IMPROVEMENTS IN THE PROCESS OF DESULPHURATION AND IN THE APPARATUS EMPLOYED FOR SUCH PROCESS
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by George Davies at the Office of
the Commissioners of Patents, with his Petition, on the 9th April
1866. A communication from abroad by Amédée Francois Rémond, of
Brussels, in the Kingdom of Belgium.
I, GEORGE DAVIES, of No. 1, Serle Street, Lincoln's Inn, in the County of
Middlesex, and No. 87, St. Vincent Street, in the City of Glasgow, Civil
Engineer and Patent Agent, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN THE PROCESS OF DESULPHURATION AND IN THE APPARATUS
EMPLOYED FOR SUCH PROCESS," (a communication to me from abroad by Amedée
Francois Rémond, of Brussels, in the Kingdom of Belgium,) to be as
follows:-
This Invention relates to a process of and apparatus for desulphurating
liquids, such as the sulphide of sodium (to obtain caustic alkali), sulphuret of
barium, or others, and then (after decantation of the desulphurated liquid)
removing the sulphur which with the oxide employed for that purpose has
formed a metallic sulphuret, and reforming again the primitive oxide, in order
to its being used again for a subsequent operation, without fear of any loss of
the said oxide which the manipulation by hand would occasion, and which
loss might be considerable, according to the value of the oxide employed.
The importance of substituting a mechanical means which will not neces-
sitate the removal of the oxide (oxide of copper, for example) will be readily
understood by the following description of the various operations for the pro-
duction of caustic soda :-The process of desulphurating sulphide of sodium
by the oxide of copper having been already proposed is not in itself new, but
it has not been employed hitherto owing to the inevitable losses caused by the
displacement of the oxide in removing the sulphur, and also in removing the

page_text: oxide itself for the purpose of its being desulphurated and used again. By
the aid of the apparatus hereafter described the oxide employed for the desul-
phuration is not handled at all, but remains constantly in the machine or
apparatus. When the sulphide of sodium, dissolved in a sufficient quantity
of water, together with an equivalent of oxide of copper, is placed therein
the sulphur is precipitated and forms with the oxide an insoluble sulphuret of
copper, which deposits at the bottom of the apparatus. It is then left to
repose a sufficient length of time for the liquid, then containing hydrate of
soda or caustic alkali in solution, to become clear. The liquid is then drawn
off and fresh water admitted in order to remove all the hydrate of soda, which
is generally effected by a single washing, and the sulphuret of
in the machine.
copper remains
I would here observe that during the time of the desulphuration of the
liquid the vessel containing the latter is agitated in order that all the
particles of the oxide of copper (or other oxide employed) may come in
contact with the sulphur of the sulphide of sodium. This operation lasts but
a short time, and the perfect desulphuration of the liquid is ascertained by
the aid of the known re-agents or tests. The vessel containing the sulphuret
of copper is then placed over a furnace and heated till it becomes sufficiently
dry to be removed from the vessel and passed through an aperture into a
reverberatory furnace, which is then closed, and the sulphuret is submitted to
a very strong heat, which has the effect of driving off the sulphur in the form
of sulphurous acid gas, leaving oxide of copper in the pan of the furnace. The
sulphur in the operation of disengaging forms also a subsulphate of protoxide
of copper, but upon increasing the temperature of the interior of the appa-
ratus this subsulphate is decomposed and becomes again oxide, so that the
whole is retransformed into oxide and is ready for use over again in subsequent
operations. The oxide is then allowed to fall through a passage in the bottom
of the pan on to a pair of rollers, which reduce it to powder, and it then
passes into the vessel to effect the desulphuration of a further quantity of
sulphurated liquid, and the operation proceeds as before. The oxide being
neither handled nor removed from the apparatus cannot suffer any loss; the
apparatus itself fulfilling all the functions which are or may be employed for
the desulphuration of the liquid, ar for extracting sulphurous acid gas from
the metallic sulphuret.
I would remark that during the desulphuration of the metallic sulphuret
care must be taken to admit air into the apparatus, in order to oxydize those
particles of copper which the heat may have reduced to a metallic state. The
improved machine or apparatus in which the above-described process is

page_text: carried on is constructed as follows:-At the upper part of the apparatus is a
furnace so constructed as to receive the metallic vessel containing the metallic
sulphuret to be dried; beneath this is a reverberatory furnace or desulphu-
rating chamber, furnished with an aperture above the pan through which the
sulphur is to be introduced, and which when the furnace is in action is closed
with a fire-brick stopper. This furnace is provided with a fire-place and
damper, and also an opening for admitting atmospheric air when required.
In the centre of the pan of the furnace is a valve leading to a passage which
(when the valve is opened) conducts the oxide on to a pair of crushing rollers
placed below for the purpose of reducing the oxide to powder; below these
rollers is placed the metallic vessel, into which the oxide falls, and into which
is also introduced the liquid to be desulphurated; this vessel is mounted upon
gudgeons or trunnions upon a carriage, so that it can be rocked or agitated
during the desulphuration, and is provided near the bottom with a pipe and
stop-cock for drawing off the clear liquid after desulphuration. The carriage
is mounted upon wheels on a railway, so that after running off the liquid the
carriage can be moved sideways clear of the apparatus, and a small travelling
crane is provided for the purpose of raising the vessel from the carriage and
placing it over the furnace first above named, in order to dry the sulphuret
before placing it in the desulphurating chamber.