IMPROVED PROCESSES AND FURNACE WITH APPLIANCES FOR THE ECONOMICAL PRODUCTION OF BARYTA
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by Thomas James Smith at the
Office of the Commissioners of Patents, with his Petition, on
the 28th January 1873.-A communication from abroad by
Cyprien Marie Tessie du Motay, of Paris, France, Chemist.
I, THOMAS JAMES SMITH, of the Firm of Robertson, Brooman, and
Company, of 166, Fleet Street, in the City of London, Patent Agents,
do hereby declaro the nature of the said Invention for "IMPROVED
PROCESSES AND FURNACE WITH APPLIANCES FOR THE ECONOMICAL PRODUCTION OF
BARYTA," to be as follows:-
-
The two natural minerals of baryta are the sulphate of baryta and
the carbonate of baryta. The present Invention relates to an
economical and practical means of producing this substance.
It is necessary previously to bring sulphate of barium, which is the
more abundant of these minerals, to the state of sulphuret of
barium. For this purpose the Inventor has constructed a special furnace,
the description of which will be first undertaken, and which is equally
applicable to the other process of the transformation of carbonate of
baryta into baryta. In the second place the different methods which

page_text: the Inventor has discovered for the extraction of the baryta from the
sulphuret of barium will be explained.
The reverberatory furnace from its nature is powerless to furnish at
the same time an elevated temperature and a reducing flame; but in
order to bring about the complete reduction of the sulphates and
carbonates of baryta these two chemical and physical conditions must
be absolutely fulfilled, for under the action of oxydizing flames and
corresponding temperatures it is impossible to avoid inverse reactions
which retransform the sulphurets into sulphates and the baryta into
carbonate. These inconveniences are suppresed in my system of
furnace which is founded upon the application of the principle of
recurrence in order to produce and store up very high temperatures
which permit the continuous employment of reducing flames.
The furnace consists of a chamber heated by two hearths, the grates
of which are formed from bars of refractory carth forming between
them a receptacle into which the cinders fall. These cinders are
withdrawn by scrapers which are introduced through openings and
finally fall into the cinder bed, from which they are removed through
an opening.
The hearths are cach in communication with recurrences or chambers
which are separated by a wall. The recurrences are in their turn in
communication with a valvo and the chimney which is provided with
a register. The fuel is introduced into the hearths through doors.
Air enters through the valve and after having traversed one recurrence
it arrives hot in one of the hearths. The combustion proceeds and the 2
flamo produced passes across the top surface of the furnace, then
above the second hearth, and goes to reheat the other recurrence,
from thence proceeding away through the chimney. At the end of
about an hour's work the position of the valve is reversed and fuel is
fed to the other hearth which in its turn receives the heated air proceed- a
ing in an opposite direction.
r
Instead and in place of solid combustibles burning in the heaters of
the recurrential furnace just described the gases generated in gazogenes
may be advantageously substituted.
This furnace is applied to the manufacture of sulphuret of barium 634
by the reduction of the sulphate of baryta and to the manufacture of
baryta by the reduction of carbonate of baryta.

page_text: The description of these operations successively is as follows:-
Sulphuret of Barium.-The reduction taking place at red heat it is
necessary in order to obtain the reducing temperature to heat the
furnace before charging it for at least an hour. It is then charged
3 with sulphate mixed with from 30 to 40 per cent. of coal, the recurrences
are put in action and are changed every two hours, the matters being
stirred at cach change. At each stirring it is necessary to take care to
charge the grate with coal in order to obtain a great excess of carburated
hydrogen and oxide of carbon in the furnace; the reduction is complete
O at the end of 7 or 8 hours, so that three operations may be made in
the 24 hours. The product is cooled in water, or preferably is placed
in closed boxes in order to avoid the production, through contact with
the air, of a certain quantity of hyposulphite of baryta and other
analogous products.
The reduction of the precipitated sulphates is complete, that of
natural sulphates is from 85 to 90 per cent. With an ordinary
reverberatory furnace more than 65 per cent. is never obtained. The
consumption of coal is also considerably reduced.
Caustic Baryta. The operation is effected in nearly the same conditions
as the preceeding. As the temperature of the recurrential furnace
must be still more raised it is necessary before the charging to heat
the furnace with the cinder box open, and to a white heat for from 1½
to 2 hours. The carbonate is then charged, mixed with 30 per cent.
of coal, and the recurrences are brought into play, and they must be
charged once an hour or at least once every hour and a half; the
atmosphere consists almost entirely of carburated hydrogen and oxide
of carbon, which will take fire at every opening of the furnace, a little
excess of coal is therefore necessary. At each change the furnace is
stirred, and the operations lasts 8 hours, or three operations to the 24.
Transformation of the Sulphuret of Barium into Carbonate of Barium
and Baryta. The sulphuret of barium obtained can in its turn be
converted either into carbonate of baryta or directly into baryta.
Carbonate of Baryta.-In order to transform the sulphuret of
barium into carbonate of baryta a current of carbonic acid may be
simply caused to pass through the sulphuret in solution. But in this
case during the decomposition hyposulphite of barium is produced,
which mixed with the carbonate and acted upon by the carbon rc-

