Improvements in the Manufacture of Baryta.
Year: 1898

page_text: [Communicated from abroad by LA SOCIÉTÉ BONNET RAMEL SAVIGNY, GIRAUD ET
MARNAS, of 15, Route de Vaulx, Lyons, in the Republic of France, Dyers.]
Improvements in the Manufacture of Baryta.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of this invention to be as follows:-
In manufacturing baryta on an industrial scale, sulphide of barium in solution
is usually taken and this is decomposed by oxide of zinc. Insoluble sulphide
of zinc is thus obtained and a concentrated solution of hydrated baryta which is
purified by successive crystallisations.
This process is somewhat costly owing to the large quantity of oxide of zinc
required and the difficulty of regenerating this oxide. In addition to this, the
hydrated baryta is very costly if its price is compared with the relatively low
cost of sulphide of barium.
Proceeding in a different manner, numerous attempts have been made to
manufacture baryta by the calcination of carbonate of baryta, either alone or
mixed with carbon, but all such attempts have failed in practice owing to the
fact that poor results are obtained, due:
1st. To the impurities given by the substances constituting the vessels.
retorts or furnaces in which the reaction takes place, and which are attacked
by the baryta, and 2ndly. To the prejudicial effects of the combustion gases,
which invariably contain water vapour causing a slight and partial fusion of the
mass, which fusion considerably impedes the decomposition of the carbonate of
baryta it may even be said to almost prevent it, since a very poor yield is
obtained in this manner (40 to 50%).
For this reason many means have been suggested or patented for obviating
these defects, but, as they are complicated and costly they have not given good
results in practice; that is to say, speaking from an industrial point of view,
baryta cannot be economically obtained directly from carbonate of baryta.
The subject of this invention is a novel process by means of which a decom-
position which is almost theoretically complete (less than 1% even) of the car-
bonate of baryta is obtained industrially. In carrying this process into practice
we proceed in the following manner:
Finely powdered carbonate of baryta is taken and intimately mixed with
about 8% of carbon reduced to powder; this mixture is then calcined in a
crucible which is internally lined, upon its bottom and sides, with a covering of
cardboard, paper or other vegetable fibre, into which is introduced the mixture
of carbonate of baryta and of carbon which has just been referred to. This
mixture is covered with a sheet of cardboard, and the crucible closed with a lid
luted with earth.
This crucible is then placed in a direct flame or in a gazogene furnace and
heated for ten hours, say, at a temperature of 1100° to 1200° C. During this

page_text: operation, the gases formed by the action of the carbon upon the carbonate of
baryta escape through the interstices of the lid expel the moisture and prevent
the external gases from entering the closed crucible, which is a very important
point for obtaining a good decomposition of carbonate of baryta.
The carbon envelope insulating the baryta in this manner from the substance
constituting the crucible, the baryta retains its purity and is prevented from
adhering to the walls, which is a cause of considerable waste and of injury to
the crucibles.
After the crucible has been heated as above stated, it is either removed from or
allowed to cool in the furnace. When it has cooled, there remains in the crucible
a block of anhydrous baryta surrounded by its envelope of calcined cardboard.
This anhydrous baryta is pure being mixed only with a small excess of carbon,
with the ashes of this latter and with the impurities which may be contained
in the carbonate of baryta, but the whole of the carbonate is decomposed, and
an almost theoretical yield is obtained, that is to say, 99 to 99.5% of the car-
bonate is transformed into baryta.
Either artificially manufactured carbonate of baryta or natural carbonate of
baryta (witherite) may be employed.
The crucibles used may be of plumbago, coke dust mixed with refractory earth
or of refractory earth alone. We prefer, however, to employ either plumbago
crucibles or those formed of coke dust mixed with refractory earth.
The important, capital and novel feature of our process resides, as is apparent,
in the employment of the internal lining or envelope of cardboard, paper or other
vegetable fibre more or less agglomerated and capable of yielding carbon upon
calcination.
If this envelope were not employed, the crucibles would be attacked, a poor
yield would be obtained and the baryta would be less pure.
This carbon lining also enables the same crucible to be used a large number
of times for effecting the decomposition of the barytic salt, which is of great
importance from an economic standpoint.
The anhydrous baryta thus obtained is sufficiently pure, if pure carbonate of
baryta has been used, to be ready for sale commercially, because a mass rich in
anhydrous baryta from 94 to 96% is obtained. This anhydrous baryta possesses
advantages over the hydrated baryta obtained by the decomposition of sulphide
of barium by oxide of zine, because packing, freight and other similar charges
are avoided.
If it is desired to obtain hydrated baryta with this anhydrous baryta, it is only
necessary to dissolve it in water and allow it to crystallize, after having removed
the insoluble residue by filtration or by allowing it to become deposited.
The hydrated baryta thus obtained is chemically pure, more so than that
obtained by the process having for its base sulphide of barium.
By means of our process, an hydrous or a hydrated baryta is obtained at a cost
far below that of the same products as hitherto manufactured industrially by the
known and usually adopted processes.

