed be much diluted with inert gases, such as for
instance the gases from lime kilns, it will be necessary to pass the carbonic acid con-
taining gases through a series of vessels in which the solution of the sulphide is
contained. The gas conduit should be so arranged that the vessels can be used in
series, or so that any one or more may be employed either individually or together.
The diluted sulphuretted hydrogen given off from the earlier vessels of the series
becomes absorbed in the solution contained in the vessels later on in the series, so that
the inert gas can to a great extent be allowed to pass away freely into the atmosphere.
The carbonic acid containing gas now being passed into the solution in which the

page_text: sulphuretted hydrogen has been concentrated will result in a much stronger sulphuretted
hydrogen than can be obtained by the direct passage of the original carbonic acid
gas only. The sulphuretted hydrogen thus evolved may be burnt with air and used
again in the first process, or by combustion with only a limited amount of air can be
converted into water vapour and sulphur as has already been described in the complete
specification of Harrison Blair No. 313 February 18th 1858.
The solution of the alkaline carbonate or bicarbonate as excess of carbonic acid
has usually to be employed must be evaporated to dryness and calcined in order to
make it fit for the market. The alkaline carbonate formed by these processes is trans-
formed into caustic alkali by boiling with a solution of caustic lime or milk of lime,
or by heating the solid carbonate with ferric oxide dissolving in water and boiling
down the resulting solution.
In making the bicarbonate of the alkalies, from the products of these processes the
crude carbonates are saturated with moist carbonic acid gas, or the soda crystals, or
monohydrated carbonate produced as before described, are saturated with carbonic
acid gas produced either by the action of acids on carbonates, or by the process before
mentioned relating to the aforesaid third process.
I have also found that alkaline carbonates may be produced by employing the first
process as before described and merging the second and third processes into one, that
is to say the heated alkaline sulphate produced in the first operation is treated with
current of carbonic acid and hydrogen whereby the sulphide is produced and car-
bonated as soon as it is formed, the mixture of CO, and H, being preferably produced
by heating a mixture of steam and water gas or the other gases aforesaid, but unless
the greatest care be taken in regulating the temperature the alternative process does
not produce such good results as when the operations are conducted in three stages.
I desire to state that I do not lay claim to that portion of the process wherein the
alkaline chlorides are decomposed by a current of sulphurous acid, air and steam, as
my invention relates more to the formation of sulphides of the alkalies from their
sulphates, but I have described the first operation in order to show how the sulphuretted
hydrogen produced in the third of the series of operations may be utilised and waste
avoided.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. The production of sulphides of the alkalies by the passage through them, while
in a heated state, of a current of reducing gases consisting largely of hydrogen or
hydrocarbon vapours and the conversion of the sulphides thus obtained into carbonates
by the passage of a current through them of pure or impure carbonic acid gas sub-
stantially as is herein described, and
2. The use of what is technically known as water gas for the purposes of the afore-
said reduction, and for the manufacture of the carbonic acid gas for use in the processes
as herein set forth.
Dated this 30th day of Mor 1080