page_text: produces sulphuret of barium in sufficient quantity to injure the
purity of the baryta to the extent of 97 per cent. of baryta for 3 per cent.
of sulphuret. In order to obtain an absolutely pure carbonate I
commence by boiling in equal weights sulphuret of barium with chloride
of magnesium, chloride of barium, and hyposulphuret of magnesium, 5
are produced in equal quantities which decompose during the boiling
into magnesia and sulphydric acid. The chloride of barium thus
formed remaining in the presence of the magnesia is treated with
water, and it is into the bath thus formed that I pass a current of
carbonic acid until the complete transformation of the magnesia into 1
bicarbonate of magnesia, which in reacting while hot upon the chlorido
of barium produces carbonate of baryta and chloride of magnesium.
This chloride serves again to convert into chloride of barium another
equivalent quantity of sulphuret of barium. The carbonato of baryta
being insoluble is easy to separate. It is found in an absolutely puro 1
state and is suitable not only to producing baryta but also for employ-
ment in the manufacture of crystal instead of oxide of lead.
Baryta. Two methods are used for the conversion of the sulphuret
of barium directly into baryta which possess the advantage of expelling
all the sulphur contained in the sulphurets in the form of sulphhydric 20
acid, which can be employed for the production of sulphur or sulphurous
acid.
First Method. One equivalent of sulphuret of barium being given
as an example, the sulphuret is dissolved in water and boiled with
one equivalent or more of oxide of lead until when by double exchange 2
all sulphuret of the alkaline sulphuret is carried to the lead, whilst the
oxygen on the other hand is combined with the barium in order to
form caustic soda. The barytic solution is put on one side and
collected.
The insoluble residuc of the sulphurct of lead is then treated with 30
onc equivalent of hydrochloric acid which transforms the lead into
chloride of lead. This chloride is mixed with an equivalent of magnesia
or lime, and the necessary quantity of water for the transformation of
thic chloride of lead into oxide of lead, and the magnesia of the lime
into chloride of magnesium and calcium.
The oxide of lead regenerated is suitable to decompose a fresh
equivalent of sulphuret of barium. The chloride of magnesium or
3

page_text: calcium is put on one side in order to reproduce the failing case of
hydrochloric acid by one of the methods devised by the Inventor for
that purpose. The sulphhydric acid is wholly or partly burnt in special
chambers either in order to generate sulphur or to produce sulphurous
acid. In putting this method into practice it is preferred instead of
the oxygen to employ oxide of zinc or the hydrate of the oxide of zinc,
because the sulphur of zinc is more easily attackable by the hydrochloric
acid than it is by the oxide of lead.
Instead of the oxide of lead as the intermediate agent it is preferred
to use oxide of zinc. In this case in order to cause the sulphuret of
zinc to return to the state of oxide recourse is had to the combined and
new employment of the following reactions :-A current of air in excess,
or oxygen, or better still of air in excess and sulphurous acid and
steam with or without the intervention of nitrous vapours is made
to pass upon the sulphuret of zinc at a dull red heat. The sulphur.is
partly or wholly transformed into sulphate, which, boiled with chloride
of potassium or sodium, gives sulphate of potass or soda and chloride
of zinc. This chloride is then decomposed by magnesia or lime, and
oxide of zinc is revivified. When the whole of the heated sulphuret of
zinc has not been transformed into sulphate the oxygen remaining after
the washing of the sulphate is suitable for the direct transformation
of the sulphuret of barium into baryta, as explained above. Whence
it will be perceived that whatever may be the result of the treating of
the sulphurets of zinc at a low temperature the oxides of this metal
are ceaselessly regenerated and are suitable for use again in tho
transformation of the sulphuret of barium into hydrated baryta.
Second Method. Dry Plan.-In the recurrential furnaces with blown
gas at the temperature of fusion of the steel or nickel, the sulphurets
of baryta, and the carbonates are decomposed, caustic soda is produced.
But this phenomenon of decomposition can only be industrially
employed upon foundations of magnesia, dolamite, or lime, completely
sheltered from contact with silica or alumina, for the baryta at the
temperature of which it is produced combines with these two bodies so
as to form insoluble compounds. The sulphuret of barium mixed
with one or two equivalents of sulphate of baryta or sulphate of lime
is also decomposed in recurrential gas furnaces and brought to the
state of caustic baryta. The sulphites, hydrosulphites of baryta, and

page_text: other salts of the series undergo in the same circumstances the same
transformation.
Third Method. Wet Plan.-This method is based upon the following
reactions :-
First. The fluosilicates of baryta when they are boiled with solutions
of sulphurets of potassium, sodium, or barium, expel all the sulphuret
in the form of sulphhydric acid, employable as above pointed out, and
transform these sulphurets into fluorides, whilst the silicium of the
fluoride of silicium oxydizes and remains in the liquor in the state of
insoluble silica.
Secondly. The fluorides thus generated, treated with caustic lime or
by carbonate of lime, separately or together, produco potass, soda,
baryta, or the carbonates of these bases.