O Alkalies and Alkaline Earths from the Corresponding Sulphates, together with Sulphurous Acid or Sulphur, and Apparatus therefor.
Year: 1885

page_text: O
Alkalies and Alkaline Earths from the Corresponding
Sulphates, together with Sulphurous Acid or Sulphur, and
Apparatus therefor.
I, WILLIAM PHILLIPS THOMPSON Fel. Inst. P.A. of the Agency for Foreign
Patent Solicitors 6 Lord Street Liverpool in the County of Lancaster and
323 High Holborn, in the County of Middlesex, Civil Engineer do hereby
declare the nature of the said invention for A NEW OR IMPROVED PROCESS
FOR OBTAINING SILICATES OF THE ALKALIES AND ALKALINE EARTHS FROM THE
CORRESPONDING SULPHATES, TOGETHER WITH SULPHUROUS ACID OR SULPHUR, AND
APPARATUS THEREFOR (a communication from abroad by Dr Julius Weeren,
Professor, and Franz Weeren Engineer both of Charlottenburg in the Kingdom
of Prussia and Empire of Germany) and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
Several attempts have been made to discover a method of manufacturing the
silicates of the alkalies and alkaline earths from native or artificial sulphates
producing simultaneously sulphur, sulphurous and sulphuric acid, so that this
method may be profitably carried out on a large scale.
The methods and apparatus hitherto employed for this purpose, were for the
most part unsuitable for extracting all the substances in question, and consequently
the utilization of one or the other substance had to be abandoned.
This invention relates to a method distinguished by the simplicity of the means
and the cheapness of the employed agents, and in which by suitable manipulations
and operations, useful products are obtained.
For this purpose the sulphates of the alkalies and of the alkaline earths
are mixed in variable proportions with silicic acid and fused in the afterwards
ID 71

page_text: described double shaft furnace or in a reverberatory or in a closed furnace. On
one hand a silicate is hereby formed which can further be worked, and on the
other hand sulphurous acid is obtained which may either be used in this state, or
converted in lend chambers before or after condensation, into sulphuric acid or be
reduced to sulphur. Figure 1 of the annexed drawing shows a double shaft furnace
suitable for manufacturing from the above described mixture the silicate liberating
the sulphurous acid or if preferred converting the same in a more or less complete
manner into sulphur. Through the charging apparatus a the mixture is introduced
with the necessary quantity of coke into the smelting shaft a¹. The charge is
mixed as intimately as possible and formed into blocks in order to prevent the
formation of sulphide, the melting column must be kept as low as possible. For
this purpose the distance of the outlet channel d from the eyes may be variable
according to the nature of the material. The blast necessary to the combustion of
The silicates
the coke enters through the nozzle b, and if preferred in a hot state.
produced leave the furnace through the tap hole c and the products of combustion
containing in this case the whole of the sulphur of the sulphate in the form
of sulphurous acid, leave the furnace through the channel d through which they
reach without considerable loss of heat generated therein, by the heat produced by
the combustion, the reduction shaft e.
To obtain a longer continuous working the walls of the shaft furnace are very
thin and cooled with water.
The reduction of the sulphurous acid into sulphur, when sulphur is intended to
be produced, is effected in the shaft e by means of charcoal or other carbonaceous
substance introduced into the shaft through the opening f. As already stated the
products of combustion produced intentionally in the smelting shaft and contain-
ing sulphurous acid enter at a high temperature into the reduction shaft e, this
temperature is partly communicated to the coke in heating the same to a high
degree, partly it is used for the chemical process of the transformation of the
sulphurous acid by means of coal.
This transformation is further more dependent on the combustion temperature
of the reduction.
When therefore in certain circumstances, the heat produced in the reduction
shaft by the entrance of the hot combustion products is not sufficient for the said
reduction of the sulphurous acid into sulphur, the requisite heat may be introduced
into the reduction shaft. To regulate the temperature, the reduction shaft is sur-
rounded by a hollow space g, through which as may be necessary, either the hot
gases of a furnace may be conducted, or cold air may be passed.
"
As in the reduction of sulphurous acid to sulphur the formation of carbonic
oxysulphide (C.O. S.) must be avoided, as otherwise the sulphurous acid would be
over reduced," which will happen when sulphur vapour in the presence of carbonic
oxide is in contact during a certain time with carbon, when the same is highly
heated, it is not suitable to complete the reduction immediately entirely in the
reduction shaft but it is preferable to cool the gases in the smelting shaft before the
whole quantity of sulphurous acid contained therein is reduced or partly over
reduced, whereby the sulphur already produced is removed by condensation.
The gases are then afresh placed in contact with incandescent coke, for which
purpose the apparatuses afterwards described are constructed. On leaving these
apparatuses the gases are once more conducted through condensers.
The gases pass from the reduction shaft e (Figure 1) at a suitable temperature
through the flue à into the condensing apparatus B. (Figure 3) in which they are
freed from their contents of sulphur. From B the gases are conducted into other
reduction apparatus of different arrangement according as the coke necessary for
the reduction is heated in specially designed chambers, or if it is to be heated by
so-called surface action.
Figure 2 is a vertical section of the apparatus with surface action, and Figure 2ª
a cross section of the same.