page_text: 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:-
In manufacturing baryta on an industrial scale, sulphide of barium in solution
is usually taken and this is decomposed by oxide of zinc. Insoluble sulphide
of zine is thus obtained and a concentrated solution of hydrated baryta which is
purified by successive crystallisations.
This process is somewhat costly owing to the large quantity of oxide of zinc
required and the difficulty of regenerating this oxide. In addition to this, the
hydrated baryta is very costly if its price is compared with the relatively low
cost of sulphide of barium.
Proceeding in a different manner, numerous attempts have been made to
manufacture baryta by the calcination of carbonate of baryta, either alone or
mixed with carbon, but all such attempts have failed in practice owing to the
fact that poor results are obtained, due: 1st. To the impurities given off by
the substances constituting the vessels, retorts or furnaces in which the reaction
takes place, and which are attacked by the baryta, and 2ndly. To the prejudicial
effects of the combustion gases, which invariably contain water vapour causing
a slight and partial fusion of the mass, which fusion considerably impedes the
decomposition of the carbonate of baryta; it may even be said to almost prevent
it, since a very poor yield is obtained in this manner (40 to 50%).
For this reason many means have been suggested or patented for obviating
these defects, but, as they are complicated and costly they have not given good
results in practice; that is to say, speaking from an industrial point of view,
baryta cannot be economically obtained directly from carbonate of baryta.
The subject of this invention is a novel process by means of which a decom-
position which is almost theoretically complete (within 1% even) of the car-
bonate of baryta is obtained industrially. In carrying this process into practice
we proceed in the following manner:
Finely powdered carbonate of baryta is taken and intimately mixed with
about 8% of carbon reduced to powder; this mixture is then calcined in a
crucible which is internally lined, upon its bottom and sides, with a covering of
cardboard, paper or other vegetable fibre, into which is introduced the mixture
of carbonate of baryta and of carbon which has just been referred to.
mixture is covered with a sheet of cardboard, and the crucible with a lid luted
with earth.
This
This crucible is then placed in a direct flame or in a gazogene furnace and
heated for ten hours, say, at a temperature of 1100° to 1200° C. During this
operation, the gases formed by the action of the carbon upon the carbonate of
baryta escape through the interstices of the lid expel the moisture and prevent
the external gases from entering the closed crucible, which is a very important
point for obtaining a good decomposition of carbonate of baryta.
The carbon envelope insulating the baryta in this manner from the 'substance
constituting the crucible, the baryta retains its purity and is prevented from
adhering to the walls, which is a cause of considerable waste and of injury to
the crucible.
:
After the crucible has been heated as above stated, it is either removed from or
allowed to cool in the furnace. When it has cooled, there remains in the crucible
a block of anhydrous baryta surrounded by its envelope of calcined cardboard.
This anhydrous baryta is pure being mixed only with a small excess of carbon,
with the ashes of this latter and with the impurities which may be contained
in the carbonate of baryta, but the whole of the carbonate is decomposed, and
an almost theoretical yield is obtained, that is to say, 99 to 99.5% of the car-
bonate is transformed into baryta.
Either artificially manufactured carbonate or baryta or natural carbonate of
barvta (witherite) may be employed.
The crucibles used may be of plumbago, coke dust mixed with refractory earth

page_text: or of refractory carth alone. We prefer, however, to employ either piumbago
crucibles or those formed of coke dust mixed with refractory earth.
The important, capital and novel feature of our process resides, as is apparent,
in the employment of the internal lining or envelope of cardboard, paper or other
vegetable fibre more or less agglomerated and capable of yielding carbon upon
calcination.
If this envelope were not employed, the crucibles would be attacked, a poor
yield would be obtained and the baryta would be less pure.
This carbon lining also enables the same crucible to be used a large number
of times for effecting the decomposition of the baryta salt, which is of great
importance from an economic stand point.
The anhydrous baryta thus obtained is sufficiently pure, if pure carbonate of
baryta has been used, to be ready for sale commercially, because a mass rich in
anhydrous baryta from 94 to 96%, is obtained. This anhydrous baryta possesses
advantages over the hydrated baryta obtained by the decomposition of sulphide
of barium by oxide of zinc, because packing, freight and other similar charges
are avoided.
It it is desired to obtain hydrated baryta with this anhydrous baryta, it is only
necessary to dissolve it in water and allow it to crystallise, after having removed
the insoluble residue by filtration or by allowing it to become deposited.
The hydrated baryta thus obtained is chemically pure, more so than that
obtained by the process having for its base sulphide of barium.
By means of our process, an anhydrous or a hydrated baryta is obtained at a cost
far below that of the same products as hitherto manufactured industrially by the
known and usually adopted processes.
Having now particularly described and ascertained the nature of the said
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 :-
In the direct and industrial manufacture of baryta by means of carbonate of
baryta, the process above described consisting in arranging upon the whole of
the interior of the crucibles employed, a lining or envelope of cardboard, paper
or other vegetable fibre, for the purpose of totally insulating during calcination,
the mixture of carbonate of baryta and carbon from the walls of the crucible,
thus insulating it from the prejudicial action of the gases, and thereby enabling
the almost total decomposition of the carbonate of baryta to be obtained, and
consequently of obtaining a purer and richer baryta and also to obviate the
corrosion of the crucibles.
Dated this 92nd day of duconst 1800
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.