page_text: Figure 3 shows the arrangement of a plant for the production of alkaline
silicates and alkaline earths with recovery of sulphur. A is a double column
furnace in which the sulphates are fused with silicic acid and in the second column
of which a portion of the sulphurous acid produced is reduced to sulphur as
described. The latter substance is condensed in a cooling chamber B and the gases
then pass into one of the reduction furnaces C in which again sulphurous acid is
reduced to sulphur and separated in the condensation chamber D. The gases now
poor in SO, pass through wash towers E E in which the remaining traces of
sulphurous acid gas are removed. His a distillation apparatus in which the water
from the towers is freed from SO, by heating. The gas passes through tube G to
the furnace A. and passes again through the process.
The apparatus contains first a shaft s, which is filled with coke (coal or other
carbonaceous substance) The coke is introduced through the opening z, which can
be closed. The remains of the coke burnt in the shaft are removed through the
door y. The apparatus contains further a system of ascending and descending
channels made of refractory materials which on the one side, are in communication
by a series of openings with the lower part of the coke shaft 8, and on the other
side by a single channel t¹ with a valve x. The coke shaft 8 is provided in its
upper part with a flue v in which a throttle valve y is placed whereby the pipe v
can be tightly closed. The apparatus contains also the channels 83 and t which are
placed below the coke shaft transversely through the apparatus and provided with
suitable valves and with a series of openings discharging into the main channel of
the apparatus and serving for several purposes.
The apparatus is worked in the following way:
First it is necessary to heat the walls of the rising and descending channels. For
that purpose the shaft s is filled with coke which is ignited through the opening z.
The valve y is now shut, the valve z opened and the valvez acting as a cut off
towards wand a communication with the flue towards the main chimney. The
coke in 8 burns then by the natural draught of the chimney communicating
with x, and heats itself and the shaft to a temperature which can be easily
regulated, producing generator gases rich in carbonic oxide (CO) which are burnt
at their entrance into the channel system through u by the air entering through
and t and which heat the channel system of the apparatus on their passage to the
flue x¹.
The
After some time z is shut and the valve x reversed so that the effect of
the draught censes and the communication with the condensing chamber B
(Figure 3) is established; y is opened in order to establish a communication with
a second condensing chamber D, (Figure 3) and the valves and t are shut.
sulphurous acid and the gases containing the products of combustion of the shaft
furnace enter into the apparatus through W and pass through it in a direction
opposite to that of the products of combustion namely, the generator gases from 8,
whereby they become highly heated in the channel system and supply, thus the
temperature necessary for the reduction of the sulphurous acid by the coke in the
shaft 8,
The gases leave the apparatus through and aro conducted to a second
condensing system D (Figure 3).
When the temperature has gradually diminished until the decomposition of the
sulphurous acid ceases the apparatus is shut off and re-heated.
•
One of the channels 83 or t can be opened during the reduction, and gases
containing sulphurous acid can be conducted out of the condenser through it
directly through the coals, whenever the temperature of the furnace is found too
high.
In lieu of burning the coke in the shaft 8 and of producing in this way the heat
necessary for heating the flues, generator gases may be introduced through s³ or t
and air through t or for the purpose of burning the coke, and the chambers can
be heated by the heat thus produced. In this case the opening alone is used for

page_text: filling the shaft 8. To obtain a continuous working several reduction apparatus
must be combined with a shaft furnace.
To extract the last portions of SO² the gases containing them are washed in the
well known manner in wash columns before they are allowed to escape into the air.
The wash water enriched to a certain degree is introduced into the evaporating
apparatus H and freed therein from the sulphurous acid by boiling, the sulphurous
acid flows through the conduit G into the double shaft furnace A (Figure 3) in
which it is returned to the reduction process.
This boiling has still another purpose. In spite of the above described process it
is impossible to avoid the formation of small quantities of C.O.. S which would
prevent the complete extraction of sulphur. When COS combines with H₂O (water)
we get H, S + CO₂ COS + H₂O = (SH₂) + (CO2)3 when suitable quantities
of gases containing sulphurous acid are introduced through the conduit F
into the wash columns, we will have the subsequent re-action 2 SH2 + SO,
3 S+ (H₂O) that is to say, sulphur which can easily be extracted.
=
If substances containing water are smelted in the shaft furnace, the working is
modified as follows: When sulphurous acid, aqueous vapour and carbon at a high
temperature re-act on each other, they decompose according to the formula SO₂ +
H, O + 3 C = SH, +3 CO, when SO, is added to the H, S formed in the pro-
portion of 2 molecules H. S to 1 molecules SO₂, sulphur and water are produced.
For this purpose the gases containing sulphide of hydrogen are put together in
the condenser with other gases containing the quantity of SO, requisite for
decomposition; the different gases re-act on each other, and the action is com-
pleted in the wash columns, The produced sulphur is separated from the water by
filtration and the aqueous solution treated either with sulphurous acid or with
sulphide of hydrogen, according to the gas it contains.
When it is not profitable to smelt the sulphates with silicious substances in the
blast furnace because they are not obtainable in sufficient quantity, which may
occur under certain circumstances, they can be fused also in reverberatory furnaces,
on ore hearths or in crucible furnaces.
The silicates produced by the above described processes can be utilized in several
ways; alkaline silicates for making soluble glass or for glass making, the mixtures
thereof with alkaline earths and lead oxides for glass, the silicates of barium and of
strontium may serve for the starting point of the manufacture of all the commercial
combinations of these salts with organic and inorganic acids, double salts etcetera.
In this case the silicates are decomposed and treated directly or indirectly in the
usual manner for the production of the intended combination.
Having now particularly described the nature of the invention and in what
manner the same is to be performed, as communicated to me by my foreign
correspondents, I declare that what I claim is
1st. A process for obtaining silicates of potassium sodium, barium, strontium,
magnesium, calcium and lead oxide by smelting their sulphates with silica in blast
furnaces with simultaneous extraction of the sulphur or for producing silicates of
barium and strontium in the reverberatory furnace, or other closed furnace by
fusing their sulphates with silica or substances containing silicic acid in order to
obtain a product suitable for the manufacture of their salts.
2nd. A double blast furnace in which alkaline sulphates are converted by
smelting with silica into silicates with simultaneous reduction of the sulphurous
acid produced in the second shaft by carbon by means of the heat contained in the
gases and that set free by the decomposition of the sulphurous acid and the water
by carbon into sulphide of hydrogen and carbonic oxide.
3rd. A reduction furnace for sulphurous acid in which the reducing material is
lodged in chambers heated from the outside and through which the gases containing
the sulphurous acid pass in horizontal or vertical position.

page_text: 4th. A reduction furnace for reducing sulphurous acid which can be heated, by
the help of a system of flues of refractory material in combination with a shaft
filled with carbonised fuel and a suitably adapted, reversing contrivance, by the
generator gases produced in the furnace itself or introduced from outside, and in
which after the return of the gases containing sulphurous acid, they can be heated
to the temperature necessary for reduction in the shaft filled with fuel.
5th. The process of reducing as completely as possible sulphurous acid by
passing it repeatedly over incandescent carbon in a reduction furnace and by
subsequently condensing the sulphur formed each time in the corresponding
apparatus, the whole substantially as described and shown in the accompanying
drawings.